RU2198232C2 - Method of gold sedimentation and device for method embodiment - Google Patents

Abstract

FIELD: gold hydrometallurgy (heap leaching), particularly, methods for gold separation from cyanide solutions on metal more active than gold. SUBSTANCE: process is carried out through filler from alternating layers from graphitized fleecy jersey fabric and granulated zinc located in precipitating cell. Process solutions are supplied simultaneously to all existent layers of graphitized fleecy jersey fabric and granulated zinc from distributing chamber. Device has vibratory drive for producing pulsating efflux of process solution and cleaning of graphitized fleecy jersey fabric from slime. Located in device lower part is conical bin for collection of gold-containing slime. In realization of claimed method on said device, specific productivity was attained up to passage of producing solutions amounting to 50-70 cu.m/day per sq.m of cell cross-section. Merits of use of said method and device for sedimentation of gold from cyanide solutions consist in that they make it possible to recover gold continuously in production process with high productivity, produce more qualitative gold-containing slimes with gold content up to 37% and above and to solve problem of process solution fatigue. Device is distinguished by its stability in operation and suitable for processing reach and great volumes of lean solutions in gold, foe example, after heap leaching. EFFECT: higher efficiency. 2 cl, 1 dwg, 1 tbl

Description

 The invention relates to the field of gold hydrometallurgy (heap leaching process), in particular to methods that allow the separation of gold from cyanide solutions on a metal that is more active than gold.

 Known methods for the deposition of gold on zinc chips, on zinc or aluminum dust.

 As a prototype, a method of deposition of gold was selected, including passing the production cyanide solution through granular zinc when exposed to vibration, and a device for the deposition of gold, including a housing with a precipitation cell filled with granular zinc, nozzles for input and output of the solution and vibrodrive (see DE 3429458 A1 Cl. C 22 B 1/04, 02.20.1986).

The disadvantage of this method and device is to obtain a sludge with a low gold content, the rapid fatigue of cyanide solutions due to the accumulation of a large amount of impurities and a decrease in performance both at the dissolution stage and at the gold deposition stage. In addition, in the case of heap leaching, it is necessary to create additional metal-intensive structures for processing hundreds of m ^{3 of} technological solutions formed in the leaching process, and use filters with high performance.

 The technical result of the method and device is to increase the stability and productivity of the deposition of gold from production cyanide solutions and reduce the fatigue of solutions.

 This is achieved in that the method of deposition of gold, including passing the production cyanide solution, in particular after heap leaching, through granular zinc, with vibration, is characterized in that the solution is passed through a filler from alternating layers of granular zinc and graphitized batting and the solution is supplied to all layers at the same time.

 This is also achieved by the fact that the device for the deposition of gold, comprising a housing with a precipitation cell filled with granular zinc, nozzles for input and output of the solution and a vibrodrive, is characterized in that it is equipped with a distribution chamber for the production solution, a hopper for collecting gold-containing sludge and a tank for settling sludge and the precipitation cell is filled with a storage ring in the form of alternating layers of granular zinc and graphitized batting.

 Parallel layers of graphitized batting and granular zinc are located in a detachable sedimentation cell. The vibrodrive serves to create a pulsation regime of the outflow of the technological solution and to clean the graphitized batting from sludge. At the bottom of the device is a cone-shaped hopper for collecting gold-containing sludge.

 The advantages of using the new method and device for the deposition of gold from cyanide solutions are that they allow to continuously extract gold with high performance in the technological cycle, to obtain better gold-containing sludge with gold content up to 37% or more, and to reduce the fatigue of technological solutions. The device is stable in operation and can be used to process a large volume of solutions poor in gold content after heap leaching.

 Reducing the content of impurities in the gold-containing sludge is achieved due to the difficulty of cementing them by reducing the natural potential difference on a bimetallic pair of graphitized batting - zinc. Moreover, a negative potential is formed on graphitized batting. Layers of graphitized batting are used in the filler as an element of a bimetallic pair with a highly developed surface for the electrochemical deposition of gold from poor production solutions and for the accumulation of gold-containing sludge. The surface of the zinc granules remains clean during the deposition process, does not fade, is not contaminated with sludge. Zinc during the deposition of noble metals dissolves and accumulates in solution in an amount equivalent to the mass of noble metals, that is, in an amount an order of magnitude smaller than in the case of simple cementation on zinc. Gold and silver are deposited on graphitized batting in the form of black slimy particles and, when the pulsation mode is switched on, the outflow of the solution in the cell is washed off into the conical part of the device. The supply of the production cyanide solution simultaneously to all layers of the filler from alternating layers of granular zinc and graphitized batting allows to reduce the hydrodynamic resistance of the filler. A high filtration rate in the cell is achieved due to the fact that the production solutions mainly migrate through layers of zinc granules, and is determined by the geometric parameters of the elements of the precipitation cell, which remain constant during the deposition process. The deposition process is controllable and easy to maintain.

 The drawing shows a diagram of a device for the deposition of gold.

