This paper presents the results of a study of phase transformations occurring in copper-telluride by-products during its processing of oxidation-distillate roasting at low pressure. The results show that copper telluride is oxidized through intermediate compounds to the most stable tellurate (Cu₃TeO₆) at low temperatures. The increase in the roasting temperature above 900 °C and the presence of an oxidizer favor the copper orthotellurate decomposition. Thus, the tellurium extraction rate is 90–93% at a temperature of 1000 °C, the oxidant flow rate is 2.2 × 10⁻² m³/m²·s, and the roasting time is 60–90 min. One of the decomposition products is copper oxide alloy, which is the basis of the residue. The second product is tellurium in oxide form, which evaporates and then condenses in the cold zone of the condenser in crystalline form. The main constituent phase of the condensate is tellurium oxide (TeO₂), which can be further processed during one operation to elemental chalcogen by thermal reduction or electrolytic method.

The practicability of a pyrometallurgical scheme for raw material processing is established as a result of the analysis of methods intended to dearsenate and process gold-arsenic concentrates as well as equipment for the process execution. The conceptual design of vacuum equipment without forced movement of the dispersed material in the sublimator and of the reaction zone materials is proposed. In-process tests for the sublimation of arsenic sulfides from gravity and flotation concentrates received from the Bakyrchik deposit were executed at the pilot facility. As a result, it was found that more than 97–99% of arsenic passes into the gas phase and condenses in a sulfide form suitable for compaction by smelting. More than 99.5% of precious metals are concentrated in the sublimation residue. As a result of smelting residue from the sublimation of arsenic sulfides in a cyclone furnace, together with copper concentrates to copper matte, the gold recovery was 93.7–93.9% of the total amount loaded. Silver was 65.7–68% concentrated in copper matte, with a considerable amount in the dust. If the cyclone smelting dust is involved, the recovery rate of gold and silver can be increased to 97–99% and 94–95%, respectively. As a result of crucible smelting, the degree of recovery of gold in matte was 95.4%, with its content in slag being 3.6 g/t. The received matte according to the proposed scheme can be directed to the conversion process by obtaining blister copper, which is subjected to electrolytic refining with the recovery of gold from slimes.

In this study, the carbothermic reduction of sodium antimonate in crucible smelting was investigated. The optimal process temperature was determined to be 900 °C, with 10% coke consumption (with an ash content up to 15.33%) and a feed particle size of minus 1 mm. The process does not involve the addition of slag-forming components. Sodium participates in the formation of the slag phase. According to the smelting results, the amount of antimony recovered as crude metal reached 71–72%, while the Sb content in the crude metal reached up to 94.5%. A significant portion of antimony (up to 27%) volatilizes with off-gases. A notable sodium content was detected in the crude antimony, reaching up to 8% in some samples, while more than 80% of sodium was transferred to the slag phase. Arsenic, present in the initial concentrate at a level of 0.6%, was distributed approximately equally among the metallic, slag, and gas phases. Lead was predominantly concentrated in the crude antimony. Iron preferentially dissolved in the crude antimony. Other impurities were distributed in comparable amounts between the metallic and slag phases. Tellurium, present in sodium antimonate at 0.79%, was detected in some samples within the slag phase.

The paper presents the study results of the thermal behavior of synthetic copper telluride in an inert atmosphere at pressures of 92 and 0.07 kPa under isothermal and non-isothermal vacuum-thermal conditions. The thermal analysis results showed that the synthesized copper telluride undergoes polymorphic transformations at 185.7, 259, 318, 350, 470, and 834.5 °C. These transformations were established by early studies and are characteristic of copper tellurides of stoichiometric and non-stoichiometric compositions. It was found that the reduction of the pressure in the system slightly increases the final value of mass loss of the synthetic sample. The X-ray phase analysis results of the residues obtained at constant and increasing temperatures at a pressure of 0.07 kPa showed the absence of the formation of new phases relative to the initial composition. A change in the quantitative ratio of the available phases was found in the direction of an increase in the amount of Cu0.656Te0.344 relative to the initial composition with an increase in the process temperature.

Приведены результаты исследований, направленных на извлечение теллура в форме оксидов пирометаллургическим способом из его соединений с медью. В качестве объекта изучения использован технический теллурид меди ТОО «Корпорация Казахмыс» (Казахстан), содержащий кристаллические фазы, мас.%: Cu₇Te₄ – 36,5, Cu₅Te₃ – 28,5, Cu₂Te – 12,9, Cu_2,5SO₄(OH)₃·2H₂O – 16,2 и Cu₃(SO₄)(OH)₄ – 6,0. В результате проведенных физико-химических исследований и технологических экспериментов показана принципиальная возможность переработки технического теллурида меди окислительно-дистилляционным обжигом с извлечением теллура в отдельный продукт. В качестве окислителя использован кислород воздуха. Установлено, что понижение давления в интервале 80–0,67 кПа при одинаковой температуре влечет за собой повышение степени извлечения теллура. Однако приемлемое с технологической точки зрения значение этого показателя (93,0–98,0 %) при всех давлениях (в течение 1 ч) достигается при температуре 1100 °С. Увеличение экспозиции до 3 ч дает незначительный положительный эффект. Дифрактометрическими исследованиями огарков от технологических экспериментов было отмечено снижение содержания оксидов меди в интервале давлений 80–40 кПа и рост содержания фазы Cu3TeO6. При последующем увеличении разрежения от 40 до 0,67 кПа происходит заметное снижение количества куприта и, как следствие, резкий рост количества оксида одновалентной меди. Для теллурата меди отмечено замедление прироста его объема при давлениях 40–20 кПа и резкое падение его содержания при давлениях ниже 13,3 кПа. Полученный конденсат представляет собой сыпучую смесь кристаллических фаз диоксида теллура (67,7 %) и оксисульфата теллура (32,3 %) и является промпродуктом для дальнейшего получения элементного теллура.