The Study Of Beneficiating Process Of West Hubei High Phosphorus Oolitic Hematite

Oolitic hematite is an important kind of sedimentary iron deposits, which is a complicated and internationally-known refractory iron needs to be developed urgently. This paper comprehensively analyzes and compares the studies already conducted by other researchers, which cover different regions Oolitic hematite with different separation methods, combined with separation conditions and separation principles, analyze and make comments on concrete separation effects. In accordance to the mineralogical characteristics and grinding size characteristic of Oolitic hematite, a flowsheet of stage-grinding and stage-separation is proposed which may deal with this ore successfully. Through studying floatation characteristics of apatite and chlorite, explain the effects of pulp environment and regulators on apatite and chlorite floatation in the real floatation process of Oolitic hematite. Finally a systemic flowsheet is proposed to deal with Oolitic hematite and the effects of flotator and the effects of floatation column in the floatation of fine concentrate are compared.The mineralogy of Oolitic hematite has been studied systemically by SEM, XRD analysis etc, which reveals the crystalline structure, occurrence state, natural interlocking assemblages of different minerals. The studies show that concentric annular structure is the characteristics of Oolitic hematite ore. The interbed of hematite and chlorite is very intricate. The majority of quartzes and apatites among Oolites have large disseminated grain size, part of quartzes and apatites are large in the Oolites. Therefore a flowsheet of removing large quartz and apatite firstly in raw grinding then desilicating and enriching iron after fine grinding on the base of disseminating characteristics and mineralogical properties.Reagent condition and dosage are determined by single factor experiments for Oolitic hematite reverse floatation. The results are as follows:pulp density 20%, NaOH adjusting pH to 10, causticized starch dosage 10kg/t, conditioning for 2 minutes, adding lime 4kg/t, and then conditioning for 2 minutes, and collector sodium oleate 8kg/t. In order to disperse the pulp and improve the dephosphorization effects, sodium silicate is added with 20g/t.Pulp environment and dispersants on apatite and chlorite in the floatation process of Oolitic hematite has been studied. The results show that pH value and the dosage of sodium oleate and sodium silicate have very important effects on the floatability of apatite and chlorite. Ca2+ and Mg2+ have depression effect on the floatation of apatite and chlorite using sodium oleate as collector, but this impact can be reduced to some extent by increasing the pH value and increase the dosage of collector. Sodium silicate can be used as dispersant when dosage is appropriate but abundant sodium silicate can depress the floatation of quartz. Dephosphorization and desilication can be achieved simultaneously when sodium silicate is used appropriately and rationally in the reverse floatation of Oolitic hematite.The floatation results of run-of-mine in different grinding fineness are studied; separation index is affected primarily by fine fraction ore. Because the dissociation degree of gangue is better in the coarse fraction of floatation tailing, and the hematite content of floatation tailing is very high, Fe recovery can be increased by HIMS (high intensity magnetic separation) after separating the large gangue by screening firstly. Size analysis of concentrate shows that the products of-0.080+0.054mm size fraction have higher iron content; the products of +0.080mm size fraction should be regrinded. Fine fraction and regrinded coarse fraction are reseperated for the purpose of desilication and iron enrichment.Size analysis and XRD analysis of concentrate show that the key factor affecting the Fe grade of concentrate is that there is a kind of very fine silicate distributed in the concentrate, and this silicate is very difficult to separate from concentrate by conventional separation methods.In this paper size of the mineral is determined by laser particle analyzer, the liberation degree of quartz is analyzed by computational analysis of sizing curves before and after dissolution by acid, The results show that the minimal granularity of quartz in slime is 1.5 micron, and the minimal granularity of quartz in concentrate deslimed is 3.7 micron. The majority of quartz in fine concentrate may be liberated only when grinding fineness reaches to -0.028mm. It is very difficult to remove these fine quartzes completely.Based on intensive research, a stage grinding and stage floatation processing flowsheet is proposed finally, the concentrate Fe grade and Fe recovery reach to 57.52% and 77.34% respectively, the P content in concentrate is only 0.12%. This process realizes the aim of dephosphorization and desilication simultaneously and has great pertinency. The optimal separation index is obtained using this processing flowsheet compared with other conventional processing flowsheet. This processing flowsheet has great instructive significance on development of other Oolitic hematite.