ラテライトNi抽出残滓を用いたDR用ペレットの強度および被還元性

抄録

Pelletizing and reduction tests for direct reduction process using laterite nickel leached residue were carried out. Green pellet showed sufficient compressive strength and drop resistance for handling without addition of bentonite. The compressive strength of fired pellet was greatly increased when a small amount of limestone was added and the maximum strength was achieved at the CaO/SiO₂ratio of 0.2. Pellet with a compressive strength of 240kg/pellet and a porosity of 30% was obtained by means of a pot-grate furnace at a firing temperature of1220°C. When reduction tests were carried out by using noncoking coal as reductant, the highest degree of reduction of 85.8% was achieved at a reduction temperature of 1100°C.
It is clarified that the melting point of gangue minerals such as forsterite and silicate are lowered by addition of CaO, and at the same time MgO component moves into iron oxide to compose a solid solution of magnesioferrite and magnetite (MgO-Fe₂O₃-FeOTe₂O₃).