Comparative Study of Behavior of Lumpy, Small Lumpy, and Lean Chrome Ores During Reduction at Different Temperatures

Resumo

The chemical composition of raw material used plays a vital role in achieving the required product quality, in particular, in ferrochrome alloy production. Different types of ore are used in the South Africa ferrochrome industry, including lumpy and small lumpy chrome ores. Reduction of lumpy ore has its own features during manufacture when used alone in the furnace or mixed with small lumpy chrome ore. It is important to test lean chrome ore and investigate its behavior alone and when blended with other chrome ores. Many phases can form during reduction, governing final product composition. Therefore, it is important to understand the behavior of a specific type of ore during its reduction and its effect on phases formed on mixing with different types of chrome ores. In this research, behavior is studied during reduction of lumpy, small lumpy, and lean ores at 1300 and 1500°C. A graphite crucible is used, placed in a silica crucible. After preparing the leading sample, the mixture is placed in a tubular ceramic furnace and established at the required temperature. Products obtained at different temperatures are rapidly water quenched to avoid much oxidation. Behavior is evaluated with solid-phase reduction and with reaction of a solid reducing agent with different ore melts. The amount of phases formed at the working temperatures is evaluated. x-Ray phase analysis and scanning electron microscopy are used for identification and quantitative evaluation of phases present in the products.