Progress in Non-ferrous Metal Vacuum Metallurgy

The Zhonghao Cat. No.: TF843iTF13:A system of two components (1,2) has activity coefficients and vapor pressures therein, respectively. X is both related to the concentration of components/components and temperature, and the saturation vapor pressure/V of pure component materials is determined by the fact that element 1 is enriched in the gas phase at temperature>1 and the fraction of 1.2 gas-liquid phase equilibrium is shown. Using the gas-liquid equilibrium composition map, the degree of separation of the alloy components during vacuum distillation and the composition of the product can be quantitatively estimated. For the AB binary system, the mass fraction of the gas phase components is represented by 'and the foot', and the mass fraction of the liquid phase components is expressed by the '' and the foot''. 1954 In 1956, he studied in the Graduate School of Metallurgy at the Central South School of Mining and Metallurgy (now Central South University). Now he is Professor at Kunming University of Science and Technology and director of the Institute of Vacuum Metallurgy Materials. Long-term study of non-ferrous metal vacuum metallurgy teaching, research and engineering. Developed the theory of vacuum distillation of metals, formed a theory system of heavy-duty gold vacuum metallurgy, and developed the new technology of rough lead fire refining. It simplifies the refining process. Invented a multi-stage continuous distillation vacuum furnace with internal heating, in the cloud, Laibin, etc. More than 30 factories have been applied and the economic efficiency has been outstanding. The development of horizontal vacuum furnaces and related process technologies has been successful. The large-scale non-ferrous gold vacuum metallurgy workshop in China has been built in the Bunduan Smelter. He has won many awards at the national, provincial, and ministerial levels. The "coarse lead fire refining process" has won the second prize of the State Science and Technology Progress Award in 1989. "Hard zinc vacuum evaporation and enrichment of gallium indium silver" won 2003 National Technology Invention Award second prize. Published more than 1 papers and 4 monographs. He applied for 10 patents and was elected to the Chinese Academy of Engineering in 1999. The development of vacuum technology and the popularity of vacuum equipment have become the basis for vacuum metallurgy. After the 1970s, some vacuum processes occurred in non-ferrous metals metallurgy, such as the vacuum distillation technology of Pb-Sn alloys in tin refineries and the appearance of equipment. In the 1990s, horizontal vacuum furnaces were used to treat hot-dip galvanizing slag. Hard zinc followed by lead-silver separation in vacuum, vacuum refining lithium, crude selenium distillation, crude cadmium distillation ... ... widely used in production. This article briefly reviews some of the advances made in non-ferrous metal vacuum metallurgy in the past three decades. It briefly explains its role and should pay attention to several aspects of development.

1 The basic principles of vacuum metallurgy 1.1 Determination of the possibility of separation of alloys After thermodynamic analysis, the authors propose to use separation factor to judge the possibility of separation of alloy or crude metal components by distillation. For the vapor density of the split, the mass fraction of component 4 in the gas phase material is a value at a certain temperature and a series of //4, and a graph can be made. The gas-liquid composition diagram can guide the selection of technical conditions and raw material composition for vacuum distillation of alloys and crude metals to achieve the desired product.

1.3 The distillation of metals and alloys in the volatile atmosphere in vacuum has two difficulties: one is to operate at the temperature of the boiling point of the material, which usually requires a high temperature; and second, atmospheric oxygen is at the distillation temperature. Under the oxidation of the metal. Therefore, there are only a few low boiling metals such as Zn, Cd, and Hg in traditional metallurgy. In the vacuum, the oxidation does not substantially exist, and the evaporation temperature of the metal also decreases accordingly, so that evaporation and distillation of the metal can be achieved. For example, the boiling point of lead is 174 (TC, evaporation of lead in a vacuum, l (TC around A 86X102Pa, in the vacuum of 10Pa, lead can be quickly volatile. Vacuum to promote metal evaporation, but not vacuum The higher the better, the research shows that many metals

Complex process. We have developed an internally heated multi-stage continuous distillation vacuum furnace for solder processing as shown. The process consumes only about 500 kWh/ton of material, the operating cost is only 15% 20% of the material electrolysis method, it has no pollution to the environment, and it has less floor space and occupants. The metal recovery rate is high (>99%). The vacuum furnace is now used in tin refineries throughout the country. Such a vacuum furnace can also be used for the separation of tin from lead, tin-bismuth alloy separation, lead-silver separation, and germanium-silver separation processes.

2 Vacuum Distillation Separation of Crude Metals and Alloys 2.1 Vacuum Distillation Separation of Pb-Sn Alloys For the Pb-Sn system, the :1 gas-liquid phase equilibrium composition is shown. Pb and Sn are well separated by vacuum distillation. Vacuum distillation of Pb-Sn alloy is only a physical process. Lead vaporizes, tin leaves, and lead vapor cools down to lead metal, which directly produces metallic tin and metallic lead. Do not use chemical reagents, do not generate compounds, and remove compounds. 1. Observe the hole 2. Feed tube 3. Pedestal 4 Electrode 5. Lead tube 6. Vacuum 7 Outlet tube 8. Set lead disk 9. Evaporation disk 10 Heating element 11.Schematicofcontinuousmulti-stage 2.2.Schematicofcontinuousmulti-stage 2.2Steam-iron alloy (hot-dip galvanizing slag, hard zinc) Vacuum distillation and extraction of high purity zinc u Zn-Fe system gas - The liquid equilibrium diagram () shows that it is entirely possible to extract zinc by vacuum distillation. Hot galvanized slag and hard zinc are essentially zinc-iron alloys. In order to achieve industrial vacuum distillation of hard zinc, hot galvanized slag and high purity zinc, we have developed a series of vacuum distillation equipment and its technology. One of the horizontal vacuum distillation furnaces is shown. Depending on the raw material and purpose, its structural size and material can be adjusted. Successfully developed equipment and technology were used in Shaoguan Smelter, Wuhan Iron and Steel Industry Company smelting plant, Shuikoushan Lead and Zinc Plant, Anshan, Yiwei, Guiyang and other places, with good economic returns, no pollution to the environment, and a new type for China. Equipment and technology, with export prospects.

