Journal articles: 'Gypsum'

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Anikwe., M. A. N., Nnamnani D.E., Ikengannyia E.E., J. C. Eze., and Obidike-Ugwu, E. O. "SOIL TILLAGE VARIANTS AND SULPHUR FERTILIZATION AFFECT NODULATION, N2 FIXATION AND YIELD OF BAMBARA GROUNDNUT (Vigna subterreana) IN SOUTHEAST NIGERIA." Journal CleanWAS 7, no. 2 (April 19, 2023): 76–82. http://dx.doi.org/10.26480/jcleanwas.02.2023.76.82.

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Management efficiency can increase crop productivity through enhanced N2 fixation in the plant-soil system. This study examined soil tillage variants and sulphur fertilization effects on nodulation, N2 fixation effectiveness and yield of Bambara groundnut [Vigna subterranea] in a degraded Ultisol in Agbani Enugu, Southeast Nigeria. Twenty-four experimental units were laid out in a Randomized Complete Block Design (RCBD). The six treatments comprised No-Till+No Gypsum (NTGo), No-Till+Gypsum1 (NTG1), No-Till+Gypsum2 (NTG2), Till+No Gypsum (TGo), Till+Gypsum1 (TG1), and Till+Gypsum2 (TG2). No-till+gypsum2 plots had significantly higher soil N content than each corresponding No-till+no gypsum plot by 15-40 %. At 30 DAP, the plots treated with till+gypsum1 (21 kg/ha), till+gypsum2 (42 kg/ha), no-till+gypsum2 (42 kg/ha), no-till+gypsum1 (21 kg/ha), and till+no gypsum had 62-63 % higher soil sulphur content (P= 0.05) than the control plots. The nodule count per plant in plots treated with no-till+gypsum2 (42 kg/ha) was greater than that in the control plot, plots with no-till+gypsum1 (21 kg/ha), and plots with till+gypsum2 (42 kg/ha) by 72-74 % at 30, 60, and 90 DAP across two seasons. Compared to the untreated plots, nodulation effectivity was raised by 79-89 % in the No-till+gypsum2 plot. The plots treated with no-till+gypsum2 (42 kg/ha) had the highest yield (0.94 t/ha), followed by plots treated with no-till+gypsum1 (42 kg/ha) with 0.93 t/ha dry seed yield and till+gypsum2 (42 kg/ha) with 54-55 % greater yield (P=0.05) than the control plot. Sulphur treatment boosted nodulation by 68 % and nodule effectiveness by about 78 %. The no-till+Gypsum2 application enhanced the average yield of Bambara groundnuts by 56 %. The soil application of S enhanced the amount of accessible S in the soil. Results show that the tillage system and S fertilization impact Bambara groundnut on degraded Ultisols. Dry matter yield was best with a high S supply in both S increments and no-till systems. The number and effectiveness of nodules increased at different S rates and no-tillage. Because of the increased S application rate, there was a considerable increase in N accumulation due to a greater N2 fixation rate. The study recommends using no-till systems and sulphur fertilization practices to enhance crop productivity, especially in degraded Ultisols. The study provides valuable insights into sustainable agriculture practices that boost yields while conserving soils.

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Xie, Zhiqing, Xiaoming Liu, Zengqi Zhang, Chao Wei, and Jiarui Gu. "Application of the Industrial Byproduct Gypsum in Building Materials: A Review." Materials 17, no. 8 (April 16, 2024): 1837. http://dx.doi.org/10.3390/ma17081837.

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The industrial byproduct gypsum is a general term for byproducts discharged from industrial production with calcium sulfate as the main ingredient. Due to the high number of impurities and production volume, the industrial byproduct gypsum is underutilized, leading to serious environmental problems. At present, only desulfurization gypsum and phosphogypsum have been partially utilized in cementitious materials, cement retarders, etc., while the prospects for the utilization of other byproduct gypsums remain worrying. This paper mainly focuses on the sources and physicochemical properties of various types of gypsum byproducts and summarizes the application scenarios of various gypsums in construction materials. Finally, some suggestions are proposed to solve the problem of the industrial byproduct gypsum. This review is informative for solving the environmental problems caused by gypsum accumulation.

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Ni, Tie Quan, Chang Jun Ke, and Bing Yuan. "Effects of Modified Gypsum on Autoclaved Products Strength." Advanced Materials Research 374-377 (October 2011): 1235–38. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1235.

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The modified tests are put on by selecting gypsum from different habitats, using doping technology and calcination technology. The tests results can be summarized as follows. Different kinds of gypsums have different effects on the strength of fly ash autoclaved products, and so do the gypsums collected from different habitats. Low-purity gypsums helps to improve the strength of autoclaved products. Low-purity scatter of gypsum can be achieved by means of natural doping and artificial doping, and natural doping is better. Calcined gypsum could increase the strength of fly ash products within a certain range, and the best calcining temperature is about 650°C.

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Jacques, S. D. M., A. González-Saborido, O. Leynaud, J. Bensted, M. Tyrer, R. I. W. Greaves, and P. Barnes. "Structural evolution during the dehydration of gypsum materials." Mineralogical Magazine 73, no. 3 (June 2009): 421–32. http://dx.doi.org/10.1180/minmag.2009.073.3.421.

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AbstractThe dehydration of pure and waste gypsums has been examined using in situ synchrotron angledispersive X-ray diffraction. Pure gypsum was studied under a number of defined environments; various industrial waste gypsums were also studied under a common standard environment. It is found that the dehydration of gypsum to anhydrite proceeds via the hemihydrate and γ-anhydrite phases and the interplay and behaviour of these phases has been determined by full structural ‘Rietveld’ refinement. In the study of the pure gypsum system, the hemihydrate structure is shown to be preserved as water is lost. A ‘zero-water hemihydrate’ is observed before refinement in the higher symmetry γ-anhydrite cell is possible. The waste gypsum materials studied showed significant differences in the temperatures at which key transformation events occurred; these observations raise implications concerning the re-use of by-product gypsum materials. Finally, high temperature data are re-examined in the search for a variation of the anhydrite structure.

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Zhang, Ye, Peng Xuan Duan, Bao Sheng Jia, and Fan Zhang. "A Comparative Study on the Basic Properties of FGD Gypsums." Advanced Materials Research 374-377 (October 2011): 1758–63. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1758.

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Compared with natural gypsum, the basic properties of FGD gypsum are studied based on the test results and then the influence of FGD gypsum’s chemical constituents, impurities and particle size distribution on its products is analyzed. The results indicate the impurities play an important role on the FGD gypsum behavior. Finally, the differences between FGD gypsum and natural gypsum are summarized.

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Darmawan, Imelda, Octarina Willy, and Johan Arief Budiman. "Setting time of construction gypsum, dental plaster, and white orthodontic gypsum." Journal of Dental Research, Dental Clinics, Dental Prospects 14, no. 3 (September 21, 2020): 167–70. http://dx.doi.org/10.34172/joddd.2020.036.

