Study On The Mineral Processing And Purification Of Low Grade Alkalifeldspar Ore

The feldspar is an important raw material for ceramics and glass manufacturing industry. With the top grade development of glass-ceramic products, the more high-purity ? low iron feldspar raw material is in demand. Although in our country feldspar resource is abundant, they must be got rid of the iron because of the high containing iron. At present, there are a lot of problems in our country feldspar ore processes, such as inefficient grinding efficiency, backwards of beneficiation technology, the old manufacture equipments and so on. Due to these weaknesses, feldspar ore processes in China is not taking form of large-scale and industrialization.Aiming at above problem, in this paper, the raw ore characters and property of a low-grade alkaline feldspar in Yichun of Jiangxi Province was studied. And efficient wet continuous grinding was adopted to instead stony weel-grind machine or intermittent pebble grinding. The ore grinding fineness test had been studied by using different grinding medium such as ceramic balls, steel bars and steel balls. According to harmful minerals such as iron and titanium mainly concentrated in fine-grained ore, ore grinding fineness should be controlled at -74μm 55%～60%. Based on the results of the testing, the laboratory experiments, semi-industrial experiments and industrial experiments had been done and the results obtained were satisfying.A reasonable beneficiation process flow of laboratory experiments about this alkaline feldspar ore is determined as "selective grinding-flotation-desliming-magnetic separation". It was effective to remove iron and color impurities from the ore after selective grinding, flotation of pyrite using butyl xanthate, desliming and high-gradient magnetic separation. From the experiments, a high-grade feldspar concentrate was obtained containing 0.17 percent Fe₂O₃ and 0.058 percent TiO₂ with the yield of 72.70 percent. This final feldspar concentrate is suitable for the ceramic industry.Based on the laboratory experiment results, the beneficiation process flow of "selective grinding-classification-pyrite flotation-magnetic separation-mica flotation" was adopted in the semi-industrial experiments. A high-grade feldspar concentrate was obtained containing 0.17 percent Fe₂O₃ and 0.06 percent TiO₂with the yield of 67.85 percent by using a closed-circuit process composed of selective grinding and classification operations, flotation of pyrite using butyl xanthate, high-gradient magnetic separation and flotation of mica using dodecylamine(DDA). The results of the experiments showed that beneficiation process flow of laboratory experiments had a fine adaptability and stability under large-scale and continuous production condition.Based on the laboratory experiment and semi-industrial experiment results, industrial experiments were carried out finally. From the experiments, final feldspar concentrate was containing 0.10 percent Fe₂O₃ 0.03 percent TiO₂ and 13.54 percent K₂O+Na₂O with the yield of 67.85 percent. Its product index corresponds to the super grade to Chinese factory's standard and export grade standard. At present, such technique had already been in practical production application.A new process purification technique of low-grade alkaline feldspar ore had been gained through this paper and researches concerned, which had changed the quality of feldspar from low-grade product to high-grade one in Yichun of Jiangxi Province and expanded the source of shortage high-grade feldspar as raw material in our country.