Samchylieiev I. Complex processing of iron- and molybdenum-containing raw materials to produce inorganic compounds of molybdenum and iron

The thesis is devoted to the establishment of regularities in the process of complex processing of iron and molybdenum-containing raw materials and the development on their basis of technological parameters for the preparation of inorganic compounds of molybdenum and iron. The physicochemical processes of leaching molybdenum with ammonia solution, concentration of the obtained solution for precipitation of ammonium heptamolybdate and heat treatment of the precipitate of iron (III) hydroxide in this wor are considered. It has been theoretically and experimentally found out that the processing of iron and molybdenum-containing raw materials is possible both in acidic and alkaline environments. Sulfuric acid can be used as acid reagent, while the concentration of sulfate ions is maintained at a level of not less than 0,8 mol/l and the acidity of the solution is not lower than pH = 1. As alkaline agents, NaOH, Na2CO3 and NH4OH can be used, provided that the pH of the solution does not rise above 12 due to possible contamination of the desired product (ammonium heptamolybdate) with iron salts. The main technological parameters of ammonia leaching process of molybdenum are determined. A technological scheme has been developed and an estimate of raw material costs for processing the spent oxide iron-molybdenum catalyst to produce ammonium paramolybdate and pigmentary iron oxide (ІІІ) has been carried out.