RU2044083C1 - Granular materials lixiviation method - Google Patents

Abstract

FIELD: granular materials lixiviation. SUBSTANCE: granular materials lixiviation method provides for solution infiltration through material layer and separate separation of products from process. Separated from process of infiltration solution and material are combined, agitated, separated and fed once more in process of infiltration. In the case, for agitation they use 10 100 mass per hour from total amount of material. Agitation lixiviation is exercised with L:T (3-10) 1. EFFECT: Method facilitates process of lixiviation and increases output of valuable components extraction. 3 cl, 2 tbl

Description

 The invention relates to hydrometallurgy and can be used for leaching of granular materials.

A known method of leaching of granular materials by leaching a leach solution through them, followed by unloading the material and solution [1]
However, this method is ineffective due to the low speed of the process and low gold recovery (70-80%).

The closest in technical essence and adopted for the prototype is the camir process of leaching of gold and silver, including the supply of a leach solution from below through an ore layer. In this case, the solution is discharged from above, and the leached ore is discharged from below [2]
The disadvantages of this method is the duration of the process and the low recovery of gold.

 The objective of the invention is to eliminate these disadvantages.

 The essence of the invention lies in the fact that, in the known leaching method, which includes letting the solution through a layer of material and separately and continuously removing products from the process, according to the invention, the solution and material removed from the leakage process are combined, agitated, then separated and re-introduced into the leakage process. Moreover, 10-100 wt. per hour of the total amount of material and lead agitation leaching at W: T (3-10): 1.

 In the present invention, a part of the material (10-100 wt. Of the total amount) is removed from the process of percolation leaching (seepage) and is subjected to intensive agitation leaching (for 1-5 s) with highly turbulent movement of solid particles and solution. Such intensive mixing is especially effective with a high ratio of W: T, since dilute solutions (pulps) have a high activity and, in addition, in dilute solutions, the maximum concentrations of valuable components that prevent their dissolution are not reached.

 After agitation, the material and the solution are again fed to the leach by seepage, where further dissolution of the valuable components takes place.

 Conventional agitation leaching of granular materials is usually carried out at a ratio of W: T (0.8-2): 1, since solid particles are maintained in suspension by creating a high pulp density. However, the leaching of thick pulps is slow and incomplete due to the low diffusion rate of the reactants to the gold surface and the removal of leachate products. In the case of increasing W: T (degree of dilution of the pulp), firstly, the volume of equipment increases; secondly, pulp exfoliation occurs and to maintain solid particles in suspension (for mixing) additional energy costs will be required.

 Therefore, for effective leaching, it is enough to remove from the percolation process only a part of the material, the value of which is 10-100 wt. per hour of the total amount of material established experimentally and subject it to intense turbulent mixing. Such agitation leaching is possible with a high W: T equal to (3-10): 1, the value of which was also established experimentally.

 Thus, the invention, due to the withdrawal of part of the material from the process of leaching to agitation leaching and its subsequent return to the percolation process, allows, by intensifying the process of leaching of granular materials, to increase the extraction of a valuable component.

 PRI me R 1 (prototype). As a starting material, an intermediate product of refinement of a gravitational gold-containing concentrate with a gold content of 250 g / t is used. Material in an amount of 1.2 tons with a particle size of 20% minus 0.074 mm is constantly loaded into the upper part of the column and treated with a cyanide solution with a concentration of 2 g / l by passing the solution from the bottom of the column. The speed of loading the column with material is equal to the speed of unloading the column.

The solution, seeping (under hydrostatic pressure) through a layer of material, dissolves the gold and at the end of the process merges through the top of the column. After this, the gold-containing solution is sent to cementation, where gold is extracted. The leached material is loaded with the strokes available in the column into the pan, where it is washed with water and analyzed. During the experiment, six tail samples were taken for analysis. After averaging, the gold content in cyanidation tails was 50 g / t, which corresponds to 80% gold recovery
The rate of unloading of sands was selected in such a way that the residence time of the material in the apparatus was 48 hours

 Similar experiments were conducted with a duration of stay of material in the apparatus of 24 and 72 hours

 The results are presented in table 1.

