RU2526350C1 - Device for leaching - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: device contains a conical reactor with a lid, a lower branch pipe of the input and an upper branch pipe of the output of a reaction mixture. It includes a unit of forced circulation consisting of a pump and connecting tubes. The unit of forced circulation includes internal and external contours. The internal contour is made in the form of a tube, which is placed vertically inside the reactor, with the tube facing a branch pipe of the input with the lower end, and in the upper part the tube is made in the form of an arch, placed in the horizontal plane and adjoining the internal wall of the reactor. The branch pipe of the input is equipped with a nozzle, which forms an ejection system with the lower end of an internal contour, and the branch pipe of the output of the reaction mixture is placed in the middle of the reactor lid and is made with a possibility of immersion into the reaction mixture.

EFFECT: intensification of leaching of metals and their compounds.

1 dwg, 1 tbl

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 mixing device - mechanical mixers, aerial lifts, impellers (1. Metallurgy of precious metals. (Foreign experience). Meretukov MA, Orlov AM - M .: Metallurgy, 1990 ) A common disadvantage of the known leaching devices is the low speed of the process and, as a consequence, low productivity, which is especially important when processing poor raw materials.

In particular, for cyanide leaching of gold from ores and concentrates, reactors are used that include a vessel with pulp inlet and outlet pipes and a pulp mixer. Typically, pulp mixing is carried out by means of mechanical, pneumatic or pneumomechanical mixers. Intensification of mixing and leaching is achieved using systems of external circulation of the reaction mixture or forcing the leach solution, carried out by centrifugal pumps. Options are proposed in which the pulp is pumped out from the bottom or top of the cone reactor by pumps and returned to the reactor by pump (2. RF Patent 2051982 from 01/10/1996, 3. RF Patent 2062806 from 06/27/1996, 4. RF 2098503 from 10.12.1997, 5. Japan patent, application No. 59-28 613, publ. 14.07.84, 6. RF patent 2439174 from 10.11.11).

The disadvantages of the known apparatus with the injection of the reaction mixture or solution into the lower zone of the reactor include the gradual accumulation of large pulp particles in the lower part of the apparatus, which reduces the efficiency of cyanide pulp and increases the duration of the leaching of precious metals into the cyanide solution.

The closest in technical essence to the proposed one is the installation for leaching precious metals from gravity concentrates selected as a prototype, containing a conical reactor with a lower inlet pipe and an upper outlet pipe for the reaction mixture, a forced circulation unit consisting of a pump and connecting pipes (7. Frolov Yu.I., Sharapova OI, Chernov V.K., Khomutov V.V. Processing of gravity concentrates of precious metals (Kolyma, 1987, No. 3, p.40).

In a known installation, the gravity concentrate is leached in a "fluidized bed" mode with a cyanide solution continuously supplied to the conical reactor from the bottom up through the lower pipe at the apex. The solution discharged from the reactor through the drain pipe in the upper part enters the pump sump and is then pumped back into the reactor by the pump, thus circulating in a closed circuit between the drain pipe, sump and reactor.

The disadvantages of the prototype include the fact that the leaching of gravity concentrates in the "fluidized bed" does not provide a complete separation of the contacting phases due to the entrainment of the upward flow of the solution of fine fractions. During cyanidation of materials with finer grinding, for example, flotation concentrate, pulp discharged from the reactor into the external circulation circuit contains a large amount of solid particles. Under these conditions, the forced circulation pump is subject to intense wear. To reduce this negative phenomenon, the intensity of the introduction of circulating products and mixing in the reactor are forced to limit. Accordingly, the leaching rate is limited.

The present invention is aimed at eliminating these disadvantages and has the task of increasing the dissolution rate. The technical result is expressed in increasing the intensity of mixing and reducing wear of the working body of the circulation pump.

The problem is solved when using a leaching device, including a conical reactor with a cover, a lower inlet pipe and an upper outlet pipe for the reaction mixture, a forced circulation unit, consisting of a pump and connecting pipes, characterized in that the forced circulation unit includes internal and external circuits, the inner circuit is made in the form of a pipe, which is located vertically inside the reactor, with the lower end of the pipe facing the inlet pipe, and in the upper part and in the form of an arc located in a horizontal plane and adjacent to the inner wall of the reactor, the inlet pipe is equipped with a nozzle, while the nozzle and the lower end of the pipe of the internal circuit form an ejection system, the outlet pipe of the reaction mixture is located in the center of the reactor cover and immersed in the reaction mixture.

A variant of the claimed device is presented in the drawing. The device includes a conical reactor 1, a circulation pump 7, a suction reaction mixture from the outlet pipe of the reactor 3, the inlet pipe 6 of the reactor, equipped with a nozzle for pumping the circulating mixture, the pipe of the internal circuit 2 and the pipe of the external circuit 4. To discharge the reactor at the end of leaching, pipe 5 .

