Academic literature on the topic 'Electroplating - Waste reuse'

Pollution prevention, often referred to as source reduction, encompasses all activities that lead to reductions in the amount and/or toxicity of wastes. Waste minimization, on the other hand, refers to all activities including source reduction, on-site reuse, and recycling that lead to reductions in the amount and/or toxicity of waste generated, stored, treated, or disposed of by a given facility. Pollution prevention generally is regarded as the most cost-effective component of integrated waste management strategies. This paper describes an industrial pollution prevention program at an aging manufacturing facility in the Midwestern United States. The study focuses on metal electroplating and galvanizing. The facility under study produces fabricated metal products for farm and industrial use. The facility performs many operations including electroplating, conversion coating, cleaning, machining, grinding, impact deformation, shearing, welding, sand blasting, hot-dip galvanizing, painting, assembly and testing. Many of these processes result in the production of a variety of pollutants (gaseous, solid, and liquid) that must be disposed of in some fashion. For example, the electroplating line results in the production of acids and rinse water containing zinc and chromium and the hot-dip galvanizing line results in the production of acids and rinse water containing zinc and iron. All of these wastes must be treated as hazardous substances. The painting processes result in the production of used industrial acids, solvents, and chemicals used for cleaning and de-greasing metal components. Most of the recommended operational and process modifications were simple to implement, and their pay-back periods were fairly short.

Modern requirements to electroplating waste treatment necessitate development of technologies that would allow on-site recycle and reuse of both treated water and residuals of water processing. The most prospective option for introduction of recourse-saving wastewater purification is associated with application the method of ferritisation. In this connection, the paper presents an advanced ferritisation process for reduction of initial concentrations of heavy metals (HM) in exhausted nickel electroplating electrolytes from 100 mg/L to 0.3 mg/L. Effects of main technological parameters of such wastewater treatment at thermal and electromagnetic pulse methods of activation of the ferritisation process were determined experimentally. Kinetics of removal of nickel and iron ions from aqueous solutions was investigated. Phase compositions and properties of sediments from wastewater treated were studied. The sediments are predominantly characterised by crystalline nanostructures, ferromagnetic properties and chemical stability, supporting opportunities for their environmentally sound utilisation. Proposed comprehensive process for treatment of liquid industrial waste flows would prevent contamination by toxic effluents; ensure rational use of water, raw materials and energy inputs.

This paper examines the environmental conditions at the premises of printed circuit boards (PCBs) manufacturers, which have electroplating plants. It provides a brief overview of the key aspects of adverse environmental impacts of wastes generated by PCB manufacture and electroplating plants. The aim of this research was to improve the test method for evaluation of wastewater effect on the soil salinity at the premises of PCBs manufacturers. The object of research was the process of extraction and use of copper from wastewater generated by PCBs manufacture and electroplating. As an example, the process of sludge formation during PCBs etching has been reviewed. With the etching line capacity of 14 m2/h, one-shift manufacturing process will result in the production of up to 2,500 kg of sludge monthly. For enterprises with capacities of 2,000–4,000 m2 circuits, this means annual accumulation at their premises of up to 70 tons of wastes in the form of sludge. Estimates suggest that the upper half-meter layer of the aeration zone will be qualified as slightly saline in one year after accumulation of the sludge. In subsequent years, the salt content will increase and saline soil can be found at the depths of 1.5–2 m over ten years of storage. The authors of this paper propose to treat spent etching solutions applying regeneration technology in order to reduce the amount of sludge. With this technology, it is possible to use the extracted metal as a secondary raw material for copper production and re-use the regenerated solution in PCBs etching. This paper provides estimated hazard indices calculated for the storage of sludge at the manufacturer’s premises before and after the implementation of the proposed technology. With regards to findings of the study, it has been proposed to reuse copper recovered from wastes as a raw material for the industry.

A South African developed tubular cellulose acetate reverse osmosis (RO) system from Membratek (Pty) Ltd was evaluated for the treatment of nickel rinse water and mixed electroplating effluent. Spiral wrap polyamide (DuPont) and thin film composite (FilmTec) membranes were evaluated for cadmium and chromium rinse water treatment, respectively. Preliminary laboratory results have shown that nickel rinse water should be treated economically with tubular RO. Approximately 92% of the rinse water could be recovered for reuse. The RO brine is of suitable quality for reuse in the electroplating process. Plant payback for a 5 m3/h nickel/water recovery RO plant was determined to.be 1.3 years (approximately 2 000 mg/ℓ Ni in feed). No severe membrane fouling was encountered during the investigation. However, membrane fouling can affect the process adversely and this will be studied further. Approximately 90% water, of suitable quality for reuse as rinse water in the plating process, could be recovered from mixed electroplating effluent. Effluent volume for subsequent treatment with lime was significantly reduced. It may also be possible to treat cadmium and chromium rinse waters with RO. Approximately 92% and 91% water, of suitable quality for reuse as rinse water, could be recovered with spiral wrap polyamide and thin film composite membranes, respectively. Membrane fouling was experienced during cadmium rinse water treatment. However, water flux could be restored by chemical cleaning. Very little fouling was experienced during chromium rinse water treatment. The fouling potential of the rinse waters for the membranes and subsequent cleaning procedures will be studied further. Preliminary results have shown that payback for 5 m3/h RO cadmium/water and RO chromium/water recovery plants should be 3 and 7 years, respectively. Reverse osmosis has been shown to be a very effective technology for water and chemical recovery and for effluent volume reduction. The electroplating industry causes serious pollution and wastes large volumes of water. Consequently, RO is a technology that may be applied to good effect in the electroplating industry to control pollution and to save scarce water.

