Fe-Ni-Cr Crude Alloy Production from Direct Smelting of Chromite and Laterite Ores

Abstract

Ferrochromium and ferronickel which are obtained from the reduction of chromite and laterite ores , respectively, are the important alloying materials in the production of stainless steel. The present study is possibly the first of its kind related to production of crude stainless steel melt by direct smelting of chromium and nickel ore without use of ferrochromium and ferronickel alloys. The feasibility of producing Fe-Ni-Cr crude alloy by direct smelting of chromite and laterite ores from local sources with activated carbon as reducing agent at 1400 o to 1550 o C using graphite crucible under argon atmosphere were conducted in a vertical tube furnace. It was found that the grade and composition of chromite and laterite ores are the main factors to produce the alloy. The smelting of 10-13% SCO chromite ore and 87-90% LIM laterite ore produced alloys with average iron, nickel and chromium content about 82%, 6.22% and 2.17%, respectively, at an average iron, nickel and chromium recovery of 98%, 97% and 87%, respectively. The high recovery of iron and nickel in the alloy indicates a high reducing condition in the smelting experiment. It is also shown that the solubility of Ni in the slag increases with Ni concentration in the alloy and the FeO concentration in the slag.

Effect of Spark Plasma Sintering (SPS) at Temperatures of 900 and 950oc for 5 Minutes on Microstructural Formation of Fe-25Ni-17Cr Austenitic Stainless Steel

“…Therefore, this steel is used for high temperature components of jet engines, power plants and nuclear reactors. In general, the stainless steel has been widely developed as wrought and casting products [5]- [7]. Wrought products are found in the form of sheets, bars, pipes and profiles that need an additional process such as forming, joining, machining, finishing to become the final product.…”

Optimal Combination of Calcination and Reduction Conditions as well as Na₂SO₄ Additive for Carbothermic Reduction of Limonite Ore

“…[16][17][18][19][20] Many studies on the thermal analysis of laterite nickel ore report that the free water is removed at temperatures between 333 K and 383 K, dehydration occurs at 553 K, the serpentine phase transforms into enstatite and olivine at 898 K, and the recrystallization reaction happens at 1093 K. 21) Zevgolis et al 22) pointed out that a higher speci c surface area is helpful to the carbothermic reduction of laterite nickel ore, and the limonite-type laterite nickel ore has a lower reduction rate. As indicated by previous study, 23) the mineral phase of limonite-type laterite nickel ore could be simpli ed by calcining at 1173 K. Therefore, after being calcined in advance, the following carbothermic reduction process (at a reaction temperature of 1373 K) could enhance the nickel grade of the laterite nickel ore, accompanied by a lower recovery rate.…”