RU2190670C1 - Method for extracting metals from fine-ground clay-sludge ore and technogenic raw material - Google Patents

Abstract

FIELD: mining industry, metallurgy. SUBSTANCE: method involves charging basic raw material in column onto false bottom; supplying leaching solution from the bottom into column; upon introducing required amount of leaching solution at liquid : solid ratio of (0.25-0.5) : 1, interrupting supplying of leaching solution. As a result of processing basic material with leaching solution, productive solution and sludge are obtained. Method further involves washing sludge with ascending flow of washing solution and simultaneously displacing leaching solution, with flow speed of leaching and washing solutions being below basic material fluidizing rate. In case of complex metal extraction, basic material is processed with two or more leaching solutions supplied one after another. EFFECT: reduced consumption of leaching solution, increased concentration of useful components in productive solution. 4 cl, 1 dwg, 4 tbl

Description

 The invention relates to the field of metallurgy and can be used in the mining, metallurgical and other industries for leaching of metals from finely divided clay-sludge ore and industrial raw materials.

 A known method for the extraction of metals, including leaching of feedstock to obtain cake and productive solution (see RF patent 1619711, publ. 1994).

 This method has a low efficiency of metal extraction due to the high flow rate of the leaching solution, low concentrations of metals in productive solutions and high energy consumption. In addition, the method has a low degree of extraction of metals from finely divided clay-sludge ore and industrial raw materials, since the productive solution contains fine solid particles of the feedstock, which does not allow to effectively extract metal from it.

 Closest to the proposed invention is a method of extracting metals from raw materials, comprising treating the feedstock with an upstream leaching solution and washing the cake with an upstream washing solution (see US Pat. No. 4,501,721, G 01 G 7/00, 02/26/1985).

 However, this method has a low efficiency of metal extraction due to the high consumption of leaching solution and high energy costs. In addition, cake washing is carried out in the repulpation mode; therefore, washing waters contain low metal concentrations and must be processed separately from productive solutions. Pulps after washing are not dump and need to be neutralized from toxic leaching solutions. This method cannot work on finely ground clay-sludge ore and man-made raw materials, since the circulating and productive solutions contain solid particles.

 The present invention solves the problem of increasing the efficiency of metal extraction. The technical result is to reduce the consumption of leaching solution, increasing the concentration of useful components in the productive solution, reducing energy consumption and simultaneously leaching cake washing from toxic leaching solutions to produce harmless waste products.

 The technical result is achieved in a method for extracting metals from finely divided clay-slurry ore and industrial raw materials, including processing the feedstock with an upward flow of leaching solution and washing the cake with an upward flow of washing solution, according to the invention, the raw materials are loaded onto a false bottom before treatment, the treatment with leaching solution is carried out with T equal to (0.25-0.5): 1, and the subsequent washing of the cake is carried out with the simultaneous displacement of the leaching solution from the raw material.

 For complex extraction of metals after processing and washing, additional processing and washing are carried out using various leaching solutions.

 As a leaching solution, solutions from the series are used: aqueous and non-aqueous solutions of acids, bases, halogens, inorganic and organic salts.

 Distinctive features of the proposed method are loading the raw materials before processing on the false bottom, processing the leaching solution at W: T equal to (0.25 - 0.5): 1, and subsequent washing of the cake with the simultaneous displacement of the leaching solution from the raw materials. This allows you to reduce the consumption of leaching solution, increase the concentration of useful components in the productive solution, reduce energy consumption, which will affect the increase in metal extraction efficiency.

 For complex extraction of metals after processing and washing, additional processing and washing are carried out using various leaching solutions.

 For the best implementation of the method, solutions of the series are used as a leaching solution: aqueous and non-aqueous solutions of acids, bases, halogens, inorganic and organic salts, and water is used as a washing solution.

 The proposed method is illustrated in the drawing, which shows a diagram of a device for the extraction of metals.

 The diagram shows column 1 with a false bottom 2, tank 3 with a leach solution and tank 4 with a wash solution.

 The method of extraction of metals from finely divided clay-sludge ore and industrial raw materials is as follows.

 Column 1 with false bottom 2 is loaded with feedstock. The leach solution from the tank 3 is fed into it from below. The rate of upward flow of the leach solution is less than the rate of fluidization of the particles of the feedstock. After the introduction of the required amount of leach solution, its flow is stopped. When feeding the leach solution, not only flooding of the lower part of the charge takes place, but also capillary wetting, accompanied by the rise of the leach solution above the level of flooding, which accelerates the leaching process. The required amount of leaching solution is determined by the content of the useful component (metal) in the feedstock and the need to obtain concentrated productive solutions. The lower the content of the beneficial component, the lower the amount of leach solution. It was experimentally established that when extracting metals from finely ground clay-sludge ore and man-made raw materials, the optimum value is W: T = (0.25 - 0.5): 1. As a result of the feedstock, leaching solution produces cake and productive solution. Then the cake is washed with an upward flow (from bottom to top) of the washing solution with the simultaneous displacement of the leaching solution. The washing solution is supplied to the column from the tank 4. The flow rate of the washing solution is lower than the fluidization rate of the feedstock. There is no mixing of the leach solution with the wash due to the lack of convective mass transfer in the thin pores of the feedstock. As a leaching solution, solutions from the series are used: aqueous and non-aqueous solutions of acids, bases, halogens, inorganic and organic salts. As a washing solution, water is used.

 As the leach solution moves, displaced from below by the wash solution, the metal (useful component) continues to be leached while the leached cake is washed from the leach solution. In this case, the flow rates of the leaching and washing solutions are less than the fluidization rate of the feedstock, i.e., the feedstock particles are not in suspension. The fluidization rate is determined experimentally for each type of raw material. The low speed of the washing and leaching solutions provide transparent productive solutions.

