RU2439174C2 - Leaching device - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: device includes reactor and external assembly for forced circulation of reaction mixture. External assembly consists of circulation pump, connection pipe and mixing chamber located in the direction of mixture after circulation pump and equipped at least with two ejecting nozzles connected to the pump and outlet holes directed towards each other. At that, mixing chamber in lower part has the discharge tube submersed into the reactor.

EFFECT: increasing dissolution speed owing to increasing the mixing intensity; increasing the solution saturation with gaseous oxidiser at pressure increase in reaction chamber.

1 tbl, 1 dwg

Description

The invention relates to chemistry and metallurgy, in particular to hydrometallurgy, and can be used to dissolve various substances, for the oxidative leaching of metals and compounds from ores, concentrates, industrial products of enrichment, sludge and other materials.

For leaching various raw materials, aggregates are traditionally used, which are tanks equipped with a device for mixing with mechanical stirrers, aerial lifts, impellers / Metallurgy of precious metals. Foreign experience. Meretukov M.A., Orlov A.M. - M.: Metallurgy, 1990 /. The common disadvantages of the known devices for leaching are the low speed of the process and, as a consequence, low productivity, which is especially important when processing lean materials.

Closest to the claimed is a device for leaching metals and compounds, including a reactor equipped with nodes of the upper and lower discharge, communicating with each other through an external pipeline with a circulation pump and a mixing chamber located along the mixture behind the circulation pump, the reaction input device the mixture into the mixing chamber is made in the form of opposing nozzles equipped with ejectors of a gaseous oxidizer, and at the outlet of the mixing chamber Credited spring loaded plug (RU 971 030 505 A, IPC C22B 9/22 from 10.03.1999).

The leachable feed is placed in the reactor and the leach agent is fed. Using a circulation pump, the reaction mixture is pumped out from the bottom of the reactor, saturated with air through an ejector, and fed into the mixing chamber. The movement of the leaching agent relative to the raw material, achieved by the interaction of the opposing jets, provides a high speed process. However, the unstable system for maintaining excess pressure in the mixing chamber with the help of a spring-loaded plug does not allow to saturate the mixture effectively and to use a gaseous oxidizing agent. Upon exiting the mixing chamber, the unused oxidizer escaped from the reaction mixture.

The present invention is aimed at eliminating this drawback and has the objective of increasing the dissolution rate by increasing the mixing intensity, increasing the saturation of the solution with a gaseous oxidizing agent with increasing pressure in the reaction mixture.

The problem is solved due to the fact that the mixing chamber in the lower part has a discharge pipe immersed in the reactor.

A variant of the claimed device is presented in the drawing. The device includes a reactor 1 equipped with a mechanical stirrer 2, a circulation pump 8, a suction leach mixture from the bottom of the reactor, a mixing chamber 3, equipped with nozzles 4 for pumping a circulating mixture into the chamber and ejectors 5 for pumping a gaseous oxidizer, a pipe 6 connecting the pump 8 and mixing chamber 3, discharge pipe 7.

The device operates as follows. The source dispersed material (ore, concentrate, sludge, etc.) containing a valuable component, together with the leaching reagent in the desired proportion in the form of pulp, is loaded into the reactor 1 with the stirrer 2 on. As necessary or continuously turn on the circulation pump 8, an injection pulp from the bottom of the reactor 1 into the nozzles 4 of the mixing chamber 3. Through the ejectors 5, a gaseous oxidizer (air or oxygen) is injected into the nozzles. With a continuously operating pump, the circulation of the mixture through the mixing chamber 3 and the reactor 1 also occurs continuously. A mixer is necessary for continuous mixing of the pulp in the reactor and maintaining it in a suspended averaged state, which is required for stable operation of the pump.

The specified device design provides the following technological advantages. As in the known device (prototype), in the mixing chamber in the collision zone of the jets emanating from the nozzles, not only extremely intensive mixing of the particles of the processed material, leaching reagent and oxidizing agent occurs, but also additional mechanical abrasion of the particles, the removal of sparingly soluble reaction products and other passivating films from the surface of solid particles. In addition, the immersion of the discharge pipe in the reactor causes excessive pressure in the chamber and brings the reactor to an autoclave mode of operation. Unlike the prototype, in which the overpressure is provided by the valve, in the proposed device, the pressure mode is more calm, without pressure surges that are inevitable when the valve is activated. The output of the pulp saturated with oxidizing agent into the depth of the pulp in the reactor provides intensive aeration and increases the leaching rate as a whole. The overpressure in the chamber corresponds to the immersion depth of the discharge pipe, so it is buried as much as possible.

When using oxygen as an oxidizing agent, the degree of its use increases.

With the inventive device, the following experiment.

The reactor with a volume of 1.5 m ³ is equipped with a mechanical stirrer rotating at a speed of 200 rpm. A circulation pump with a capacity of 20 m ³ / h and a pressure of 4 bar is located under the reactor. At a height of 1 m from the upper edge of the reactor there is a mixing chamber having a discharge pipe with a diameter of 110 mm in the lower part immersed in the reactor. The lower end of the discharge pipe was 50 cm from the bottom of the reactor. Narrowing nozzles are installed on opposite vertical sides of the mixing chamber, directed towards each other. At the inlet of the nozzles, ejectors are installed, to which compressed air is supplied under a pressure of 5 atm. The reactor, circulation pump and mixing chamber are connected by an external pipe with a diameter of 57 mm.

A 1 m ³ pulp consisting of a gold-containing concentrate with a particle size of 100% - 1 mm and a cyanide alkaline solution was loaded into the reactor, a mechanical stirrer and a circulation pump were turned on. At specified intervals, samples of the solution were taken and analyzed for gold content, after which the rate (increase in the amount in the solution) and the degree of dissolution of gold were calculated.

For comparison, the leaching experiment was carried out in the same reactor, but working on the principle of a prototype. The unloading of the mixing chamber was carried out through a valve that relieves excess pressure. According to the analysis of samples of the solution, the degree of leaching of gold was calculated.

The results of the experiments are presented in the table.

Leaching time, hour Prototype device Proposed device leaching rate,% leaching rate,% 0.5 32,0 36.0 1,0 54.0 59.0 1,5 81.0 86.0 2.0 88.1 92.0 3.0 92.5 96.0

The data show that the degree of dissolution of gold for comparable periods of time is 5-10% higher than similar parameters in the prototype device. The process speed is similarly higher.

The inventive device is suitable for leaching ore raw materials and industrial products of any composition. Recoverable metals can be ferrous and non-ferrous, incl. noble and rare metals. To saturate the reaction mixture with an oxidizing agent, ejectors communicating with the atmosphere can be used.

Claims (1)

A device for leaching metals and their compounds, including a reactor and an external unit for forced circulation of the reaction mixture, consisting of a circulation pump, a connecting pipe and a mixing chamber located along the mixture behind the circulation pump and equipped with at least two ejection nozzles connected to pump and outlet openings directed towards each other, characterized in that the mixing chamber in the lower part has a discharge pipe immersed in the reactor.