RU2130340C1 - Method for concentrating useful metallic minerals - Google Patents

Abstract

FIELD: concentration of native ore elements and native alloys of gold, silver, copper, metals of platinum group and other kinds of high-forgeability minerals. SUBSTANCE: method involves multiple-stage crushing, grinding and screening of rock into several products relatively homogeneous by size; grinding the largest fraction by impacts and concentrating by screening till concentrate of tough (forgeable) useful minerals is left on screening surface and friable minerals opened during impacting fall into undersize fraction. Grinding and screening operations with smaller fraction are conducted till fraction sizes of 0.08 or 0.074 mm are obtained. Method allows concentrates with content of useful component approximating 99% to be produced by enlarging forgeable particles. EFFECT: increased efficiency in producing concentrates with increased content of useful component, simplified ecologically clean method and reduced production cost.

Description

 The invention relates to the field of ore processing of native elements and natural alloys - gold, silver, copper, platinum group metals and other types of useful minerals with high ductility (ductility).

 In relation to ores of native elements and alloys in all technological enrichment schemes, operations such as disintegration, screening, crushing, grinding and classification by size of a piece are preparatory, providing the following basic and expensive processes for mineral processing - gravity, flotation, chemical, electrical (Mining business. Terminological reference book. M., Nedra 1990, 694 p.).

 The main disadvantages of technological schemes and cycles in general: 1) re-grinding of the useful component and the complexity of the operations for its extraction; 2) obtaining a collective concentrate and the need for additional operations for its separation; 3) the inevitability of environmentally hazardous operations and the use of a complex of treatment facilities; 4) in all flotation and chemical enrichment methods - high consumption of water, oils, reagents.

 Closest to the invention is a method based on the use of different grinding speeds of ore components, which leads to the accumulation of part of free gold and gold pyrite in the circulating load of the mills at the 2nd and 3rd stages of grinding and subsequently allows the gravitational conclusion of this part gold and gold pyrite from the grinding cycle into a separate concentrate (Nekrasov B.D., Sulina Yu.P., Nazarova E.P. et al. Using the mineralogical composition of pyritic copper-zinc ore for improving the scheme of its enrichment, - In the book: The material composition and enrichment of mineral raw materials. M., Nauka, 1978, S. 223 - 225).

 The disadvantages of this method are: unregulated process, the need to use, after two to three stages of grinding, the gravity method of enrichment with further gold extraction by amalgamation, cyanidation, flotation.

 The purpose of the invention is to increase the efficiency, environmental safety and reduce the concentration of ores of native metals and alloys and other minerals by drastically reducing the number of stages and operations in the beneficiation cycle and using such a grinding and screening sequence that allows the product to be enriched during sieving.

 The essence of the invention lies in the fact that the rock is crushed, crushed, classified into several relatively uniform in size products; the largest fraction is crushed by impact and enriched by screening, repeating grinding and screening until a concentrate of viscous (malleable) useful minerals remains on the sifting surface, and brittle nonmetallic and newly discovered ore minerals of small sizes go into the under-sieve fraction; the same grinding and screening (enrichment) operations are carried out with the next, finer fraction, and so on to a fraction of +0.08 (or +0.074) mm inclusive.

 The invention is based on the use of natural differences in the viscosity (brittleness) of useful minerals, on the one hand, and minerals that do not represent immediate practical value under given conditions, on the other hand. Typical widespread non-metallic brittle minerals include most rock-forming silicates - quartz, feldspar, amphiboles, pyroxenes, olivines, almost all sulfides, sulfosalts, arsenides, oxides, hydroxides, carbonates, sulfates. These minerals are destroyed by mechanical impact when a certain degree of destruction passes through a sieve with a given diameter of the hole. In contrast, particles of native metals, alloys, and some sulfides with a high value of viscosity (ductility) change under the influence of shock loads (deform) without breaking the continuity; the numerical characteristic of the shape of the piece changes in the direction of increasing the length D and width W (hence, the cross-sectional area) and decreasing the thickness E. Moreover, the deformed piece, due to an increase in two parameters, not only does not pass through the sieve of a given class, but can also larger class.

 Due to these differences in the crushability of minerals, useful components can be enlarged during crushing and grinding and enriched by screening crushed rock.

 In the proposed method, the rock containing native minerals is subjected to preparatory crushing, grinding and sieve classification with fractional fraction, depending on the size range of useful particles in the ore. Preparatory crushing and grinding is carried out to a maximum piece size equal to the maximum particle size of the useful mineral contained in the ore of this deposit. All further operations relate to the main methods of mineral processing: the largest fraction is subjected to regrinding and dumped onto a sieve classifier; the resulting oversize fraction is again crushed and dumped onto the same classifier; the operations are repeated until the viscous (unchained) useful minerals or concentrate containing a predetermined amount of the useful mineral is obtained on the screening surface of the first (top) sieve; brittle non-metallic minerals destroyed by grinding and exposed small-sized ore mineral particles go into the sublattice fraction and are distributed according to the corresponding particle size classes. To enrich the next, finer fraction, reduce the clearance of the grinding device or use a second machine with a predetermined lower clearance; re-grinding and screening of this fraction until relaxed useful minerals remain on the screening surface of the first (top) and second sieve; in the same way enrichment (regrinding and screening) of the third, fourth and all subsequent fractions is carried out, up to the fraction +0.08 mm inclusive.

