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New experimental results have been obtained on the behavior of arsenic and other associated metals (Re and others) under conditions of oxidative and reductive sintering. It has been established that the extraction of arsenic strongly depends on the process temperature during oxidative sintering. The extraction of arsenic into dust media at 873 K is 50% and rhenium is 88–90%. The effect of excess air on the extraction of arsenic and rhenium into dust was studied: the higher the excess air coefficient, the more complete the extraction of arsenic and rhenium into the dust. The obtained data indicate that achieving a high level of arsenic extraction from the initial product is not possible during oxidative sintering. The best arsenic removal results were reached under the conditions of reductive sintering of initial material by natural gas. The extraction of arsenic into dust at 823 K was 88%, and at 1373 K arsenic is almost completely converted into dust. Obtained new experimental results have a fundamental importance for the selection and organization of a comprehensive technology for the processing complex in composition refractory gold-copper-arsenic-bearing products.

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A laboratory setup has been developed to study the regularities of crystallization of aluminium chloride hexahydrate from hydrochloric acid solutions. The influence of the AlCl3 content in the initial solution, the consumption of gaseous HCl, and the behavior of impurities on the crystallization of AlCl3·6H2O from aluminium chloride solutions of leaching cinder obtained as a result of chlorinating ash burning from thermal power plants in Kazakhstan have been studied. The behavior of impurity metals in the process of crystallization of aluminium chloride solution has been studied, and their distribution between the products of the crystallization process has been established. It is shown that aluminium chloride content in the solution decreases with an increase in the consumption of hydrochloric acid. It was found that under the conditions of crystallization of AlCl3·6H2O, all impurities, except for barium, pass by 98% into the mother liquor. To reduce barium and other impurities in the obtained crystals of AlCl3·6H2O, it is proposed to carry out multiple washing of the crystals with hydrochloric acid (32% HCl). It has been shown that a decrease in the acidity of the washing solution from pH = 10 to pH = 5.5 ensures the isolation of ACH crystals with a minimum content of impurity metals, ppm: 3-5 Ca; 3-6 Fe; 1-3 Mg; 0.1-0.5 Ti; 1-3 Na; 20-30 P2O5. The moisture content of the obtained crystals is 4-5%; the particle size is 400-900 microns. As a result of mathematical processing, regression equations were constructed that adequately predict aluminium chloride content in the solution and its extraction into crystalline hydrate, depending on the consumption of hydrochloric acid. The optimal parameters of the crystallization process have been established: Т = 60 ºС, HCl concentration in the solution - 26-30%, HCl gas consumption = 0.5 l/min, duration 1 hour.

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