Views: 0 Author: Site Editor Publish Time: 2022-09-19 Origin: Site
In recent years, the strong demand for stainless steel has stimulated the demand for nickel metal, which has led to the continuous high price of nickel. Driven by the high nickel price, domestic and foreign manufacturers have launched ferronickel projects, making ferronickel take an increasing proportion in the global nickel output. The production of ferronickel in China began in 2005. The nickel metal content in ferronickel products was only 2000 tons, reaching 30000 tons in 2006 and 130000 tons in 2007, which attracted great attention from people in the nickel industry all over the world.
RKEF process is a pyrometallurgical process widely used in laterite nickel smelting plants at present. Its processes include drying, roasting pre reduction, electric furnace smelting, refining, etc.
① Dry. Rotary drying kiln is adopted to mainly remove some free water and crystal water from ores.
② Roasting - prereduction. Preheat the ore and selectively reduce some nickel and iron.
③ Electric furnace smelting. Reducing metal nickel and part of iron, separating slag and nickel iron to produce crude nickel iron.
④ Refining. Generally, ladle refining is used to remove impurities in crude ferronickel, such as sulfur and phosphorus.
(2) Rotary kiln direct reduction method
This method is the only one in the world that uses rotary kiln to directly reduce and smelt nickel oxide. It is mainly divided into the following processes: ① material pretreatment: grinding, mixing and pelletizing; ② Smelting process: rotary kiln roasting, metal oxide reduction and reduction metal aggregation; ③ Separation treatment: the clinker produced by the rotary kiln is separated into nickel iron alloy by gravity separation and magnetic separation.
(3) Blast furnace smelting process
At the end of 2005, nickel laterite ore was smelted by blast furnace. At present, 300m3 blast furnace has been applied to the production of ferronickel alloy, and ferronickel containing about 5% nickel can be obtained. This kind of ferronickel can meet different types of steel with a little refining. The process is mainly divided into the following processes.
① Crush and screen the raw ore, in which the raw ore block with particle size of 10-60mm is the raw material for blast furnace smelting, and the ore powder with particle size of less than 10mm is mixed with coke powder, quicklime and limestone for sintering to obtain sintered ore block.
② Crush and screen the sinter block. The sinter block with particle size of 10~50mm is used as the raw material for blast furnace smelting, and the ore powder with particle size less than 10mm is re sintered.
③ Ferronickel is obtained by mixing sintered ore block, raw ore block, coke, limestone, quicklime, dolomite and fluorite in blast furnace smelting.
Due to the high price of nickel and the prosperity of the nickel market in the past two years, many domestic plants that use small blast furnaces to smelt nickel bearing pig iron with laterite ore with low nickel content have become the main ferronickel production process in China, while other smelting methods are less used in China due to large investment, complex technology and other reasons.
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