简介：InBaotourareearthtailingsore,thegradeofrareearthisclosetothatoftheraworenearly.Therareearthsarediscardedintailingsdamcausedbyaseriouswasteofresources.Firstofall,thedecompositionproductsofbastnaesite-andmonazite-mixedrareearthtailingsinCaOinreducingatmospherewerestudiedbymeansofX-raydiffraction(XRD).TheresultsshowthatthenormalproductsareCeO_2,Ce_2O_3,Ca_5F(PO_4)_3,andCe_(0.75)Nd_(0.25)O_(1.875),andtherearenoREPO_4andREFCO_3.Secondly,theroastedproductwasextractedinHCl,andtherelationshipamongroastingtime,roastingtemperature,CaOaddition,andextractiontemperaturewasstudiedbythequadraticregression-orthogonalanalysis.Throughanalysis,theoptimumprocessconditionsofmixedrareearthtailingsextractedareobtainedasfollows:roastingtimeof60min,roastingtemperatureof800℃,CaOadditionof30%,extractiontemperatureof80℃,andextractionratioof99.18%.

简介：为提高硼的去除率，研究了电磁感应精炼过程中硼杂质在CaO-SiO2-BaO-CaF2四元渣和熔硅之间的分配系数LB，讨论了四元渣系中CaO/SiO2质量比、BaO和CaF2含量、熔炼时间对LB的影响规律。结果表明：随着CaO.SiO2渣中BaO和CaF2含量的增大，LB值增大。当CaO/SiO2质量比为1.1:1、BaO和CaF2含量分别为15%和20%时，CaO.SiO2.BaO.CaF2四元渣去除熔硅中硼杂质效果最好，LB达到最大值6.94，并且LB随着熔炼时间的延长而增大。经过两次造渣后，熔硅中硼含量由3.5×10.5降到3.7×10.6，硼的去除率达到89.4%。

简介：基于炉渣结构分子和离子共存理论,建立1273-1733K下的PbO-CaO-SiO2-FeO-Fe2O3渣系氧化铅活度热力学模型,计算PbO活度并绘制等活度曲线,考察炉渣碱度Q、氧化铁比率R和温度T对活度NPbO和活度系数γPbO的影响。结果表明,活度系数γPbO的模型计算值与文献测定值吻合程度高,说明该模型能较好地反映该渣系结构本质;NPbO呈拉乌尔正偏差,且随渣中PbO含量的升高而增大,但受温度的影响不明显;γPbO随Q的升高而增大;对于Q〉0.3的碱性渣,γPbO随R的升高而出现极大值。该研究结果可用于现代炼铅工艺的热力学研究和操作优化。