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Background. Dental plaster, white orthodontic gypsum, and construction gypsum have β-hemihydrate particles. Setting time is an essential property of dental gypsum, which can affect the strength of the material. This research aimed to compare construction gypsum, dental plaster, and white orthodontic gypsum’s initial and final setting times. Methods. Three groups were included in this experimental laboratory study: construction gypsum (A), dental plaster (B), and white orthodontic gypsum (C). Each group consisted of 10 samples. Gypsum manipulation consisted of using 120 gr of powder and 60 mL of water. Gypsum powder and water were mixed using a gypsum mixer at 120 rpm. A homogeneous mixture was poured into a mold, and the setting time was measured using a Gillmore needle, according to ASTM C266-03. The initial setting time test was measured using 113.4 grams and a 2.12-mm needle. The final setting time was measured using 453.6 grams and a 1.06-mm needle. This test was repeated until the needle failed to penetrate the gypsum’s surface. All the data were analyzed with one-way ANOVA and post hoc Tukey tests using SPSS 23. Results. The average initial setting time for groups A, B, and C were 10.39±1.19, 16.17±1.40, and 24.46±1.51, respectively. The average final setting time for groups A, B, and C were 15.97±0.79, 24.31±0.88) and 33.37±0.66, respectively. One-way ANOVA and post hoc Tukey tests showed significant differences in the initial and final setting times between the three groups (P<0.05). Conclusion. There were differences in setting time between dental plaster, white orthodontic gypsum, and construction gypsum. The construction gypsum’s setting time is suitable as a type II dental gypsum, according to ADA No.25.

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Inazumi, Shinya, Hiroaki Sano, and Mikio Yamada. "Estimation of gypsum hemihydrate content in recycled gypsums derived from gypsum boards." Journal of Material Cycles and Waste Management 18, no. 1 (October 24, 2014): 168–76. http://dx.doi.org/10.1007/s10163-014-0319-x.

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López-Pedrajas, D., M. Jiménez-Vázquez, A. M. Borreguero, F. J. Ramos, I. Garrido, J. F. Rodríguez, and M. Carmona. "Nanoencapsulated PCM slurries for the development of thermoregulating gypsums." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012104. http://dx.doi.org/10.1088/1742-6596/2116/1/012104.

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Abstract Gypsums with improved thermal properties have been obtained using a thermoregulatory nanocapsulated slurry (NPCS) as additive. In order to determine the effects of the slurries in the gypsum, physical, mechanical and thermal properties of the different composite materials (gypsum – polystyrene nanoparticles (PS) or nanocapsules (NPCM)) have been studied. Concentrated slurries from polystyrene nanoparticles without (PSS) and with encapsulated phase change material (NPCS) have been synthesized. Firstly, gypsum blocks made of nanoparticles/hemihydrate with mass ratios ranging from 0.0 to 0.42 have been produced from PSS, in order to determine the optimal weight ratio with the best mechanical/physical characteristics. Then, the thermal gypsum block from NPCM/hemihydrate has been prepared at the selected weight ratio. Although PS and NPCM addition reduces the mechanical properties, all the developed materials satisfied the mechanical European regulation EN 13279-2 which limits the mechanical characteristics of gypsums composites. The gypsum composites with PS nanoparticles presented a reduction of the thermal conductivity, so these materials can be used as insulating material. The gypsum composite with NPCM/Hem = 0.3 had an improvement in the thermal storage capacity of 88.76 % and seems to be a good alternative for applying the thermal energy storage technology in buildings.

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Wankhade, Sattyam V., Kaushal V. Sanghavi, Vilas Rajguru, and Jyoti Lokade. "A Comparative Evaluation of Six Commonly used Types of Die Materials for the Property of Abrasion Resistance, at Two Time Intervals: An in vitro Study." International Journal of Prosthodontics and Restorative Dentistry 3, no. 1 (2013): 1–6. http://dx.doi.org/10.5005/jp-journals-10019-1067.

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ABSTRACT Background and objectives This in vitro study evaluated and compared the abrasion resistance of types IV and V gypsums, resin-modified type IV and type V gypsums, synthetic gypsum, and epoxy resin die material at two different time intervals spanning a period of 24 hours. Materials and methods A total of 10 dies of each die material were fabricated and tested for abrasion resistance at each time interval. An average of five readings was taken for the test, measuring the rate of abrasion of the materials. Results All the tested properties of the epoxy resin material were far superior to those of the other materials (being tested). Resin-modified type IV gypsum had significantly better abrasion resistance than its type V counterpart at setting. However, when tested at 24 hours, both materials had comparable resistance to abrasion, which was the highest among the gypsum-based materials. Interpretation and conclusion Epoxy die resin had the most superior physical properties of all. A significant decrease in the rate of abrasion (-38 to -83%) was noted, when the gypsumbased products were tested at 24 hours. From the data obtained in this study, it is recommended that when gypsum-based materials are used, to wait at least 24 hours prior to separating casts from impressions (and subsequent laboratory procedures) to avoid damage to the casts and dies. Abbreviations RR IV: Resin modified type IV gypsum; RR V: Resin modified type V gypsum; S: Synthetic gypsum; V: Type V gypsum; IV: Type IV gypsum. How to cite this article Wankhade SV, Sanghavi KV, Rajguru V, Lokade J. A Comparative Evaluation of Six Commonly used Types of Die Materials for the Property of Abrasion Resistance, at Two Time Intervals: An in vitro Study. Int J Prosthodont Restor Dent 2013;3(1):1-6.

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Wang, Junjie, and Engui Liu. "Physicomechanical Properties of Gypsum with Mineral Additions at Elevated Temperatures." Coatings 13, no. 12 (December 15, 2023): 2091. http://dx.doi.org/10.3390/coatings13122091.

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Gypsum, from either nature or industrial by-products, can be a lower-cost and cleaner alternative binder to Portland cement used in construction projects, such as affordable housing in developing countries. Although various building products have successfully used gypsum as the binder, some drawbacks of this material have still been claimed, for example, in the aspects of mechanical strength and some other physical properties. Using mineral additions to gypsum seems to be a possible solution to create composite gypsum with improved properties. This work has investigated the possibility of two common minerals (silica flour and talc powder) in modifying composite gypsum’s physical and mechanical performance at elevated temperatures (100–1100 °C), including hydration, strength, thermal conduction and stability, and microstructure. The results suggest that 10% gypsum replacement by silica flour or talc powder modifies gypsum’s physical and mechanical properties, with silica flour performing better than talc powder. The performance of composite gypsum at elevated temperatures depends on the treatment temperature and reflects the combined effects of gypsum phase change and the filler effects of silica flour or talc powder. Thermal treatment at ≤200 °C increased the thermal resistance of all gypsum boards but decreased their compressive strength. Thermal treatment at ≥300 °C significantly increased the compressive strength of gypsum with silica flour and talc powder but induced intensive microcracks and thus failed the thermal insulation. This investigation indicates that silica flour can potentially raise the mechanical performance of gypsum. At the same time, talc powder can hold water and lubricate, which may help with the continuous hydration of gypsum phases and the rheology of its mixtures.

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Zhou, Xiao Xiang, Xue Ying Zhang, and Xue Feng Dong. "The Analysis and Operation Control for the Gypsum’s Low Purity of Wet FGD." Advanced Materials Research 726-731 (August 2013): 225–29. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.225.

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Gypsum is the main product of wet desulfurization, combined with the actual operating conditions of desulfurization unit, the factors affecting the purity of gypsum is analyzed. Combining with the comprehensive utilization of gypsum requirements, from every aspect of characteristics of coal, limestone’s quality and operation control, improve the gypsum’s quality of wet desulfurization in coal-fired plant.

