11. Describe modern technologies of processing of mineral raw materials containing rhenium.
To extract rhenium from fine and lump waste heat-resistant nickel alloys (HRNA) offered the following technologies:
- High-temperature oxidation stripping Re2O7;
- Sintering the batch, followed by an oxidative leaching;
- Direct leaching hydrochemical concentrated solutions of mineral acids;
- Electrochemical methods based on dissolution of the anode material, is brought into solution either rhenium or a nickel base with a concentration of rhenium in the anode mud.
In an industrial environment use the technology of ion exchange sorption of rhenium in the processing of sulfuric acid solutions of complex composition. Recyclable solutions contain rhenium (0.55 ... 1.10 g / l), chromium (VI) and Cr (III) in high concentrations, selenium and arsenic. Rhenium is selectively removed by the anion resin A170, wherein the maximum concentration of rhenium in the desorbate is 29.8 g/l. After recrystallization ammonium perrhenate appropriate varieties of AP-1.
To extract the rhenium from waste alloys used chlorination with chlorine gas at room temperature in the liquid medium of dimethylformamide (DMF) and water. The process takes place in a single step, does not require heat supply from the outside and allows the performance to achieve the degree of 25.7% rhenium.
Waste multicomponent alloys can be processed by the electrochemical anodic dissolution. The components of alloys quantitatively distributed between a liquid (solution) and the solid (slurry) phase. Rhenium ~ 70% is concentrated in the sludge, and 25 ... 30% goes into the electrolyte from which it removed amines liquid extraction followed by ammonium re-extraction. In implementing this complex technology as commercial products obtained potassium perrhenate KReO4.
Figure 1. Two variants of the acid leaching of wastes containing rhenium alloy LS-32.
коксовые отходы - coke wastes
сплавление с - fusion with
мех/ое измельчение - mechanical grinding
окислит/о-кислотное выщелач/ие - oxidation acid leaching
фильтрация - filtration
раствор выщелачивания - solution of leaching
промывка экстракта - washing of the extract
экстракция рения - extraction of Re
регенерация экстрагента - regeneration of extractant
экстрагент - extractant
реэкстракт - reextract
упарка и кристаллизация - evoparation and crystallization
товарная соль - marketable salt
кислотное выщелачивание без окислителя - acid leaching without oxidizer
раствор выщелачивания на извлечение цветных металлов - leaching solution for non-ferrous metals
остаток выщелачивания - remains of leaching
высокотемпературная отгонка - high-temperature distillation
остаток отгонки на переработку - residue of distillation for recycling
улавливание возгонов - catching of sublimates
растворение возгонов - dissolution of sublimates
выпарка - evoparation
рафинат - raffinate
экстракт на выделение - extract for allocation
12. Describe modern technologies of processing of mineral raw materials containing germanium
Germanium ores are very rare. They are found in small quantities as the minerals germanite and argyrodite. Germanium minerals are also present in zinc ores, and commercial production of germanium is carried out by processing zinc smelter flue dust. It can also be recovered from the by-products of combustion of certain coals.
Currently, Ge is recovered mainly from by-products of the zinc industry. The overall production processes can be divided into two steps:
(1) production of Ge concentrate (primary production)
(2) production of Ge end products
Pyrometallurgical processes are based on the volatility of GeO and GeS. Hydrometallurgical processes are based on precipitation of germanium as its sulfide or hydroxide or with tannic acid.
