RU2624497C2 - Method for flotation of refractory complex ores of noble metals - Google Patents

Abstract

FIELD: mining engineering.

SUBSTANCE: method of flotation of refractory complex ores of noble metals includes grinding refractory complex ore of noble metals down to 0.1-0.5 mm, directing it to gravitational differentiation with the formation of conditionally called "heavy", "intermediate" and "light" fractions having different physical properties in terms of density, size and morphology of the disclosed particles and mineral phases, and flotation of these fractions in separate cycles to obtain a combined gold-containing sulphide concentrate. Gravitational differentiation is done on screw units with a large area of the separation surface and applying centrifugal forces. With the gravitational differentiation, the outputs of the "heavy", "intermediate" and "light" fractions are maintained close to the percentage ratio of 10:45:45, respectively. The "heavy", "intermediate" and "light" fractions of gravitational differentiation enter flotation in separate cycles in a closed circuit with basic and control operations. If necessary, the "heavy" fraction of gravitational differentiation is re-milled prior to the flotation. If necessary, the combined gold-containing sulphide concentrate is recleaned. The flotation of fractions of gravity differentiation is carried out at a pulp pH of 5.5, a pulp density of 30% solid, a liquid glass rate of 400-500 g/t, a butyl xanthate of 250-300 g/t, pine oil of 70-80 g/t, polyacrylamide when flotation of the "light" fraction is 8-10 g/t with a dosage in control operations twice smaller than the amount of collector and foaming agent, and in recleaning - three times smaller than the quantity of reagents.

EFFECT: increase of efficiency of enrichment of refractory complex ores of noble metals with an increase of qualitative and quantitative parameters of processing and reduction of losses of valuable components.

7 cl, 2 ex

Description

The invention relates to non-ferrous metallurgy, in particular to the enrichment of ores of precious metals, and can be used in mining and processing and metallurgical industries for the processing of natural and man-made mineral raw materials.

The modern subsoil use strategy is aimed at a balanced consumption of natural resources with a high degree of complexity and rationality of their use. The trend of a steady deterioration in the quality of mineral raw materials of precious metals, accompanied by the depletion of reserves of rich, easily ore-rich ores, has led to the need to involve complex ores with a variable and complex material composition, low valuable and elevated harmful components, with disseminated mineral phases from thin to emulsion, with a high proportion of slurry component.

Flotation refers to one of the main methods of beneficiation of precious metal ores along with gravity. The problems of flotation processing of refractory refractory gold-bearing ores are caused by thin intergrowth of ore minerals among themselves and with rock minerals; the presence of gold in sulfides and rock minerals, the presence of “invisible” forms of noble metals of emulsion dimension and in colloidal form, the presence in ores of natural gold solvents (mercury, fluorine, iodine, etc.), harmful impurities and components with high sorption activity, for example, organic phases, clay-micaceous minerals, etc. To reveal mineral complexes of finely disseminated ores, fine and ultrafine grinding of ore is required to the first micrometers, as a result of which the amount of Amines, the efficiency of separation processes sharply decreases, technological indicators of processing deteriorate, metal losses increase and, in general, also due to the highly developed surface of finely ground material, its sorption ability increases, which during flotation processing leads to an increase in pulp viscosity, worsening of the conditions for fixing flotation reagents to the surface sulfides and native gold, including an increase in the consumption of reagents and the duration of flotation, the need to expand the front of the opera ations, the degree of reduction of the mineral phases of selection, complexity of wastewater treatment systems, which affects the production costs. Ultrafine grinding requires special equipment and high energy consumption. It should be borne in mind that the cost of grinding ore is 80% or more of the total cost of ore preparation before beneficiation. The schemes and technologies of mechanical enrichment of refractory ores are becoming more complicated, and the efficiency and profitability of their processing are reduced. Of particular relevance in such conditions is the technology of ore preparation, preliminary ore dressing, and the intensification of subsequent technological operations in various ways. In the flotation of precious metal ores, there are many ways to intensify the process, including ultrasonic and high-pulse treatment of water, pulp, reagents, steaming, purging the pulp with nitrogen, oxygen and oxygen-containing gas mixtures, the addition of bioactive substances, modification of parts and components of standard equipment, the use of combinations of reagents and catalysts, etc.