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Chro, M. Fatah and Jamila, J. Tahir. "Suitability of Gypsum from Fatha Formation for Production of Building Materials in Bazian -Takiya area, North-East Iraq." Tikrit Journal of Pure Science 26, no. 3 (July 10, 2021): 53–59. http://dx.doi.org/10.25130/tjps.v26i3.142.

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Gypsum products are one of the most widely used materials in the industry. The wide use of gypsum as a building material over a very long period of time. A number of manufacturers introduce different professional quarries, but their physical and chemical properties were still questionable. Five gypsum samples were taken for chemical and physical analysis. Chemical analysis shows that gypsum are of high purity, more than 95.25% with varying amount of impurities; SiO2 (1.49-1.87) %, Na2O (0.17-1.00) %, MgO (0.03-0.13) % Al2O3 (0.06-0.23) % and Fe2O3 (0.05-0.09) %, .This can be used for Plaster of Paris without any purification of gypsum. The (SO3 and CaO) % shows that all studied samples are suitable for gypsum production as the final coating and building gypsum. The physical analysis shows that the colors of gypsum samples are suitable for building, Plaster of Paris, final coating and Juss according to the color chart of minerals and to Iraqi standard specification. The fineness percentage is less than 8%. Thus the specifications of all samples are agreements to standard specifications for building gypsums. In terms of setting time, the sample 1 and 2 are suitable for building gypsum and plaster of Paris and classified as Borax. However, samples 3, 4, and 5 are suitable for anhydrous calcined gypsum – final coat and classified as Knee cement. Moreover, the setting time for all the samples increased with the increase of the water powder ratio.

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Ciarkowska, Krystyna, and Anna Miechówka. "Gypsic rendzinas of Nida Basin (southern Poland): a review." Soil Science Annual 69, no. 2 (June 1, 2018): 101–8. http://dx.doi.org/10.2478/ssa-2018-0010.

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Abstract The article presents the overview of the gypsic rendzinas that occur in the Nida Basin (Niecka Nidziańska) as based on authors’ results and observations and also literature data. The influence of gypsum forms (selenite, shale and compact gypsum) and allogenic admixtures on the properties of rendzinas was described. Furthermore, attention was paid to the specific climate conditions of the Nida Basin reflected in the native vegetation cover on the gypsum-derived soils. Finally, there is a proposal for classification of this area’s gypsic rendzinas and the soil properties were described for the specified soil units.

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Rai, Abhishek K., Jayanta K. Pati, Christian G. Parigger, and Awadhesh K. Rai. "Plasma Spectroscopy of Various Types of Gypsum: An Ideal Terrestrial Analogue." Atoms 7, no. 3 (July 21, 2019): 72. http://dx.doi.org/10.3390/atoms7030072.

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The first detection of gypsum (CaSO4·2H2O) by the Mars Science Laboratory (MSL) rover Curiosity in the Gale Crater, Mars created a profound impact on planetary science and exploration. The unique capability of plasma spectroscopy, which involves in situ elemental analysis in extraterrestrial environments, suggests the presence of water in the red planet based on phase characterization and provides a clue to Martian paleoclimate. The key to gypsum as an ideal paleoclimate proxy lies in its textural variants and terrestrial gypsum samples from varied locations and textural types have been analyzed with laser-induced breakdown spectroscopy (LIBS) in this study. Petrographic, sub-microscopic, and powder X-ray diffraction characterizations confirm the presence of gypsum (hydrated calcium sulphate; CaSO4·2H2O), bassanite (semi-hydrated calcium sulphate; CaSO4·½H2O), and anhydrite (anhydrous calcium sulphate; CaSO4), along with accessory phases (quartz and jarosite). The principal component analysis of LIBS spectra from texturally varied gypsums can be differentiated from one another due to the chemical variability in their elemental concentrations. The concentration of gypsum is determined from the partial least-square regressions model. The rapid characterization of gypsum samples with LIBS is expected to work well in extraterrestrial environments.

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Ismaeal, Ammar S. "Diagnostics and Characterization of Micro morphological Features of some Soil Series in Baiji City, Central Iraq." Tikrit journal for agricultural sciences 22, no. 2 (June 30, 2022): 132–47. http://dx.doi.org/10.25130/tjas.22.2.15.

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Three pedons were selected representing the soil series of the study area in Baiji city, which are Khadraniya, Al-Sharqat, and Manjour soils series, representing calcareous and gypsiferous soils, to diagnose some of micro-morphological Features in soil series horizons. Pedons were morphologically described, and disturbed and undisturbed soil samples were collected from each horizon. The presence of (calcic) and (gypsic) horizons has been diagnostic by morphological field results, ccumulation of lime and gypsum in soil matrix as vertical gypsic threads and beards and aggregates under gravel and gypsum crystals the size of coarse sand, as well as some lime and gypsum as nodules intertwined within soil structure units in soil horizons that reflects the influence of parent material and primary sedimentation sources .The results of morphological characteristics are represented by the presence of gypsum crystals in distinct shapes, including lenticular, and spindle as Enhedral and subhedral, and the size of fine to coarse sand, as well as the granules that in filling pores, as well as the presence of pores in vughs and chamber, as well as the spongy and granular structure, as well as the presence of iron coating in the form Encases of gypsum crystals.

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Prałat, Karol, Justyna Ciemnicka, Artur Koper, Katarzyna Ewa Buczkowska, and Piotr Łoś. "Comparison of the Thermal Properties of Geopolymer and Modified Gypsum." Polymers 13, no. 8 (April 9, 2021): 1220. http://dx.doi.org/10.3390/polym13081220.

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The paper presents the results of research concerning the influence of micromaterials on the heat conductivity coefficient λ, specifically heat Cp and thermal diffusivity a of modified gypsum and geopolymer. Microspheres, hydroxyethyl methylcellulose (HEMC) polymer, and aerogel were used as the gypsum’s modifying materials. The study also investigated an alkali potassium-activated methakaolin-based geopolymer with the addition of aluminium dust. During the measurements of thermal parameters, the nonstationary method was chosen, and an Isomet device—which recorded the required physical quantities—was used. When compared to the reference sample, a decrease in the thermal conductivity and diffusivity of the hardened gypsum— and a simultaneous increase in specific heat—was observed with the addition of micromaterials. The geopolymer sample was characterized by the lowest value of thermal conductivity, equal to 0.1141 W/(m·K). It was over 62% lower than the reference sample containing only gypsum. The experimental values of the thermal conductivity of the gypsum samples with the addition of HEMC, aerogel and microspheres were, respectively, over 23%, 6%, and 8% lower than those of the unmodified gypsum samples. The lowest values of thermal conductivity were observed in the case of the gypsum samples modified with polymer; this resulted from the fact that the polymer caused the greatest change in the structure of the gypsum’s composite, which were expressed by the lowest density and highest porosity.

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Santa Cruz Astorqui, Jaime, Mercedes del Río Merino, Paola Villoria Sáez, and César Porras-Amores. "Analysis of the Relationship between Density and Mechanical Strength of Lightened Gypsums: Proposal for a Coefficient of Lightening." Advances in Materials Science and Engineering 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/7092521.