1. Discharge port 2. Furnace housing water jacket 3. Suction tube 4. Condensation wall 5. Masonry 6. * ffl hole 7. Heater 8. Feeding tank field 5 vacuum furnace equipment schematics Hard zinc needs to be improved é”— and other elements In the slag enrichment, the hot dip galvanizing slag should be as much as possible to improve the zinc recovery rate and ensure that the production of zinc containing iron is less than 0.003%, while the preparation of high-purity zinc, the zinc iron content is less than 3ppm. The hot-dip galvanizing slag produced during the hot-dip galvanizing of steel was vacuum distilled. The industrial test obtained only 0.00004% of the zinc content of the iron, and the hard zinc produced during the processing of the slag was calculated. The calculation shows that the slag contained in the zinc vapor is only 141 when the hard zinc is distilled. Zinc is almost entirely contained in the slag. From small-scale trials to industrial trials, the output of zinc contained 10% of lanthanum in the slag, accounting for more than 97%, consistent with the above calculations. Indium and silver in hard zinc also have similar conditions and are concentrated in the slag. Hard zinc vacuum treatment was industrialized in 1997 and produced zinc. The slag was enriched with gallium, indium and silver at 10 times, and the direct recovery rate was 97%. In addition, vacuum distillation grade zinc was used, and various grades of zinc contained iron. They are all below one-thousandth.

2.3 Other coarse metal refining and alloy separation Distilling lead silver alloy in vacuum can successfully separate lead and silver, and directly obtain lead metal and silver. The application of existing industrial vacuum furnaces has already achieved this task. The properties of niobium in niobium-silver alloys are similar to that of lead. The separation of niobium and silver by vacuum distillation has reached the stage where industrial tests can be carried out (1)'(1). Obtained 5% of Ag containing 5%, including "high lead germanium"; Second, lead-antimony alloy containing up to tens of percent lead. Experiments conducted in a semi-industrial vacuum furnace developed by us show that vacuum distillation of high-lead lanthanum can yield fine borides containing PbO 2%, and coarse Pb-Sb alloys should not be treated by vacuum distillation. In addition, we have done some research on the vacuum refining of crude pans and crude zinc, manganese extraction by vacuum distillation of ferromanganese, and vacuum distillation of silver zinc shells.

3 Vacuum treatment of ores and metallurgical intermediates and reduction of metal oxides in vacuum Compounds, ores, and metallurgical intermediates can also be heated and evaporated in vacuum to separate their components, or to partially vaporize certain compounds. For example, we use a vacuum evaporation method to separate 90% crude arsenic from arsenic cobalt, and the cobalt product also satisfies post-processing requirements. Heat treatment of copper-zinc concentrates in vacuum can more completely concentrate zinc into the condensate. The distillation residue is very pure copper matte. For the vacuum distillation of tin-arsenic-lead alloy (carbon residue), crude tin containing trace amounts of arsenic, 80% of arsenic-containing 80% of arsenic, and 80% of lead 80% lead were obtained, and arsenic and tin were realized. Complete separation. The vacuum treatment of the copper slag can reduce the amount of copper discarded with the slag by one-half to two-thirds.

Some of the reduced products of metal oxides are partially or completely gaseous at the reaction temperature. Such reactions can be performed more smoothly in a vacuum, and can be classified into carbon reduction or metal thermal reduction according to the type of reducing agent. The carbon dioxide reduction of magnesia is taken as an example, because the reaction products are all gaseous, making the reaction easier in vacuum, and the reaction temperature decreases. Thermodynamic calculations show that at atmospheric pressure it is necessary to reach 18760 to reach 1 atm. If the residual pressure is 102 Pa in vacuum, the reaction can be performed at 130 °C. In addition to focusing on vacuum carbon reduction of magnesium oxide, The study of reduction of zinc oxide, lithium oxide, etc. in vacuum is also significant.

In addition, vaporizing the metal in a vacuum, controlling the condensation conditions, or performing a chemical reaction in a vacuum to prepare an ultrafine powder is also a promising milling method.

4 Conclusion The application of vacuum technology in metallurgy, the metallurgical process from the atmospheric pressure to the vacuum operation, so that the metallurgical operation of the environment and operating conditions have undergone great changes, the previous can not be carried out in the vacuum, can be achieved, such as metal Distillation, some of the things that you can do in the past, can perform better in a vacuum, such as reducing or eliminating pollution to the environment.

However, after all, vacuum metallurgy has been used for too short time, and there are still insufficient researches on depth and breadth, and the types and degree of equipment needed to be improved. Vacuum metallurgy will be increasingly developed and new vacuum metallurgical processes and equipment will emerge.

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