RU2612162C1 - Method of flotation extraction of rare metals - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of flotation extraction of rare metals comprises pre-crushing and further flotation under UV emission. Material is crushed in time period from 5 to 10 minutes in amino acetic acid conditions, then classification is performed to determine the grain size class -0.074+0 mm. The prepared material is delivered to the flotation process, where liquid glass is used as depressant, then collector is added, the collector comprises over 95% of sodium diisobutyldithiophosphinates, then pine oil is added as foaming agent. Simultaneously with chemicals addition the pulp is subjected to UV emission during time period from 6 to 12 minutes.

EFFECT: increased efficiency of flotation enrichment of ores comprising rare metals, including rhenium under UV exposure, and increased selectivity of separation of valuable elements.

1 dwg, 2 tbl

Description

The invention relates to the field of mineral processing, in particular to flotation processing of ores (including black shale materials) containing rare metals, and can be used in the mining and processing industry for the extraction of rare metals.

A known method of flotation of ores of rare metals and tin (patent RU No. 2381073, publ. 02/10/2010), including sequential treatment of the pulp with a reagent - collector - ether phosphorus-containing compounds and sulfoxylate collector and separation of the concentrate. As the sulfoxyl collector, amine salts of alkyl sulfates of the general formula are used: ROSO ₃ NH _n (CH ₂ CH ₂ OH) _m (R = C _10-22 , n, m = 1-3). According to the flotation scheme, the process is carried out in two stages: first, in an alkaline medium at a pulp pH of 8.5-10.0, a flotation concentrate is obtained, and then in an acidic medium at pH 0.7-2.0, it is refined, and at each of these stages of the pulp is treated with organophosphorus and sulfoxyl collectors.

The disadvantage of this method is that it does not make it possible to obtain high technological parameters, insufficiently selective reagents are used that do not allow rhenium to be extracted.

A known method of processing black shale ores with the extraction of rare metals (patent RU No. 2493272, publ. 09/20/2013), including leaching the ore with a solution of sulfuric acid with the dissolution of rare metals, while leaching is carried out in an autoclave with a solution of sulfuric acid, consisting of free and bound sulfuric acid when the ratio of H ₂ SO _{4 (freedom)} : H ₂ SO _{4 (bond)} = 2: 1, containing 25-45 g / l of iron sulfate, 70-90 g / l of aluminum sulfate and 0.5 g / l of nitric acid, at a temperature of 140-160 ° C, in the range of the total concentration of H ₂ SO _{4 (total)} equal to 350-450 g / l, with a pulp density T: W = 1: 0.7-0.9, preferably 1: 0.8, with a constant redox potential in the system equal to Eh 350-450 mV, for 2-3 hours to a residual concentration of free H ₂ SO _{4 (freedom)} within 45- 75 g / l

The disadvantages of the method is the long duration of the process, low extraction efficiency of rare metals, the process is environmentally harmful due to the use of sulfuric acid.

A known method of flotation concentration of ores containing sulfide minerals and gold (patent RU No. 2426598, publ. 08.20.2011), including grinding the ore, preparation of a gas-water emulsion, saturation of a mineral suspension with gas bubbles by mixing it with a prepared gas-water emulsion, mineralization of gas bubbles and separation mineralized bubbles in the form of a flotation concentrate, characterized in that the oxygen-water gas-water emulsion is prepared by the photoelectrochemical method by passing water through the anode chamber of the flow membrane electrolyzer and exposing it to ultraviolet radiation to produce a highly active oxidizing agent-ozone, hydroxide radicals, hydrogen peroxide, and the mineral suspension containing crushed ore is pre-saturated with hydrogen bubbles predominantly with a size of 50 microns or less, passing it through the cathode chamber of a flowing membrane electrolyzer, after the collector is introduced into the suspension upon exiting the cathode chamber, then the suspension is mixed with an oxygen-water emulsion, the resulting mixture is sent to the fleet chamber machine, where it is mixed and additionally saturated with air bubbles of ordinary flotation size.

The disadvantages of this method include the low recovery of the useful component in the foam product, due to the low probability of fixing the extracted fine particles of the useful component on the surface of the bubble. The low probability of fixing is associated with a significant decrease in surface tension at the gas-water interface. Mechanical dispersion of the gas phase is associated with the reverse process - coalescence, that is, the fusion of small bubbles and the formation of large ones. To shift the equilibrium towards small bubbles and fix their size in the range of predominantly less than 50 microns, it is necessary to supply surfactants into the dispersible volume. Without the introduction of a surfactant, coalescence of small bubbles occurs and it is not possible to obtain a thin gas-water emulsion. The use of surfactants at high concentrations allows us to achieve this goal and to increase the likelihood of encountering bubbles and fine particles of a useful component obtained by deep processing of ores. But a high concentration of surfactants leads to a decrease in the surface tension of the suspension, which prevents the positive effect of the use of collector reagents and the formation of particle-bubble flotation complexes. As a result, the positive effect of the use of small bubbles obtained by mechanical crushing of the gas phase disappears, the extraction of valuable minerals in the flotation concentrate practically does not increase.