There is a method of extracting fine particles of precious metals from placers, including disintegration, screening according to class 10 mm with the withdrawal of a class with a particle size of more than 10 mm into a dump, washing with vibration classification of the material according to a class of 2 mm, screw separation of a class with a particle size of less than 2 mm to obtain tailings and clay fraction , which are discharged into the dump, and the concentrate entering the screw cleanup separation with the tailings to the dump. The concentrate of the purification screw separation is refined on the concentration tables to obtain the finished concentrate and tailings (US Pat. RU 2548272, V03V 7/00, V03V 5/52, publ. 04/20/2015).

The disadvantage of this method is the significant loss of fine, microscopic and submicroscopic gold with six waste products at all stages of processing.

A known method of extracting gold and a device for the enrichment of gold-containing raw materials, including cleaning pulp of gold-containing raw materials from particles of maximum particle size greater than ~ 1.5 mm and less than ~ 0.04 mm, separation of the pulp into fractions with different maximum particle sizes by hydroclassification, the direction of each fraction to vibroconcentration the concentrates of which are separately enriched on concentration tables with additional concentration of superconcentrates by magnetic and electrostatic separation (Pat. RU 2483807, B03B 9/00, publ. 06/10/2013).

The disadvantage of this method is the loss of fine, microscopic and submicroscopic gold at the stage of refining, where material with a particle size of more than 1.5 mm and less than 0.04 mm is removed from the process, and at the stage of gravitational enrichment of fractions with a particle size of less than 0.2 mm.

A known method of extracting gold from poor low-sulfide ores, including crushing of gold-bearing ores with a low content of heavy sulfide component, three stages of grinding with intercyclic preliminary centrifugal jigging and withdrawal of tailings from the third stage of preliminary enrichment and directing the jigging concentrate to gravity dressing, the concentrate of which is fed to refinement and tails - for flotation with the production of tailings and concentrate, which together with gravity concentrate follows ultrasonic processing goes to cyanidation sorption and desorption (US Pat. 2,465,353, S22V 11/00 (2006.01), publ. 27.10.2012).

The disadvantages of the method are the limitation of the use of the method by ores with a low content of a heavy sulfide component and significant losses of gold with dump tailings of the depositing stage and fine grades of flotation tailings. In addition, the gravity method (depositing) is used as an enrichment tool based on one determining property of raw materials (density), and not as a means of preparing the material for further enrichment, taking into account the totality of the technological properties of mineral ore complexes.

The closest in technical solution and the achieved result is a method for beneficiating polymetallic ores, including the classification of the initial ore, depositing to obtain heavy, light and dump fractions, collective flotation of the light fraction together with the fine classification product, selective flotation of the combined collective flotation concentrate and heavy deposition fraction ( Pat. SU 811559, B03B 7/00, B03D 1/00, publ. 07.27.1999).

The disadvantage of this method is the need for regrinding of the heavy and light jigging fractions before flotation, that is, the whole mass of ore, which leads to increased sludge formation during fine and ultrafine grinding and, consequently, an increase in the loss of valuable components and energy consumption, to which losses with a dump jig fraction are added.

The purpose of the present invention is to increase the flotation efficiency of refractory refractory noble metal ores with the most achievable extraction of valuable components into conditioned products and minimize their losses by gravitational differentiation of the feedstock into fractions according to the combination of physical properties.

The technical result is an increase in the concentration efficiency of refractory refractory ores of precious metals with an increase in the qualitative and quantitative indicators of processing and a decrease in the loss of valuable components.

