Abstract:
Methods of extraction of cadmium from ores and zinc-containing materials are considered in the article. The
Waelz process of Achisai ores (0.1–0.2 % of Cd) is carried out in the presence of 45–55 % of coke from the
mass of ore charge in furnaces. Up to 92–95 % of cadmium is extracted into the sublimates. The yield of sublimates
is 16–18 % of the mass of the ore charge. Sublimates of the Waelz process contain from 0.05 to 1.2 %
of Cd. The efficiency of the processing cadmium-containing ores and semi-products by the Waelz process
largely depends on the degree of replacement of coke breeze with less expensive materials. Research results
are presented, which justify the possibility of using oil sludge while the Waelz processing cadmiumcontaining
materials, by calculating ΔGT 0, determined thermodynamic probability of cadmium recovery from
cadmium-containing compounds in the presence of carbon, oil sludge and its constituent hydrocarbons in
different temperature zones of the Waelz furnace. Due to thermodynamic modeling with the use of the software
complex «Astra» there were established the equilibrium recovery degree and transition of cadmium to
the gas phase, the composition of the gas phase in the temperature range of 300–1500 K and pressures of
0.05–0.5 MPa. It is established that the initial reactivity of the reductant with respect to CdO varies in a series,
and with respect to CdS this series has the form: H2>CnHm>>CdSO4 >H2O>C. At high temperatures, the
form of the reductant does not affect the distillation of Cd (it is > 99 % at T > 1300 K). The interaction in the
system CdO-CdS-oil sludge is observed at temperature > 400 K by the reduction of Cd from CdO. Subsequently,
Cd is reduced from CdS at T > 1100 K reaching maximum at T ≥ 1300 K.
