CN-117187565-B - Method for recovering valuable metal by vacuum carbothermal reduction of tin ash

Abstract

The invention relates to a method for recovering valuable metals by vacuum carbothermal reduction of tin ash, belonging to the technical field of nonferrous metal pyrometallurgy. Mixing tin ash with carbon powder according to a metal amount and carbon ratio of 2-4:1, carrying out vacuum carbothermal reduction-directional condensation at 900-1200 ℃ under the pressure of 1-20 Pa for 1-3 hours, finally obtaining crude tin I in an evaporation zone, condensing lead-zinc mixed vapor entering gas phase through a lead liquid catcher to obtain crude lead I, condensing the crude lead I through a zinc liquid catcher to obtain refined zinc, carrying out vacuum evaporation I on the obtained crude tin I to obtain refined tin and crude lead II, carrying out vacuum evaporation II on the obtained crude lead I and the obtained crude lead II to obtain crude tin II and refined lead, and returning the crude tin II to the vacuum evaporation I process. The method has the advantages of simple process, convenient operation, simple required equipment, low cost, high universality of raw materials, good operation environment and safe and controllable process.

Inventors

• LI YIFU
• ZHANG HUAN
• YANG BIN
• CHEN XIUMIN
• LIU DACHUN
• XU BAOQIANG
• TIAN YANG
• JIANG WENLONG

Assignees

• 昆明理工大学

Dates

Publication Date

20260512

Application Date

20230825

Claims (2)

1. 1. The method for recovering valuable metals by vacuum carbothermal reduction of tin ash is characterized by comprising the following steps of: Step1, vacuum carbothermic reduction-directional condensation: Mixing tin ash with carbon powder in a mass ratio of 2-4:1 according to the total mass of tin and zinc, carrying out vacuum carbothermic reduction-directional condensation under the conditions of the temperature of 900-1200 ℃ and the pressure of 1-20 Pa for 1-3 hours, and finally obtaining crude tin I in an evaporation zone, condensing lead-zinc mixed vapor entering a gas phase through a lead liquid catcher at the temperature of 500-700 ℃ to obtain crude lead I, and condensing the crude lead I through a zinc liquid catcher at the temperature of below 200 ℃ to obtain refined zinc; Step 2, volatilizing the crude tin I obtained in the step 1 in vacuum to obtain refined tin and crude lead II; Step3, carrying out vacuum volatilization II on the crude lead I obtained in the step 1 and the crude lead II obtained in the step 2 to obtain crude tin II and refined lead, and returning the crude tin II to the vacuum volatilization I process; The vacuum volatilization I condition in the step 2 is that the temperature is 800-1100 ℃, the pressure is 1-100 Pa, and the time is 1-2 h; The vacuum volatilization II condition in the step 3 is that the temperature is 700-900 ℃, the pressure is 1-100 Pa, and the time is 1-2 h.
2. 2. The method for recycling valuable metals by vacuum carbothermal reduction of tin ash according to claim 1, wherein the tin ash in the step 1 comprises 20-30% of Sn, 50-60% of Pb, 5-15% of Zn, 0.01-0.1% of Sb, 0.001% of Bi and 0.001% of Cu.

Description

Method for recovering valuable metal by vacuum carbothermal reduction of tin ash Technical Field The invention relates to a method for recovering valuable metals by vacuum carbothermal reduction of tin ash, belonging to the technical field of nonferrous metal pyrometallurgy. Background The sources of tin ash are wide, and the tin ash comprises waste residues (tin oxide) generated by tin smelting, smoke dust generated by soldering tin (wave soldering) in the electronic industry, tin-containing friction waste scraps generated by steel plants or friction material plants or automobile repair plants, waste cosolvent generated during ceramic manufacture, waste tin foil and the like. The existing treatment process of tin ash is carbothermal reduction, the comprehensive recovery rate of metal is only about 50%, and the treatment process has the problems of large smoke and dust amount, low comprehensive recovery rate of metal, low added value of products and the like. In the patent with publication number CN 102618727A, a method for extracting tin alloy from tin ash is disclosed, and the oxidation, dehydration, decarboxylation and decomposition reactions of organic matters in the tin ash are utilized to reduce the metal oxide of the tin alloy in the tin ash and remove the impurities such as carbide in the tin ash, thereby extracting the tin alloy and realizing the regeneration and the recycling of the tin alloy. The treatment process of the method generates a large amount of waste liquid, and the treatment process takes a long time. The patent with publication number CN 1962163A discloses a method for reducing and purifying tin wires by using waste tin ash, which comprises the steps of impurity removal, neutralization, smelting reduction, separation and purification, compression molding, drawing, winding and packaging and the like by using a temperature gradient to repeatedly condense and liquate. The method has long processing flow, complex steps and difficult operation. Disclosure of Invention The invention provides a method for recovering valuable metals by vacuum carbothermal reduction of tin ash, aiming at the problems and the defects of the prior art. The method has the advantages of simple process, convenient operation, simple required equipment, low cost, high universality of raw materials, good operation environment and safe and controllable process. The invention is realized by the following technical scheme. A method for recovering valuable metals by vacuum carbothermal reduction of tin ash comprises the following steps: Step1, vacuum carbothermic reduction-directional condensation: Mixing tin ash with carbon powder according to a metal amount and carbon ratio of 2-4:1, carrying out vacuum carbothermal reduction-directional condensation under the conditions of 900-1200 ℃ and 1-20 Pa for 1-3 hours, and finally obtaining crude tin I in an evaporation zone, condensing lead-zinc mixed vapor entering a gas phase through a lead liquid catcher at 500-700 ℃ to obtain crude lead I, and condensing the crude lead I through a zinc liquid catcher at a temperature below 200 ℃ to obtain refined zinc; Step 2, volatilizing the crude tin I obtained in the step 1 in vacuum to obtain refined tin and crude lead II; And 3, carrying out vacuum volatilization II on the crude lead I obtained in the step 1 and the crude lead II obtained in the step 2 to obtain crude tin II and refined lead, and returning the crude tin II to the vacuum volatilization I process. In the step 1, the mass percentage of tin ash is 20-30% of Sn, 50-60% of Pb, 5-15% of Zn, 0.01-0.1% of Sb, 0.001% of Bi and 0.001% of Cu. The vacuum volatilization I condition in the step 2 is that the temperature is 800-1100 ℃, the pressure is 1-100 Pa, and the time is 1-2 h. The vacuum volatilization II condition in the step 3 is that the temperature is 700-900 ℃, the pressure is 1-100 Pa, and the time is 1-2 h. The invention can prepare three products of refined tin, refined lead and refined zinc, wherein the content of tin in the refined tin is more than 99.9 percent by mass, the content of lead in the refined lead is more than 99.99 percent by mass, and the content of zinc in the refined zinc is more than 99.9 percent by mass. The recovery rates of tin, lead and zinc in the tin ash are respectively up to 99.0-99.5%, 98.2-99.0% and 99.1-99.6%. The devices or traps described above without specific mention of the structure are all existing devices and trapping devices known in the art. The beneficial effects of the invention are as follows: the method realizes the comprehensive recovery of metal resources in the tin ash, and respectively obtains three products of refined tin, refined lead and refined zinc. Compared with the traditional treatment process, the method has the advantages of no generation of three wastes, safe and reliable whole process, convenient operation, simple required equipment, low cost, high metal recovery efficiency and environment-friendly operation.