RU2506330C1 - Method for opening tungstenite concentrates - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy of rare metals. A method for opening of tungstenite concentrates involves preliminary machining of tungstenite concentrates and further treatment of activated tungstenite concentrates with NaOH solution. Activated tungstenite concentrates with double total amount of energy, which corresponds to surface of areas of coherent dissipation and microdeformations with at least 22 kJ/mole of tungstenite, is subject to further treatment. Further treatment is performed with 20% of NaOH solution at the temperature of 99°C during 3 hours.

EFFECT: providing effective opening of tungstenite concentrates with extraction of 99% of WO₃ to the solution.

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Description

The invention relates to the metallurgy of rare metals, in particular to the processes of opening minerals of refractory metals.

Wolframite is a fairly difficult-to-open mineral, which determines the variety of methods for processing tungsten concentrates.

A known method of sintering tungsten with soda (Zelikman AN Metallurgy of refractory rare metals. - M .: Metallurgy, 1986. S.35-38), The process is carried out at a temperature of 800-900 ° C. The resulting specs are leached with water at a temperature of 80-90 ° C. The process is multi-stage.

The disadvantages of this method are: high temperature and energy intensity of the process; danger of corrosion of the furnace lining by active melt; the need to dilute the concentrate to a WO ₃ content _of 20-22%, which leads to a decrease in furnace productivity.

An autoclave-soda method for the decomposition of tungsten concentrates is also known (ibid., P. 44-47). The process is carried out at temperatures of 200-225 ° C, a pressure of 2.5 MPa for 4-5 hours. The process is characterized by a significant excess of reagent, the need for special safety measures with high-pressure apparatuses, the extraction of tungsten into the solution for the most part or substantially lower than 98.6% and the dependence on the composition and origin of the tungsten concentrate.

There is also a method of fluorination of tungsten concentrates (Karelin V.A., Karelin V.I. Fluoride technology for processing concentrates of rare metals. - Tomsk: Publishing House NTL, 2004. S.166-172). The two-stage process is carried out in a flame reactor at temperatures: in the first stage, more than 2000 ° C; on the second - at 350 ° C. In addition to using active fluorine, the process is complicated by the use of special equipment.

There is also a method of decomposition of tungsten concentrates with solutions of sodium hydroxide (Zelikman AN Metallurgy of refractory rare metals. - M .: Metallurgy, 1986. P.52-53). The process is carried out in steel reactors with a stirrer and a steam jacket at a temperature of 110-120 ° C, 25-40% NaOH solution for 4-10 hours, depending on the composition and size of the concentrate, temperature and concentration of alkali.

The disadvantages of this method are: applicability for processing rich standard tungsten concentrates, the need for fine grinding of the concentrate (less than 40 microns) for its complete decomposition (98-99%); high duration of the process.

There is also known a method of alkaline decomposition of high calcium tungsten concentrates using mechanical activation (Liu Mao-sheng, Sun Pei-mei, Li yun-jiao et al. Mechanical Activated Caustic Decomposition of Tungsten Concentrate with a High Content of Calcium / ICHM '92. Changsha: International Academic Publishers, 1992, p. 296-301). Preliminary machining of tungsten concentrates in the activator in a sodium hydroxide solution for 4-5 hours provides 99% recovery of tungsten in the solution, followed by leaching at a temperature of 150-160 ° C for 2 hours.

The disadvantages of this method are: the high temperature of the leaching process and the significant duration of the machining process. In addition, the joint activation of the concentrate with sodium hydroxide will inevitably lead to contamination of the final product with the activator material.

The degree of activation is determined only by the duration of the machining, which, when changing the activation or activator parameters, does not allow the practical application of this method due to the lack of methods for monitoring the degree of deformation of the crystal lattice of the concentrate phases.

A known method of opening tungsten concentrates (Bogatyreva EV, Evaluation of the effectiveness of mechanical activation of low-grade tungsten concentrate. Vestnik MGOU. Moscow, Technique and Technology, No. 2 April-June, 2011, pp. 11-20) (the closest analogue), including preliminary mechanical treatment of low-grade tungsten concentrates and subsequent processing of already activated concentrates with NaOH solution. Using mechanical activation of the tungsten phase of low-grade tungsten concentrate as an example, the possibility of a quantitative assessment of the fraction of stored energy is shown. The possibility of predicting the reactivity of individual phases of mineral raw materials is established. However, in this method, the threshold value of the total amount of energy is not determined, which ensures the efficient opening of tungsten concentrates.

The invention solves the problem of simplifying the processes of opening tungsten concentrates, reducing energy consumption both at the pre-activation stage and at the stage of processing the activated material.

EFFECT: effective opening of tungsten concentrates.

The problem is solved in a method for opening tungsten concentrates, including preliminary machining of tungsten concentrates and subsequent processing of activated tungsten concentrates with NaOH solution. Activated tungsten concentrates with the assimilated amount of energy corresponding to the surface of the regions of coherent scattering and microstrains of at least 22 kJ / mol of tungsten are subjected to further processing, while the treatment is carried out with a 20% NaOH solution at a temperature of 99 ° C for 3 hours.

The degree of deformation of the crystal lattice was estimated by the amount of energy absorbed using the method described in the work of E.V. Bogatyreva, A.G. Ermilova “Assessment of the fraction of energy stored during the mechanical activation of mineral raw materials” Inorganic materials, 2008, volume 44, p.242-247:

ΔE _∑ = ΔE _d + ΔE _S + ΔE _ε ,

where ΔE _d is the amount of energy absorbed in the form of changes in the interplanar spacings of the mineral crystal lattice:

ΔE _d = KE _latt .

