Investigation of the effect of mechanical activation on the carbothermal reduction of chromite from Muğla region

Chromite is the only ore mineral of metallic chromium and chromium compounds and chemicals. Chromite comprises a range of the spinel group of mineral, described as (Mg,Fe+2)O.(Cr,Al,Fe+3)2O3. The most important uses of chromium are in metallurgical applications, like as stainless steel production, and in chemical applications, like as leather tanning, pigments, dyes, the printing and photography, metal plating.Ferrochromium is one of the most important alloying materials for the production of stainless and high-alloy ferritic steels. High-carbon ferrochromium is currently produced in submerged-arc furnaces. Disadvantages of this process are the limited use of chrome ore fines and friable chrome ores as well as its dependence on both expensive metallurgical coke and electrical energy. To improve cost effectiveness, solid-state carbothermal prereduction has grown in importance.Mechanical activation of minerals by intensive grinding is a non-traditional way of influencing the processes in extractive metallurgy. The resulting creation of fine particles, the increase in specific surface area and the formation of defective structures accelerate metallurgical processes. The reaction temperatures decrease and yield increase with mechanical activation.In this thesis, the carbothermal reduction of mechanically activated chromite with graphite and metallurgical coke under an argon atmosphere was investigated at temperatures between 1100 and 1400°C and the effects of the mechanical activation on chromite structure were analyzed by x-ray diffraction, scanning electron microscopy and specific surface area analysis. The activation procedure led to amorphization and structural disordering in chromite and accelerated the degree of reduction and metalization in the mixture of chromite and reductant.