The device operates as follows. The source dispersed material (ore, concentrate, sludge, etc.) containing a valuable component, together with the leaching agent in the desired proportion in the form of pulp, is pumped into the reactor to the level at which the outlet pipe 3 is immersed in the reaction mixture using the pump 7 . The liquid part (discharge) of the reaction mixture through the outlet pipe of the reactor is discharged into the external circulation circuit and, under pressure, is returned by the pump 7 to the lower part of the reactor cone through the nozzle of the discharge pipe 6. The input stream at a high speed, increased when passing through the narrowing nozzle, rushes to the lower expanded end face (bell) of the pipe forming the internal circuit of circulation. With the optimal location and diameters of the injection nozzle and the bell, an ejection effect occurs, in which a large sand part of the concentrate is involved in the internal circulation stream. In accordance with the contour of the pipe, the reaction mixture rises to the top of the reactor and at high speed “shoots” in the horizontal direction tangentially to the inner wall. A similar character of pulp input, only from the outside, is realized in a hydrocyclone. As a result, phase separation is carried out in the reactor. The solid phase in a rotational trajectory descends to the lower part of the cone and again entrained in the pipe of internal circulation. The liquid phase of the reaction mixture with fine particles (discharge) is displaced to the center of the upper part of the reactor and carried away through the outlet pipe into the external circulation circuit. Thus, two circuits are formed. A mixture of solid and solution circulates and mixes inside the reactor, and a leach solution with a minimum of solid particles circulates along the external circuit. The driving force of pulp mixing is the pump, but a large abrasive part of the concentrate does not enter the pump. The service life of the impeller of the pump increases dramatically. Without prejudice to the pump, the circulation rate and leaching rate can also be increased.

The additional effect of the ejection unit, in which cavitation effects occur, leads to a more complete opening of valuable particles finely disseminated into the empty rock and, as a result, leads to an increased degree of leaching.

With the inventive device, the following experiment.

The reactor with a volume of 0.8 m ³ had the shape of a cone with a diameter in the upper part of 0.7 m. The inlet and outlet of the circulation pump with a capacity of 12 m ³ / h and a pressure at the outlet of 4 Atm are connected to the corresponding reactor pipes with a pipe with a diameter of 57 mm. Inside the reactor, in accordance with the claims, a pipe with a diameter of 70 mm is reinforced with a bell in the lower part.

A 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, and a circulation pump was turned on. At predetermined time intervals, samples of the solution were taken and analyzed for gold content, after which the rate (increase in the mass of gold 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 operating on the principle of a prototype without an internal circulation pipe, nozzle in the discharge pipe and ejection unit.

The results of the experiments are presented in the table.

Leaching time, hour Proposed device Prototype device Leaching rate, g / hour The degree of leaching,% Leaching rate, g / hour The degree of leaching,% 0.5 77.6 24.0 58.3 18.0 1,0 64.8 62.0 51.8 37.0 1,5 51,4 77.0 43.9 58.0 2.0 40.5 91.1 36,2 63.0 3.0 9.2 95.5 10.5 72.0 10.0 10.5 96.2 17,2 90.2

After long-term operation of the installation in the mode of the device proposed in the invention (150 hours of operation under load), the state of the pump impeller was evaluated. Noticeable wear was not detected.

Subsequent operation of the installation according to the prototype variant led to significant wear after 100 hours.

Comparative analysis of well-known technical solutions, including the device selected as a prototype, and the alleged invention allows us to conclude that it is the totality of the claimed features ensures the achievement of the perceived technical result. Due to the introduction into the device of the internal circulation circuit of the pulp, the rate of leaching of gold from the concentrate in the proposed device is 1.3-1.5 times that of the same indicator in the prototype device. The service life of the impeller of the pump in the proposed embodiment of the device, depending on the nature of the processed material increases several times.

Claims (1)

A device for leaching metals and their compounds, containing a conical reactor with a cover, a lower inlet pipe and an upper outlet pipe for the reaction mixture, a forced circulation unit consisting of a pump and connecting pipes, characterized in that the forced circulation unit includes internal and external circuits, this inner circuit is made in the form of a pipe, which is located vertically inside the reactor, with the lower end of the pipe facing the inlet pipe, and in the upper part of the pipe is made in the form of an arc, located dix in the horizontal plane and adjacent to the inner wall of the reactor, the entry conduit is provided with a nozzle, forming with the lower end of the inner contour of the pipe ejection system, and the reaction mixture output pipe located centrally of the reactor cover and configured to be submerged in the reaction mixture.

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