Sintering with Sodium Carbonate and Leaching of Wolframite Cakes

Focuses on the processing of tungsten raw materials through various operations, including sintering, leaching, purification, and the production of technical tungstic acid. Modern research aims to enhance these processes, particularly the sintering of wolframite concentrates with alkali metal compounds and the leaching of concentrates and cakes. Experiments revealed that reactions between tungsten minerals and sodium carbonate from Akchatau ores commence at temperatures above 520–550 °C, intensifying between 750 and 850 °C. The concentrates were sintered at 750, 800, and 850 °C with a sodium carbonate excess coefficient of 1.05 to 1.2 to evaluate the effect on sodium tungstate extraction. Water leaching was conducted under a probabilistic–deterministic experimental design, analyzing five factors at four levels. Tungsten extraction was assessed based on solution density and the composition of the insoluble residue. Data processing established polynomial trends for tungsten trioxide extraction, and a material balance for sinter leaching was calculated from experiments using 100 g samples with a liquid-to-solid ratio of 2:1. The findings can be applied to improve tungsten processing technologies.