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This article develops a relationship between the reduction of density in lightened gypsum and the addition of expanded and/or extruded polystyrene waste from the construction sector and their mechanical behavior. The equations determined in this study allow us to know the flexural and compressive strengths of a lightened gypsum/plaster compound once its density is known. The results show that there is an exponential relationship between the density of the compound and its strength. The methodology followed included a compilation of the results obtained in previous research works on lightweight gypsums, analyzing the relationship between density and mechanical strength and comparing them with the equations developed in this research. The results obtained by previous researchers have a good adjustment with the proposed models, and only perlite compounds present greater deviations in the compressive strength analysis. Also, a dimensionless lightening coefficient is defined which can help to determine the best application for a lightweight gypsum compound, comparing it with an ideal lightweight gypsum.

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Algnaby, Yasir Hamod, and Hawazin Dyaa Aldawri. "Effect of Levels of Organic Matter on Adsorption and Liberation of Gypsum Soil." IOP Conference Series: Earth and Environmental Science 1213, no. 1 (July 1, 2023): 012101. http://dx.doi.org/10.1088/1755-1315/1213/1/012101.

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Abstract In an experiment for iron adsorption for nine levels of iron (0,1,2,5,10,25,50,100,200)mg/L. This experiment was carried out to find the behaviour of iron in soils of varying gypsum and organic content to know the conditions for adsorption and liberation of iron in them, using three gypsums (10,20,30)% with percentages of organic matter from sheep feces (0,1,2)%. The Langmeyer equation, the Feinrendlach equation, and the Timken equation were used, through which the most excellent adsorption and binding energy were calculated. The most outstanding adsorption values were In medium gypsum soil with sheep feces (2%) with a ratio in the Langmeyer equation (46.948) mg/kg. The highest binding energy value was (7.497) L.mg-1 in soils with low gypsum content as a control. Lanckmeyer equation was chosen as the best It is fair to describe the adsorption process with a capacity determination coefficient of (85)%. In comparison, the highest value for the maximum adsorption of the Freindlch equation was recorded (0.788) litre.mg-1 in soils with high gypsum content with sheep feces by (2%). The highest percentage of binding energy in medium soils, gypsum control, was (16.195) mg.kg-1. The highest binding energy value in the Tamken equation was (12.436) mg.kg-1 in medium gypsum control soil. The highest binding energy value was (2.844) L.kg-1 in medium gypsum soil control. As for the liberation experiment, the highest values for liberated iron were in the high levels of addition (18.513) mg.kg-1 in soils with low gypsum content (2)% of sheep feces, noting the low values Released iron with low values of adsorbed iron.

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Pérez-López, Alberto, Miguel García-López, and Miguel González-Gil. "Integrated Interpretation of Electrical Resistivity Tomography for Evaporite Rock Exploration: A Case Study of the Messinian Gypsum in the Sorbas Basin (Almería, Spain)." Minerals 13, no. 2 (January 17, 2023): 136. http://dx.doi.org/10.3390/min13020136.

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In this study, we conduct an investigation of the Sorbas Basin (Almería, Spain) on the Messinian gypsum unit using geophysical prospecting methods. Geophysical electrical resistivity tomography (ERT) methods were applied to study the subsurface of this gypsum unit, the exploitation of which could be of interest economically, with different commercial specifications for alabastrine and selenitic gypsums. For the interpretation of the different ERT images, the data for the surface geology, borehole cores, and seismic refraction conducted at a point within the ERT profiles were used. The results obtained from this investigation can be used as a reference for other similar studies in other regions. It was observed that selenitic gypsum is more resistive than alabastrine gypsum; therefore, the diagenetic processes of dehydration (anhydritization) and hydration (gypsification) increase the “percolation” phenomenon through possibly ensuring a greater connectivity of the shale matrix. Fracturing and moisture can be used to fully determine the resistivity of the purest and most resistive gypsum, to the point of considerably lowering the resistivity in an entire area affected by fracturing. The use of different tests with different lengths for the same profile can help one better understand the structure of the gypsum body in the subsurface, especially when there are shale intercalations or more- or less-pure levels of gypsum that do not reach a value of a few meters in thickness, because these thinner levels of a few meters are not defined in the ERT images when the test is performed at depths of up to 75 m.

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Morales-Segura, Mónica, César Porras-Amores, Paola Villoria-Sáez, and David Caballol-Bartolomé. "Characterization of Gypsum Composites Containing Cigarette Butt Waste for Building Applications." Sustainability 12, no. 17 (August 28, 2020): 7022. http://dx.doi.org/10.3390/su12177022.

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Cigarette butts are one of the most common waste on the planet and are not biodegradable, so they remain on the landscape for many years. Cigarette butt composition makes it suitable to be added during the manufacture of construction materials, so it can be considered a waste recovery material, helping to reduce the ecological footprint of the construction sector. This article shows the characterization of gypsum composites containing cigarette butt waste. Several gypsum specimens were prepared incorporating different percentages of cigarette butt waste (0.5%, 1.0%, 1.5%, 2.0% and 2.5%). Samples without waste additions were also prepared in order to compare the results obtained. Samples were tested for density, superficial hardness, flexural and compressive strength, bonding strength and acoustic performance. Results show that it is possible to add cigarette butts in a gypsum matrix, resulting in better mechanical behavior than traditional gypsums.

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King, George A., Mayhew J. Ridge, and Graham S. Walker. "Salts in gypsum and calcined gypsum." Journal of Applied Chemistry and Biotechnology 23, no. 8 (April 25, 2007): 635–38. http://dx.doi.org/10.1002/jctb.5020230810.

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Costa, Cristiana, António Fortes, Fernando Rocha, Angela Cerqueira, Delfim Santos, and Maria Helena Amaral. "Characterization of Portuguese gypsums as raw materials for dermocosmetics." Clay Minerals 54, no. 3 (July 31, 2019): 277–81. http://dx.doi.org/10.1180/clm.2019.36.

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AbstractPortuguese gypsum deposits utilized by the cement industry were characterized mineralogically, chemically and technologically for possible application in dermocosmetics. The deposits studied (Loulé, Óbidos and Soure) correspond to small outcrops in diapiric anticline areas. In principle, they represent gypsites which are white, and generally of higher quality for traditional applications (e.g. white cement), or greyish, and generally not adequate for cements and mortars. The analytical methods used to characterize the materials were wet sieving and X-ray sedimentation, X-ray diffraction, X-ray fluorescence spectrometry and assessment of abrasiveness, plasticity, texturometrics (adhesivity and firmness), oil absorption and cooling rate. The Óbidos gypsum displayed greater mineralogical and chemical quality (almost pure calcium sulfate) and had a finer grain size (<63 μm), whereas Loulé and Soure gypsums contain mineralogical impurities (mainly quartz). The Óbidos gypsum shows good characteristics in general for application in dermocosmetics because of its absorption, plasticity, adhesivity, firmness and low abrasiveness.

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Erbs, Alexandre, André Nagalli, Karina Querne de Carvalho, Vsévolod Mymrin, Fernando Hermes Passig, and Wellington Mazer. "Properties of recycled gypsum from gypsum plasterboards and commercial gypsum throughout recycling cycles." Journal of Cleaner Production 183 (May 2018): 1314–22. http://dx.doi.org/10.1016/j.jclepro.2018.02.189.

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Zhang, Ji Xiu, Peng Xuan Duan, and Ye Zhang. "A Comparative Study on Preparation of High Strength Gypsum by Flue Gas Desulfurization Gypsum and Natural Gypsum." Applied Mechanics and Materials 395-396 (September 2013): 641–45. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.641.