 The application of this method in the option of dry grinding and screening is possible up to a fraction, including +0.08 mm; smaller fractions are enriched in pneumatic cyclones or in a closed cycle "pneumatic cyclone - crusher - screen with sieves 0.08 and 0.04 mm".

 Example 1. A sample of gold-quartz ore of the vein deposit Dukat weighing 10 kg with a free gold content of 560 g / t is crushed on a jaw crusher to -30 mm, crushed on a hammer mill to -3 mm, divided by a sieve classifier into 6 fractions.

 The -3 + 2 mm fraction is crushed in one stage in a cone crusher of the KID brand and passed through the same sieve classifier; gold nuggets and its intergrowths with quartz and galena were caught on a sieve with a hole diameter of 2 mm (10 wt.% of all gold extracted during the entire enrichment cycle of this sample).

 The fractions -2 + 1 mm are crushed in one stage in the same cone crusher and lowered into the classifier. On a sieve with d 1 mm weakly deformed particles of gold are caught and, in addition, on a sieve with d 2 mm, flattened nuggets (only 20 wt.%) Are caught. After reducing the cone gap, the fractions of -1 + 0.2 mm are crushed in three stages until a pure gold concentrate is obtained on a sieve with d 0.2 mm (60%) m, in addition, flattened gold particles are caught on a sieve with d 1 mm ( 5%). After reducing the cone gap, the fraction of -0.2 + 0.08 mm was crushed in 4 stages to obtain 0.08 mm 2% gold on a sieve with d. After reducing the cone clearance to a minimum, the fraction of -0.08 + 0.04 is ground in 3 stages to obtain a sieve with d 0.04 mm 1% gold. After de-islamation of the fraction, -0.04 is twice crushed on a cone crusher; 0.5% gold is obtained on a sieve with d 0.08 mm, 0.6% gold on a 0.04 mm sieve. The lamellar sublattice fraction contained a collective concentrate of sulfides and gold (0.2% gold of its total weight in the sample).

 Thus, 95% of the total mass of gold was captured in crushing-screening operations in fractions of -2 + 0.2 mm, 5% in the remaining fractions.

 Example 2. Quartz-carbonate-copper vein ore from the Kondopoga Basalt deposit weighing 10 kg is crushed on a jaw crusher to -30 mm, divided by a sieve classifier into 6 fractions. The -30 + 3 mm fraction was crushed in one stage in a cone crusher of the KID brand and lowered into the same classifier. On a sieve with d 3 mm, 91% of native copper (of the total extracted mass) was obtained, including flattened nuggets up to 4.5 cm long. After refinement and screening of the fraction -3 + 1.25 mm, on a sieve with d 1.25 mm concentrated 2.5% of native copper. In addition, 2.72% of the copper was retained on a sieve with d 3 mm. After refinement and screening of the -1.25 + 0.2 mm fraction due to flattening and enlargement of some of the grains of native copper, 2.13% of copper passed to a sieve with d 1.25 mm, 0.4% of copper remained on a sieve with d 0.2 . In subsequent operations, a sieve with d 0.08 mm 0.15% copper was left, 0.5% copper was transferred to a sieve with d 0.2 mm; 0.7% of copper remained on a sieve with d 0.04 mm, 0.18% of copper passed to a sieve of 0.08 mm. 0.12% copper was consumed in the -0.04 mm sublattice fraction with a content of 0.025% in this product. After deslamation and double completion, 0.07% of copper remained on a 0.04 mm sieve, 0.12% of copper in a lined sublattice concentrate.

 Thus, the total recovery of +0.08 mm into the collective product was 99.67% copper.

 Example 3. A sample weighing 2 kg of silver quartz-manganesederite-sulfosol ore from one of the deposits in Yakutia was crushed manually, divided by a sieve classifier into 6 fractions. Successive enrichment by grinding-screening method made it possible to extract native silver in an amount from the total mass of extracted native metal), by groups of fractions: -20 + 1.25 mm - 33%, 1.25 + 0.08 mm - 59.3%, - 0.08 + 0.04 mm - 4.6 :, -0.04 mm - 3.1%

Claims (1)

 A method of beneficiation of metallic minerals, based on multi-stage crushing, screening, grinding of rock, obtaining a concentrate with a given content of useful components, characterized in that the rock is crushed, crushed, classified into several relatively uniform grain sizes, the largest fraction is crushed by impact and enrich with screening, repeating grinding and screening until a concentrate of viscous (malleable) useful minerals remains on the screening surface, and pkie nonmetallic and again uncovered when struck ore minerals in the small size depart undersize fraction, the same operations of crushing and screening (enrichment) is performed with the next finer fraction to fraction and so +0.08 (or 0.074) mm inclusive.