RU2506333C1 - Method for opening loparite concentrates - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy of rare metals. A method for opening loparite concentrates involves preliminary machining of loparite concentrates and further treatment of activated loparite concentrates with 30% of HNO₃ solution at the temperature of 99 °C. To further treatment there subject are activated loparite concentrates with double amount of energy of variation of loparite crystal lattice parameters of at least 73 kJ/mole and with stored total amount of energy, which corresponds to surface of areas of coherent dissipation and microdeformations with at least 9.5 kJ/mole of loparite.

EFFECT: providing effective opening of loparite concentrates with extraction of 99% of rare-earth metals 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.

Loparite is a fairly hard-to-open mineral.

Known sulfuric acid method of processing loparite concentrates (Zelikman A.N. Metallurgy of refractory rare metals. - M .: Metallurgy, 1986. P.244-246). Loparite concentrate is decomposed with 85-92% sulfuric acid at 150-180 ° C, acid consumption 2-2.8 t / t of concentrate, crushed to a particle size of less than 74 microns. The addition of ammonium sulfate in an amount of 0.2 t / t of concentrate to sulfuric acid prevents the reaction mass from sintering and increases the extraction of titanium, tantalum and niobium into the solution. The duration of the complete decomposition of loparite concentrate is 20-30 minutes (degree of opening 99%). The product is leached with water. In the solid phase, most of the rare-earth metals remain in the composition of sparingly soluble double sulfates and their isomorphic mixture with calcium sulfate. Titanium, niobium and tantalum pass into the solution.

The disadvantages of this method are: multi-stage; high consumption of reagents; high process temperature; the implementation of the process in an autoclave, which complicates the hardware design; the impossibility of providing a clear separation of the valuable components of loparite, resulting in products of technical purity, therefore, its further complex processing is necessary.

There is also a method of decomposing loparite concentrates by (direct) chlorination, which is simpler from a technological point of view (ibid., Pp. 236-244). Its essence is that loparite concentrate mixed with coke is chlorinated at a temperature of 950-1050 ° C. Differences in the volatility of the resulting chlorides of the components of loparite concentrate make it possible to separate its main valuable components.

Chloride processing technology for loparite ensures the extraction of 93-94% of niobium and 86-88% of tantalum into technical oxides, 96.5-97% of titanium into technical tetrachloride, and the extraction of 95.5-96% of rare-earth metals (REM) into chloride melt.

The direct chlorination method, along with high technological parameters, has the following disadvantages:

- chlorine consumed for the chlorination of rare-earth metal oxides passes into the rare-earth chloride melt, which, during processing, goes into waste water;

- due to the presence of REM oxides in the loparite concentrate, the chlorination temperature must be maintained at 950-1050 ° C, which leads to increased energy intensity of production, a significant decrease in the life of the chlorinator and an increase in the amount of spent lining contaminated with radioactive products to be disposed of in special storage facilities.

There is also a method of fluorination of loparite concentrates (Karelin V.A., Karelin V.I. Fluoride technology for the processing of rare metal concentrates. - Tomsk: NTL Publishing House, 2004. P.73-80). The two-stage process is carried out in a flame reactor or fluidized bed apparatus at temperatures: at the first stage -350-500 ° C; on the second - 2000 ° C. In addition to the use of active fluorine, the process is complicated by the use of special equipment and its low life.

Also known is the nitric acid method for processing loparite concentrates (Pat. 2145980 RF, Method for processing loparite concentrate / Zots N.V., Shestakov S.V., publication date 02/27/2000), which is more promising when expanding the production of rare-earth metals, tantalum, niobium and tantalum from loparite concentrates. The initial concentrate crushed to a particle size of at least 95% of particles of not more than 0.075 mm is opened with a solution of nitric acid with a concentration of 650-700 g / l at a temperature of 115-118 ° C and atmospheric pressure. To increase the residence time of loparite particles in nitric acid up to 40 hours and increase the likelihood of their opening, processing is carried out in a cascade of devices. As a result of such processing, compounds of rare-earth metals and radioactive impurities pass into the solution. Tantalum, titanium and niobium completely remain in the composition of hydrated oxides in the sediment. The implementation of the method allows to reduce the discharge of chlorine ion with wastewater; reduce the temperature of the subsequent chlorination of the leach sludge to 800 ° C; reduce the cost of reagents (coke and chlorine).

