Academic literature on the topic 'Boric acid production'

The REACH regulation stands for “Registration, Evaluation, Authorization and Restriction of Chemicals” and defines certain substances as harmful to human health and the environment. This urges manufacturers to adapt production processes. Boric acid and cobalt dichloride represent such harmful ingredients, but are commonly used in yeast cultivation media. The yeast Komagataella phaffii (Pichia pastoris) is an important host for heterologous protein production and compliance with the REACH regulation is desirable. Boric acid and cobalt dichloride are used as boron and cobalt sources, respectively. Boron and cobalt support growth and productivity and a number of cobalt-containing enzymes exist. Therefore, depletion of boric acid and cobalt dichloride could have various negative effects, but knowledge is currently scarce. Herein, we provide an insight into the impact of boric acid and cobalt depletion on recombinant protein production with K. phaffii and additionally show how different vessel materials affect cultivation media compositions through leaking elements. We found that boric acid could be substituted through boron leakiness from borosilicate glassware. Furthermore, depletion of boric acid and cobalt dichloride neither affected high cell density cultivation nor cell morphology and viability on methanol. However, final protein quality of three different industrially relevant enzymes was affected in various ways.

Boric acid (H3BO3) was an inexpensive, efficient and mild catalyst for the synthesis of n-butyl salicylate from salicylic acid and n-butanol, the esterifcation process conditions were optimized, the experimental results showed that the new process used small amount of boric acid catalyst, got higher target product yield, thus reduced the cost of production.

Alfalfa is one of the most important forage crops worldwide because of its wide range of adaptability and good forage quality. Seed yield is generally considered to be of secondary importance and is characterized by often poor seed yield and seed quality. A field experiment was conducted to determine the impact of boric acid foliar applications along with a basal dose during anthesis to enhance the alfalfa seed yield in agro-ecological conditions of Sargodha. In foliar boric acid fertilization 0, 2, 4, 6, 8, 10 boric acid along with basal dose 23-80-50 (NPK kg ha-1) was used. Phosphorous and potash were applied at the time of sowing while nitrogen will be applied in two split doses; half at sowing time and half of 1st irrigation. Two foliar applications, 1st at intensive plant growth stage and the 2ndat the beginning of the blossoming of the crop. The concentration of boric acid solutions used were 2 ,4 , 6 ,8 and 10 glit-1 which produces a seed yield of 161.7, 167.9,171.3, 175.0,186.7 and 176.1 kg ha-1 in year 2015-16 while next year in 2016-17 produces a seed yield of 286.5, 299.2,304.6, 308.3, 312.1 and 310.1kg ha-1 respectively which is higher than year 2015-16. Foliar fertilization with boron influenced forming of slightly higher number of seeds in the pod. Boron influenced the average increase of yield, with a slightly greater difference compared to control. Number of seeds per pod in boric acid dose of 0, 2, 4, 6, 8 and 10 remained 6.1, 6.3, 6.4, 6.6, 6.8 and 6.7respectively in year 2016-17 which were higher than 4.3,4.4,4.5, 4.5,4.9 and 4.7 in year 2015-16. Overall 8 g liter-1 boric acid foliar fertilization produces 8.9 % higher seed yield, 11.4 % higher no of seeds per pod compared to control in the year 2016-17 while produces 15.4% higher seed yield and 13.9 % higher no of seeds per pod as compared to control in the year 2015-16.

BORIC ACID RADIOLYSIS IN PRIMARY COOLANT WATER OF PWR AT TEMPERATURE OF 250oC. The existence of oxygen in the primary coolant system of PWR could lead to corrosion, hence it is very important to suppress the oxygen concentration in the system. Therefore, study of the effect of boric acid addition into the primary coolant water system of PWR to suppress oxygen concentration resulted from gamma-ray radiation is essential to be performed. The aim of this research is to understand reaction mechanism at temperature of 2500C and the effect of boric acid adding toward oxygen concentration in the PWR primary coolant water. Methodology used is simulation using Facsimile software. Input for the software namely radiolysis reaction mechanism for pure water, G value from radiolysis product, dose rate of 1 and 104 Gy/s, aeration and deaeration system, and specific reaction of boric acid with hydroxyl radical and hydrated electron at temperature 250C and 3000C. The output are in the form of irradiation time vs oxygen concentration time series. The results show that the oxygen production increase significantly with the irradiation time and reach the saturated concentration at 107s. Based on the plot of oxygen’s concentration at 107s vs boric acid, several results are as following: oxygen concentration significantly suppressed by boric acid addition and gives the exponential decreasement, the higher dose rate gives the higher concentration of oxygen, the aeration system gives no effect on suppressing oxygen concentration at boric acid addition up to 0.1M.

