RU2119962C1 - Method of processing sulfide polymetallic materials - Google Patents

Abstract

FIELD: chemical technology, inorganic chemistry. SUBSTANCE: invention relates to a method of oxidation of iron sulfides in an aqueous pulp and isolation of sulfur-containing concentrate by flotation. Oxidation is carried out with air oxygen under natural storage conditions. Material as an aqueous pulp is subjected for mechanical treatment (mechanical activation) at intensity of energy feeding 1.4-1.7 kJ/s, not less. EFFECT: simplified method, decreased cost and consumption of process. 1 cl, 1 ex

Description

 The invention relates to non-ferrous metallurgy, namely to hydrometallurgy, to methods of heap and tank leaching of sulfide ores and concentrates, and can be used for the processing of sulfide polymetallic products during their storage in processing plants.

 Currently, a significant amount of non-ferrous and noble metals is contained in the form of isomorphic impurities or finely divided aggregates of complex topology with iron sulfides. For example, in the form of conditionally dumped industrial products and tails of selective flotation of polymetallic and gold-bearing ores. Their processing by pyrometallurgical methods, as a rule, is impractical. Hydrometallurgy does not have the ability to effectively open sulfide (for example, pyrite) products.

 Known methods for percolation (underground, heap, vat) leaching of sulfide products with an off-balance content of non-ferrous metals and gold ([1], p. 129-130), based on the transfer into a soluble form of valuable components and their subsequent extraction from the resulting productive solution. The main disadvantages of these methods are the low dissolution rate (up to several months in vats and years in heaps and underground), stringent requirements for particle size distribution (sludge must be removed) and texture, the use of environmental pollutants (solutions of cyanides, sulfuric and others mineral acids). There are known attempts to accelerate percolation leaching by applying high-frequency electrical effects, ozonation [2], but they are expensive and not effective enough.

 Known methods for autoclave leaching of iron-sulfide concentrates [3], based on the deep decomposition of iron sulfides with subsequent flotation separation of sulfur-sulfide concentrate of non-ferrous metals. The main disadvantages of these methods are large and capital and operating costs, sophisticated equipment. In addition, during the process at elevated temperatures, non-ferrous metals pass into solution, which requires the introduction of an additional operation for their deposition. Known attempts to improve the process due to preliminary mechanical (p. 162-170 [4]) or electromagnetic treatment of sulfide pulps [5]. But they were ineffective due to the lack of activators of sufficient productivity and the negative impact on the performance of subsequent operations of the hydrometallurgical cycle.

 The closest in technical essence and chemistry of the processes to the achieved result is a known method for processing pyrrhotite concentrate [6], according to which, to intensify the decomposition of pyrrhotite, the concentrate is preliminarily treated with a high-voltage electric discharge and then autoclaved oxidative leaching is carried out in aqueous pulps at a temperature above the melting point sulfur and excess oxygen pressure and other operations of the autoclave technology according to [3]. It is characterized by all the disadvantages characteristic of autoclave methods, namely, high costs, sophisticated equipment, and a complex technological scheme.

 The aim of the invention is to reduce the cost of processing iron sulfide concentrates, simplification and cost reduction of the process. This goal is achieved by oxidizing pre-treated to intensify the process of iron sulfides by atmospheric oxygen under mild conditions (atmospheric oxygen pressure and natural temperatures) using the oxidizing potential of the natural environment. As a preliminary processing of water pulps of the initial products, their mechanical activation is used - mechanical processing with an energy supply intensity of at least 1.4 - 1.7 kJ / s.

 The starting sulfides are thermodynamically stable under normal conditions. Energy-intensive processing increases their reactivity. However, it is believed that after 1.5 - 2 hours after treatment as a result of relaxation processes, the behavior of the activated fractions does not differ from the behavior of the initial fractions. We found that oxidation reactions initiated by mechanical impulses continue for a long time after the load is removed as a result of irreversible modification of the particle surface. The formed oxysulfate phase catalyzes the oxidation of iron sulfides by atmospheric oxygen in pulps under normal conditions, regenerating ferric iron, a strong oxidizing agent. The oxidation chemistry is similar to autoclave leaching: the formed iron sulfates are hydrolyzed to goethite and hematite, part of the sulfide sulfur passes into elemental form. Thus, the conditions for opening the sulfide feedstock during storage (tailing dump, dump) are created, oxidation proceeds relatively slowly with the autoclave, but does not require any additional capital and operating costs. Non-ferrous metal sulfides under these conditions (low temperatures) are thermodynamically stable. Almost complete decomposition of pyrrhotite is achieved in 6-8 months, pyrite decomposes for more than a year. After the decomposition of most of the iron sulfides, determined by the requirements of the technology, the sulfur sulfide concentrate is separated from the oxides by flotation.

 An example of a specific implementation of the method.

 The pulp of the pyrrhotite concentrate (freshly obtained or pulped stale) is processed in a centrifugal planetary mill (30g) with a solid flow rate of 3-5 kg / s, which provides an energy supply intensity of ≈1.5 kJ / kg, and is sent to the tailing dump. During storage, oxidative processes occur, leading to the decomposition of iron sulfides. Taking into account climatic conditions, decomposition of 80-90% pyrrhotite with conversion of 26-28% sulfide sulfur to elemental sulfur is achieved in 1.5-2 years. The man-made deposit thus formed is subject to development. Flotation produces a sulfosulfide concentrate enriched in non-ferrous metals by 2-5 times. The degree of enrichment depends on the content of iron sulfides in the feedstock and the degree of their decomposition.

Literature
1. Handbook of ore dressing. Special and auxiliary processes, enrichment tests, control and automation / Ed. O.S. Bogdanova, V.I. Revnivtseva, 2nd ed., Rev. and add. -M .: Nedra, 1983, 376 p.

 2. The method of leaching of sulfide ores and concentrates. Aator's certificate 815059.

 3. Schneerson Ya.M., Voronov A.B., Sirkis A.L. Complex processing of sulfide copper-nickel raw materials by the method of oxidative autoclave leaching // Non-ferrous metals, 1984, N 8, p. 21-24.

 4. Kulebakin V.G. The use of mechanochemistry in hydrometallurgical processes. - Novosibirsk: Nauka, 1988, 272 p.

 5. Ermakov V.I., Khalezov I.B., Rybakov Yu.S. and before. The influence of the electromagnetic field on the leaching of non-ferrous metal ores // Abstracts of the IX All-Union meeting on the kinetics and mechanism of chemical reactions in solids, Alma-Ata, May 1986, Chernogolovka, 1986, v. 1, p. 173-174.

 6. A method of processing pyrrhotite concentrate. Copyright certificate 1379332.

Claims (1)

 A method of processing a sulfide polymetallic material, including the oxidation of most of the iron sulfides in an aqueous pulp and the allocation of sulfur-sulfide concentrate by flotation, characterized in that the oxidation is carried out with atmospheric oxygen under natural storage conditions, and the material in the form of an aqueous pulp is subjected to mechanical treatment (mechanical activation) beforehand with an intensity of energy supply not less than 1.4-1.7 kJ / s.