SU765384A1 - Charge for smelting vanadium ferroalloy - Google Patents

Description

Nicotinic acid in the following ratio of components, weight,%:

Vanadium-containing material 30-40

Silicon-containing reducing agent 8-15 Carbon-containing reducing agent 2-G 11lam nicotinic acid production 10-25 Calcium-containing flux Else. It is also envisaged that the slurry of nicotinic acid production has a chemical composition, weight,%: manganese dioxide 50-65, caustic potash 0.71, 2, lead 0.01-0.1, moisture - the rest.

The mixture consisting, for example, of a vanadium-containing material (products of combustion of liquid fuel — sludge and ash of thermal power plants, containing,%: 5-50 V Oj 13-40 FeO, 2-25 CaO, 2-20 510.2-20 StierA-) . silicon-containing reductant (ferrosilicon containing 65-90% silicon, ferrosilicoaluminium containing 65% silicon, 10-12% aluminum), carbon-containing reductant (coke, charcoal, graphitization waste) and calcium-containing flux (calcined lime, a mixture of lime and fluorspar) and sludge production of nicotinic acid, containing,%: 50-65 MnOj, 0.7-1.2 potassium hydroxide, 0.01-0.1 Pb, up to 40 moisture, as well as impurities of silicon, iron, magnesium, calcium and aluminum oxides loaded into an electric arc furnace and smelted. In the process of melting the mixture, potassium hydroxide and manganese oxides form a liquid-mobile slag melt, vanadium-containing raw materials dissolve in KOTOj oM and reduction processes take place. Silicon and carbon restore lead, vanadium and iron from sludge. Caustic potassium forms with the oxides the potassium salts, which remain in the slag and, like a surfactant impurity, reduce the surface tension of the slag.

The vanadium alloy formed during the reduction process contains silicon, manganese, carbon and lead. Manganese, silicon, and carbon form strong compounds with vanadium, such as VS i, VMHj, VC, which reduce the solvent of lead in the alloy. Due to the high activity of lead in the alloy, it, as a capillary-active impurity, is concentrated in the surface layer of metal droplets, reducing the surface tension of the metal droplets.

A high lead concentration in the surface layer contributes to an increase in the wetting angle of the slag with metal (value greater than 90 °). This at low surface tensions of slag and slag provides

relatively high values of interfacial tension and low values of phase adhesion, which facilitates the rapid fusion of droplets, their strengthening and deposition from the donkey.

After the end of smelting and holding, the melt is released into the ladle. In the process of releasing the metal from the furnace into the ladle, the jet of metal in the slag is crushed. However, due to the high coalescing capacity of the alloy, the aggregation of droplets and their rapid release from the slag occurs. This reduces the content of metal droplets that remain after the end of the reduction.

After the melt is released from the furnace, the metal is poured into cast-iron molds. The slag that fell on the metal ingots during cooling due to the large difference in the expansion coefficients of the metal and the slag and the very poor wettability of the metal by the slag, cracks and separates from the ingot, which ensures complete separation of the slag from the metal ingot. Due to the low solubility of lead, its content in the alloy does not exceed 0.005%. When more lead is contained in the charge materials, it forms a thin deposit on the metal surface, which, when slag is separated, separates with it, since lead wets the slag well.

The amount of the reducing agent and its ratio in the charge are conditioned by ensuring the reduction of vanadium, iron, manganese, and lead oxides to obtain a vanadium alloy, which has a low solubility of lead.

When the amount of calcium-containing flux in the charge is less than 15% of its weight, the degree of reduction of vanadium decreases and acidic slags are obtained, which have a higher viscosity, which leads to an increase in losses with the slag of both unreduced vanadium and metal droplets, which during smelting do not have time to settle . If the amount of calcium-containing flux in the charge is more than 50%, then the slag multiplicity increases, and with it the loss of vanadium.

