The method of obtaining ferroboron, high purity for the production of magnetic alloys of type nd-fe-b
The invention relates to the field of foundry and metallurgy of non-ferrous metals and alloys, in particular a process for the production of ferroalloys. The method includes mixing of the boron-containing material with aluminum powder and secondary recovery of the reaction mixture in the mold. However, prior to mixing with the powder of aluminum boron-containing material is fired in air at a temperature of 300 to 500°C for 3 hours, and as a boron-containing material, a mixture of boric acid powder iron oxide in the ratio of 1:1. The invention improves the quality of ferroboron through the use of inexpensive boron-containing material and a powder of aluminum recovered in the enterprise, as well as to reduce energy consumption through the use of standard technological equipment not requiring additional equipment. 1 PL.
The invention relates to the field of foundry and metallurgy of non-ferrous metals and alloys, in particular a process for the production of ferroalloys.
The known method of producing metal alloys of the system Fe-B-Si-C with a high content of boron, based on the melting and Vashego Al2O3together with other materials and hot air in a vertical furnace with stacked layers of carbonaceous material .
The disadvantages of this method are, first, a high content of impurities (Al, Si, C), due to the introduction of flux, secondly, the complexity of the technological scheme.
Also known is a method of obtaining ferroboron by multistage recovery .
The disadvantages of this method are, first, the high cost of electricity, secondly, high carbon content, third, complex technological scheme.
The closest in technical essence and the achieved result to the claimed method is out-of-furnace smelting ferroboron, derived from bortovoy and iron ore with the use of iron-thermite precipitator .
Ferroboron, obtained by this method is unsuitable for the production of magnetic alloys of type Nd-Fe-B because it contains harmful impurities, such as carbon, silicon and aluminum.
The present invention solves the problem of reducing the amount of carbon, silicon and aluminum in the resulting ferroboron.
This object is achieved in that before mixing the quality boron-containing material, a mixture of boric acid powder iron oxide in the ratio of 1:1.
Ferroboron used in the production of rare earth NdFeB-type magnets should contain 10-15% and to have a minimum content of impurities such as C, Al, Si, Cr, mn and Some other manufacturers of magnets is used as a boron-containing raw materials of pure boron, which is poorly absorbed magnetic alloy and contains up to 5% of carbon. Also use the standard FeB brands FB-FB, which are usually made for alloying steels containing impurities Si (3-12%), Al (3-10%).
In this invention the firing process required for the decomposition of boric acid to boric anhydride (2ABOUT3), in accordance with the substance aluminothermic recovery. The decomposition of H3IN3is carried out through co-firing with iron oxide in the ratio (1:1) is close to stoichiometric, which helps to reduce energy costs. When the reduction in the percentage of boric acid in the mixture decreases the content of boric anhydride after firing, which reduces the percentage of boron in the ferroboron, and this increases the consumption of aluminum due to the recovery of excess iron oxides. The increase in N3IN3more than 50% is not profitable, because after firing in a mixture formed large agglomerates with the CLASS="ptx2">Firing the mixture (Fe2ABOUT3+H3IN3=1:1) is carried out at a temperature of 300 to 500°C for 3 hours. With increasing firing temperature of the mixture over 500°With part of the oxide of boron is carried away in the atmosphere with water vapor, which leads to decrease in the content of boron in the ferroboron. By reducing the firing temperature of less than 300°C is incomplete decomposition of boric acid, which also leads to decrease in the content of boron in the ferroboron. Burning less than 3 hours does not allow the boric acid is completely decomposed to boric anhydride, as a result, the boron content in the ferroboron is reduced. Increase the firing time for more than 3 hours is impractical, because the further decomposition of boric acid does not occur and leads to the consumption of electricity.
After that burned a mixture of powdered aluminum. Calculation of the amount of aluminum is carried out by the known method of determining the percentage of A1, necessary for recovery of the metal alloy oxide.
The method was carried out as follows.
Raw materials (powdered iron oxide and boric acid) are mixed in a mixer until smooth. The mixture is then loaded into a metal container and calcined at a temperature of 300 to 500°With the or and heated to 300°C. Preheating of the mixture before the reaction allows to reduce the consumption of aluminium powder and save zhidkofaznoi slag to the full withdrawal of metal and gases released during solidification of the ingot.
The mixture is then burnt out-of-furnace method with the upper fuse. Start aluminothermic reaction with the top heat of the reaction mixture does not require additional technological re-equipment, and the scheme itself is simple in design, because the powdery mixture is under a layer of melt.
After cooling the moulds to produce the knockout bars ferroboron.
Received ferroboron studied the chemical and x-ray spectral methods.
To obtain comparative data in parallel were melting by the method described in . The results of the comparative tests presented in the table.
The table below shows that as ferroboron, obtained by the proposed method is much higher than on the way .
Thus, the proposed method for ferroboron, high purity for the production of magnetic alloys of type NdFeB, allows to improve the quality of ferroboron through the use of budget b is through the use of standard processing equipment does not require additional equipment.
Sources of information
1. The Japan patent No. 3-2221, class C 22 C 33/04, 1984, publ. 1985.
2. The Japan patent No. 4-29731, class C 22 C 33/04, 1984, publ. 1984.
3. Pliner Y. L., Ignatenko, F. Recovery of oxides of the metals aluminum. - M.: metallurgy, 1967, S. 195.
4. Application for invention No. 2001105734/02 (005882), Russia, IPC 7 B 22 F 9/08, 9/06, dated 28.02.2001.
The method of obtaining ferroboron, high purity for the production of magnetic alloys of type NdFeB, comprising mixing boron-containing material with aluminum powder and secondary recovery of the reaction mixture in the mold, characterized in that, prior to mixing with the powder of aluminum boron-containing material is fired in air at a temperature of 300 to 500°C for 3 h, and as a boron-containing material, a mixture of boric acid powder iron oxide in the ratio of 1:1.
FIELD: converter process with use of oxygen lance.
SUBSTANCE: proposed method is used for converter processes such as AOD, MRP, AOD-L, MRP-L, CLU, ASM, Conars-Stainless steel, or vacuum processes such as VOD, SS-VOD, RH and RH with use of oxygen lance. Slag formed at the end of blowing and treatment in converter or vacuum plant is drained and removed in unreduced state; this slag is fed to electric furnace which is loaded with standard charge consisting of metal scrap and residual dust; then carbon is additionally fed and silicon if necessary; during melting, chromium oxide contained is slag is reduced by means of carbon and silicon.
EFFECT: low cost of process.