The Urochloa spp. (sin. Brachiaria spp.) is an important grass cultivated in Brazil. However, the pasture spittlebugs pest attack can limited this forage plant supply and animal production. In search of alternative pest control methods, this research evaluated the boric acid efficiency to control spittlebugs Deois flavopicta and Notozulia entreriana (Hemiptera: Cercopidae). The experiment was carried out under completely randomized design with six treatments and four replications. The treatments were boric acid at concentrations of 0.1, 0.2 and 0.4% and insecticides permethrin 50 CE (0.005%) and imidacloprid 700 WG (0.02%). The number of surviving insects after pulverization of treatments to pasture spittlebugs pest control efficiency were performed. Boric acid at the concentration 0.4% showed 100% of efficiency to control spittlebugs D. flavopicta and N. entreriana species. Thus, boric acid at 0.4% can be used to integrated pest management programs of forage grasses.

Inferential control of boric acid production system using the reaction of colemanite with sulfuric acid in four continuously stirred tank reactors (CSTR) connected in series is aimed. In this control scheme, pH of the product is measured on-line instead of boric acid concentration for control purposes. An empirical correlation between pH and boric acid concentration is developed using the collected data in a batch reacting system in laboratory-scale and this correlation is utilized in the control system for estimator design. The transfer function model of the 4-CSTR system previously obtained is used in the MPC controller design. In the experiments done previously for the modelling of 4-CSTR system, it was observed that the reaction goes complete within the first reactor. Therefore, the control is based on the measurements of pH of the second reactor by manipulating the flow rate of sulfuric acid given to the first reactor, while the flow rate of colemanite fed to the system is considered as disturbance. The designed controller&rsquo
s performance is tested for set point tracking, disturbance rejection and robustness issues using a simulation program. It is found that, the designed controller is performing satisfactorily, using the inferential control strategy for this complex reacting system.

One of the most important boron minerals, colemanite is reacted with sulfuric acid to produce boric acid. During this reaction, gypsum (calcium sulfate dihydrate) is formed as a byproduct. In this study, the boric acid production was handled both in a batch and four continuously stirred slurry reactors (4-CFSSR&rsquo
s) in series system. In this reaction system there are at least three phases, one liquid and two solid phases (colemanite and gypsum). In a batch reactor all the phases have the same operating time (residence time), whereas in a continuous reactor all the phases may have different residence time distributions. The residence time of both the reactant and the product solids are very important because they affect the dissolution conversion of colemanite and the growth of gypsum crystals. The main aim of this study was to investigate the dynamic behavior of continuous flow stirred slurry reactors. By obtaining the residence time distribution of the solid and liquid components, the non-idealities in the reactors can be found. The experiments performed in the continuous flow stirred slurry reactors showed that the reactors to be used during the boric acid production experiments approached an ideal CSTR in the range of the stirring rate (500-750 rpm) studied. The steady state performance of the continuous flow stirred slurry reactors (CFSSR&rsquo
s) in series was also studied. During the studies, two colemanites having the same origin but different compositions and particle sizes were used. The boric acid production reaction consists of two simultaneous reactions, dissolution of colemanite and crystallization of gypsum. The dissolution of colemanite and the gypsum formation was followed from the boric acid and calcium ion concentrations, respectively. The effect of initial CaO/ SO42- molar ratio (1.00, 1.37 and 2.17) on the boric acid and calcium ion concentrations were searched. Also, at these initial molar ratios the colemanite feed rate was varied (5, 7.5, 10 and 15 g/min) to change the residence time of the slurry. Purity of the boric acid solution was examined in terms of the selected impurities, which were the magnesium and sulfate ion concentrations. The concentrations of them were compared at the initial molar ratios of 1.00 and 1.37 with varying colemanite feed rates. It was seen that at high initial CaO/ SO42- molar ratios the sulfate and magnesium ion concentrations decreased but the calcium ion concentration increased. The gypsum crystals formed in the reaction are in the shape of thin needles. These crystals, mixed with the insolubles coming from the mineral, are removed from the boric acid slurry by filtration. Filtration of gypsum crystals has an important role in boric acid production reaction because it affects the efficiency, purity and crystallization of boric acid. These crystals must grow to an appropriate size in the reactor. The growth process of gypsum crystals should be synchronized with the dissolution reaction. The effect of solid hold-up (0.04&ndash
0.09), defined as the volume of solid to the total volume, on the residence time of gypsum crystals was investigated and the change of the residence time (17-60 min) on the growth of the gypsum was searched. The residence time at each reactor was kept constant in each experiment as the volumes of the reactors were equal. The growth of gypsum was examined by a laser diffraction particle size analyzer and the volume weighted mean diameters of the gypsum crystals were obtained. The views of the crystals were taken under a light microscope. It was observed that the high residence time had a positive effect on the growth of gypsum crystals. The crystals had volume weighted mean diameters of even 240 µ
m. The gypsum crystal growth model was obtained by using the second order crystallization reaction rate equation. The residence time of the continuous reactors are used together with the gypsum growth model to simulate the continuous boric acid reactors with macrofluid and microfluid models. The selected residence times (20-240 min) were modeled for different number of CSTR&rsquo
s (1-8) and the PFR. The simulated models were, then verified with the experimental data. The experimentally found calcium ion concentrations checked with the concentrations found from the microfluid model. It was also calculated that the experimental data fitted the microfluid model with a deviation of 4-7%.