 The device has a pressure vessel 1, a precipitation cell 2, an eccentric vibrodrive with an electric motor 3 and a rubber diaphragm 4, layers of zinc granules 5 and graphitized batting 6, removable walls 7 and 8, screws with wings 9, a distribution chamber for the production solution 10, gratings 11 and 12 in the sedimentation cell, the inlet and outlet nozzles of the solution 13 and 14, the hopper 15 with the sludge 16, a tank for sedimentation of the sludge 17.

 The method is as follows: from the pressure vessel 1, the production solution is sent through the nozzle 13 to the chamber for distributing the production solution 10. From the chamber 10 through the grate 11, the solution is evenly distributed in the precipitation cell 2 over all the layers of graphitized batting and granular zinc present in it and migrates to bottom of the device. Gold and silver are deposited on the layers of graphitized batting. The de-malted solution through the grate 12 enters the hopper 15, is separated from the gold-containing sludge 16, then into the sump 17 and through the pipe 14 is returned to the leaching cycle.

At a relatively low flow rate of solutions through the cell, frontal saturation of batting with gold was observed, at flows of more than 10 l / h, a slip of gold through the precipitation cell was observed until the maximum batting capacity for gold was reached. In the studies, a specific productivity was reached up to a slip of production solutions of the order of 50-70 m ³ / day 1 m ^{2 of the} section of the precipitation cell. The cost of the process of deposition of gold from production solutions after heap leaching is estimated mainly by the consumption of batting, zinc and maintenance and is about 1.5-2 rubles per 1 g of gold.

 An example implementation of the method.

Initial data: gold content in the technological solution - 5.4 mg / l; copper - 47 mg / l; zinc - 63 mg / l; iron - 75 mg / l. The thickness of the batting layer (in a compressed state - 2-3 layers) - 2.5-3 mm; the thickness of the layer of zinc granules is 5-10 mm, the diameter of zinc granules is 3-5 mm. The height of the precipitation cell was 700 mm. The cell in cross section had dimensions - 55 • 25 mm ² ; the number of layers of graphitized batting - 4; the number of layers of zinc chips is 3. The productivity of the precipitation cell varied from 1 to 20 l / h.

 The experimental data are given in the table.

 The device operates as follows.

 The filler is filled into sedimentation cell 2. For this, detachable walls 8 and 7 are removed in the settling tank 17 and sedimentation cell 2. A first layer of graphitized batting is laid on the periphery of the precipitation cell, the first layer of zinc granules is applied to it, and so on. The layers of zinc granules 5 and graphitized batting 6 in the precipitation cell 2 are closed and squeezed by a wall 7 with rubber seal using screws with thumbs 9, close the sump 17 wall 8 with a rubber seal with bolts.

 The pressure vessel 1 is filled with production cyanide solutions, and the solution is supplied to the precipitation cell 2 through the tap and the supply pipe 13. The flow rate of the solution is determined by the measured capacity after the dehydrated solution expires through the pipe 14.

 An anhydrous solution after 1-2 hours is analyzed for gold content.

 After the gold slip is established, the supply of production solutions is stopped and the vibrodrive is turned on for 5 minutes. This operation is repeated 2-3 times with an interval of 5-10 minutes.

 The vibrator is turned off and production solutions are again fed into the device until a breakthrough occurs.

 To exclude the slip of production solutions, it is recommended to have 2 devices connected in parallel.

 If the performance of the device is reduced by 50%, it is recommended to wash the precipitation cell with clean water at least 3 times using a vibrator, disassemble the device, separate the graphitized batting, dry it and burn it to obtain a gold-containing residue. Wash granular zinc from the residues of gold-containing sludge, sieve class -1 mm with a sieve. The large class is returned to the filling of the precipitation cell, the small class is separated from the sludge on the sieve -0.25 mm. The sludge is dried and sent for melting. Granules 0.25-1 mm are accumulated and subjected to acid treatment according to known technology. Then fill the precipitation cell, as described above, and resume its operation.

 Thus, the application of the method and device allows to continuously extract gold with high performance in the technological cycle, to obtain better gold-containing sludge with gold content of up to 37% or more, to solve the problem of fatigue of technological solutions. The device is simple, stable in operation and can be used for processing both rich and large volumes of solutions poor in gold content, for example, after heap leaching.

Claims (2)

 1. The method of deposition of gold, including passing the production cyanide solution, in particular after heap leaching, through granular zinc during vibration, characterized in that the solution is passed through a filler from alternating layers of granular zinc and graphitized batting, and the solution is supplied to all layers simultaneously.  2. A device for the deposition of gold, including a housing with a precipitation cell filled with granular zinc, nozzles for the input and output of the solution and a vibrator, characterized in that it is equipped with a distribution chamber for the production solution, a hopper for collecting gold-containing sludge and a tank for sedimentation of the sludge, and a precipitation cell filled with filler in the form of alternating layers of granular zinc and graphitized batting.

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