RU2607858C1 - Method of leaching waelz oxides - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to nonferrous metallurgy, in particular, to a method of extracting nonferrous and rare metals from recycled industrial wastes, in particular, to a method of extracting metals from waelz oxides. Method involves leaching by feeding solvent in form of a stream and feeding waelz oxides in form of pulp through a nozzle into a reaction zone. Leaching is carried out with exposure of reaction zone to non-ionising electromagnetic radiation with frequency in range of 5–15 kHz and power within range of 15–20 mW with supply of solvent at a rate of 0.2 m/s and supply of pulp at a rate of 5 m/s.

EFFECT: technical result is lower cost of leaching, faster process with extraction of nonferrous and rare metals.

1 cl, 2 tbl, 1 ex

Description

The invention relates to ferrous metallurgy, in particular to a method for the extraction of non-ferrous and rare metals from recyclable industrial waste.

There is a method in which the main reactions of industrial leaching processes occur in the diffusion region, creating a high intensity of pulp mixing to accelerate the process (Pogorely A.D., 1971 edition of Metallurgy, pp. 350-351).

In the known method, it is impossible to eliminate completely diffuse stages when leaching finely dispersed Waelz oxides in order to convert the metals extracted from them into sulfates.

A known method of leaching metals, in which the heat of an exothermic chemical reaction is used, which is given at a temperature of 75-80 ° C, while achieving a change in the concentration of sulfuric acid to 30%, and existing metals in the slag precipitated in the form of hydroxides (patent No. 2453619, published 10.03 .2012, IPC C22B 34/22, E21B 43/28).

In the known method, the chemical reaction is complicated by the fact that the chemicals heated to a certain temperature do not accelerate the deposition of the necessary metals.

The closest technical solution is a method in which the solvent flow is increased at a speed of at least 5 m / s (A.S. No. 418538, published 03/05/1974, IPC C22B 3/08, C22B 3/04).

The disadvantage of this prototype method is the limited ability to maintain a high speed of the Waelz oxide particles introduced with the pulp throughout the reaction zone due to the active resistance of countercurrently moving components, therefore the length of the most efficient section in which the acid-soluble oxides of the extracted metals is freely and completely transferred sulfates, is insufficient to obtain the same result with some batches of Waelz oxides.

In these batches of Waelz oxides, when they are formed in Waelz furnaces, leaching complicating parameters (seals, intergrowths, etc.) are formed, the elimination of which requires a longer solvent action.

Such batches of Waelz oxides leaving the reaction zone contain up to 6% of oxides; the metals recovered must be re-leached after leaving the reaction zone, which requires significant costs.

EFFECT: reduced costs and accelerated leaching process.

The technical solution of the proposed method lies in the fact that the reaction zone is affected by low-intensity non-ionizing electromagnetic radiation in the range of 5-15 kHz and a radiation power in the range of 15-20 mW.

The method is as follows. For testing, Waelz oxides are used in an experimental setup adapted to extract Waelz oxides. The process parameters of 5-15 kHz and 15-20 mW are explained by the achievement of acceleration of the leaching of Waelz oxides. At lower parameters (less than 5 kHz and below 15 mW), the acceleration is not efficient enough and additional leaching costs are carried out. In addition, not all metals are leached.

At higher parameters (15 kHz and 20 mW), the leaching efficiency decreases.

Example

For testing, Waelz oxides were used, which contained:

- total zinc - 61.18%, including acid soluble - 62.19%;

- total cadmium - 0.56%, including acid soluble - 0.54%;

- total india - 0.02%, including acid soluble - 0.0018%.

The sulfuric acid content in the solvent: initial - 118 g / l, final - from 45-48 g / l. The pulp density is 1.4 g / cm. The diameter of the column of the reaction zone is 0.2 m. The velocity of the solvent in it is 0.2 m / s. The diameter of the nozzle through which the pulp was fed was 0.02 m. The feed rate of the pulp was 5 m / s. The power and frequency of non-ionizing electromagnetic radiation acting on the reaction zone are 18 mW and 15 kHz, respectively.

The effectiveness of the proposed leaching method was evaluated by analyzing samples taken from the mass leaving the reaction zone after 15 minutes in the filtrate and solid (cake), in which the contents of zinc, cadmium and indium were determined.

During the tests, 5 samples were taken during leaching without exposure to the reaction zone of electromagnetic exposure and during leaching with electromagnetic exposure.

The results of the analyzes are presented in tables 1 and 2.

Tests of the proposed method showed that, in contrast to the prototype, the proposed method allows all types of Waelz oxides to be leached with the necessary completeness.

Claims (1)

The method of extracting metals from Waelz oxides by leaching, including feeding the solvent in the form of a stream and feeding Waelz oxides in the form of a pulp through a nozzle into the reaction zone, characterized in that the leaching is carried out with the action of non-ionizing electromagnetic radiation on the reaction zone with a frequency in the range of 5-15 kHz and power in the range of 15-20 mW when feeding solvent at a speed of 0.2 m / s and feeding pulp at a speed of 5 m / s.