When slime production is introduced into the mixture, production of nicotinic acid in an amount of less than 10% by weight of the charge introduced with manganese is not enough to completely bind vanadium in the ferroalloy to the intermetallic compounds, thus increasing the solubility in the lead alloy due to the formation of VPb compounds. This causes a decrease in the surface activity of lead and an increase in the surface tension of the ferroalloy, which, ultimately, leads to an increase in metal losses from the waste slag and poor separation from the metal, i.e. the number of non-metallic inclusions in the alloy increases. The amount of sludge introduced into the mixture of nicotinic acid production more than 25% by weight of the charge reduces the content of the leading element in the vanadium alloy. In addition, this leads to an increase in the cost of the alloy, since it leads to the need to remelt the ballast additive. In a 1.1 MVD electric arc furnace, a campaign was conducted for the smelting of ferrosilicate from a mixture containing vanadium-containing material, a silicon-containing reducing agent, a carbon-containing reducing agent, a calcium-containing flux, and a slurry of nicotinic acid production. Sludge from CHP plants containing,%: 18 Vj Oi, 35 FeO, 4, are used as vanguine-containing material. Hardness - slag-forming impurities FS 75 with a silicon content of 78.2% is used as a silicon-containing reductant (coke-containing material is coke). with a content of 85% C solid) as a calcium-containing flux - a mixture consisting of 90% burnt lime (95.6% CaO) and 10% fluorspar. Used for the smelting of ferroalloy of nicotinic acid production,%: 64.8 MnOj, 1.1 potassium hydroxide, 34 moisture, 0.01 Pb, the rest is applied to silicon, iron, magnesium, calcium, aluminum oxides. Of these charge materials with different component ratios, three vanadium alloy melts are carried out. For comparison, the smelting is carried out on the charge from the same components, but without the introduction of nicotinic acid production sludge into the mixture. After the melts are finished, the melt is released from the furnace and the ladle, then the slag is drained, and the metal is poured into cast-iron molds. In the course of slag discharge, samples with a mass of 5 kg are taken, in which, after crushing and magnetization studies, the content of metal inclusions is determined under a microscope. Samples are also taken from metal ingots in which the number of nonmetallic inclusions is determined by studying thin sections cut along the height of the ingot under a microscope. The composition of the mixture, the obtained metal and the results of the analyzes are presented in the table. As can be seen from the table, when using the proposed charge for smelting vanadium ferroalloy, the content of metal inclusions in waste slag is reduced by 4.7-8 times, compared to the usual mixture, and the content in metal of nonmetallic inclusions is 18-22 times. The obtained vanadium ferroalloy according to the content of the main components and impurities meets the technical conditions for ferrosiliconadium of brands ZhVdK and ZhVdKM. The expected economic effect from the introduction of the proposed charge is 20 thousand rubles. in year.

OopMi a of the invention 1. A mixture for melting a vanadium ferroalloy consisting of a vanadium-containing material, silicon and carbon-containing reducing agents and a calcium-containing flux, in order to reduce the loss of metallic inclusions from the slag and improve the separation of the slag from the metal in solid form additionally contains ischam production of nicotinic acid in the following ratio of components, wt.%:

Vanadium containing

30-40

material 5 Silicon-containing 8-15

reducing agent

Carboniferous

2-5

reducing agent

Slime production 0 nicotine acidic 10-25 you

Calcium-containing

Rest.

flux

2. The mixture for smelting vanadium ferroalloy according to claim 1, characterized by the fact that the sludge from the production of nicotinic acid has the following chemical composition (wt.%): Manganium dioxide 50-65 Caustic potassium 0.7-1.2 Lead 0.01-0 1 Moisture Else Sources of information. taken into account during the examination 1. Ryss MA Ferroalloy production. Metallurgists, 1975, s, 288-289

Claims (1)

Claim 1. The mixture for smelting vanadium ferroalloy, consisting of vanadium-containing material, silicon and carbon-containing reducing agents and calcium-containing flux, characterized in that, in order to reduce the loss of metallic inclusions with slag and improve the separation of slag from metal in solid form, it additionally contains a slurry of nicotinic acid production in the following ratio of components, wt.%: material 30-40 Silicon-containing reducing agent 8-15 Carbon containing reducing agent 2-5 Sludge production nicotinic acid you 10-25 Calcium-containing flux Rest. 2. The mixture for smelting vanadium ferroalloy pop. 1, I am distinguished by the fact that the slurry of nicotinic acid production has the following chemical composition (wt.%): Manganese Dioxide 50-65 Caustic potassium 0.7-1.2 Lead 0.01-0.1 Moisture Else.