 PRI me R 2 (according to the invention). A cyanide solution was passed through a column continuously loaded with the same material (but without strokes) as in Example 1. At the same time, sands (50 wt. Per hour of the total amount of material, which corresponds to 600 kg / h) were unloaded into the pump sump from the bottom of the column by gravity . The solution, seeping through a layer of material, is discharged through the top of the column and is also fed to the sump, where the necessary ratio W: T 6: 1 is created. The resulting pulp is pumped to the hydrocyclone, where it is separated into sands and solution. In the sump, pump, pipeline and hydrocyclone, intensive mixing (within 1-5 s) takes place in a highly turbulized stream. In the pipeline, leaching occurs under pressure, which further intensifies the dissolution of gold. The rapid dissolution of precious metals is also facilitated by the very good oxygenation of the cyanide pulp, which occurs in the sump, pump, piping, hydrocyclone and the top of the column.

 Sands fall into the upper part of the column, in which the material is again subjected to percolation leaching. With the withdrawal of 50 wt. per hour of the total amount of material, which corresponds to 600 kg / h, the duration of the percolation cycle for an individual particle was 2 hours, after which the material again fell on agitation leaching and then again on percolation.

 A total of 24 turns of material were carried out, i.e., the sands were discharged 24 times into the sump, campaigned, got into the hydrocyclone, and then into the column for percolation leaching. The total duration of the leaching process was 48 hours, of which almost 48 hours were spent on percolation leaching, and 70-80 seconds on campaigning.

 The solution after hydrocyclonation through an intermediate tank enters the bottom of the column under a small hydrostatic pressure of 0.5-1.0 atm into the percolation leaching process.

After leaching was completed, the gold-containing solution was drained from the column, intermediate tanks and highways. The leached sands were washed in the column with water supplied to the bottom of the column. The washed cyanidation tails were unloaded by gravity into the hopper. After averaging, samples were taken for analysis. The gold content in cyanidation tails was 22 g / t, which corresponds to a gold recovery of 91.2%
Similar experiments were carried out with a leaching process of 24 and 72 hours.

 The effect of leaching duration on gold recovery is presented in Table 1.

 Gold-containing solutions were combined with prom solutions; gold was recovered from the combined solution by carburization.

 As can be seen from table 1, the proposed method of leaching of granular materials in comparison with the prototype can significantly intensify the process and increase the extraction of gold at almost equal energy costs.

 The dependence of gold recovery on process parameters is presented in table 2.

 From table 2 it follows that the optimal conditions for the process are the amount of material displayed on the campaign per hour and the corresponding 10-100 wt. and the ratio W: T during agitation, equal to (3-10): 1. When withdrawing for agitation, more than 100 wt. per hour of the total amount of material, energy costs increase (it is necessary to install a more powerful pump), which do not lead to an adequate increase in gold recovery; when removing less than 10 wt. the extraction of gold falls per hour of the total amount of material.

 With a dense pulp (W: T <3: 1) it is difficult to organize its transportation due to the sanding of the equipment; in addition, with dense pulps, the hydroclassification process becomes ineffective. To agitate too diluted pulps (W: T> 10: 1), additional energy costs are required, an increase in equipment volumes (due to an increase in pulp volumes), which reduces the efficiency of the claimed process.

 Thus, the proposed method of leaching of granular materials allows to intensify the process and increase the extraction of valuable components (for example, gold and silver).

Claims (3)

 1. METHOD FOR LEACHING GRAIN MATERIALS, including the solution percolating through a layer of material and the separate and continuous removal of products from the percolation process, characterized in that the solution and material removed from the percolation process are combined, agitated, separated and re-introduced into the percolation process.  2. The method according to claim 1, characterized in that 10-100% wt. / h of the total amount of material.  3. The method according to claim 1, characterized in that the agitation is carried out with a ratio of W: T equal to 3-10: 1.

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