Shaoguan Smelter Dust Mention Cadmium Technology And Equipment Improvements

By analyzing the development of production and operating situation in Shaoguan Smelter, we think the productive output and capacity of the cadmium system is crucial for the further improvement and stability of the quality of zinc products in the future. At the same time, the difficulties brought to the follow-up refine process and cost control due to the low-grade crude cadmium are also analyzed. It is thought to be necessary and practical to enhance the grade of crude cadmium. The following views are put. forward in this paper on the basis of continuous experiment and combined with production experience of many years.1. The electric precipitation dirt supply condition can be improved and production efficiency can be enhanced by improving the equipment arrangement so that the precipitation dirt treatment capacity can be increased.2. The volatilization rate of cadmium in the mixed material can be raised and the phase composition of cadmium in the precipitation dirt can be improved by reasonably controlling the fresh air distribution and roasting temperature in the sintering process.3. For the precipitation dirt with high degree of oxidation, the leaching efficient can be increased by 40% if the neutral leaching process is changed to an acid one, which is a shortcut to enhance the productiveoutput and capacity of the cadmium system.4. If the following measures are taken, the grade of cadmium products will be improved greatly, even 1# refined cadmium can be produced directly.(!) Controlling the PH value of weak acid leaching terminal point at about 5, so that redundant impurities will not be leached.(2) Adding base slag to control the PI I value of the precipitation dirt slum' at about 6 after acid leaching process, which can lower the concentration of impurities in the lixivium preliminarily.(3) Adding a small amount of zinc powder before the replacement in the solution can replace some impurities which reduction potentials are higher than cadmium, such as Pb, Sn and Tl.(4) Adding concentrated sulfurie acid to keep the PH value of the solution at about 5 after cadmium is replaced, which can prevent Fe and residual Zn from mixing into sponge cadmium.(5) Adding caustic soda and a small amount of NaNOS in the caustic fusion process can further lower the content of impurities in cadmium and stirring the melted cadmium with a pine wood rod before casting can remove the oxygen in it.Under the guidance of these opinions, the technological process of the extraction of cadmium from precipitation dirt and the equipment arrangement are optimized in this paper and a new technological processis designed.