Jinchuan Gaobing Nickel Grinding Factory

The plant designed in 1964 by the Beijing Nonferrous Metallurgy Design Research Institute. In 1981, the design scale was expanded: one high ice nickel was 180t/d, and the second high ice nickel was 30t/d.
There are two beneficiation processes for copper- nickel separation, namely direct separation of copper and nickel from raw ore and separation of copper and nickel from high-ice nickel. Selection depends primarily on two methods ore characteristics, the ratio of copper and nickel, metallurgical requirements on product quality, as well as copper and nickel separation process to PGE and other factors. The original ore is directly separated from copper and nickel, which can simplify the smelting process, save energy and recover higher, but it is difficult to achieve the desired separation effect for complex refractory ores, such as serpentine type ore; The copper-nickel separation technology is not limited by the nature of the ore and has strong adaptability. Further, a copper-nickel matte nickel separation, because after melting, a platinum group element enriched in nickel-iron alloy, alloy retrievable magnetic separation. The nickel-iron alloy is subjected to secondary vulcanization to obtain secondary high-ice nickel, and secondary copper-nickel separation and enrichment of platinum group elements are performed. This method is adopted by Jinchuan Gaobing Nickel Grinding and Floating Factory.
(1) Ore properties: High-ice nickel is a product in the smelting process. It is quite artificial copper and nickel-sulfur mineral, and its physical and chemical properties are similar to those of natural nickel minerals. The material composition and metallographic structure of high-ice nickel directly affect the separation of copper and nickel, and slow cooling is the key to determine the structure of high-ice nickel metallography. The basic phase composition of high ice nickel is nickel sulfide (Ni ₃ S ₂ ), copper sulfide (Cu ₂ S) and alloys, of which sulfide accounts for more than 90%. High ice nickel contains precious metals such as platinum, palladium , gold, silver, etc., and most of them are concentrated in the alloy. The distribution of cobalt in high-ice nickel is mainly related to iron. The high iron is high in cobalt, and the low in iron is low in cobalt. Silver sulfide and copper sulfide are isomorphous, so silver is mainly concentrated in copper sulfide.
The yield of nickel sulfide and copper sulfide in high ice nickel depends on the copper to nickel ratio. The yield of nickel-iron alloy depends on the sulfur content of high-ice nickel. The yield is not high, but the yield is low. The copper-nickel ratio of the alloy is about 1:4. The main chemical composition of high-ice nickel is shown in the following table.

High ice nickel is hard and brittle, easy to break, and has a density of 5.5t/m ³ . In the molten state, after slow cooling, the crystal grains become large; at a temperature of 530 ° C, the nickel sulfide starts to crystallize, and the solid solution copper sulfide is precipitated, which creates favorable conditions for copper-nickel separation. Therefore, it is especially important to control the slow cooling process between 700 ° C and 400 ° C, especially 570 ° C to 520 ° C. If the cooling is too fast, the crystal grain size of each phase becomes fine, which is not conducive to the separation of copper and nickel. In addition, high ice nickel has a high iron content, which makes the composition of high ice nickel similar to that of copper, nickel pyrite and pyrrhotite, and the three floats are similar, and the separation is difficult. The increase in iron content causes the phases to precipitate in a fine-grain state, which is also unfavorable for separation. However, the production practice of Jinchuan proves that iron content of less than 5% has no significant effect on the separation.
(2) Process: The separation of copper and nickel from high-ice nickel is separated in a strongly alkaline medium (pH=12.5) depending on the floating speed of nickel sulfide and copper sulfide. The nickel-iron alloy in high-ice nickel is magnetic and can be separated by magnetic separation. Nickel-iron alloy is rich in ductility, and has a high density. It accumulates in the grinding circuit and concentrates magnetic separation at the time of production to obtain a nickel-iron alloy with high platinum group elements. The process flow of the high ice nickel grinding plant is shown in the figure below. [next]

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In order to extract precious metals more efficiently, the alloy products with magnetic properties in the high-ice nickel separation are smelted and vulcanized in the alloy vulcanization furnace to obtain secondary high-ice nickel, and then the secondary alloy products are obtained by slow cooling-grinding, floating and magnetic. The precious metal enriched in the secondary alloy is 5 to 8 times that of the primary alloy. The properties of the secondary high-ice nickel are basically similar to those of a high-ice nickel, and the process flow is also the same.
The process index, unit consumption index and main equipment of Gaobing Nickel Grinding and Floating Factory are shown in the following table.