RU2293844C2 - Method for underground lixiviation of non-ferrous metal ores - Google Patents

Abstract

FIELD: mining industry, possible use for extracting nickel.

SUBSTANCE: method includes creation of force and product mines, forcing lixiviating acid solutions into force mines with oxidizing and following extraction of ore bed, output of productive solution through product mines, refining of solution. Treatment with sulfurous solutions with their delay in formation is performed at pH≤1,5, and productive solutions are drained at pH≤1,0.

EFFECT: simplified technology, decreased flow of reagents, increased recovery of main metal.

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Description

The invention relates to mining and can be used for underground leaching of non-ferrous metal ores, in particular nickel, cobalt, etc.

A known method [1] of underground leaching of metals from ores, which includes opening the ore deposits by wells, placing casing strings, filters, heads and electrodes in them, supplying technological solutions and electricity. What is new is that when technological solutions and electric energy are supplied, the migration of solutions and electric current are directed across the stratification of leached minerals.

The disadvantage of this method is the complexity of the technology, requiring knowledge of the exact structure of the seams, special electrical equipment and is characterized by insufficiently high recoverability of metals due to the dependence of this process on the slightest mismatch of the bedding of the layers and crystal lattices. minerals with electrical parameters.

The prototype of our invention is a method [2] of underground leaching of non-ferrous metal ores at the place of their occurrence, including the creation of injection and pumping mine workings, feeding leaching acid solutions to the pumping workings with acidification and subsequent mining of the ore formation, withdrawing the productive solution through the pumping workings, processing the solution , which consists in the fact that acidification is carried out with the aging of the solutions in the formation and bringing the pH to> 3.0 in the presence of an oxidizing agent, productive solutions are removed at a pH of 1.5-2 5 and gradually raise it to the end of leaching to 3.0, then the pH in the formation is raised above 3.0 with the introduction of the oxidizing agent.

The disadvantage of this method is the complexity of the technology, in which it is necessary to change the pH at least 4 times in one technological cycle, which requires the creation of a complex technology for supplying expensive reagents to the ore body, without achieving high levels of extraction of the base metal into the solution.

The tasks to which this invention is directed is to simplify the technology, reduce the consumption of reagents and increase the yield of the base metal, in this case nickel.

This problem is solved in that in the method of underground leaching of non-ferrous metal ores, in particular nickel and cobalt, at the place of their occurrence, including the creation of injection and pumping mine workings, the supply of leaching solutions of acid to the injection workings with acidification and subsequent mining of the ore formation, the conclusion of the productive solution through pumping outs, processing of the solution, acidification with sulfuric acid solutions with their aging in the reservoir are carried out at pH≤1.5, and productive solutions are removed at pH≤1.0.

When acidified with sulfuric acid solutions with their aging in the formation at pH≤1.5, the maximum amount of nickel is leached. However, at the same time, a sufficiently large (from 10 to 35 g / l) ferric iron passes into the solution. The latter, if the pH of the solutions remains unchanged in the form of hydroxide, will begin to precipitate when it is still in the ore bed, coprecipitating nickel with it. The content of the latter in freshly precipitated sediments reaches 1.5–3.0%, which reduces its extraction by 10–20%.

When acidified with sulfuric acid solutions with their aging in the formation at pH≤1.5 and the withdrawal of productive solutions at pH≤1.0, the precipitation of iron hydroxide, accompanied by the deposition of nickel, is prevented, which allows along with simplification of the technology (it is not necessary to change the pH of acidifying solutions several times ), by reducing the consumption of reagents (acidification occurs once with a small consumption of acid) to achieve an increase in the yield of the base metal, in this case nickel. Examples of implementation are given in the table.

Table No. Type and characteristics of oxidized nickel ore Underground leaching time, days The content of Fe in the productive solution, g / l The Ni content in the productive solution, g / l pH Nickel recovery in solution,% when acidified productive solution Ore of the 1st type, composition wt.% Iron - 30% Magnesium Oxide - 14% Silica - 35% Nickel - 1.2% one thirty 35 2,5 1.3 ≤1.0 60 2 thirty 33 2,5 1,5 1,0 60 3 thirty 1.9 2.0 > 2.0 > 1.5 40 Ore of the 2nd type, composition wt.% Iron - 10% Magnesium Oxide - 40% Silica - 20% Nickel - 0.7% one thirty 12 1,0 1.3 ≤1.0 70 2 thirty 10 1,0 1,5 1,0 70 3 thirty 0.9 0.8 > 2.0 > 1.5 fifty

The leaching of acid solutions into the injection workings with acidification and subsequent mining of the ore bed was carried out with the initial acidity of the solutions for ores of the first composition 100 g / l, for the second 150 g / l., Which, after partial neutralization due to interaction with the carbonate components of the rocks, reached pH level 1.3-1.5 (see experiments 1-2 tables). This level was maintained for 30 days. The productive solution after acidification to pH≤1.0 through the pumping out was removed and analyzed.

As the results of experimental work, the implementation of the technology according to the invention (experiments 1-2 tables) allows, along with simplification of the technology (it is not necessary to change the pH of acidifying solutions several times), while reducing the consumption of reagents (by 4-5% (acidification occurs once with a small flow acid) to increase the yield of the base metal, in this case, nickel by 20% compared with the known method (experiments 3 tables).

Information sources

1. RF patent No. 2092687, cl. E 21 B 43/28 "Method for the underground leaching of metals", applicants Vorobyov A.E., Zabelsky V.K. et al., publ. 10/10/1997, application No. 95105622/03, 04/04/1995

2. RF patent No. 2003106536, cl. E 21 B 43/00 “Method for the underground leaching of non-ferrous metal ores containing reducing agents at the site of occurrence", applicants Grebnev G.S., Zabolotsky A.I., Savenya N.V. et al., publ. 20/09/2004, Application No. 2003106536/03, 07/03/2003

Claims (1)

The method of underground leaching of non-ferrous metal ores, in particular nickel, at the place of their occurrence, including the creation of injection and pumping mines, feeding leaching solutions of acid to the pumping mines with acidification and subsequent mining of the ore formation, the output of the productive solution through the pumping mines, processing solution different the fact that acidification with sulfuric acid solutions with their aging in the formation is carried out at pH≤1.5, and productive solutions are removed at pH≤1.0.