 The productive solution is drained from the nozzle in the upper part of the column. Then the washing solution is drained into another container. At the end of the process, the leached and washed material is discharged from the column, fresh raw materials are loaded and the process is repeated.

 For complex extraction of metals after processing and washing, additional processing and washing are carried out using various leaching solutions of the initial one. In this case, the leach solutions can be fed one after another with the subsequent displacement of them with a washing solution or to separate them from each other with a layer of washing solution.

 Example 1

 In a cylindrical column with a diameter of 100 mm and a height of 360 mm, 3 kg of gravity concentration waste with a gold content of 2.84 g / t was loaded. The feedstock is 76% represented by a clay-slurry fraction (less than 0.01 mm). At the end of the backfill, a leach solution containing 5 g / l sodium cyanide at pH = 12.3 was applied to the bottom of the column. The flow rate of the leach solution is 65 ml / hour. The fluidization rate of the feedstock is 300 ml / hour. After the appearance of the leaching solution on the surface of the backfill, its flow was stopped and washing was started with an upward flow of the washing solution, which was used as water, while the leaching solution was forced out of the column into the reservoir for collecting the productive solution. The flow rate of the washing solution is 70 ml / hour. Comparative results of metal extraction by the proposed method and prototype are given in table 1.

 The results presented in the table show that the proposed method allows to obtain more concentrated productive solutions at a lower consumption of leaching solution. After washing, the cakes contained less than 0.1 mg / L of cyanide, which is less than the MPC for discharge into open water bodies.

 Example 2

In a cylindrical column with a diameter of 100 mm and a height of 680 mm, 8 kg of pyrite cinders of sulfuric acid production with a grain size of 0.1 mm, containing 2.1 g / t of gold and 23 g / t of silver, were loaded. From the bottom, 2.8 L of leaching solution was fed into the column during the day, using an ammonia solution of sodium thiosulfate as the solution. The leach solution flow rate is 110 ml / hour. The fluidization rate of the cinder 600 ml / hour. Then the cake was washed with an upward flow of washing solution — a solution of calcium nitrate with a density of 1.08 g / cm ³ —with simultaneous displacement of the leaching solution. The flow rate of the washing solution is 100 ml / hour. The results of the experiment in comparison with leaching in the apparatus of the prototype are presented in table.2.

 As follows from the presented results, the proposed method allows to obtain more concentrated productive solutions for gold and silver at a lower consumption of leach solution. After washing, the cakes contained less than 1 mg / L of thiosulfate, which is less than the MPC for discharge into open water bodies (2.5 mg / L).

 Example 3

 3 kg of concentrate containing 400 g / t silver and 4 g / t gold were loaded into a cylindrical column with a diameter of 100 mm and a height of 360 mm. The concentrate was ground to - 0.074 mm (100%). At the end of the backfill, a leaching solution containing 3.8 g / l sodium cyanide at pH = 12.3 was applied to the bottom of the column. The leach solution was supplied at a rate of 100 ml / hour. The fluidization rate of the concentrate is 600 ml / hour. After pouring 1.5 L of the leach solution and the appearance of the latter on the surface of the backfill, its supply was stopped, after which the cake was washed with an ascending stream of the washing solution, which was used as a solution of sugar in water. The feed rate of the washing solution is 100 ml / hour. The results are shown in table. 3.

 As follows from the presented results, the proposed method provides more concentrated productive solutions in comparison with the prototype with a lower consumption of leaching solution.

 Example 4

 In a cylindrical column with a diameter of 100 mm and a height of 680 mm, 8 kg of pyrite cinders of sulfuric acid production with a grain size of 0.1 mm were loaded, containing 2.1 g / t of gold, 23 g / t of silver, 3000 g / t of copper and 6000 g / t of zinc . From the bottom, 2000 ml of a leaching ammonia solution of sodium thiosulfate was fed into the column during the day. Then, 500 ml of water was dispensed into the column at a rate of 200 ml per hour. After that, 500 ml of a solution of sulfuric acid with a concentration of 200 g / l was fed into the column, after which leaching and separation solutions displaced 5 l of water at a rate of 200 ml / hour. The fluidization rate of the cinder 600 ml / hour. Samples of the productive solution were analyzed for gold, silver, copper and zinc. The results of the experiment are given in table.4.

 As can be seen from the presented results, the proposed method allows the separation of valuable components in the leaching process using different composition of leaching solutions. At the same time, the boundary between leaching and separating (displacing) solutions is quite sharp, which makes it possible to obtain concentrated productive solutions and waste solutions that do not need to be neutralized.

Claims (4)

 1. A method of extracting metals from finely divided clay-sludge ore and industrial raw materials, comprising treating the feedstock with an upward flow of leaching solution and washing the cake with an upward flow of washing solution, characterized in that the raw materials are loaded onto a false bottom before treatment, treatment with a leaching solution is carried out at W: T equal to (0.25-0.5): 1, and the subsequent washing of the cake is carried out with the simultaneous displacement of the leaching solution from the raw material.  2. The method according to claim 1, characterized in that for the complex extraction of metals after processing and washing of the feedstock, additional processing and washing are carried out using different composition of leaching solutions.  3. The method according to claim 1 or 2, characterized in that as a leaching solution using solutions from the series: aqueous and non-aqueous solutions of acids, bases, halogens, inorganic and organic salts.  4. The method according to claim 1 or 2, characterized in that water is used as the washing solution.

Images