One of the most commonly used boron compounds, boric acid, is produced by dissolving colemanite (2CaO×
3B2O3×
5H2O) in aqueous sulfuric acid whereby gypsum (CaSO4×
2H2O) is formed as a byproduct and must be separated from the main product. This process consists of two steps, dissolution of colemanite and formation of gypsum. The amount of boric acid formed depends on the first step, dissolution of colemanite. In the latter step, gypsum crystals are formed and stay in the reaction mixture to grow up to a size large enough to be filtered out of the solution. Filtration of gypsum crystals is a crucial process in boric acid production because it affects the purity and crystallization of boric acid. In this study it is aimed to investigate the effects of particle size of colemanite, stirring rate and reaction temperature on the dissolution of colemanite, gypsum formation and particle size distribution of gypsum formed in the reaction of boric acid production. Colemanite, sulfuric acid and distilled water were used as reactants for the boric acid production reaction in this study.The colemanite minerals were provided from a region of Emet, Kutahya, Turkey. Three types of colemanite minerals having different chemical composition and particle size were used. The sulfuric acid was supplied by Eti Holding A.S. Hisarcik 1 and Hisarcik 2 colemanites were crushed in a jaw crusher, ground in a hammer mill and then sieved. The sieve analysis was performed to learn the size distribution of Hisarcik 1 and Hisarcik 2 colemanite. Hisarcik 3 colemanite was brought from Emet Boric Acid Plant. The maximum diameter of the colemanite minerals was 150 &
#956
m. The experiments were performed at different particle sizes of colemanite (0-150, 0-250 and 250-1000 &
#956
m), temperatures (70- 90 &
#61616
C) and stirring rates (350-500 rpm). The photographs of gypsum crystals were taken. The boric acid and calcium ion concentrations were determined for each experiment. Also, the solid content of the solution in the reactor were measured. The dissolution of colemanite can be followed by monitoring the boric acid concentration change in the slurry. The crystallization of gypsum from the solution can be found from the calcium ion concentration in the solution. The crystallization kinetics of calcium sulfate dihydrate was studied. The growth of the gypsum crystals were examined under the light microscope and the particle size distribution of gypsum crystals were analyzed by of the laser diffraction instrument.

