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The Nickel Smelting Technology (NST – nickel fusion technology) process improves on various shortcomings commonly found in conventional plants, through the selection of modern technology and equipment proven to work on a grand scale in other industries.
Its design aims to confine the dust produced, thus assuring excellent environmental standards. The process is largely inspired by the cement industry, which introduced in recent years the recycling and re-utilisation of hot gases in an effort to save energy.
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From 1996 to 2000, the effectiveness of the NST process in treating laterite nickel ores has been extensively tested, at the laboratory scale and through pilot trials. Conclusive demonstrations were carried out in existing commercial plants in 2001 with an ore sample from Koniambo. Independent revisions validated the viability of the proposed metallurgical processing technique.
The fundamental process used in the production of ferronickel from nickel ore laterites is a proven technology and is used internationally. Its elementary stages consist in eliminating the sterile or feable-content rock contained in the extracted material, the crushing, the drying, the calcination and the pereduction of the remaining portion through means of a combustible fossile. Fusion in an electric furnace completes the reduction and separates the scoria in fusion from the unrefined ferronickel which is then refined and soaked to obtain the final product.
Metallurgical Plant
Provided with two electrodes, a CC electric smelter of 80MW and 15m in diameter smelts the calcinate partially reduced at 1600°C. The remaining nickel oxyde in the furnace is reduced to metal through carbon, and a sufficient amount of iron is produced to create ferronickel with a 35% content.
The gas effluents of the furnace are burnt, cooled and diluted with air, then pushed through the aid of a ventilator towards a combustion chamber in the calcinatory flash. The scoria in fusion is continuously extracted from the furnace and transported in 75tonne pots, towards the scoria stock area. The unrefined ferronickel is poured into 65tonne pockets, situated in the refining area.
During the refining process, the ferronickel is de-sulphurated in a 8.5MW pocket furnace. Reactors are mixed with the unrefined ferronickel in fusion, to eliminate the sulphur. The refined ferronickel is soaked in water, to produce a final solid product called ‘shot’.
With a size varying from 3 to 50mm, the shot is packed into containers that are sent off to the world markets.
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Mine and geology 
