| In recent years, China's import of nickel oxide ore has been increasing year by year with the rapid development of China's stainless steel industry, the growing shortage of national nickel sulfide ore, as well as the lack of China's nickel oxide ore reserves. China's nickel ore treatment process has always been targeted on nickel sulfide ore, and the pyrometallurgical treatment of nickel oxide ore is not mature yet. At the same time, the differences in chemical component and mineral composition of oxidized nickel ore have also led to the different treatment processes. Therefore, the current domestic enterprises mainly produce ferronickel with nickel oxide ore by electric furnace smelting or blast furnace smelting. Pellets as an ideal metallurgical furnace charge are widely used in blast furnace and electric furnace smelting as far as the metallurgical properties are concerned.In this paper, one kind of imported nickel oxide ore (Nil.55%, TFe36.31%, MgO 9.30%, SiO215.87%) as raw material was used to produce pellets. The experimental study mainly included the balling property of nickel oxide ore, the influence of bentonite ratio on the pellet qualities, as well as the influence of basicity (R=(MgO+ CaO)/SiO2) on the physical and chemical properties of pellets. The optimum technological parameters and basicity on pellet production with nickel oxide ore were determined by the theoretical analysis and experimental research. The conclusions can be made as follows:(1) Green pellets can be successfully made by nickel oxide ore with the relative coarse granularity (-180mesh55.8%,-200mesh34.6%,-300mesh11.6%) and the property indexes are good:impact strength is more than 20 times/0.5m, compressive strength is close to 14N per pellet, shock temperature of single crude pellet exceeds 450℃.(2) Oxidized nickel ore is of good hydrophilicity, with maximum molecular water content and capillary water content of 22.53% and 54.02% respectively. Thus, the optimal balling moisture of nickel oxide ore reaches 23～24% and the suitable balling time is 30min.(3) The influence of bentonite ratio to green ball properties is not so obvious. The single fired compressive strength also rises from 645.9N to 1256.9N when the bentonite rate is improved from 0% to 2%. But the compressive strength of nickel oxide ore pellets is still low. When the basicity increases, the fired pellet strength can be improved to 1200N because of the low-melting binding phase produced in the roasting stage. Therefore, the production of oxidized nickel ore pellets can be carried out without bentonite.(4) The increase of pellet basicity by adding lime to nickel oxide ore has the little effect on the green ball qualities, but both the fired pellet compression strength and metallurgical properties get remarkable improvement. When the basicity of nickel oxide ore is improved from 0.60(the initial basicity) to 1.10, the maximum palletizing temperature of crude pellets decreases from 1300℃to 1250℃, and the high-temperature roasting time reduces from 60min to 30min. The single fired compressive strength also rises from 645.9N to 1256.9N. At the same time, the reduction degradation index (RDI+ 3.15) increases from 96.44% to 99.57%. The reduction swelling index (RSI) reduces from 5.38% to 4.14% and the reduction index (RI) improves from 90.3% to 94.1%. But the start softening temperature falls from 1177℃to 1126℃and the softening temperature interval decreases from 44℃to 31℃. Thus, the proper basicity of Nickel oxide ore pellet is 1.10 in this experiment.
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