| Iron ore is the basic raw material in iron and steel industry. In order to meet the needs of the steel industry, scholars have researched a series of measures to improve the grade of iron ore concentrate, such as new type high-efficiency magnetic separation equipment, reverse flotation reagents and related combined process. Among them, the research on gravity concentration technology especially cyclone is seldom involved, and some regimes of reagent is complex in flotation technology. It is unfavourable to reduce the processing cost. Therefore, with the purpose of increasing iron content and reducing silicon content, this paper researches the selection of magnetite rough concentrate in two ways:gravity concentration using cyclone and reverse flotation collectors.A Φ50mm cyclone was designed and processed, and the separate experimental system was constructed to study the technological parameters (overflow diameter, immersion depth of overflow pipe, cone structure, feeding pressure and pulp density) which influence the separation effect of water-only cyclone.It shows that:change cone structure under the same parameters, the cyclone with single cone of90°has the best concentrate index. For single cones, separation effect is best in middle size of overflow pipe depth, overflow pipe diameter, and spigot diameter. For mulriple cones, TFe grade increases with increasing of overflow pipe diameter, overflow pipe depth, and decreasing of spigot diameter, but recovery is reducing relatively. In low feed pressure (0.04MPa) and pulp density (23%), iron concentrate grade reaches more than69%.The processing of cyclone increases but grade decreases with increasing feed pressure and pulp density. The research has got the69.03%of TFe grade and3.49%of SiO2content in optimum technological parameters. The high-grade magnetite separation experiment results indicate that:Cyclone can be used in the gravity-flotation complex process as select equipment, thus obtaining the high-purity iron concentrate. According to the TFe grade and SiO2content of each size fraction,we know for-0.038mm fine fraction, gravity concentration using cyclone have no significant effect in increasing iron content and reducing silicon content.In flotation test, this paper researches the flotation property of3collectors (oil-soluble AC1201/DDA and DDA·HCL) in reverse flotation, and discusses the mechanism between reagent and mineral. When the dosage of10%AC1201is250g/t, a concentrate with a TFe grade of69.82%,the SiO2content of1.89%and the recovery of91.27%are obtained in the situation of pH=7. The index of TFe grade reached69.1%,recovery is95.38%, while the SiO2content is reduced to3.34%with100g/t of20%DDA in the pH=9. A concentrate with a top TFe grade of70.32%, the SiO2content of1.07%are obtained under the80 g/t dosage of the DDA-HCL, but the recovery of85.09%is the lowest. Through the separation result, it shows that:DDA of oil-soluble has mediocre collecting property while DDA-HCL is better. Relatively, AC1201of oil-soluble as a perfect collector has the two advantages mentioned above, and fits separation in neutral environment. After add caustic starch as inhibitor in the flotation system, the concentrate grade and separation effect becomes worse. Mechanism analysis shows that the combined collectors absorb on the quartz surface, and change the Zata potentials of quartz remarkably, and it is the most obvious in around pH=7.1t is physical adsorption because there is no new product on the surface of the quartz after reagent treatment.In addition to the above experiments, this paper develops a mathematical model of magnetic material content and TFe grade. It provides a kind of effective method for judging concentrate quality quickly and guiding production. |
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