Metal sulphides and separating the platinum group metal enrichment process output platinum group metal concentrate high in nickel matte copper, nickel, iron, and cobalt.
High nickel niobium is an intermediate product of smelting platinum-containing metal copper-nickel symbiotic sulfide ore, mainly containing Ni 3 S 2 , Cu 2 S, Cu-Ni-Fe alloy and platinum group metal. The content of platinum group metals varies with the origin of high nickel bismuth. For example, high nickel bismuth containing platinum group metals in China and Canada is 0.002% to 0.005%, and South Africa and the former Soviet Union are 0.05% to 0.1%. The precious metal in the high nickel bismuth needs to be enriched 1000 to 5000 times in order to obtain a concentrate containing 50% of the precious metal. Therefore, it is necessary to use a combination of fire method, wet method and electrometallurgy to obtain a desired platinum group metal concentrate from high nickel bismuth in the case of reducing or avoiding the dispersion loss of the platinum group metal. The higher the platinum group metal grade of high nickel ruthenium, the shorter the enrichment process and the higher the recovery rate of the platinum group metal. The main extraction methods are layered smelting, electrochemical dissolution, grinding and floating separation, pressure leaching, chlorine leaching and the like.
Layered melting is commonly known as the top-bottom method. The high nickel niobium block is reduced and smelted together with sodium sulfate and coke in a blast furnace or an electric furnace, and the formed Na 2 S and Cu 2 S in the high nickel niobium form a less dense isomorphous melt, and not with Na 2 . The S 3 Ni 3 S 2 has a high density and is divided into two layers due to the difference in density, and can be peeled off after cooling. The top layer of Na 2 S-Cu 2 S is mainly rich in gold, silver and selenium , and the bottom layer of Ni 3 S 2 is rich in more than 90% of the platinum group metals in the original high nickel bismuth. After the bottom layer is crushed, the platinum group metal is finally concentrated in the anode mud by oxidative roasting, reduction smelting, and crude nickel electrolytic refining treatment. The platinum group metal concentrate is then extracted from the anode mud. This method has a long production cycle and many materials. The separation of copper and nickel is not good enough and has been rarely used.
The electrochemical solution is dissolved in a high concentration of nickel ruthenium as a soluble anode in an acidic electrolyte. Copper, nickel, iron, etc. are dissolved into the electrolyte, and the gold, silver and platinum group metals are not dissolved and are enriched in the anode slime. The platinum group metal concentrate is extracted from the anode mud. This method has a long production cycle, many feeds, and a large anode mud yield. The precious metal has a large dispersion loss in the electrolyte and the sponge copper produced by the cathode, and it has been rarely used.
The high-nickel niobium melt was ground and slowly cooled in the steel mold for 72 h. During the slow cooling process, the crystal grains continued to aggregate and grow, and finally three phases of Cu 2 S, Ni 3 S 2 and Cu-Ni-Fe alloy were formed. More than 90% of the platinum group metals in the original high nickel niobium are finally enriched in the copper-nickel alloy (Cu-Ni-Fe). After the crystallized high nickel crucible is crushed and ground, the components of each phase are separated by magnetic one flotation or flotation (see high nickel honing float separation method).
The magnetically-flotation separation magnetically selected copper-nickel alloy (Cu-Ni-Fe) is treated by a copper-nickel alloy to extract a platinum group metal. The magnetic separation tailings re-flotation separates copper concentrate (Cu 2 S) and nickel concentrate (Ni 3 S 2 ). The key of this method is to achieve a certain degree of metallization of high nickel bismuth in the stage of converter blowing to obtain high nickel bismuth, that is, 10% to 15% of sulfur deficiency, to produce a sufficient amount of Cu-Ni-Fe alloy phase for enrichment. Platinum group metals. In addition, the cooling rate of the high-nickel niobium ingot must be strictly controlled so that the phases can be fully crystallized and aggregated, and fully dissociated when ground. This method is used in South Africa, Canada, and China.
Flotation separation When the high nickel niobium Cu-Ni-Fe alloy has a small amount of phase, fine particles and poor dissociation, the copper concentrate containing few platinum group metals is first floated, and the platinum group metal is concentrated. Ni 3 S 2 is mainly in nickel concentrate containing a small amount of Ni-Cu-Fe alloy. The nickel concentrate is melt cast into a nickel sulfide anode, and then nickel sulfide electrolytic refining is performed. Or the nickel concentrate is subjected to oxidative roasting, reduction smelting, and then crude nickel electrorefining. Finally, the platinum group metal concentrate is obtained by treating the platinum group metal with nickel anode mud. This method has a long cycle, many materials are returned, and the recovery rate of precious metals is low, which has been used less.
The pressure leaching is controlled by pressurizing and leaching the fine nickel ruthenium in a sulfuric acid solution. The leaching temperature of 103 to 443 K and the oxygen partial pressure of 0.3 to 0.7 MPa oxidize the sulfide of nickel and copper to soluble sulfate separation, and the platinum group metal is concentrated in the insoluble residue. The residue is then processed to produce a platinum group metal concentrate. The Impala Platinum Company of South Africa used this method to treat high nickel niobium with a precious metal grade of 0.1% and finally a concentrate containing about 45% of the platinum group metal.
Chlorine leaching Chloride gas is introduced into the hydrochloric acid solution to leach the fine high nickel ruthenium. The ruthenium metal such as copper, nickel, iron or cobalt is transferred into the solution to be separated from the noble metal. The precious metal is enriched in an insoluble residue mainly composed of elemental sulfur. The residue is separated from the elemental sulfur to extract a platinum group metal concentrate.
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