| China is rich in tungsten resounces of the world, and the basic reserves of scheelite, accounting for 70.4 percent of the whole country. However,81.1 percent of the ore grade is lower than 0.4 percent. Due to the complex component, low grade, associated with other metals, and hard utilization, the bulk of tungsten is difficult to be recycled. With fewer resources of high-grade ore in our country, people pay more attention to the efficient exploitation and utilization of the low-grade scheelite.Adopting the flotation technology at normal temperature, the economic and technical indicators of Yunnan Malipo Bazi 2000t/d scheelite flotation plant are not ideal since the operation. The average of ore grade is around 0.3%, concentrate grade is lower than 40% and the theoretical recovery rate is less than 55%. Besides, the hard-controlled operation in the flowline and the serious phenomenon of full tank make the economic and technical indicators unstable.This thesis tries to find the potential to further improve the concentrate grade on the basis of studying on the process mineralogy of ore. By investigating the flowsheet of plant, We analyze and find the possible reasons of the troubles, which are effect on the production of the plant. On the basis of the plant at present, we make some experiments, such as the gringding fineness compared with ball mill and rod mill,a new method of adding inhibitors,the comparison study of kinds of collectors and combined collector and other tests for optimization of process, the grade of tungsten concentrate has some improved, but the exiting problems are not thoroughly solved. In order to get the high-grade concentrate tungsten and solve the problem of the separation between scheelite and gangue minerals, we conduct the technological study on Thickened heating concentration; conclusions are as follows; the amount of sodium silicate,the temperature of heating concentration and stirring time, which have important influence on the index; we do some ondition tests about modulus values of sodium silicate, and choose the best modulus values of sodium silicate as inhibitors; the experimental results tell us that after heating and stirring, the rough concentrate shoud be directly dilution and flotation without removing reagents, which is helpful to improve the recovery of eating concentration; throuth these tests, the concentrate grate and recovery of cleaning zone get significantly increased. The whole process is divided into two sections, as the rough zone and the cleaning zone, because of this, the cycling midst product is reduced, because of this the problem of full groove is solved very well, and provide guarantee for the stable production of plant.At last, the technological process of pre-desulfurization-rougher flotation at normal then heating concentration is recommended by the laboratory. The raw tungsten ore containing WO30.263%. The closed-circuit test of the whole rocess reached the technical indicators, including 62.37% of the WO3 in concentrate scheelite and 74.93% in the recovery rate, and we study on the effect mechanism of the reagent by means of dynamic potential on the surface of single mineral. It also received a similar index in industry based on the technology recommended by the lab. In contrast with the original process, it not only had the stability of economic indicators, but also the grade of concentrate tungsten increased by 25.2% and the recycling rate increased by 17.78%. Besides, the monthly profits can be increased by 2.84 million, all of which got the good economic benefit. |
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