Research On The Properties Of Slag With Low Lime In Nickel Laterite Smelting Process With Electric Furnace

The world’s land-based nickel resources aresulfide nickel ore and nickel laterite ore.With high-grade sulfide nickel ore resource depletion, the use of nickel laterite becomesincreasingly widespread attention.Industrial smelting laterite nickel ore on account ofhigh SiO2content, itadd a certain amount of lime to achieve good fluidity anddesulfurization capacity of slag, which causes the increased amount of slag duringmelting, reducing the effective volume of the furnace, and ultimately reducing theutilization factor furnace.The amount of slag in smelting process can be reduced and theutilization factor furnacecan be improvedwithno lime or low lime, but it may causes anincrease in slag viscosity and increase the melting temperature; Ifin this case, the use ofpartially reduced mannerincreasing the FeO content of the slag to reduce the viscosityand improve the desulfurization efficiency purposes, is theoretically feasible.This workstudiedon nickel laterite smelting process with low lime, by testing slag viscosity,studyingslag structure through infrared and Raman analysis, researchingdistribution ofelements between slag and iron, and exploring refractory corrosion.Get the followingmain conclusions.The MgO-SiO2-FeO-Al2O3-CaO slag viscosity was studied about different slagbasicity and different FeO content. With increasing basicity of the slag, its viscositydecreases at the same temperature, and a sharp change of viscosity called "turningpoint" turns up in the vicinity of1500℃. MgO/SiO2molar ratio (basicity) increasingfrom0.6to1.0decreases the viscosity of15.01P to3.98P at1550℃.The viscosity of theslag decreases with FeO content increasing, and when the temperature above1490℃and FeO content of15%,20%and25%the viscosity of the slag is in the range of1.8~4.5P with small change.Application of infrared spectroscopy and Raman spectroscopy found that with theFeO content or slag basicity increasing, complex three-dimensional space framestructure ofQ3relative content reduces significantly, and the moreQ3decrease the greaterthe viscosity reduction, along with Q1increasing significantly andQ0changing irregular.The cyclic structure of Q2tends toincrease or first rise later reduce. Along with the slagviscosity decreasing, the shape of the peak from sleek peak to sharp sleek, and thesmaller slag viscosity the sharper peak. The influence ofbasicity and FeO content on Ni, S and P distribution betweenmetal and slag were exploredat1550℃. The resultsshowed thatwith improved slagbasicity thedesulfurizationand dephosphorizationabilityof slag strengthens, but Nicontent in the slag maintains at around0.01%. Basicity increasing from0.6to1.0,thecontent of S increases from0.017%up to0.069%while P from0.004%to0.012%inslag. With FeO in slag increased from5%to25%, the capability of desulfurizationsignificantly drops from0.078%to0.043%, while0.017%of P to0.023%in slag, and asubstantial increase Ni content in slag.The experiment of slag erosion was conducted on magnesia refractories, andexperimental results showed that with the increase in basicity of0.6,0.8and1.0respectively refractory erosion amount were4.84mm,3.00mm and2.58mm. FeOcontent increasing from5%to15%and25%,and refractory erosion amount were0.92mm,2.42mm and3.50mm. Chemical reaction of acidic slag andalkaline refractoryand slag flow scouring erosion arethe major factors.Back scattering scanning showedthat SiO2and FeO easy permeate into the magnesia refractories, and almost all ofAl2O3exists inthe slag. For the characteristics oflaterite smelting with low limeandcomprehensive evaluation of the slaggy properties,draw conclusionsthat lateritesmelting with low lime technology route is feasible, and there is a good prospect fortreatment of high silicon highmagnesium type nickel laterite.