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In this paper, the flue gas desulfurization gypsum (FGD) generated from thermal power plant is used to produce high strength gypsum. Compared with the properties of high strength gypsum using natural gypsum, the basic properties of super high strength gypsum prepared by FGD gypsum are investigated based on the test results of strength, thermal expansion rate, crystal appearance and size. The results indicate there is little difference of the properties of high strength gypsum prepared by FGD gypsum and natural gypsum. And furthermore, the FGD gypsum can be used as the good raw material of high strength gypsum preparation instead of natural gypsum.

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Pribadi, Sigit, and Sri Gunawan. "TACTICAL DECISION MAKING TERKAIT DENGAN KEPUTUSAN SELL OR PROCESS FURTHER PRODUK GYPSUM MENGGUNAKAN PENDEKATAN DIFFERENTIAL ANALYSIS." JURNAL STIE SEMARANG 11, no. 03 (November 21, 2019): 22–35. http://dx.doi.org/10.33747/stiesmg.v11i03.384.

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Gypsum is a by-product of phosphoric acid production, which is a solid waste from the extraction of P2O5 content in phosphate rock. Gypsum can be directly sold as bulk gypsum (split off point) or furtherly processed into purified gypsum. Similarly, purified gypsum can also be furtherly processed into granulated gypsum which has the lowest water and P2O5 content. A differential analysis based on the use of relevant cost data is needed to identify alternatives that provide the greatest benefits to the company, related to alternative decisions to sell gypsum at the split-off point or to process it further. his study aims to develop a differential analysis that is used as a basis for tactical decision making related to the decision to sell gypsum products at the split-off point or to be furtherly processed into purified gypsum and/or granulated gypsum. This study uses a qualitative research approach while the research method used is a case study research method. The result shows that the decision to furtherly process gypsum into purified gypsum and granulated gypsum generates additional profit compared to selling gypsum at the split-off point. The production and sales of granulated gypsum generate the highest profit compared to purified gypsum and bulk gypsum at the split-off point

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Calaforra, José-María, and Fernando Gázquez. "Gypsum speleogenesis: a hydrogeological classification of gypsum caves." International Journal of Speleology 46, no. 2 (May 2017): 251–65. http://dx.doi.org/10.5038/1827-806x.46.2.2125.

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Shao, Duoduo, Bin Zhao, Lili Gao, Yiyi Xu, Zhiguang Wang, and Jilin Cao. "Preparation of Whitening Dihydrate Gypsum and Short Columnar α-Hemihydrate Gypsum with FGD Gypsum." Crystal Research and Technology 52, no. 9 (August 29, 2017): 1700166. http://dx.doi.org/10.1002/crat.201700166.

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Wahyuni, Siti, Haslinda Z. Tamin, and Harry Agusnar. "THE DIFFERENCE ON COMPRESSIVE STRENGTH AND DIMENSIONAL CHANGE OF COMMERCIALLY TYPE III GYPSUM COMPARED TO RECYCLE GYPSUM TYPE III TO PRODUCE WORKING CAST." Dentika Dental Journal 19, no. 2 (December 12, 2016): 121–27. http://dx.doi.org/10.32734/dentika.v19i2.414.

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Gypsum is derived from pure calcium sulfate dehydrate which is a common material that is commonly used in denture manufacturing process. This study aimed to know the difference on compressive strength and dimensional change of commercially type III gypsum compared to recycle type III gypsum to produce working cast. The type of research is laboratory experiment. A total of 40 samples for each test is divided into five groups which consists of commercial type III gypsum, pure recycled type III gypsum, pure recycled type III gypsum with 10%, 20%, 30% type III commercial gypsum. The difference on compressive strength and dimensional change between the groups was analyzed using one way ANOVA and is them tested with LSD test. The result showed that there was a significant difference (p<0,05) between compressive strength and dimensional change of commercial type III gypsum compared to pure recycled type III gypsum and pure recycled type III gypsum with 10%, 20% and 30% type III commercial gypsum. In conclusion, addition of 30% commercial gypsum in recycled gypsum the compressive strength was higher than other recycled gypsum types.

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Zhang, Ji Xiu, Peng Xuan Duan, and Ye Zhang. "Study on Preparation of High Strength Gypsum by Flue Gas Desulfurization Gypsum." Applied Mechanics and Materials 405-408 (September 2013): 2681–85. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2681.

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In this paper, the flue gas desulfurization gypsum (FGD) generated from thermal power plant is used to produce high strength gypsum. The basic properties of super high strength gypsum prepared by FGD gypsum are investigated based on the test results of strength, thermal expansion rate, crystal appearance and size. The results indicate that the properties of high strength gypsum prepared by FGD gypsum above α50 standard. This can be a reference for gypsum-based α super high-strength gypsum related product development.

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Zhao, Zi Yu, Guang Tao Zhou, Su Zhi Zhang, and Bi Bo Xia. "Study on Gypsum Molding Material Properties and Alloy Liquidity." Advanced Materials Research 154-155 (October 2010): 852–55. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.852.

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In this paper the influence of gypsum-water ratio, filler types and calcination temperature on gypsum bending strength were analyzed by the means of experiments. Spiral-shaped gypsum mold was made by gypsum molding material and mobility experiment was conducted on Pb-Sn alloys. Compared with pure gypsum, gypsum mixture had better mechanical properties. The fluidity of the alloy in the gypsum mold was prone to casting pressure, pouring temperature and alloy ratio. The research results have benefit to the development of gypsum casting technology.

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Paz, Jackson D. S., and Dilce F. Rossetti. "Petrography of gypsum-bearing facies of the Codó Formation (Late Aptian), Northern Brazil." Anais da Academia Brasileira de Ciências 78, no. 3 (September 2006): 557–72. http://dx.doi.org/10.1590/s0001-37652006000300014.

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An original and detailed study focusing the petrography of evaporites from the Late Aptian deposits exposed in the eastern and southern São Luís-Grajaú Basin is presented herein, with the attempt of distinguishing between primary and secondary evaporites, and reconstructing their post-depositional evolution. Seven evaporites phases were recognized: 1. chevron gypsum; 2. nodular to lensoidal gypsum or anhydrite; 3. fibrous to acicular gypsum; 4. mosaic gypsum; 5. brecciated gypsum or gypsarenite; 6. pseudo-nodular anhydrite or gypsum; and 7. rosettes of gypsum. The three first phases of gypsum display petrographic characteristics that conform to a primary nature. The fibrous to acicular and mosaic gypsum were formed by replacement of primary gypsum, but their origin took place during the eodiagenesis, still under influence of the depositional setting. These gypsum morphologies are closely related to the laminated evaporites, serving to demonstrate that their formation was related to replacements that did not affect the primary sedimentary structures. The pseudo-nodular anhydrite or gypsum seems to have originated by mobilization of sulfate-rich fluids during burial, probably related to halokinesis. The rosettes of gypsum, which intercept all the other gypsum varieties, represent the latest phase of evaporite formation in the study area, resulting from either intrastratal waters or surface waters during weathering.

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MENG, QINGFENG, JOHN HOOKER, and JOE CARTWRIGHT. "Lithological control on fracture cementation in the Keuper Marl (Triassic), north Somerset, UK." Geological Magazine 155, no. 8 (September 14, 2017): 1761–75. http://dx.doi.org/10.1017/s001675681700070x.

