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

Abstract

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

Determining rational parameters for the treatment of concentrated wastewater from etching site by using combined systems producing sediments of predefined composition

“…These compounds of a crystalline structure quickly sediment during processing, their volume and humidity are much lower than those of iron hydroxides [9]. A fairly common method of such processing of spent etching solutions is the method of ferritization using variable magnetic fields [12]. At the same time, the energy efficiency of STS processing process increases, magnetite deposits are formed, which are easily disposed of.…”

Influence of Technological Factors on the Formation and Transformation of Iron-Containing Phases in the Process of Ferritization of Exhausted Etching Solutions

“…The ferritization process promotes the rapid formation of dispersed substances with magnetic properties. The disadvantages of traditional ferritization are its temperature requirements-temperatures above 75 • C. In research paper [27], it was shown that an alternative to thermal ferritization is the activation of the reaction mixture with alternating magnetic fields (AMF) at ambient temperatures. Using this activation method, in research paper [28], iron-containing ferromagnetic compounds of various phase compositions were obtained from liquid industrial waste, the structure of which contains nickel, zinc, and copper ions.…”

Layered Double Hydroxides as the Unique Product of Target Ionic Construction for Energy, Chemical, Foods, Cosmetics, Medicine and Ecology Applications

“…For example, during the chemical purification of washing water from galvanic production from heavy metals using alkaline precipitators, it was found that when Fe 3 + and/ or Al 3 + cations are present in wastewater or salts of these metals are used as coagulants, the residual content of heavy metal cations is significantly lower than those calculated from the solubility of the corresponding hydroxides. The process of formation of a precipitate with reduced solubility in the presence of Fe-ions was called "ferritization" [10][11][12] because heavy metal ferrites were found in the sediment. However, an analysis of published data shows that ferrites are characteristic of metals that easily form oxides in an aqueous medium (Zn, Cu).…”