Removal of arsenic from arsenic tailings slurry in a concentrator by sulfide-sulfate method
Investigation of beneficiation plant tailings and the comparative results of tailings is not performed dearsenication tailings slurry was sampled and analyzed (Table 2) has special significance. The tailings slurry of the concentrator contains lime which is alkaline. Table 2  Comparison of the results of the tailings investigation take   kind   point not    Take off    arsenic Take off   arsenic    Rear pH Cas mg / liter PH Cas mg / liter Overflow well     On its surface 11.30 0.10 8.90 0.90 in 11.30 0.23 8.50 0.50 in 11.10 0.50 8.10 0.36 Drainage well 4.80 2.710 6.20 0.05 The concentrator is not performed when the removal of arsenic, the arsenic content in the tailings and increases with increasing depth, and in the Far East's multiple metal joint Tailings field, the content of arsenic decreased with increasing depth . The arsenic content of the water discharged from the drainage well is the lowest. This indicates that the tailings slurry after arsenic removal by the sulfide - sulfate method is gradually deoxidized by itself after being stored under natural conditions, and the pH value is stabilized at about 6.0 . Under these conditions, the pulp is not harmful to the surrounding environment. This is because the concentration of arsenic in the water phase is not  Exceeding the maximum allowable concentration does not cause arsenic to be washed out of the solid phase. The arsenic- free pulp can also be automatically deoxidized under natural conditions. But this will lead to the opposite result, because arsenic can be washed away from the slurry violently. This proves that it is reasonable, feasible and necessary to use sulphide - sulfate method to remove arsenic from arsenic-containing tailings slurry. The slag removal method was used to test the slurry of the concentrator under laboratory conditions. After the pulp is processed, it is clarified for one month and the arsenic content does not exceed 0.05 mg / L. Therefore, the arsenic removal of the tailings slurry by the sulfide - sulfate method can reduce the arsenic content in the sewage to the highest allowable concentration and obtain a stable waste that can be stored for two years. In the production practice of sorting tungsten ore, the purification of tailings slurry and the utilization of circulating water are first realized. The various process indicators have not been reduced. When sorting sulphide ores, tailings slurry due to the presence of a solid phase native sulfides, such as pyrrhotite, etc., it can reduce the consumption of a single iron sulfide. Because pyrrhotite can dephosphorize the solution. As a result, the consumption of sodium sulfide required to obtain iron monosulfide is reduced by 75% compared to the initial consumption of the concentrator . This did not reduce the effect of arsenic removal (see Table 3 ). Under the conditions of the re-introduction purification system , the arsenic content in the purified circulating water and tailings slurry did not exceed the maximum allowable concentration. If the purification system is destroyed and the consumption of ferrous sulfate is reduced, the pH of the purified tailings slurry is still alkaline and no purification will occur. Due to lower consumption of sodium sulfide, it is expected to obtain about 70,000 rubles for money. When the tungsten oxide ore deposits and native tungsten ore beneficiation process industrial testing, with the sulfide - - USSR National Institute of Science on a non-ferrous metals were tested for arsenic removal tail kraft pulp. It should be noted that the tailings slurry can be treated with the sulfide - sulfate method under different conditions for the use of different processes in these ores (flotation - re-election process for the separation of oxidized ores and flotation process for the selection of sulfide ores). The arsenic content in the liquid phase was reduced to 0.05 mg / l. Under natural conditions, even if the pulp save a half years, the concentration will not be increased. Tailings slurry was added to the combined scheelite concentrate, obtained when the hydrochloric acid solution is selected from the selection of other characteristics of a process flow of such ores -. This will result in a sharp increase in the calcium content of the slurry aqueous phase. In order to avoid the complexity of the purification process by avoiding the calcium which is harmful to the flotation of scheelite, it is recommended to neutralize the hydrochloric acid solution with soda before mixing with the tailings slurry. According to the test results, the following methods of arsenic removal were adopted: The hydrochloric acid solution was treated with a 10% soda solution (used in an amount of 7.2 to 7.5 kg / ton of ore) prior to mixing with all spent tailings . The combined tailings slurry is treated with a mixture of iron monosulfide and ferrous sulfate. When preparing the mixture, the consumption of sodium sulfide and iron sulfate is 0.7 to 0.8 kg / ton and 24 to 26 kg / ton ore, respectively. The water cycle after purification by the sulfide - sulfate method, the comparison of the fresh water and the cycle selection index shows that the use of circulating water does not reduce the quality of the concentrate and the WO 3 recovery rate of the concentrate . Based on the results of industrial tests for ore sorting, followed by sulfide - sulphate purification of tailings pulp and the use of recycled water processes, the design department is recommended to design. From the comparison of drug consumption, in many cases, the consumption of these agents is very large, and effective measures are needed to reduce their consumption. If the sulfide - sulfate method is used, the circulating water will be contaminated by SO 2 - 4 and Na + ions, which will greatly enhance the mineralization of the circulating water. In order to prevent river water from being contaminated by these ingredients that exceed health standards, it is necessary to dilute the waste water with river water. As more drug consumption at the time of purification, so make this - to promote the use of the method is limited. In order to reduce drug consumption and mineralization of circulating water, should take some supplementary measures. 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