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AbstractThe spatial arrangement of gypsum veins as preserved natural hydraulic fractures have been characterized in the Triassic Keuper Marl Formation (UK), a caprock for hydrocarbon reservoirs and CO2 sequestration. The marls cropping out are subdivided into five discrete fracture units based on the presence and abundance of gypsum veins. The nodular gypsum in evaporite horizons provides excess gypsum for nodule-rooted horizontal gypsum veins. Our petrographic observations demonstrate that the development of gypsum veins in beds lacking macroscopic evaporites is closely associated with disseminated gypsum cement in the marls. We interpret that the gypsum veins in marl are sourced from disseminated gypsum cements in the host rocks, based on stratigraphic correlations, and much lower Sr concentrations than gypsum nodules. Gypsum was transported to adjacent veins mainly through diffusion in the low-permeability marls. The localization of gypsum veins and varied Sr concentrations of veins and nodules indicate that the diagenetic fluids are a mix of connate water with meteoric water rather than brines transported from evaporite beds along faults to non-evaporite beds. This results in the absence of gypsum fillings in fractures in rocks without primary gypsum cements. The study implies that the cementation of natural fractures in low-permeability rocks can highly depend on the presence of cement minerals in the host rock.

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Savi, Olindo, Rafael Alves Souza, Nilson Tadeu Mascia, and Mateus Henrique Souza. "The physical and mechanical properties of recycled gypsum and potential application of pre-molded panels." Revista Brasileira de Engenharia e Sustentabilidade 4, no. 2 (December 15, 2017): 21. http://dx.doi.org/10.15210/rbes.v4i2.11743.

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This study analyses the physical properties of recycled gypsum and mechanical performance of pre-molded gypsum panels made of recycled gypsum. A compatation with commercial gypsum physical properties and mechanica behavior of pre-molded commercial gypsum panels is also carried out. After collection, recycling and grinding gypsum residues, the quality of the powder produced was evaluated in terms of units of mass and fineness modulus. Additional tests of the dry paste were conducted for assessment of hardness, water absorption, and compressive strength of recycled gypsum. The commercial potential of the material was evaluated by the bending strength testing pre-molded panels. The results demonstrate that gypsum recycling is sustainable, ecologically correct and feasible for the production of pre-molded elements with great potential use in civil construction. Keywords: gypsum panels, mixed pastes, sustainable, gypsum pastes.

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Jordan, David L. ""Peanut Response to Interactions of Soil pH and Gypsum"." Archives of Agriculture Research and Technology (AART) 1, no. 4 (December 28, 2020): 1–2. http://dx.doi.org/10.54026/aart/1020.

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Soil pH and supplemental calcium applied as gypsum can affect peanut yield. The interaction of soil pH and gypsum applied at flowering is not clearly defined in the peer-reviewed literature. Research was conducted in North Carolina in the USA to determine peanut yield when grown in soil with pH values of 4.5, 5.2, 5.6, and 6.0 when no gypsum or gypsum at 340 and 680 kg/ha was applied at the flowering stage of peanut. Peanut yield increased as soil pH increased in absence of gypsum. Applying gypsum at both rates increased peanut yield when soil pH was 4.5 or 6.0 compared with the no-gypsum control. However, at a soil pH of 5.2 gypsum did not increase yield. At a soil pH of 5.6 gypsum did not affect yield when applied at 340 kg/ha; gypsum at 680 kg/ha decreased yield. Results from these experiments demonstrate that peanut response to gypsum can be dependent on soil pH and that soil pH should be considered when deciding when to apply gypsum to supplement native calcium in soil.

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Weimann, Karin, Christian Adam, Matthias Buchert, and Juergen Sutter. "Environmental Evaluation of Gypsum Plasterboard Recycling." Minerals 11, no. 2 (January 21, 2021): 101. http://dx.doi.org/10.3390/min11020101.

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Gypsum is widely used in the construction sector, and its worldwide consumption has been increasing for several decades. Depending on the lifetime of the used gypsum products, an increase of gypsum in construction and demolition waste follows. Especially against the background of a circular economy, the recycling of waste gypsum is of growing importance. However, the use of recycled gypsum only makes sense if it is environmentally friendly. Therefore, an evaluation of the environmental impacts of industrial-scale processing for the recycling of post-consumer gypsum waste was conducted. The evaluation was performed with an established life cycle assessment software. Original data provided by the industry and complementary data from a database for life cycle assessments were used for the calculations. Two scenarios for recycled gypsum with different transportation distances were calculated. These results were compared with the results of the environmental evaluation of gypsum derived from coal-fired power plants (FGD gypsum) and natural gypsum. The results showed that the utilization of recycled gypsum can be environmentally advantageous compared to the use of natural gypsum or FGD gypsum, especially in the impact categories of land transformation and resource consumption (abiotic depletion potential). For most environmental impact categories, the specific transportation distances have a strong influence.

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36

Huang, Gang, Yu-Cai Song, Liang-Liang Zhuang, Chuan-Dong Xue, Li-Dan Tian, and Wei Wu. "Genesis of Gypsum/Anhydrite in the World-Class Jinding Zn-Pb Deposit, SW China: Constraints from Field Mapping, Petrography, and S-O-Sr Isotope Geochemistry." Minerals 14, no. 6 (May 29, 2024): 564. http://dx.doi.org/10.3390/min14060564.

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The world-class Jinding deposit in SW China has ~15 Mt of Zn and Pb metals combined, in an evaporite dome containing amounts of gypsum/anhydrite. These gypsum and anhydrite are mainly located in limestone breccias (Member I), gypsum-bearing complexes (Member III), and red mélange, with some occurring as veins in clast-free sandstone (Member IV) and as fractures/vugs of host rock. The gypsum/anhydrite and dome genesis remain equivocal. The gypsum in limestone breccias and in red mélange with flow texture contains numerous Late Triassic Sanhedong limestone fragments. The δ34S (14.1%–17%), δ18O (9.7%–14.6%), and 87Sr/86Sr ratios (0.706913–0.708711) of these gypsum are close to the S-O-Sr isotopes of the Upper Triassic Sanhedong Formation anhydrite in the Lanping Basin (δ34S = 15.2%–15.9%, δ18O = 10.9%–13.1%, 87Sr/86Sr = 0.707541–0.707967), and are inconsistent with the Paleocene Yunlong Formation gypsum in the Lanping Basin (87Sr/86Sr = 0.709406–0.709845), indicating that these gypsum were derived from the Upper Triassic Sanhedong Formation evaporite but not from the Paleocene Yunlong Formation, and formed as a result of evaporite diapirism. The δ34S (14.3%–14.5%), δ18O (10.1%–10.3%), and 87Sr/86Sr ratios (0.709503–0.709725) of gypsum as gypsum–sand mixtures in gypsum-bearing complexes are similar to the 87Sr/86Sr ratios of gypsum in the Yunlong Formation of the Lanping Basin and Cenozoic basins in the northern part of the Himalayan–Tibetan orogen, suggesting that the material source of this gypsum was derived from the Yunlong Formation, and formed as a result of gypsum–sand diapirism. The gypsum veins in clast-free pillow-shaped mineralized sandstone and the gypsum in host rock fractures and vugs formed after the supergene minerals such as smithsonite. The δ34S (−16.3%~−12.7%) and δ18O (−9.8%~−4.7%) of this gypsum indicate that the gypsum is of supergene origin with sulfate derived from the reoxidation of reduced sulfur. We confirmed that the Jinding dome is genetically related to diapir of the Late-Triassic Sanhedong Formation evaporite. Clast-free sandstone and gypsum-bearing complexes in the dome were produced by diapir of the Paleocene Yunlong Formation unconsolidated gypsum–sand mixtures.