Known nanotechnological method of extracting rhenium from rocks and ores of black shale formations and products of their processing (patent RU No. 2455237, publ. 10.07.2012), based on the preparation of a colloidal salt solution from samples that are previously crushed and ground, poured with a heated aqueous solution, after why the resulting suspension is thoroughly mixed, kept at room temperature for at least 24 hours, filtered to nanosized particles, rocks of black shale formations and / or products of their processing are taken as samples of rocks, crushed it is carried out to a grain size of not more than 0.080 mm, the aqueous solution is prepared from polyvinyl alcohol with a concentration in the aqueous solution of 0.05%, taken in the ratio of the sample to 15: 1, the aqueous solution is heated to boiling and boiled for at least 1 h, filtering carried out to a nanoparticle size of not less than 1200 nm, and if the rhenium content in this solution is not less than 0.0001 mg / kg, it is recovered by evaporation of a colloidal salt solution to a dry residue.

The disadvantage of this method is its low efficiency due to low extraction, as well as the long speed of the proposed method.

The flotation concentration method (patent RU No. 2149689, published on 05.27.2000) adopted for the prototype includes preparing the pulp by exposure to it with ultraviolet radiation, followed by flotation, according to the invention, the pulp is exposed to ultraviolet radiation together with reagents for 2-3 minutes, and then throughout the flotation process. Allows you to increase the selectivity of the separation of useful components in the enrichment of bimetallic and other more complex types of ores.

The main disadvantage of this method is the lack of selectivity of the flotation process, as well as the use of the proposed reagents does not provide effective extraction of rare metals, since chelating compounds are not formed.

The technical result of the proposed method is to increase the efficiency of flotation concentration of ores containing rare metals, including rhenium, under the influence of ultraviolet radiation and increase the selectivity of separation of useful components.

The technical result is achieved by grinding material in a time interval of 5 to 10 minutes in an aminoacetic acid medium, then a classification process is carried out to isolate the fineness class -0.074 + 0 mm, after which the prepared material is sent to the flotation process, where it is used as a depressant water glass, then a collector containing more than 95% sodium diisobutyl dithiophosphinate is added, then pine oil is added as a blowing agent, while the reagents are fed, the pulp is exposed UV radiation in the time interval from 6 to 12 minutes.

The method of flotation extraction of rare metals is illustrated by the following:

FIG. 1 is a diagram of an experiment;

table 1 - the average metal content in the test ore, g / t;

table 2 - data from experiments.

The implementation of the method is as follows (Fig. 1).

The preliminary grinding of the material in a ball mill is carried out in the time interval from 5 to 10 minutes in the environment of aminoacetic acid (AUK) at a flow rate of 500 to 1000 g / t (subjected to mechanical activation), the specific surface area of the crushed material increases, which determines the best sorption of collectors at flotation, elements form chelate compounds with complexing agents, the average metal content in the ore is presented in table 1. Rhenium forms complex compounds with amine compounds that are stable in single solutions (NH ₄ ReO ₄ ). Further, the crushed ore to a particle size class of less than 0.074 mm enters the flotation process. Then, the following reagents are added to the pulp: depressor - liquid glass with a flow rate of 200 g / t ore, a collector containing more than 95% sodium diisobutyl dithiophosphinate (C ₈ H ₁₈ PS ₂ ⋅ Na), the molecule of which contains electron-donor sulfur and phosphorus atoms, which and determines its tendency to complexation, and sufficiently long alkyl radicals provide collective activity (flow rate from 100 to 200 g / t of ore), blowing agent - pine oil with a flow rate of 40 g / t of ore. Simultaneously with the supply of reagents, the pulp is exposed to ultraviolet (UV) radiation in the time interval from 6 to 12 minutes. This leads to a modification of the initial surface structure, a change in the chemical and phase composition of the surface layer. Molecular oxygen reacts with UV radiation, resulting in the formation of atomic oxygen. Atomic oxygen reacts with molecular oxygen to form ozone. Along with ozone, a whole series of “activated oxygen” compounds is formed, including OH hydroxyl, atomic oxygen, hydrogen peroxide, hydrogen dioxide H ₁ O ₂ , as well as dimers and trimers of hydrogen peroxide. The high oxidizing potential of the mixture of activated oxygen supplied to the solution is sufficient to break the bonds of rare metals (rhenium) with other ore elements. As a direct consequence of such a break in bonds, the proportion of exposed ore in the processed sample usually increases by 15–20 times in comparison with the initial one. Remaining to some extent compact, as in crystalline ore, its structure becomes hydrated and somewhat amorphous. A significant increase in the proportion of ore uncovered due to breaking chemical bonds allows a significant increase in the extraction of rare metals from a given ore volume.

The results of laboratory studies showed that preliminary mechanical activation in the presence of aminoacetic acid and further flotation under the influence of ultraviolet radiation make it possible to obtain a concentrate with a high content of rare metals, including rhenium (table 2).

Claims (1)

The method of flotation extraction of rare metals, including pre-grinding and subsequent flotation, which occurs under the influence of ultraviolet radiation, characterized in that the material is ground in a time interval of 5 to 10 minutes in an aminoacetic acid medium, then a classification process is carried out to isolate the fineness class -0.074+ 0 mm, after which the prepared material is sent to the flotation process, where liquid glass is used as a depressant, then a collector containing more than 95% d isobutyl dithiophosphinate sodium, then add pine oil as a blowing agent, at the same time as the reagents are supplied, the pulp is exposed to ultraviolet radiation in the time interval from 6 to 12 minutes.

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