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为了研究腐泥土型红土镍矿在焙烧过程中物相转变及固结机制问题,通过微型烧结试验和三角锥法软熔特性试验,对原矿和焙烧后的团块进行了化学成分、X射线衍射(XRD)和软熔特性分析,并通过添加熔剂CaO改变团块碱度,结合冶金相图进行了分析。研究结果表明,自然碱度的红土镍矿经高温焙烧后主要由尖晶石(MgFe_2O_4)、镁橄榄石((Mg,Fe)_2SiO_4)和顽火辉石(MgSiO_3)构成。随着碱度从0.5上升到2.0,顽火辉石相继转变为低熔点的透辉石(CaMgSi_2O_6)和高熔点的镁黄长石(Ca_2MgSi_2O_7)以及镁蔷薇辉石(Ca_3MgSi_2O_8)。红土镍矿的软熔温度也随碱度的提高先降低后升高,在碱度为1.0时达到最低点。结合冶金相图分析得知,通过改变碱度可以显著增加红土镍矿烧结过程液相量,红土镍矿烧结理想的黏结相为透辉石。
In order to study the phase transformation and solidification mechanism of saprolite-type lateritic nickel ore during roasting process, the chemical composition, X-ray diffraction (XRD) and reflow characteristics were analyzed. The basicity of the briquette was changed by adding flux CaO, and the metallurgical phase diagram was analyzed. The results show that the calcined lateritic nickel ore mainly consists of spinel (MgFe_2O_4), forsterite ((Mg, Fe) _2SiO_4) and enstatite (MgSiO_3) after calcination at high temperature. With the increase of alkalinity from 0.5 to 2.0, enstatite successively transformed into low melting point diopside (CaMgSi 2 O 6), high melting point magnesian feldspar (Ca 2 MgSi 2 O 7), and magnesium stevensite (Ca 3 MgSi 2 O 8). Laterite nickel ore reflow temperature also increases with the increase of alkalinity decreased first and then increased at the alkalinity of 1.0 to reach the lowest point. According to metallurgical phase diagram analysis, we can know that the liquid phase of the laterite nickel ore can be significantly increased by changing the basicity, and the ideal binder phase of laterite nickel ore is diopside.