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Simionescu, Gheorghe, and Mirela Gheorghian. "Studies Regarding Production of the Moulding Form from Calcined Gypsum." Advanced Materials Research 837 (November 2013): 206–11. http://dx.doi.org/10.4028/www.scientific.net/amr.837.206.

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In the pressing form made from calcined gypsum fixed in metal, wax can be cast with pressure. The device used to tide the pressing form should not bend. If the handling work is done carefully and correct one pressing form made from gypsum can be used for multiple wax models. To be used in construction the pressing forms, calcined gypsum must meet certain requirements regarding its constitution and functionality. To provide these requirements research work must be done to investigate characteristics such as: minimum compressive strength (wet and dry state), hardening time of calcined gypsum, gypsum dilatation after curing. To produce the pressing forms from calcined gypsum the following methods and operations have been used: operations concerning production of gypsum with the best physicochemical and mechanical properties in order to be used for construction of pressing forms (determining the quality of gypsum based on water and plaster ratio; establishing the influence of epoxy and curing solution on the mechanical resistance of the obtained gypsum; determining the influence of lime, boric acid, zinc chloride, sodium chloride on the hardening period of calcined gypsum); production of the models from wood and metal; fixing the model on the gypsum cushion; finding on the model the separation line and restrict the area used for gypsum moulding; applying grease on the model, on the plate under the model, on the walls and on all parts that come in contact with liquid gypsum to be poured; preparation of the gypsum solution.

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Cheah, Chee Ban, Leng Ee Tan, and Mahyuddin Ramli. "Influence of different types and contents of gypsum on mechanical properties and porosity of sulphate activated binder." IOP Conference Series: Materials Science and Engineering 1289, no. 1 (August 1, 2023): 012085. http://dx.doi.org/10.1088/1757-899x/1289/1/012085.

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Abstract Fly ash (FA) is pozzolanic, while blast furnace slag (GGBS) is latent hydraulic. These two materials react slowly in the presence of water to harden. Adding an alkali activator such as strong hydroxide could boost the hardening process, but the safe handling of highly corrosive materials is the primary concern. Therefore, the present work prescribed various types of gypsum to activate FA and GGBS as a binder phase for making mortar. It aimed to investigate the influence of different types and contents of gypsum on the mechanical properties and porosity of sulphate-activated binder. Gypsum is a less corrosive material to provide calcium and sulphate ions for activating GGBS and FA. The main component of gypsum was calcium sulphate. Gypsum provides calcium sources that promote more C-S-H to be formed. A few types of gypsum were studied with their effect on FA/GGBS blended mortar. Furthermore, the mechanical strength and porosity of gypsum-activated GGBS/FA blended mortar were assessed. The mortar containing white gypsum exhibited the best mechanical performance among all types of gypsum. On the other hand, red gypsum and dental gypsum were established to be more effective in pore refinements, lowering the mortar’s total porosity. In conclusion, white gypsum is the most suitable material for activating the FA/GGBS blend among the various types of gypsum examined.

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Rambe, Muhammad Rahman, Rizky Febriani Pohan, Fithriyah Patriotika, Sahrul Harahap, and Alvi Sahrin Nasution. "Potential of Gypsum Waste as a Substitution and Filler Material in Concrete Manufacturing." Fluida 16, no. 2 (November 30, 2023): 120–31. http://dx.doi.org/10.35313/fluida.v16i2.4471.

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Gypsum is a dental and construction material that used only at certain times. Gypsum waste can be mixed with food waste so that it endangers the environment. The gypsum waste needs to be separated and recycled. This study examines the potential use of gypsum waste as substitute and filler material in concrete manufacture, including: gypsum characteristic based on XRF, concrete maximum load, concrete compressive strength, concrete water absorption and heavy metal concentration analysis. Gypsum compositions used is 0%, 10%, 20%, 30%, 40% and 50%. The gypsum characterization results showed that there was 98.92% oxide, gypsum was included in type III gypsum, heavy metals such as: Fe = 10 ppm and Al = 16500 ppm, metallic elements such as: Si = 1950 ppm, Ca = 182900 ppm, Mg = 4560 ppm, K = 2200 ppm, and non-metallic elements namely: P = 580 ppm. The highest and lowest of maximum load and concrete compressive strength in the gypsum use as substitute and filler material are produced at the addition of 50% and 10% gypsum, respectively. The gypsum addition as substitute or filler material reduces the concrete water percentage. The heavy metals concentrations resulting from the 28-day-old concrete immersion were: Fe = <0.084 ppm and Al = <0.156 ppm.

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Doleželová, Magdaléna, Jitka Krejsová, and Alena Vimmrová. "Adhesive Strength of Gypsum Composites with Lightweight Fillers." U.Porto Journal of Engineering 7, no. 2 (March 5, 2021): 52–59. http://dx.doi.org/10.24840/2183-6493_007.002_0007.

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Gypsum composites with several types of lightweight fillers were studied. Gypsum starts to be more important material nowadays, because it is one of the most environmentally friendly building binders. Therefore, there are new ways of the larger utilization of gypsum based materials to be sought. Even though the use of fillers in the gypsum is generally not necessary, because gypsum (opposite to cement or lime) does not shrink, fillers can be used for economic reasons or to improve some other properties of the gypsum material, e.g. thermal or fire resistance. We studied the adhesive strength of gypsum composites, containing three types of lightweight fillers (perlite, expanded clay aggregate and recycled PUR) and compared them with the properties of gypsum mortar with siliceous sand. It was found, that the type of the filler has principal impact on the adhesive strength of the gypsum composite.

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Aimaq, Mohammad Bashir, and Saleh Mohammad Salehy. "Determining and detection of chemical and mineral composition of gypsum obtained from Karkar-Doodkas, Baghlan province." International Journal of Innovative Research and Scientific Studies 3, no. 3 (September 2, 2020): 93–97. http://dx.doi.org/10.53894/ijirss.v3i3.40.

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A library and laboratory research experiment was conducted in 2020 on determination and detection of mineralic and chemical appearances of mineralic gypsum in Karkar and Doodkash of Baghlan Province to determine the amount of gypsum minerals in the stones of the areas, detect the composition of gypsum stones and evaluate the importance of gypsum stone in Baghlan Province. The laboratory results indicated that the percentage of mineralic gypsum in composition of mineralic appearances of gypsum stone in Karkar and Doodkash were 95 percent. Despite the slight presence of some other minerals like Sylvine and Iron minerals in composition of the gypsum stone in both the locations were possible. The analyzed laboratory results by XRF machine revealed that besides of the mentioned elements in composition of mineralic appearances of gypsum stone, the elements such as silicon, iron, potassium, chlorine and aluminum were also present in different percentages. Therefore, it can be concluded that the mineralic appearances of gypsum stones in Karkar and Doodkash are the most important gypsum stone in Baghlan province and it can be used for production of constructional gypsum, Ghori Cement Factory and other similar uses.