Zinc borate is a flame retardant additive used in polymers, wood applications and textile products. There are different types of zinc borate having different chemical composition and structure. In this study, the production of zinc borate that had the molecular formula of 2ZnO.3B2O3.3,5H2O was studied. The aim of this study was to investigate the effects of reaction parameters on the properties of zinc borate that had been synthesized by the reaction of boric acid and zinc oxide at the existence of the seed crystals and to determine the optimum experimental conditions for zinc borate production reaction. Reaction kinetics was also investigated to find a suitable kinetics model. The effect of boric acid to zinc oxide ratio -H3BO3:ZnO ratio- (3:1, 3.5:1, 5:1 and 7:1), the particle size of zinc oxide (10µ
m and 25µ
m), stirring rate (275 rpm, 400 rpm, 800 rpm and 1600 rpm), temperature (75°
, 85°
and 95°
) and size of seed crystals (10µ
m and smaller size) on reaction rate, reaction completion time, composition and particle size distribution of zinc borate were investigated. Experiments were performed in a continuously stirring, temperature controlled batch reactor with a volume of 1.5L. During the experiments samples were taken to be analyzed in regular time intervals. The analyses of the samples gave the concentration change of zinc oxide and boron oxide in the solid as well as the conversion of zinc oxide to zinc borate with respect to time and the rate of reaction was calculated. The products were also analyzed for particle size distribution. The experimental results showed that the reaction rate increased with the increasing H3BO3:ZnO ratio, particle size of zinc oxide, stirring rate and temperature. The reaction completion time was also decreased by increasing H3BO3:ZnO ratio, stirring rate and temperature. The particle size of final product, zinc borate, decreased with increasing stirring rate and size of zinc borate used as seed and increased with increasing particle size of zinc oxide used as reactant. The average particle sizes of the final product zinc borates synthesized at the end of the experiments were ranged between 4.3 µ
m and 16.6 µ
m. The zinc borate production reaction was mainly fitted the unreacted core model for the case of diffusion through product layer controls.

Forming sheet metal parts in the absence of lubricants is not practical in production operations. In practice, large amounts of liquid and grease lubricants are utilized in sheet forming to ensure that there is sufficient lubrication to reduce asperity interaction and increase formability. In the present investigation, an alternative environmentally friendly lubricant is introduced for sheet metal forming processes. This lubricant is based on a combination of boric acid and canola oil, both of which are natural, environmentally friendly, and have independently demonstrated good lubrication potential. Utilizing a specialized sheet metal stretching apparatus, an optimized boric acid and canola oil formulation was evaluated for use in metal forming operations. Based on the experimental results, the optimized lubricant shows substantial potential for providing the manufacturing community with a commercially viable and environmentally friendly lubricant that will eliminate expensive disposal costs.

Life cycle management of RPV heads is a significant issue for utilities with PWR plants. Experience has shown the potential for primary water stress corrosion cracking (PWSCC) of the Alloy 600 CRDM nozzles and/or Alloy 182 J-groove welds which can lead to leaks if allowed to propagate. Non-destructive examinations to detect the PWSCC at an early stage are expensive and potentially time consuming while failure to perform timely inspections can lead to leaks, boric acid corrosion, and the possible need to perform repairs during outages when no provisions have been made for inspections or repairs. Decisions regarding the optimum long term strategic plan can be made based on economic modeling of alternative strategies in combination with probabilistic risk modeling based on plant-specific and industry generic inspection results. This paper describes the key factors in developing a strategic plan that takes into account planned costs, potential repair costs, costs of lost production, and other consequential costs, while ensuring safety. Modeling tools discussed include welding residual stress analyses, fracture mechanics calculations, crack initiation and growth modeling, and probabilistic Monte Carlo simulation.

The aluminium alloys are widely employed in the aeronautical, aerospace and automotive industries as they provide good heat conductivity, corrosion resistance, high strength to weight ratio even at high temperatures. Cutting fluids are still widely used in the machining of aluminium alloys to cope with problems associated with the heat generation. However, the growing social concern towards environmental conservation has made it necessary to develop cleaner production technologies such as dry machining in which no cutting fluids are employed. Solid lubricant assisted machining is a novel concept to control the machining zone temperature without polluting the environment. The surface quality of the machined parts is one of the most important product quality characteristics and one of the most frequent customer requirements. The present study focuses on investigating the effect of boric acid powder as solid lubricant on surface quality. Experiments have been conducted using Taguchi’s L9 orthogonal array. The influence of machining parameters viz. cutting speed, feed, rake angle and tool nose radius on surface quality has been investigated.

