ABSTRACT

Chromia-bearing raw materials in nickel and copper matte smelting are difficult to process due to their tendency of forming solid chromite spinel precipitates, leading to formation of mushy slag and buildups in the smelting vessel. The solubility of chromia in smelting slags, and especially in mattes, are not known accurately and new data for iron-silicate slags in equilibrium with low-iron nickel mattes have been measured at 1350–1450°C. Typical copper-bearing nickel mattes with Ni:Cu≈2 (w/w) in the DON (Direct Outotec Nickel) process with 2 to 10 wt% [Fe]_matte have been equilibrated in carefully controlled S₂-O₂-SO₂-Ar gas atmosphere experiments with the corresponding silica saturated iron-silicate slags. The phase assays post quenching were measured by electron probe X-ray microanalysis, including the molten slag and matte as well as the solid phase of chromite spinel. Laser ablation ICP mass spectrometry was used to measure the trace elements in the matte. An additional variable in the slag composition was magnesia concentration, varying from zero to 10 wt% (MgO)_slag. The solubility of chromium in the slag at 1400°C was ≈0.7 wt% (Cr) and in the nickel matte 30–100 ppm [Cr], depending on the iron concentration of the sulfide matte. The impact of MgO on the chromium concentration in slag was small and within the experimental error of the measurements.

摘要

镍和铜锍冶炼中的含铬原料难以加工，因为它们倾向于形成固体铬铁矿尖晶石沉淀物，导致在冶炼容器中形成糊状渣和堆积物。氧化铬在熔炼渣中的溶解度，特别是在锍中的溶解度尚不清楚，新的硅酸铁渣与低铁镍锍平衡的数据已在 1350-1450°C 测量。_{在 DON（直接奥图泰镍）工艺中含 2 至 10 wt% [Fe]锍}的典型含铜镍锍 Ni:Cu≈2 (w/w)已在严格控制的 S ₂ -O ₂ -SO _2中平衡- 用相应的二氧化硅饱和的硅酸铁渣进行氩气气氛实验。淬火后的相分析通过电子探针 X 射线微量分析来测量，包括熔渣和冰铜以及铬铁矿尖晶石的固相。激光烧蚀ICP质谱法用于测量磨砂中的微量元素。渣成分中的另一个变量是氧化镁浓度，从 0 到 10 wt% (MgO)_渣。铬在 1400°C 时在炉渣中的溶解度约为 0.7 wt% (Cr)，在镍锍中的溶解度为 30–100 ppm [Cr]，这取决于硫化锍的铁浓度。MgO 对渣中铬浓度的影响很小，并且在测量的实验误差范围内。