The essence of the invention is as follows. Many modern types of noble metal ores are characterized by "double" and even "triple" tenacity, due to the presence of ordinary and poor splices of valuable minerals among themselves and with rock minerals or splices of the closed type, the presence of mineral complexes and splices with an intermediate (4-6 g / cm) density and peculiar morphology, a high proportion of clay-micaceous components that are carriers of submicroscopic and colloidal gold. All these factors reduce the degree of contrast of technological properties (gravitational, flotation, magnetic). When flotation selection of such ores without special preliminary ore preparation, all of these factors cause the loss of precious metals. The use of gravity apparatus with a large separation surface at the ore preparation stage, combined with the application of centrifugal forces, makes it possible to differentiate the initial ore into "narrow" fractions, which differ simultaneously in density, size and morphology of the discovered particles and mineral phases. These principles are implemented on screw devices. Gravity differentiation according to the totality of physical properties is not an operation of gravity concentration (enrichment itself) and does not provide for the production of finished products, but is an operation of ore preparation.

Refractory refractory noble metal ore ground to fineness of 0.1-0.5 mm or tails of preliminary gravity dressing of the same size are sent to gravitational differentiation on a screw apparatus with a large separation surface area to obtain the conditionally called “heavy”, “intermediate” and “light” fractions having a different set of physical properties in terms of density, size and morphology of the disclosed particles and mineral phases. The size of the grinding before differentiation is determined by the size of the disclosure of the bulk of the minerals of the carrier of gold. During gravitational differentiation, the outputs of the “heavy”, “intermediate” and “light” fractions are maintained close to the percentage ratio of 10:45:45, respectively. The specified percentage ratio of the fractions yields corresponding to the optimal distribution of the material over the set of physical properties is regulated by the operating parameters of gravitational differentiation according to the state of the helical water flow, mass transfer of mineral particles in the trench and stratification, according to morphological characteristics. Each selected fraction of gravitational differentiation enters a separate flotation cycle, which includes the main and control operations to obtain sulfide gold-bearing concentrates, intermediate products and tails. If necessary, the “heavy” fraction is refined before flotation, and the combined gold-containing sulfide concentrate is refined. The density of the pulp during sulfide flotation is 30% solid; nomenclature and consumption of reagents used: sulfuric acid (slightly acidic medium, pH 5.5), liquid glass - 400-500 g / t, butyl xanthate - 250-300 g / t, pine oil - 70-80 g / t; during flotation of the light fraction, a flocculant (polyacrylamide, 8-10 g / t) is additionally fed.

The method allows one to obtain sulfide gold-bearing concentrate containing 50-54 g / t gold with 70-80% recovery from a poor and ordinary refractory refractory ore with a gold content of 1-4 g / t according to a closed-cycle scheme. The quality of the obtained flotation concentrates increases by 20-30% with an almost one and a half increase in the degree of extraction compared with the flotation process without prior differentiation.

A significant difference of the claimed invention and its advantages in comparison with the prototype and other known technical solutions is that the proposed flotation method improves the concentration of refractory refractory noble metal ores by gravitational differentiation of raw materials based on the formation of fractions with different ratios of mineral complexes and phases with different densities , size, morphology of the revealed particles and mineral phases with an increase in the qualitatively-quantitative pok ence of processing and reduction of losses of valuable components.

Example 1

In the partially oxidized primary ore with a gold content in metosomatically altered rocks, ore mineralization is predominantly represented by iron oxides and hydroxides (magnetite, hematite and hydrohematite), to a lesser extent, by sulfides of iron, arsenic, copper, bismuth, lead, zinc, bismuth tellurides and native in gold. The main carrier mineral of gold is pyrite, with its content in ore of 0.2%, characterized by a large range of grain size fluctuations (from 0.01 to 2-3 mm), uneven distribution in the ore. Ore with a gold content of 1.9 g / t was crushed to a particle size of 0.2 mm, corresponding to the size of the disclosure of the bulk of the pyrite, sent for gravitational differentiation on a screw lock, where the principles of a large area of the dividing surface in combination with the application of centrifugal forces to obtain heavy , intermediate and light fractions with a percentage ratio of the outputs of the fractions, 11.42: 42.40: 46.18 (close to 10:45:45). The obtained fractions were transferred to the main and control sulfide flotation in a closed cycle to obtain a combined flotation concentrate with a content of 51.07 g / t of gold with 88.16% recovery and a yield of 3.28%. According to the scheme with preliminary gravitational differentiation, the extraction of gold in the final flotation sulfide concentrate increased by 21.15%, the metal content - by 7.92 g / t compared with the results of flotation processing of ore without gravitational differentiation. Losses of gold with tails decreased by 2.8 times to 11.84% with a gold content of 0.23 g / t.

