Method for removing lead and purifying bismuth from lead-bismuth material through vacuum distillation

Abstract

The invention relates to a method for removing lead and purifying bismuth from a lead-bismuth material through vacuum distillation. According to the method, the lead-bismuth material is put in vacuum smelting equipment, and the difference between the vapor pressures of the lead and bismuth elements is utilized to carry out distillation separation, wherein the vacuum degree in the equipment is controlled within 0.01Pa, the heating temperature is controlled within 850-950 DEG C and a certain distillation time is ensured. The whole process is a physical process which is different from the chemical process of removing lead through blowing of chlorine, so that the process does not generate smelting waste, crude lead alloy and crude bismuth alloy are produced, the direct recovery rates of the elements are high, the offering price of the crude lead alloy is high and the crude bismuth alloy is beneficial for the refining in the next step. The achieved technical economical indexes are as follows: the Pb content in the crude bismuth alloy is less than 1%, the Bi content in the crude lead alloy is less than 6.5%, the direct recovery rate of Pb is greater than 95%, the direct recovery rate of Bi is greater than 97%, both the products are alloys so that the generation of harmful smelting waste is prevented, the capacity is 9-10 tons in every 24 hours, and the energy consumption is 400-420 kilowatt hours for 1 ton of materials.

Description

technical field [0001] The invention relates to a method for vacuum distillation of lead and bismuth materials to remove lead and purify bismuth, which belongs to the field of heavy metal pyrometallurgy. Background technique [0002] Lead bismuth material is a kind of crude metal in heavy metal metallurgy. It is the main raw material for processing refined bismuth products. Its lead content is generally 2% to 20%, and the rest is mostly bismuth, containing a small amount of silver, arsenic and other impurities. [0003] At present, most of the treatment processes in the world's producing countries are chlorination refining methods. The method is to put the lead-bismuth material into the refining pot to melt, keep the temperature in the pot at 600-650°C, and use several glass tubes to pour the lead-bismuth melt. Slowly bubble in Cl 2 , so that Pb and Cl 2 The reaction produces PbCl 2 , molten PbCl 2 Floating on the surface of the melt, the ingot is scooped out by the oper...

AI Technical Summary

Problems solved by technology

This procedure has many disadvantages: PbCl 2 During the reaction, a large part of Bi and Ag also react with Cl 2 Reaction into PbCl 2 Floating, greatly reducing the direct yield of Bi and Ag; the obtained PbCl 2 The product contains Cl — Higher, not conducive to comprehensive recovery, the direct sale price is very low, which reduces the value of this part of the metal; in the production process, Cl 2 Can not fully participate in the reaction, part of Cl 2 Escaping, strong corrosion leads to serious corrosion of exhaust gas collection equipment, some Cl 2 Escape into the atmosphere and pollute the environment; Cl 2 It is a toxic gas, which has potential safety hazards and has strict requirements on the operating environment and labor protection.