Pyrite slag containing iron oxide can be used for raw material for ironmaking. However, due to the different calcination process and the nature of the raw material components, the sulfur content in the slag is relatively high. In addition, the contents of copper , lead , zinc , calcium and magnesium also affect the direct iron making. The pyrite cinder is treated by the beneficiation process recommended in this test to obtain a satisfactory iron concentrate. The sulfur content is already low, 0.23%, and can be used as a raw material for direct iron making. However, the contents of copper, lead and zinc are still high, 0.42%, 0.29% and 0.48% respectively. In order to obtain higher quality iron concentrate products, it is necessary to further remove copper, lead, zinc, calcium and magnesium. To this end, we conducted further de-mixing tests on pyrite cinder.
There are also many studies on the removal of impurities from pyrite slag at home and abroad. S removal method mainly: Cleaning desulfurization: sulfur removal sulfide ore flotation method; method of metal oxide ore by flotation, and other non-ferrous sulfur; chemical processing methods, and biological desulfurization.
Zhu Shenhong of Qingdao Institute of Civil Engineering and Architecture used chemical separation to treat sulfuric acid slag. SA and NA were used as additives to remove the residual sulfur and enrich the iron in the slag. The method has the advantages of simple process, low cost, no pollution and obvious economic benefits. When processing 56.85% iron and 0.96% sulfur containing slag, an iron concentrate with an iron grade of 61.04% and a sulfur content of 0.34% can be obtained.
Feng Yali and Li Haoran's biological desulfurization method treats pyrite cinder and obtains better process indicators. The effects of slurry concentration, Fe 3 + concentration and pH on the concentration of free Tf bacteria (T. thermophilus) and desulfurization rate were studied. The results show that the desulfurization of slag is the combination of the direct leaching of Thiobacillus ferrooxidans and the indirect leaching of Fe 3 + by bacteria. The desulfurization rate and the oxidation activity of the strain are affected by the adsorption of bacteria on the solid phase and in the liquid phase. The concentration of pulp, pH and the influence of Fe 3 + ; the addition of ferric ions can affect the activity of the strain, inhibit the leaching, and easily precipitate on the mineral surface, reducing the oxidation rate. After the desulfurization of the slag, the iron concentrate standard can be reached.
Conventional methods for removing copper include: sulphide xanthate flotation method - acid leaching method, separation-flotation method, sulphation-water immersion method, and the like. Since the copper in the pyrite cinder is mainly combined with copper oxide. The combination of copper oxide is a co-melt of copper minerals of iron minerals formed during high-temperature calcination, and it is difficult to separate, and iron is also dissolved while removing copper. Therefore, the removal of copper from the slag by the above method is not ideal.
Qi Zhiyuan, Zhu Shenhong, Ge Xueyu and others have made corresponding research on the removal of copper from pyrite cinder. A good selection index was obtained by the lime method. The method adds lime, water glass, butyl xanthate, and 2# oil during the flotation process, and 70% of the copper can be separated. The grade of copper can be reduced from 0.45% to 0.14%.
Luo Huihua, Sun Jiashou, Qi Zhenlong et al. studied the conditions of FeCl 3 leaching copper concentrate. When the concentration of Fe 3 + was 540g/L, the temperature was 90 Â°C, and the liquid-solid ratio was L:S=8, the leaching rate of copper was stirred for 16h. It is 71.5%. The mixture of hydrochloric acid and sulfuric acid slag was used instead of FeCl 3 to stir and leaching for 20 hours, and the leaching rate of copper was 69.2%. The use of slag in the hydrochloric acid slurry system to leaching copper concentrate not only makes full use of resources, but also solves the environmental problems of pyrite slag, in order to make full use of the low-grade copper concentrate and sulfuric acid slag that the smelter is not willing to recycle. A new way.
The arsenic high- arsenic pyrite ore slag is treated by chlorination method under the following process conditions: grinding particle size -150 mesh, mixing chlorinating agent with calcium chloride 9% and ferrous chloride 5%, with 0.5% bentonite, 5% reduction of coal powder, the firing temperature 1200 deg.] C, temperature maintained for 45 minutes can produce good effect volatilization chloride. Tin, arsenic, lead, antimony, indium, bismuth, cadmium and other volatile average rate of over 90%. By adding ferrous chloride and siliceous additives, the arsenic content of the ball can be reduced to the ironmaking requirements. The precipitation rate of each metal in the chloride dust collecting liquid is more than 95%. The lead and tin separated well after the arsenic removal by the dust collecting sediment. The process is closed and there is no secondary pollution.
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