Thermal Properties of High-Magnesia Oxidized Nickel Ore

The content of elements in the main mineral components of the ore, such as serpentine, talc, and chlorites, were determined. It was shown that, during heat treatment of the ore, in addition to the decomposition of hydrates and carbonates, serpentine decomposes and new phases (forsterite and enstatite) form. On the bases of analysis of the properties of the ore, patterns of phase transitions during heated in inert and reducing atmosphere were identified. It was found that the coal-thermal reduction of nickel and iron from oxides begins at temperatures above 800 °C, and from serpentines begins at temperatures above 1250 °C. It was found that, when heating the ore above 1200 °C in a mixture with a reducing agent, the metals reduce and form iron-nickel alloy. During electro-thermal smelting, the mode of which was determined by the melting points of slag (SiO2 – MgO – FeO – CaO – Al2O3 system) and ferronickel, the ratio of Ni / Fe in the metallic phase was determined by the consumption of reducing agent (coal, coke).

Simulation of the joint processing of pyrrhotite concentrate and nickeliferous oxidized ore

In this paper the issues of improving the efficiency of processing of pyrrhotite concentrates and magnesia-silicate nickeliferous ores are reviewed. An original technology is proposed, its basic stages are partial oxidative roasting of the concentrate and joint contractile melting the calcine with nickel ores to gain matte. Roasting of the pyrrhotite concentrate allows to extract 70-80% of sulfur from the concentrate into gases riched with SO2, reduce desulfurization during melting and extract nickel, copper, cobalt and precious metals from both raw materials into the matte. The implementation of fluxing potential of nickel ore completely eliminates the use of fluxes during smelting and increases the specific productivity of metallurgical units in concern of raw materials. On the laboratory scale, the modeling of the main technological operations is performed to justify the technology. The possibility of separation of slag and matte with joint reagent-free melting (1400 ºC) of the product of partial oxidative roasting and oxidized nickel ore, taken in equal quantities, is theoretically justified and experimentally confirmed. Parameters of the roasting of the pyrrhotite concentrate: temperature 800 ºС, desulfurization degree 71.7%. Pyrrhotite concentrate contained (% wt.) 1.9 Ni, 0.2 Cu, and 0.06 Co. Oxidized nickel ore contained (%wt.) 1.2 Ni, and 0.06 Co. The slag basicity module (about 1) provides relatively low content of non-ferrous metals in the slag (% wt.): 0.24 Ni, 0.08 Co, and 0.04 Cu. Matte contained (%wt.) 8.9 Ni, 0.22 Co, 0.5 Cu, 58.7 Fe, 25.0 S, and 6.6 O. Extraction level in the matte was 87.8% nickel, 48.0% cobalt, and 73.3% copper from their content in the initial mixture. High levels of matte enrichment degree with respect to the charge were achieved; their values were 5.5 for nickel, 5.7 for cobalt, and 4.5 for copper. Desulfurization degree during melting and metallization degree of matte were close to zero. The matte was suitable for processing with known routes. The results are expected to be used in the development of technologies aimed to resumption of processing of oxidized nickeliferous ores from the Ural deposits.

Development of the New Method for Oxidized Nickel Ore Processing

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