K is the coefficient of relative change in the volume of the unit cell of the concentrate phase (modulo);

E _latt is the energy of the crystal lattice of a mineral.

ΔE _s is the amount of energy absorbed in the form of the surface of the areas of coherent dispersion (CSR):

E _surf - surface energy of the mineral before activation;

V _mol is the molar volume of the mineral;

D _i , D ₀ are the sizes of the regions of coherent dispersion of the mineral after MA and before treatment, respectively.

ΔE _ε is the amount of energy absorbed in the form of microdeformations:

.

.

E _Y - Young's modulus of the mineral;

ε _I , ε _o - rms microdeformation of the mineral after and before MA, respectively.

Pretreatment is carried out to the total amount of energy absorbed in the form of a surface of areas of coherent scattering and microstrains equal to at least 22 kJ / mol of tungsten.

Assessing the amount of absorbed energy allows not only to evaluate, but also to control the reactivity of the activated material not by the degree or speed of its reaction, that is, at the final stage of the autopsy, but by the degree of its structural violations immediately after extraction from the activator.

EFFECT: simplification of the autopsy process is achieved due to the leaching process at atmospheric pressure and low temperature in a conventional agitator. The use of autoclaves is not required.

The technical result is a reduction in energy consumption, achieved both by reducing the duration of machining, and by reducing the temperature of the leach.

The greatest activation effect is manifested when the total amount of energy of the regions of coherent scattering and microstrains assimilated as a surface is not less than 22 kJ / mol of tungsten. The degree of extraction in this case is 98-99%. For inactive standard and low-grade tungsten concentrates, under the same opening conditions, it was 38.3 and 25.4%, respectively.

A decrease in the total amount of energy absorbed in the form of coherent scattering and microstrains to 18.66 kJ / mol of tungsten is accompanied by a decrease in the degree of WO ₃ extraction to 94% (under the same leaching conditions).

A decrease in the total amount of energy absorbed in the form of coherent scattering and microstrains to 8.86 kJ / mol of tungsten is accompanied by a decrease in the degree of WO ₃ extraction to 60% (under the same leaching conditions).

Standard and low-grade tungsten concentrates were mechanically activated. Standard concentrate with a particle size of ~ 100% fraction (-0.125 + 0.106 mm), containing,%: W 40.4; Fe 7.23; Mn 10.1; Si 2.26; Sn 7.35; Al 1.38; S 0.17; Cu 0.052; Pb 0.024; Mo <0.003; P 1.83; As <0.01. Low-grade concentrate with a fineness of -93.8% fraction (-2.00 + 0.071) mm, containing,%: W 12.7; Fe 25.2; Mn 3.86; Si 2.83; Sn 9.09; Al 1.53; S 0.56; Cu 0.23; Pb 0.18; Mo <0.003; P 1.79; As 0.31.

Activation was carried out in a LAIR-0.015 centrifugal planetary mill with an acceleration of 25 g.

The total amount of energy corresponding to the surface of the regions of coherent scattering and microstrains can be estimated during machining on periodically selected samples of tungsten concentrate or can be predicted in advance by conducting trial mechanical activation under various conditions.

Specific examples of execution are presented in the table below.

MS: MK - the ratio of the mass of grinding media and the mass of the loaded concentrate.

Z is the degree of filling the drum of the mill with balls,%.

τ _a - the duration of the machining (activation).

T: W - the ratio of solid and liquid components in the pulp during leaching.

In the table:

- for a standard tungsten concentrate, the tungsten phase has E _latt = 29536.97 kJ / mol, V _mol = 43.20 cm ³ / mol, E _surf = 1.97 J / m ² , E _Y = 309.86 GPa.

- for a low-grade tungsten concentrate, the tungsten phase has E _latt = 29616.26 kJ / mol, V _mol = 41.56 cm ³ / mol, E _surf = 2.04 J / m ² , E _Y = 322.83 GPa.

E _surf and E _{Y are} determined by the method described in the work of Zuev V.V., Aksenova G.A., Mochalova N.A. et al. “Study of the specific energy values of the crystal lattices of minerals and inorganic crystals to assess their properties” Ore dressing. 1999. No. 1-2. S.48-53

When calculating E _latt , E _surf , E _Y , V _{mol, the} content of guberite in tungsten of standard and low grade concentrates was taken into account. According to the technique described in the work Maksimyuk I.E. “Casseterites and Wolframites” Ed. S.A. Yushko. - M .: Nedra, 1973. 136 p. according to the crystal chemical parameter a, it is 67% and 30%, respectively.

The data presented show that the total amount of absorbed energy in the form of areas of coherent scattering and microstrains correlates with the degree of extraction of a valuable component. Data on the conditions of mechanical activation are given since these are the only benchmarks to date used by most researchers.

Claims (1)

A method for opening tungsten concentrates, including preliminary machining of tungsten concentrates and subsequent treatment of activated tungsten concentrates with a NaOH solution, characterized in that the activated tungsten concentrates are subjected to subsequent processing with the assimilated total amount of energy corresponding to the surface of the regions of coherent dispersion and microstrains of at least 22 kJ / mol while the treatment is carried out with a 20% solution of NaOH at a temperature of 99 ° C for 3 hours