Possibilities of zinc extraction from galvanic sludges by means of electrolysis

The aim of this work is a proposal of innovative technology of metal waste processing -sludge and filtration cakes from galvanizing plants. The paper deals with possibilities of zinc obtaining from waste of galvanic sludge, which arises during galvanic plating. A leaching process in a sodium hydroxide environment was optimized in the laboratory conditions, resulting in separation of zinc from iron and other organic and inorganic components from sludge. The obtained leach was processed by means of the electrolysis in order to get pure zinc. The stainless plate was used as a cathode, nickel plate as an anode. Results of chemical analyses of individual intermediate and final products at the hydrometallurgical processes are presented in this paper.

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“…The zinc ions contents were fluctuating. All depended on the delivered sludge sample and the used leaching agent [12,13].…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…Literature data on hydrometallurgical treatment of wastes mainly consider the leaching method in sulfuric, nitric or hydrochloric acid [7]. Previous results of the leaching of galvanic waste were published in [11][12][13].…”

Section: )mentioning

confidence: 99%

POSSIBILITIES OF ZINC EXTRACTION FROM GALVANIC SLUDGE BY MEANS OF LEACHING IN SODIUM HYDROXIDE AND FOLLOwING ELECTROLYSIS

Rigoulet

Drápala

Brožová

et al. 2022

METAL 2022 Conference Proeedings

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“…But the technical and economic indicators of this method were unsatisfactory for use in the industry. The method of regeneration of etching solutions with double electrolysis with the formation of mercury amalgam [12] has not been widespread in production due to its significant energy costs.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Determining the rational parameters for processing spent etching solutions by ferritization using alternating magnetic fields

Kochetov

Samchenko

Lastivka

et al. 2022

EEJET

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This paper reports the results of studying the application of a ferritization method for the integrated purification of used etching solutions. A feature of this work is the use of energy-saving activation of the process by alternating magnetic fields. Its advantages are shown in comparison with traditional thermal activation. The influence of magnetic induction amplitude and key technological parameters of ferritization on the quality of cleaning an etching solution has been studied. The qualitative and quantitative composition of sediments obtained after the ferritization of etching solutions was investigated. Used etching solutions are large-tonnage waste of industrial enterprises. They contain harmful pollutants that have a detrimental effect on the environment. It is promising to treat these solutions in order to obtain valuable commodity products. It is established that with an optimal value of magnetic induction amplitude of 0.1 Tl, the degree of extraction of iron ions from the solution reaches a value of 99.99 %. The best values for the main technological parameters of the process have been determined: the concentration of iron ions in the reaction mixture is 6.6 g/dm3; pH, 11.5; the duration of ferritization is 15 min. The residual concentration of iron ions in purified solutions does not exceed 0.3 mg/dm3. Thus, according to the norms of current standards, they can be reused in production. Comparative analysis indicates the advantages of electromagnetic activation of the reaction mixture. The phases of magnetite Fe3O4 and iron monohydrate δ ‒ FeOОН were detected by the method of X-ray phase analysis in ferritization sediments. It is established that with an amplitude of 0.1 Tl, the sediment contains only magnetite. The study's results indicate the possibility of further use of sediments for the manufacture of important ferromagnetic substances. The application of the improved ferritization process in production will achieve less energy consumption compared to well-known processing technologies

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Processing of Metal Waste—Sludge from the Galvanizing Plants

Drápala

Rigoulet

Brožová

et al. 2022

Metals

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This paper deals with the possibility of obtaining zinc from waste galvanic sludge, which is formed during galvanic plating. The aim of the experimental and practical part was to obtain zinc after the leaching of galvanic sludge. Leaching was performed in sulfuric acid, nitric acid and hydrochloric acid at different temperatures and time intervals with the addition of oxidizing agents as hydrogen peroxide or ozone. A separation of the leach and filtrate using filtration followed. The leach was further processed by a precipitation of iron and other metals using various agents. After a further filtration, the electrolysis was performed in order to obtain pure zinc on the cathode at the electrical voltage of approximately 3.5 V. Leaching using a solution of sodium hydroxide or potassium hydroxide was also performed when the prior dissolving of a major part of zinc into the leach occurred, while iron and non-ferrous metals remained in the leaching residue. After the filtration of the leach, the electrolysis with a high zinc yield of a purity of more than 99% followed. This way seems to be an optimal one for building a semi-industrial line for galvanic sludge recycling. All the partial products, i.e., the leach, the leaching residue, the filtrate, the solid precipitate and the separated metal on the cathode were subjected to chemical analyses. The analyses results are presented in tables and graphs.

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Possibilities of zinc extraction from galvanic sludges by means of electrolysis

Cited by 3 publications

References 8 publications

POSSIBILITIES OF ZINC EXTRACTION FROM GALVANIC SLUDGE BY MEANS OF LEACHING IN SODIUM HYDROXIDE AND FOLLOwING ELECTROLYSIS

POSSIBILITIES OF ZINC EXTRACTION FROM GALVANIC SLUDGE BY MEANS OF LEACHING IN SODIUM HYDROXIDE AND FOLLOwING ELECTROLYSIS

Determining the rational parameters for processing spent etching solutions by ferritization using alternating magnetic fields

Processing of Metal Waste—Sludge from the Galvanizing Plants

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