SU1054426A1 - Reaction additive for oxidizing roasting of vanadium slag - Google Patents

Abstract

1. REACTIVE ADDITION FOR. OXIDATIVE 9 BURNING OF VANADIUM SLAG, containing soda ash, characterized in that, in order to eliminate the formation of charge mixture during an increase in firing temperature, an increase in the degree of vanadium into soluble compounds and extraction of vanadium from slag, it additionally contains nepheline concentrate: , wt.%: Soda Ash 50-80 Nepheline concentrate 20-50 9 2. The reaction additive according to claim 1, wherein the nepheline concentrate has the following composition, wt.%: 40-45 Dioxide silicon 25-30 aluminum oxide 2-3 iron oxide sodium oxide cl 18-20 and potassium else “k calcium oxide 4i y od

Description

This invention relates to ferrous metallurgy, in particular, to the chemical processing of vanadium slag into technical vanadium dioxide. The limiting stage of a complex process of chemical processing is the oxidative roasting of slag in kilns in a mixture with reactive additives in order to convert vanadium into water or acid-soluble compounds. Technological calcined soda, sylvinite, lime are used as reactive additives (limestone is sodium sulfate 1 J. Applying sylvinite as a reactive additive causes the release of large amounts of chlorine, which pollutes the air pool and corrodes the apparatus. Use as reactive additives technical soda or lime does not ensure maximum transfer of vanadium into water- or acid-soluble compounds due to the formation of cakes of the charge during roasting and incomplete oxidation into aadium containing phase, the formation of various kinds of suspensions in solutions based on liquid glasses, filtering gypsum during filtration of slurries, difficulties in dosing of reactionary additives with variations in the chemical composition of vanadium slag. As a result, the formation of hardly soluble compounds of vanadium – vanadium bronzes and others. the technical essence and the achieved effect of the invention is soda ash C2}. The disadvantage of its use in roasting is the impossibility of roasting with an increase of nnyh temperatures due to the formation of cakes charge that inhibit the burning process and the completeness of the oxidation of vanadium reduces .fazy stimulates possible to form vanadium bronzes. The disadvantage of using soda (sodium carbonate) is also high activity with respect to other components of the mixture with the formation of silicates, titanates, aluminates and other alkali metal salts. This complicates and increases the cost of subsequent purification of vanadium pentoxide from impurities and significantly increases the consumption of reactionary additives, and also contributes to the formation of suspensions in solutions, which complicates their filtration. The purpose of the invention is to eliminate the formation of batch cakes with increasing calcining temperature, increasing the degree of vanadium conversion into soluble compounds and extracting vanadium from slag. The goal is achieved by the fact that the reaction additive for oxidizing calcination of vanadium slag containing soda ash additionally contains nepheline concentrate in the following ratio, wt. ), has the following composition, wt., silica; alumina; iron oxide; sodium oxide; 18-20; and potassium; calcium oxide; an oxidizing roasting the slag to increase the temperature to 850-900 0 sinters without forming the charge instead of slag at 700-750 with one firing soda. The possibility of increasing the firing temperature is achieved due to the fact that, along with low-melting alkali metal oxides (Na20), nepheline concentrate introduces a certain amount of silicon oxides (Si02) and aluminum (Ap205) in accordance with the indicated chemical composition. The total amount of the reaction additive is calculated based on the stoichiometrically required amount of alkali metal oxides, the reaction additive to form soluble vanadium compounds. The selected ratios of the components of the mixture are optimal, since with the introduction of less than 20 nepheline concentrate and more BO soda into the mixture, respectively, less silicon oxide and aluminum and more alkali metal oxides are added. At the same time, the formation of charge blends during its firing process is not eliminated.

With the introduction of more than 50 nepheline concentrate and less than 50 soda into the mixture, an excess of silicon oxides and aluminum oxides are introduced and the activity of alkali metal oxides decreases. In addition, the total weight of the additives increases significantly, which reduces the firing performance.

An excess of silicon oxides -I aluminum leads to the formation of suspensions in solutions that impede filtration of the slurries.

The insufficient amount of alkali metal oxides does not provide an increase in the transfer of vanadium into soluble compounds and its removal from slag.

Example. A portion of the slag 30 g composition, containing, wt .: SlOg 16.8; MPO 8.4; MDO 2.5; CaO 1.5; fepfi 33.6; 205 South 8.3; CrO.O; P205, burned in a muffle furnace with free access of air ..

The results of burning and leaching the mixture at 700 ° C are given in Table. 1. and at 850 With - in tab. 2

As can be seen from the table. 1, when the low-temperature firing mode (at) the addition of nepheline concentrate reduces the extraction of vanadium by 6-10%. The content of the dump cakes is increased by 1.7-2. Vanadium extraction into water-soluble compounds is also lower than usual.

As the oxidation calcination temperature increases to 850 ° C, the results change dramatically. At optimum

the ratio of the components of the mixture (80-. 50 soda and 20-50 concentrate) is the total extraction of vanadium into solutions higher by 3.5-5.0% compared with the results of roasting with one soda (Table 2, experiments 3-). The content of v-o in cakes is significantly reduced. When the ratio of the components of the mixture of 50% soda and 50% nepheline concentrate significantly increases the amount of water-soluble vanadium compounds (Table 2, test 4) and the content decreases. in dump cakes.

When the ratio of mixture components is within 25% soda and 75% nepheline concentrate, the results for vanadium extraction deteriorate sharply (Tables 1 and 2, experiment 5). Under production conditions, this may cause an increase in the duration of oxidative roasting and a decrease in the productivity of kilns. Therefore, this ratio of components is not optimal.

The effectiveness of the proposed reaction additive with the optimum ratio of components can be judged by the change in parameters as a result of its use (Table 3).

The economic effect from the application of the proposed reaction additive due to the increased recovery of vanadium from slag with an average annual production of 1000 tons of vanadium pentoxide is more than 110 thousand rubles.

Table 1

2.1

4.4

4.5 3.8 3.0 2.8

Removing vanadium from slag,%

Vanadium content in talkal cakes,

table 2

Table 3

4.0

95.0

91.0

B3

1.0

2.3

Claims (2)

- 1. REACTIVE ADDITIVE FOR. OXIDATIVE FIRING OF VANADIUM 'SLAG, containing soda ash, characterized in that, in order to eliminate the formation of baking cakes with increasing firing temperature, to increase the degree of conversion of vanadium to soluble compounds and extraction of vanadium from slag, it additionally contains nepheline concentrate in the following ratio of components, May.%: Soda Ash Nepheline Concentrate 2. The reaction additive according to π. 1, characterized in that the nepheline concentrating composition, wt.%: Silicon Dioxide Aluminum Oxide Iron Oxide Sodium Oxide and Potassium Oxide Calcium Oxide 50-80 20-50 g 40-45 25-30 2-3 has the following18-20 rest