Study on Chlorination Leaching Process in Rich Platinum Nickel Bronze Liquid

Norwegian nickel refinery, improved after treatment for platinum-rich South Africa Nickel matte (converter and nickel matte) process and product are as follows.

1. Concentrated hydrochloric acid leaches nickel.

After the nickel ice copper is ground, it is leached in a rubber lining stirred leaching tank. The nickel into solution in the form of nickel chloride, copper sulfide and precious metals remain in the leaching residue. After the nickel chloride solution is purified by extraction to remove impurities, it is made into crystalline nickel chloride, and converted into granular nickel oxide in a boiling reactor, and then reduced by hydrogen in a rotary kiln to produce a commercial nickel having a purity of 98%.

Second, in addition to nickel leaching slag decopper.

The slag after leaching nickel mainly contains copper sulfide. It is chlorinated in a nickel chloride or hydrochloric acid solution, and sulfur and precious metals are left in the leaching residue. The leaching removal copper is also a rubber-lined agitated leaching tank. The leaching tank is equipped with two sets of independent platinum-saturated calomel electrodes, and the measured data is sent to an electronic computer for processing. One set of electrodes is used to measure the redox potential of the leaching process to control the supply of chlorine gas; the other set is used to signal the alarm when the pre-adjusted redox potential range is too high or too low, and can be read at any time. Or lower than the value of the preset potential to ensure operation within the selected range of redox potential. The use of such a device is mainly to ensure that the supplied chlorine gas is not excessive, so as to prevent the dissolution of the precious metal due to an increase in the oxidation-reduction potential, or the incomplete dissolution of the copper due to the low potential. After the copper is terminated, it is subjected to pressure filtration through a propylene glycol plate and frame filter press to produce a sulfur-containing precious metal concentrate. Hydrogen sulfide is introduced into the filtered copper chloride solution to form copper sulfide precipitated by copper, and is sent to a copper system for treatment.

Third, in addition to copper concentrate desulfurization.

The filter cake of the pressure filter is successively supplied into the glass-lined stirring tank indirectly heated by the jacket through a feeding tank equipped with a weighing sensor, and the hot chlorobenzene is added to dissolve the sulfur, and the slurry after dissolving the sulfur is centrifuged by stainless steel. The pump is continuously pumped to a steam jacket heated sealed filter press to filter out the precious metal concentrate. After the filtrate precipitates sulfur crystals, the sulfur is dehydrated by a centrifuge to recover sulfur. The tetrachloroethylene solution is returned to the next desulfurization by regeneration.

Fourth, the enrichment of precious metal concentrates.

The desulfurized concentrate is subjected to sulphation roasting in a small calciner. Roasting is to place the concentrate in a steel pan in the furnace and adjust the air into the furnace to control the firing rate. In order to prevent the air from entering the furnace too fast and causing the loss of the roasted dust particles, the firing rate should not be too fast. The furnace temperature is controlled at about 500 °C. The calcined sand is leached by dilute sulfuric acid to remove heavy metal sulfate, filtered, washed, dried, mixed and discharged in a "V" type rotary mixer (capacity 1000 kg), weighed and automatically sampled for testing. The final precious metal concentrate grade produced in practice depends to a large extent on the precious metal content and insoluble components of the nickel matte material. Among the insoluble components, the content of silicon is the most affected. Under normal circumstances, when processing nickel beryllium copper raw materials containing 0.07% to 0.08% of lead , the produced precious metal concentrate contains 15% to 30% of platinum and a considerable amount of other precious metals.

Since the production process is continuous, it is difficult to accurately determine the weight and grade of a batch of raw materials and concentrates. Tables 1 and 2 list the analytical data obtained from the laboratory batch processing of platinum-rich nickel matte, which does not include losses in transportation and soot during the production process. It can be seen from the table that in this process, various precious metals are concentrated more than 330 times in the concentrate, and the recovery rates are all greater than 92%. The final concentrate yield is less than 1%.

Table 1 Grades of nickel ice copper and concentrate and precious metal enrichment rate

Table 2 Metal balance of raw materials and products

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