Because nickel ore and concentrate have the characteristics of low grade, complex composition, associated gangue and refractory materials, the production method of nickel is complicated. Depending on the type of ore, grade and user requirements, a variety of different forms of products can be produced, usually pure nickel: electro-nickel, nickel, nickel ingot, nickel powder; non-pure nickel: sintered nickel oxide and nickel- iron Wait. For nearly 30 years, it has been made from pure nickel because it is more economical. At present, the consumption of non-pure nickel in foreign countries accounts for more than 30% of the total consumption.
The production method of nickel is shown in Figure 1. Our process flow of gold-company and Fukang smelter (Kalatongke processing copper-nickel mine blast furnace output metalized high nickel matte) Production of nickel in Figure 2.
[next]
Because high nickel contains nickel and sulfur, it also contains a considerable amount of copper, and is enriched with mad metals and precious metals and cobalt in the raw materials. The separation and refining of high nickel bismuth copper and nickel is in the nickel smelting process. Prominent problems are also the key to the production of sulfide ore for many years. In the early stages of the development of nickel metallurgy, four methods are generally used to treat high nickel niobium, namely, layered melting method, beneficiation grinding separation method, selective leaching method, and low pressure base method. Since the 1970s, the advantages of high nickel bismuth at home and abroad, that is, nickel separation methods, have been gradually expanded.
The basic theoretical basis of the layered smelting method is that the high nickel bismuth and sodium sulphide are mixed and melted. In the molten state, the copper sulphide is easily dissolved in the Na 2 S, and the nickel sulphide is not easily dissolved in the Na 2 S. The density of copper sulfide and nickel sulfide is 5300-5800 kg/m 3 , while the density of Na 2 S is only 1900 kg/m 3 . When high nickel bismuth and Na 2 S are mixed and melted, most of the copper sulphide enters the Na 2 S phase, and because of its low density, it floats on the top layer, and the nickel sulphide remains on the bottom layer because of its density. When the temperature drops to the solidification temperature, the two separate more completely, and the top layer and the bottom layer after solidification are easily separated. In order to better separate the copper sulfide and the nickel sulfide, the top layer and the bottom layer are separately layered and smelted, and the layered copper sulfide and nickel sulfide are re-obtained until the process requirements are met. Due to the complicated process, poor working conditions and high production cost, it has been basically eliminated except for the fact that some factories are still in use after innovation. [next]
The use of beneficiation and separation of copper and nickel - soluble anode electrolysis traditional process, namely: blowing into high nickel bismuth - converter slag electric furnace depletion - high nickel honing float separation - anode smelting - electrolysis. The disadvantage of this process is that the production efficiency is low, the sulfur content discharged into the atmosphere is high, the power consumption is large, and the loss of valuable metals is large.
Wet selective leaching is roughly divided into five types due to different copper and nickel extraction methods.
(1) Sulfuric acid selective leaching electrowinning method. This process is used in the Finha Jalvarta refinery and the Russenburg plant in South Africa. But the process is not exactly the same. For example, the high nickel niobium content of the Hijavarta refinery in Finland is (%): Ni75, Cu15, S7, Co0.7, Fe0.5, Ni/Cu=5. Originally used two-stage atmospheric leaching due to low nickel leaching rate. It has been changed to three-stage atmospheric pressure leaching. The high nickel bismuth component treated by the Lutenberg plant is (%): about 50 for Ni, about 28 for Cu, and about 22 for S. Two-stage pressure leaching is used to extract copper and electrowinning nickel. The process of combining the leaching separation with the partial liquid phase is relatively simple: the disadvantage is that the electric energy consumption is large, and the selective leaching effect is poor when the Ni/Cu ratio is low.