In the electroplating process of acidic tin-plating in laboratory, temperature is required to control at 5 °C or so, but conditions of the laboratory is limited, the average temperature is above 5 °C, which leads to Sn2+ in the bath hydrolyze, produce Sn(OH)2 impurities, and part of Sn2+ in the anode oxidize to produce metastannic acid. As time goes by, impurities increase gradually and eventually lead to the bath not be recycled. This paper mainly studied on impurities in the waste after electroplating were synthesized after a series of oxidation, filter and reduction, which makes recycled materials recycled to the greatest extent, non-recycling materials buried deep after high-temperature incineration. After the experiment, stannous oxide and distilled water in the waste get recycled, and the purity of stannous oxide gotten recycled is above 99.5%, which can be reused.

It introduces a kind of technique method that recycling alkaline zincate zinc plating waste liquid in laboratory, involving the fields in electroplating and comprehensive utilization of waste liquid. This method is introduced that with adopting materials such as HCl, NaOH, H2O2, activated carbon, dithiocarbamate diethyl ester, chloroform, ammonia and baking furnace, incinerator, pH test paper, for treatment of the waste liquid through some processes like neutralization, filtration, chemistry precipitation, extraction, distillation, burning, so that some recycled substances in it can be reused such as distilled water, zinc oxide, and as to those can not be recycled, carry on the harmlessization handle by incineration or deep bury.

It introduces a kind of technique method that recycling sylvite zinc plating waste liquid laboratory, involving the fields in electroplating and comprehensive utilization of waste liquid. It includes the following steps: first add hydrogen peroxide and activated carbon into waste liquid to remove the organic matter in it, and then reduce the solution’s temperature with refrigeration film, and filter out the solid contents. Add NaOH solid, NaHSO3 into the solution, through chemical reactions, precipitate the heavy metal element, and finally get distilled water through distillation. It can make the recycled materials be reused, such as distilled water, boric acid, etc., and as to nonrecyclables, such as heavy metal ions (Cu2+, Cr3+), bury them deep that disposing harmless.

Com a Revolução Industrial e a adoção do modelo econômico urbano e industrial, baseado no consumo, ocorreu o aumento da geração de resíduos, frutos das diferentes atividades humanas. A galvanoplastia é um processo que embeleza e protege mecanicamente peças metálicas e está presente nas indústrias do setor metal-mecânico de Nova Friburgo. Neste processo, dois resíduos importantes são gerados: um oriundo do pré-tratamento das peças metálicas e outro das estações de tratamento de efluentes industriais. Neste trabalho, tais resíduos, denominados de (RGs), foram incorporados à borracha natural (NR) em substituição total ou parcial ao óxido de zinco (ZnO). O possível efeito ativador dos RGs sobre a vulcanização e as propriedades da borracha natural foi investigado. As misturas foram realizadas em um misturador de calandras, utilizando-se um sistema convencional (CV). A cinética de vulcanização foi estudada nas temperaturas de 150C, 160C e 170C, através de ensaios reométricos e a determinação de parâmetros tais como: tempo de pré-cura (ts1); tempo ótimo de vulcanização (t90); torques mínimo (Ml) e máximo (Mh); constantes de velocidade; e, energias de ativação. Com relação às propriedades mecânicas, a resistência à tração e a resistência ao rasgamento foram determinadas. As composições de NR contendo RGs apresentaram diminuição do tempo ts1, aumento das constantes de velocidade e diminuição das energias de ativação. No entanto, a resistência ao rasgamento foi mantida em um nível satisfatório apenas nas composições em que o ZnO foi substituído parcialmente em 25%.<br>With the Industrial Revolution and the adoption of urban and industrial economic model, based on consumption, there was an increased in the generation of wastes, as a result of different human activities. Electroplating is a process that embellishes and mechanically protects metallic parts and it is present in the industries of metalmechanical segment of Nova Friburgo. In this process, two important wastes are generated: one from pre-treatment of metal parts, other from industrial sewage station. In this investigation, these wastes, named RGs, were incorporated in the natural rubber (NR) in partial or total replacement to zinc oxide (ZnO). A possible activator effect of RGs upon vulcanization and properties of natural rubber was investigated. Mixes are prepared in a two-roll mixer using a conventional system (CV). Vulcanization kinetics was studied at 150, 160 and 170C through of rheometric tests and the determination of parameters such as: scorch time (ts1); optimum cure time (t90); minimum torque (Ml); maximum torque (Mh); constants rates (k); and, activation energies. In relation to mechanical properties, tensile and tear strength were determined. NR compositions with RGs presented a diminution in ts1 values, increase in the constants rates and diminution of activation energies. However, tear strength is maintained in a satisfactory level only in the compositions where ZnO was partially replaced in 25%.