Lead sludge from copper production is a source of rare metals, such as rhenium and osmium, whose content reaches 0.06–0.08% and 0.0025–0.0050%, respectively. The base of the sludge consists of lead sulfate. A method of reductive smelting of lead sludge from copper smelting production at 1000–1100 °C has been developed. Coke was used as a reducing agent and sodium sulfate as a slag-forming material. Optimal conditions for selective extraction of rare metals in smelting products were found: osmium in the form of metallic form into raw lead and rhenium in the form of perrhenate compound Na₅ReO₆ into sodium-sulfate slag. The developed technology makes it possible to extract rhenium with a high degree of extraction in the form of water-soluble compounds for the subsequent production of commercial salts of rhenium by the known hydrometallurgical methods. The content of rhenium in the slag phase is 0.18–0.25%, with its initial content in the slime of 0.06–0.08%. The degree of rhenium concentration at the first stage of processing is 3–3.2 times in the form of water-soluble perrhenate. Osmium and lead do not form solid solutions; osmium in crude lead is mainly concentrated in the lower zones of lead. A method of obtaining a concentrate containing 53–67% osmium from raw lead with an initial content of 0.0025–0.0050% in the slurry and a concentration number of 13,000–21,000 times has been proposed.

The basis of the concentrate is sodium hexahydroxoantimonate or mineral mopungite. Upon reduction of the concentrate with coke, ground antimony containing 0.34% arsenic was obtained. To reduce the...

Adsorption is one of the common stages in the hydrometallurgy of rare metals. Its efficiency is largely determined by the quality of the sorbent used. The purpose of this work was to create an activated sorbent based on rice husk cellulose for the extraction of rhenium from aqueous solutions. Two types of cellulose were obtained by treating rice husk with a 1.5% NaOH solution (alkaline cellulose) and a nitric acid solution in ethyl alcohol (Kürschner and Hoffer cellulose). They were tested by IR, SEM, TA, TPD-MS, and XRD methods. It was found that Kürschner and Hoffer cellulose does not contain lignin and retains structural order to a greater extent. By means of this cellulose carbonization at 600 °C and activation by physical, chemical, and combined methods, a series of sorbents were prepared and studied by different methods. It was determined that the sorbent KHC4-600VA obtained by combined activation of cellulose carbonizate by water vapor at 850 °C, followed by an alkaline treatment, has the best textural characteristics: S—~1200 m²·g⁻¹, V—1.22 cm³·g⁻¹, and R—2.05 nm. KHC4-600VA provides 90% recovery of Re (VII) ions from aqueous solutions. According to the Freundlich model, sorption proceeds favorably on the sorbent’s heterogeneous surface.

This article studies the oxidative firing process of lead sludge of copper production for the purpose of extracting rhenium. As an oxidizer, calcium hypochlorite is used, which is simultaneously an oxidizer of low-valent rhenium compounds and a binding reagent of rhenium oxides to calcium perrenate. Optimal conditions for the firing process are found: the firing temperature is 500-600°C, the firing duration is 30-60 minutes, and the oxidizer consumption is 20-40 % of the sludge mass. As a result of thermal studies and experimental work, it was established that the rhenium oxidation process begins at 180-260 °C after the decomposition of calcium hypochlorite and completely ends at 500-600 °C with the formation of calcium perrenate. During water leaching of the stub under the following conditions: T: W=1: 3, temperature of 70 °C, duration of 60 minutes, a solution containing 546 mg/l of rhenium was obtained. The degree of rhenium recovery in the solution was 93-94 %.