(2) Sulfuric acid selective leaching hydrogen reduction. This process differs from the previous process in that nickel electrowinning is replaced by pressurized hydrogen reduction. The representative factory is the US nickel port refinery that was put into production in 1974. The process is high nickel bismuth melting--water quenching-fine grinding, and then nickel powder is obtained by a pressurized hydrogen reduction method after a normal pressure leaching and two-stage pressure leaching liquid are purified. The process used at the Impala plant in South Africa is similar to that of the Nickel Refinery, with the exception of a three-stage pressurized leaching. Compared with the previous process, the process is relatively simple, but the energy consumption is relatively high; although the price of nickel powder is relatively high, the flexibility in marketing is not as good as that of electrolytic nickel.
(3) Pressurized ammonia leaching - hydrogen reduction method. Representative plants include the Canadian company's Clivec refinery and the Australian Kevinara nickel refinery. The Kwinnappa Nickel Refinery was originally designed to treat nickel sulphide concentrates and was later converted to high nickel bismuth at the Kalgoorli smelter after 1974. The method has the advantages of being leached in an alkaline medium at a lower temperature and pressure, and the structure and corrosion resistance of the device are relatively easy to solve. The disadvantage is that a large amount of ammonia is consumed, and most of the sulfur is finally oxidized to sulfate; and it is also unsuitable for raw materials having a high copper content.
(4) Hydrochloric acid leaching method. Representative factory in Canada Falconbridge pilot plant Kristiansund fine coal refinery in Norway. The method is that the finely ground high nickel lanthanum is leached with a concentrated hydrochloric acid solution at a normal pressure of about 70 ° C for 12 hours, and the leaching rate is 98.7%. The selective leaching effect of this method is very good, and the energy consumption of nickel is relatively low; however, the equipment corrosion is relatively serious and has not been basically adopted.
(5) Chlorine gas leaching method. In addition to the above-mentioned hydrochloric acid leaching method, the Kristiansund plant in Norway began testing the new chlorine selective leaching process after 1975. After several improvements, it built an annual output of (4-5.5)×10 4 t cathode in 1981. Nickel refinery. The essence of the method is that the nickel is selectively leached by chlorine gas at 110 ° C, the leaching solution is decopied by copper, the iron is neutralized by decarburization with nickel carbonate, and the nickel and cobalt are extracted by a solvent to obtain a cathode nickel and a cathode cobalt, respectively. The chlorine gas generated on the anode is returned to the leaching. Almost all of the copper and sulfur in the high nickel bismuth remain in the leaching slag in the form of CuS. The process is characterized in that the Ni 2+ in the leaching liquid is as high as 230 g/L, the total amount of the solution is small, and the chlorine gas precipitated from the anode is returned for use; compared with other processes, the process is simplified. At present, the Japanese Sumitomo Niihama Refinery, which uses the chlorine leaching method in the world.
The carbonyl process is a gasification metallurgy method and is represented by the medium pressure method adopted by the International Nickel Company's Tongya Refinery. The composition of the high nickel bismuth is (%): Ni62, Cu14, S2.0, Fe2, Co1, which is blown with oxygen to a S of 0.2% - 4% in a rotary converter, and carbonylated at 180 ° C, 7.2 MPa pressure. It produces high-purity nickel powder and Ni--Fe powder, and copper and precious metals are enriched in the residue. This method is more efficient than the Montessori method, but unlike Montenegro, the raw material does not contain sulfur and copper. Although the high pressure method is more efficient than the medium pressure method, the process is required to be carried out at 200 ° C and 18-20 MPa. The medium pressure method requires stricter nickel to copper ratio and sulfur content than the high pressure method. Russia's Norilsk North Nickel Company uses a high pressure carbonyl process, and Canada International Nickel Corporation's UK Cladac Refinery uses a low pressure carbonyl process.
From the above-mentioned development of high nickel niobium separation and refining process, the general trend is that separation and refining are closely combined to gradually simplify the process. However, the specific process conditions adopted by each plant are different, which is related to the different raw material composition and product form requirements of each plant. On the other hand, the process of separation and refining of high nickel bismuth remains to be further researched and developed.
Stainless Steel Woven Wire,Stainless Steel Mesh Screen,Stainless Woven Mesh,Stainless Woven Wire Mesh
Balanat Import&Export Co.,Ltd. , https://www.balanatwiremesh.com