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Liu, Fei, and Ming Zhang Lan. "Effects of Gypsum on Cementitious Systems with Different Mineral Mixtures." Key Engineering Materials 509 (April 2012): 20–25. http://dx.doi.org/10.4028/www.scientific.net/kem.509.20.

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Gypsum is an indispensable component of ordinary Portland cement. The main function of gypsum is to regulate the setting time of cement. Gypsum has a great influence on water consumption of standard consistence and strength simultaneously. In this article three cementitious systems are prepared by three main mixed materials: limestone, fly ash and slag. The effect of gypsum content and the relation between gypsum quantity and the fluidity of cement with Marsh cone method are studied. Experimental results show that when the gypsum was added in the three kinds of cementitious system, water consumption of standard consistence decreased obviously, and with the quantity of gypsum increased, water demand for normal consistency reduced first, up to a certain extent tended smoothly. With the increase of gypsum quantity, initial and final setting time had different degrees of extension. While a saturation quantity is achieved, setting time will keep steady. The flexural strength and the compressive strength increased gradually and tended to be stable with the increase of gypsum quantity. When gypsum content exceeded a certain range, compressive and flexural strength decreased gradually. But gypsum content and the mobility of systems had little relativity with Marsh cone method.

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Dvořák, Karel, Marcela Fridrichová, and Dominik Gazdič. "Gypsum Dehydration to Alpha-Gypsum in Mixed Chloride Solutions." Advanced Materials Research 457-458 (January 2012): 391–94. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.391.

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Brno University of Technology solves in the long term the problem of alpha gypsum preparation by dehydrating the gypsum in the solution of chloride salts. This study verified that alpha-gypsum can be trouble free prepared by gypsum dehydration in solution of a number chloride salts, among others CaCl2, MgCl2 or NaCl. In the same time it was found that owing to the different electro-chemical behavior of Potassium ions, the by heat conditioned reaction of gypsum with the KCl solution the dehydration doesn’t take place, but a partial substitution of Potassium ions by Calcium ions takes place. The product of this reaction is the mineral görgeyit, K2SO4.5CaSO4.H2O.This important problem was solved by reduction of the extremely electro-chemical high mobility of Potassium ions by the method of the mixed chloride solution with Potassium and Sodium ions, the mobility of which is in comparison with the preceding only one third. Samples of hemihydrate in the solution of mixed salts were prepared and tested in conclusion of the research.

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Bhatti, Aman Ullah, Ahmad Bakhsh, and Akbar Hussain Gurmani. "Patterns in Gypsum Requirement Before and After Gypsum Application." Pakistan Journal of Biological Sciences 3, no. 10 (September 15, 2000): 1580–82. http://dx.doi.org/10.3923/pjbs.2000.1580.1582.

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Dvorak, Karel, Marcela Fridrichova, and Dominik Gazdic. "Gypsum Dehydration to Alpha-Gypsum in Mixed Chloride Solutions." Advanced Materials Research 457-458 (January 2012): 391–94. http://dx.doi.org/10.4028/scientific5/amr.457-458.391.

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Cusa, Stephen A. "National Gypsum Company's acoustically enhanced gypsum board—SoundBreak XP." Journal of the Acoustical Society of America 133, no. 5 (May 2013): 3308. http://dx.doi.org/10.1121/1.4805492.

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Prasad, P. S. R. "Raman intensities near gypsum-bassanite transition in natural gypsum." Journal of Raman Spectroscopy 30, no. 8 (August 1999): 693–96. http://dx.doi.org/10.1002/(sici)1097-4555(199908)30:8<693::aid-jrs434>3.0.co;2-8.

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Nisya, Alinda Fitrotun. "RECYCLE LIMBAH GYPSUM BOARD BEKAS BANGUNAN MENJADI GYPSUM PLASTER." Jurnal Teknologi Kimia Unimal 13, no. 1 (May 31, 2024): 28. http://dx.doi.org/10.29103/jtku.v13i1.15924.

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Plaster of Paris atau gipsum hemihidrat memiliki banyak manfaat dalam kehidupan masyarakat, diantaranya sebagai bahan konstruksi maupun di bidang kesehatan. Penggunaan gipsum yang masif, menyebabkan penumpukkan limbah gipsum sehingga perlu dilakukan daur ulang gipsum agar dapat dipakai kembali. Jika air yang terkandung dalam kristal limbah gipsum menguap, gipsum dapat diaktifkan kembali menjadi gipsum hemihidrat. Pertama, sampel bahan baku disiapkan, kemudian dipanaskan untuk menghilangkan kandungan air bebas dari gipsum dihidrat, dan akhirnya, pemanasan dilakukan di furnace. Suhu pemanasan dan ukuran partikel adalah variabel penelitian ini. Penelitian ini bertujuan untuk mempelajari kinetika reaksi untuk menghasilkan produk gipsum hemihidrat untuk menentukan nilai parameter proses kecepatan reaksi.Persamaan kinetika reaksi orde satu dapat digunakan untuk memmodelkan reaksi dehidrasi gipsum dari bahan bangunan ini. Nilai tetapan Arrhenius dan energi aktivasi masing-masing adalah 23269,0630 s-1 dan 66395,8480 J/mol.K.

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Chen, Miao Miao, Yun Wei Yu, Chun Hua Feng, and Dong Xu Li. "Study on Flue Gas Desulphurization Gypsum Plaster." Applied Mechanics and Materials 71-78 (July 2011): 842–46. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.842.

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Flue gas desulphurization (FGD) gypsum and fly ash are two kinds of solid waste in coal-fired power plant. The possible displacement content of fly ash in gypsum plaster was investigated in this paper. The effect of various chemicals retarders, such as Citric acid, sodium citrate and SC gypsum retarder, and water retention agent on the setting time, flexural strength and compressive strength of gypsum plaster was also studied. The results demonstrate that gypsum plaster has maximum mechanical properties and enough setting time at the rate of 20% fly ash replacing calcined gypsum; SC gypsum retarder effectively delays the setting time and has lower strength loss; The optimum level of water-retention agent for effective utilization of gypsum plaster is 0.2%.

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Du, Chuan Wei, Ying Lv, and Guo Zhong Li. "Research on Preparation and Properties of New Type Desulfurization Gypsum Block." Applied Mechanics and Materials 540 (April 2014): 217–20. http://dx.doi.org/10.4028/www.scientific.net/amm.540.217.

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Desulfurization building gypsum was used as the main gelled material and fly ash was used as filler to prepare the new type desulfurization gypsum block. the mechanical properties of the new type desulfurization gypsum block was improved by adding compound excitation agent into the desulphurization gypsum-fly ash cementing material to stimulate its activity. The water resistant performance of the new type desulfurization gypsum block was improved through adding wax-alcohol compound waterproofing agent into it. Experimental results show that when the filling amount of fly ash was 20%(the quality of desulfurization gypsum), the impact on the strength of gypsum was minimal; when the dosage of compound excitation agent was 1.75%, the excitation effect of desulphurization gypsum-fly ash cementing material was best; when the dosage of wax-alcohol compound waterproofing agent was 0.4%, the water resistance of new desulfurization gypsum block was optimal.

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Journal articles on the topic 'Gypsum'

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