The Study Of Reasonable Slag Form Of Jinchuan's Nickelfash Smelting Process

Based on the character of Jinchuan's nickel concentrate which is high in iron and magnesium but low in sulfide, advanced property-measuring system RTW-06 was used to precisely measure the viscosity and the electrical conductivity of nickel flash smelting slag. The property and the form of slag in the nickel flash smelting process were also studied. The main content includes: as the slag composition is among MgO 9%~12%, CaO 2%~8%, Fe/SiO2 1.2-1.6, (1) The change regularity of slag viscosity with MgO content; (2) The change regularity of slag viscosity with CaO content; (3) The change regularity of slag viscosity with Fe/SiO2 ratio; (4) The change regularity of slag viscosity with FesO4 content; (5) The change regularity of slag electrical conductivity with MgO content; (6) The change regularity of slag electrical conductivity with CaO congtent; (7) The change regularity of slag electrical conductivity with Fe/SiO2 ratio; (8) The relation between slag viscosity and electrical conductivity; (9) The slag structure and component; (10)The selection of reasonable slag form.Study of viscosity of synthetic FeO-SiO2-MgO system showed that: the viscosity decreases with the increase of temprature at any slag content; the viscosity inreases obviously with the increase of MgO content as the Fe/SiO2 ratio is fixed.Study of viscosity of semi-synthetic FeO-SiOa-MgO system showed that: as the Fe/SiOi ratio is fixed, the viscosity decreaes with the increase of MgO content when MgO content is less 10%, but increases when MgO content is more than 10%.Study of the viscosity of semi-synthetic FeO-SiO2-MgO-CaO system showed that: (1) at any slag component, die viscosity decreases with the increase of temprature; (2) as the CaO content and the MgO content are fixed, the viscosity decreases with the increase of the Fe/SiO2 ratio, but the effect of the Fe/SiO2 ratio on the viscosity becomes fainter when it is more than 1.5; (3) as the Fe/SiO2 ratio and the MgO content are fixed, the viscosity decreases with the increase of CaO content, but decreases more slowly as the CaO content is more than 6%; (4) as the Fe/SiO2 ratio and the CaO content are fixed, with the increase of MgO content, the viscosity firstly decreases ,but increases when the MgO content is more than 10%; (5) the viscosity and the melting temperature increases obviously with the increase of Fe3O4 content.Study of the electrical conductivity of semi-synthetic FeO-SiOz-MgO-CaO system showed that: (1) at any slag component, the electrical conductivity increases with the increase of temprature; (2) as the CaO content and the MgO content are fixed, the electrical conductivity increases with the increase of the Fe/SiOj ratio; (3) as the Fe/SiO2 ratio and the MgO content are fixed, the electrical conductivity increases with the increase of CaO content, but decreases more slowly as the CaO content is more than 6%; (4) as the Fe/SiO2 ratio and the CaO content are fixed, with the increase of MgO content , the electrical conductivity decreases as temprature is less than 1290癈, but increases as temprature is more than 1 290 "C.The slag in Jinchuan's nickel flash smelting process is olivine slag, and its main component is (Fe-Mg)2SiO4.Allowing for the character of nickel concentrate and the effect of slag components on viscosity, electrical conductivity and melting point, it is concluded that the specific parameters of the reasonable slag form are as follows: For FeO-SiOi-MgO system:Fe/SiO2: 1.2Fe: 42% (Fe3O4<4%)SiO2: 35%MgO: 11%For FeO-SiO2-MgO-CaO system:Fe/SiO2: 1.4Fe: 41.5%(Fe3O4<4%)SiO2: 29.6%MgO: 12%CaO: 4%~6%By using those two slag forms, those problems that the recovery rate of those valuable metals is low and the slag form is not ideal can be effectively resolved, the output of nickel and copper can be raised, the production costs can be reduced greatly, and accordingly, the economic performance can be improved greatly.