RU2537632C1 - Device for leaching of precious metals - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: device for precious metals leaching includes a conic reactor with a lid, junction pipes for inlet and outlet of a reaction mixture, a node for force circulation consisting of a pump and connecting pipes. The node for force circulation is provided with an ejector connected to the lower part of the conic reactor. At that the ejector nozzle is connected to the outlet of the circulating pump, the ejector suction chamber is designed with a channel connecting it to an internal volume of the reactor, and the ejector diffuser is connected to a junction pipe of the reaction mixture inlet to the reactor. The junction pipe of the reaction mixture inlet is located tangentially in an upper part of the reactor, and the junction pipe of the reaction mixture outlet is located in the centre of the reactor lid, it is submerged in the reaction mixture and is connected to the circulating pump inlet.

EFFECT: increasing the speed of precious metals leaching.

1 dwg, 1 tbl

Description

The invention relates to chemistry and metallurgy, in particular to hydrometallurgy, and can be used when dissolving 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 M.A., Orlov A.M. - 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 inlet and outlet pipes, pulps and a 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. Variants 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 Patent 2098503 from 12/10/1997 / 5. Japan Patent, Application No. 59-28613, published on July 14, 1984 / 6. 6. RF Patent 2439174 of November 10, 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.

As a prototype of the proposed device, the installation for leaching precious metals from gravity concentrates was selected, 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 O.I., 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 intensive mixing mode 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 objective of increasing the dissolution rate by increasing the intensity of mixing and reducing wear of the working body of the circulation pump.

The problem is solved when using a device for leaching precious metals, including a conical reactor with a cover, nozzles for input and output of the reaction mixture, a forced circulation unit, consisting of a pump and connecting pipes, characterized in that the forced circulation unit is additionally equipped with an ejector connected to the bottom part of the conical reactor, while the ejector nozzle is connected to the outlet of the circulation pump, the suction chamber is provided with a channel connecting it to the internal bemsya reactor and the diffuser of the ejector is connected to the input nozzle of the reaction mixture in the reactor, the entry conduit of the reaction mixture is tangentially disposed in the upper part of the reactor, and the reaction mixture output pipe located centrally of the reactor lid, immersed in the reaction mixture and is connected to an input of a circulation pump.

A variant of the claimed device is presented in the figure. The device includes a circulation pump 1, a conical reactor 2, connecting pipes 3, the outlet pipe of the reactor 4, the inlet pipe of the reactor 5, the nozzle of the ejector 6, the suction chamber of the ejector 8, the diffuser of the ejector 9. To discharge the reactor at the end of leaching, a pipe 7 equipped with a valve is used.

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 pumped into the reactor to the level 10 at which the outlet pipe of the reactor 4 is immersed in reaction mixture. The liquid part (discharge) of the reaction mixture through the outlet pipe 4 of the reactor is discharged to the inlet of the circulation pump 1 and is injected under pressure into the ejector nozzle 6. The inlet stream at high speed, increased when passing through the narrowing nozzle 6, rushes into the suction chamber 8 and then into diffuser 9. With the optimal location and size of the ejector elements, the reaction mixture from the bottom of the reactor is drawn into the diffuser. The mixture of ejected and ejected media through the pipe 3 at high speed is pumped into the inlet pipe 5 of the reactor. The tangential location of the inlet pipe 5, similar to that in a hydrocyclone, causes the appearance of a classifying effect when the reaction mixture is injected into the reactor. As a result, phase separation is carried out in the reactor. The solid phase, mainly its large (sand) part, descends along the rotational trajectory to the lower part of the cone and is again entrained in the suction chamber of the ejector and further into the circulation circuit. 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 circulation pump and further into the ejector nozzle. Thus, a mixture of solid and solution is transported and mixed inside the reactor and along a part of the pipeline of the circulation unit, and a leach solution with a minimum of solid particles is transported along the other part of the pipeline of the circulation unit, including the circulation pump. The driving force of mixing and circulation of the pulp is the pump, but the large, abrasive part of the concentrate does not enter the pump. The service life of the pump impeller increases dramatically. Without prejudice to the pump, the circulation rate and leaching rate can also be increased.

The additional effect of cavitation effects arising in the ejection unit leads to a more complete opening of valuable particles finely interspersed in the gangue 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 0.75 m. The inlet of the circulation pump with a capacity of 20 m ³ / h and a pressure at the outlet of 4 atm is connected to the outlet pipe of the reactor, the pump outlet is connected to the ejector nozzle. An ejector suction chamber is connected to the bottom of the reactor in accordance with the claims. The ejector diffuser is attached to the tangential introduction of the reaction mixture into the reactor.

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, a leaching experiment was conducted in the same reactor, but operating on the principle of a prototype without an 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 70,2 23.0 38.3 14.0 1,0 60.3 58.2 31.8 27.0 1,5 53,2 73.0 23.9 36.0 2.0 44.7 92.1 20,2 51.0 3.0 19.3 96.5 18.5 72.0 10.0 14.2 97.2 17,2 90.2

After long-term operation of the installation in the mode of the device proposed in the invention (300 hours of operation under load), the condition 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 present invention allows to conclude that it is the totality of the claimed features ensures the achievement of the perceived technical result. Due to the introduction of pulp into the device of the ejector, the rate of gold leaching from the concentrate in the proposed device is 1.5-2 times higher than 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 precious metals, containing a conical reactor with a cover, nozzles for input and output of the reaction mixture, a forced circulation unit consisting of a pump and connecting pipes, characterized in that the forced circulation unit is equipped with an ejector attached to the lower part of the conical reactor, the ejector nozzle is connected to the outlet of the circulation pump, the suction chamber of the ejector is made with a channel connecting it to the internal volume of the reactor, and the diffuser of the ejector is connected to bkom enter the reaction mixture in the reactor, the entry conduit of the reaction mixture is tangentially disposed in the upper part of the reactor, and the reaction mixture output pipe located centrally of the reactor lid, immersed in the reaction mixture and is connected to the inlet of the pump.