Example 2

The mixed-type initial gold-quartz low-sulfide ore, represented by mineralized subalkaline quartz syenites, belongs to ordinary ores in terms of gold content and is distinguished by the presence of a large number of feldspars (about 65%), quartz (about 22%). The ore is characterized as very persistent and difficult to concentrate, in which the main concentrator of gold - pyrite has various shapes and sizes of precipitates - from submicroscopic, almost globular, to crystalline-grained up to 0.3 mm in size with a predominant grain size of 0.005-0.1 mm. The share of cyanated gold in ore accounts for 22.65%; Of the total amount of uncyanated gold, more than 46.60% of the metal is associated with sulfides, almost 31% - with rock and acid-soluble minerals, including iron hydroxides.

The initial ore was ground to 0.1 mm (that is, to the size of the disclosure of the bulk of the gold carrier pyrite), directed to gravitational differentiation at the screw gateway to obtain heavy, intermediate and light fractions with a ratio of the outputs of the fractions 9.62: 44.40: 45 , 88. Each fraction was supplied to sulfide flotation in a closed cycle with the main and control operations and the purification of the combined concentrate with the return of the purification product to the main cycle. Main flotation conditions: pH 5.5; liquid glass consumption - 500 g / t, butyl xanthate - 300 g / t, pine oil - 80 g / t, polyacrylamide (during flotation of the "light" fraction) - 10 g / t. In control operations, half the amount of collector and foaming agent was supplied, and in cleaning operations, three times less of the reagents. The combined sulfide concentrate obtained from ore with a gold grade of 2.54 g / t contained 51.47 g / t of gold with 87.95% recovery, 4.34% product yield and, compared with the results of direct flotation processing of ore without gravitational differentiation, the recovery increase gold amounted to 20.94% with an increase in the quality of the concentrate by 8.35 g / t.

Claims (7)

1. A method of flotation of refractory refractory noble metal ores, characterized in that refractory refractory refractory noble metal ore ground to 0.1-0.5 mm is directed to gravitational differentiation to produce conventionally called “heavy”, “intermediate” and “light” fractions having different set of physical properties in terms of density, size and morphology of the disclosed particles and mineral phases, and flotation of these fractions in separate cycles to obtain a combined gold-containing sulfide concentrate. 2. The method according to p. 1, characterized in that the gravitational differentiation is carried out on screw devices with a large area of the dividing surface and with the imposition of centrifugal forces. 3. The method according to p. 1, characterized in that during gravitational differentiation the outputs of the "heavy", "intermediate" and "light" fractions are maintained close to the percentage ratio of 10:45:45, respectively. 4. The method according to p. 1, characterized in that the "heavy", "intermediate" and "light" fractions of gravitational differentiation enter the flotation in separate cycles in a closed circuit with the main and control operations. 5. The method according to p. 1, characterized in that, if necessary, the "heavy" fraction of gravitational differentiation before flotation is crushed. 6. The method according to p. 1, characterized in that, if necessary, the combined gold-containing sulfide concentrate is purified. 7. The method according to p. 1, characterized in that the flotation of the gravitational differentiation fractions is carried out at a pulp pH of 5.5, a pulp density of 30% solid, a flow rate of liquid glass of 400-500 g / t, butyl xanthate 250-300 g / t , pine oil - 70-80 g / t, polyacrylamide during flotation of the "light" fraction - 8-10 g / t with a dosage of half the amount of collector and foaming agent in control operations, and three times less of reagents in cleaning operations.