The presence of iron (iron oxide from carbon steel piping) buildup in Boiling Water Reactor (BWR) circuits and wastewaters is decades old. In, perhaps the last decade, the advent of precoatless filters for condensate blow down has compounded this problem due to the lack of a solid substrate (e.g., powdex resin pre-coat) to help drop the iron out of solution. The presence and buildup of this iron in condensate phase separators (CPS) further confounds the problem when the tank is decanted back to the plant. Iron carryover here is unavoidable without further treatment steps. The form of iron in these tanks, which partially settles and is pumped to a de-waterable high integrity container (HIC), is particularly difficult and time consuming to dewater (low shear strength, high water content). The addition upstream from the condensate phase separator (CPS) of chemicals, such as polymers, to carry out the iron, only produces an iron form even more difficult to filter and dewater (even less shear strength, higher water content, and a gel/slime consistency). Typical, untreated colloidal material contains both sub-micron particles up to, let’s say 100 micron. It is believed that the sub-micron particles penetrate filters, or sheet filters, thus plugging the pores for what should have been the successful filtration of the larger micron particles. Like BWR iron wastewaters, fuel pools/storage basins (especially in the decon. phase) often contain colloids which make clarity and the resulting visibility nearly impossible. Likewise, miscellaneous, often high conductivity, wastesteams at various plants contain such colloids, iron, salts (sometimes seawater intrusion and referred to as Salt Water Collection Tanks), dirt/clay, surfactants, waxes, chelants, etc. Such wastestreams are not ideally suited for standard dead-end (cartridges) or cross-flow filtration (UF/RO) followed even by demineralizers. Filter and bed plugging are almost assured. The key to solving these dilemmas is 1) to break the colloid (i.e., break the outer radius repulsive charges of the similar charged colloidal particles), 2) allow these particles to now flocculate (floc), and 3) form a type of floc that is more readily filterable, and, thus, dewaterable. This task has been carried out with the innovative application of electronically seeding the feed stream with the metal of choice, and without the addition of chemicals common to ferri-floccing, or polymer addition. This patent-pending new system and technique is called Seeding And Filtration Electronically, or the SAFE™ System. Once the colloid has been broken and flocking has begun, removal of the resultant floc can be carried out by standard, backwashable (or, in simple cases, dead-end) filters; or simply in dewaterable HICs or liners. Such applications include low level radwaste (LLW) from both PWRs and BWRs, fuel pools, storage basins, salt water collection tanks, etc. For the removal of magnetic materials, such as some BWR irons, an ElectroMagnetic Filter (EMF) was developed to couple with the ElectroCoagulation (EC), (or metal-Floccing) Unit. In the advent that the wastestream primarily contains magnetic materials (e.g., boiler condensates and magnetite, and hemagnetite from BWRs), the material was simply filtered using the EMF. Bench-, pilot- and full-scale systems have been assembled and applied on actual plant waste samples quite successfully. The effects of initial feed pH and conductivity, as well as flocculation retention times was examined prior to applying the production equipment into the field. Since the initial studies (Denton, et al, EPRI, 2006), the ultimate success of field applications is now being demonstrated as the next development phase. For such portable field demonstrations and demand systems, a fully self enclosed (secondary containment) EC system was first developed and assembled in a modified B 25 Box (Floc-In-A-Box) and is being deployed to a number of NPP sites. Finally, a full-scale SAFE™ System has been deployed to Exelon’s Dresden NPP as a vault cleanup demand system. This is a 30 gpm EC system to convert vault solids/sludges to a form capable of being collected and dewatered in a High Integrity Container (HIC). This initial vault work will be on-going for approximately three months, before being moved to additional vaults. During the past year, additional refinements to the patent pending SAFE™ System have included the SAFER™ System (Scalant and Foulant Electronic Removal) for the removal by EC of silica, calcium and magnesium. This has proven to be an effective enabler for RO, NF and UF as a pretreatment system. Advantages here include smaller, more efficiently designed systems and allowed lower removal efficiencies with the removal of the limiting factor of scalants. Similarly, the SAFE™ System has been applied in the form of a BAC-UP™ System (Boric Acid Clean-Up) as an alternative to more complex RO or boric acid recycle systems. Lastly, samples were received from two different DOE sites for the removal of totally soluable, TDS, species (e.g., cesium, Cs, Sr, Tc, etc.). For these applications, an ion-specific seed (an element of the SMART™ System) was coupled with the Cs prior to EC and subsequent filtration and dewatering, for the effective removal of the cesium complex and the segregation of low level and high waste (LLW & HLW) streams.