The disadvantages of this method is; significant reagent consumption and high process duration.

There is also known a method of nitric acid opening of loparite concentrate using preliminary mechanical activation in a centrifugal planetary mill (A. Medvedev, Leaching and methods of its intensification. - M .: MISiS. 2005. P.140-144) involving preliminary machining of loparite concentrate in a planetary mill with a developed acceleration of 25g for 15 min in the "dry" mode. After machining, the loparite concentrate is treated with 25-56% solutions of nitric acid at a temperature of 90-100 ° C, T: W = 1: (3 ... 4) and a duration of 6 hours.

As a result, it was extracted into a nitric acid solution: without activation, ~ 9% REM, after 15 min. activation of 98-99% REM.

The disadvantages of this method are: high duration of mechanical activation; the use of concentrated solutions of nitric acid. The degree of activation is determined only by the duration of the machining, which, when changing the parameters of the activation or activator, does not allow the practical application of this method due to the lack of methods for monitoring the degree of deformation of the crystal lattices of the concentrate phases. In addition, as shown in the work of A.S. Medvedev, the degree of extraction of a valuable component is highly dependent on the processing conditions of activated raw materials.

A known method of opening loparite concentrates (Bogatyreva E.V. et al., The use of X-ray diffraction analysis to assess the reactivity of the loparite phase after mechanical activation, Proceedings of the International scientific-practical conference "Scientific research and their practical application. Current status and development 2010", October 4-15, 2010, Odessa), including preliminary machining of loparite - concentrates and subsequent processing of activated loparite concentrates with 30% HNO ₃ solution at a temperature of 99 ° C. The possibility of predicting the reactivity of loparite concentrate was established, however, in this method, the threshold value of the assimilated amount of energy of changing the parameters of the crystal lattice of the loparite was not determined and the threshold value of the stored total amount of surface energy of the coherent scattering and microdeformation regions, which ensure the effective opening of loparite concentrates, was not determined.

The invention solves the problem of simplifying the processes of opening loparite concentrates and reducing energy consumption at the stage of preliminary activation of the material being opened.

EFFECT: effective opening of loparite concentrates.

The problem is solved in the method of opening loparite concentrates, including preliminary machining of loparite concentrates and subsequent processing of activated loparite concentrates with 30% HNO ₃ solution at a temperature of 99 ° C. Activated loparite concentrates are subjected to subsequent processing with an assimilated amount of energy of changing the parameters of the crystal lattice of the loparite at least 73 kJ / mol and a stored total amount of energy corresponding to the surface of coherent scattering and microstrains, at least 9.5 kJ / mol of loparite.

The degree of deformation of the crystal lattice of loparite 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.

Pre-treatment is carried out to the amount of energy absorbed in the form of changes in the parameters of the crystal lattice of the loparite of at least 73 kJ / mol and the total amount of energy stored in the form of the surface of the areas of coherent scattering and microstrains of at least 9.5 kJ / mol of loparite, and the subsequent processing is carried out 30% solution of HNO ₃ at a temperature of 99 ° C.

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: reduction of energy consumption is achieved by reducing the duration of machining from 15 to 2.5 minutes.

The greatest activation effect is manifested when the amount of energy absorbed in the form of a change in the parameters of the crystal lattice of loparite is not less than 73 kJ / mol and the total amount of energy stored in the form of the surface of the regions of coherent scattering and microstrains is not less than 9.5 kJ / mol of loparite. The degree of extraction of rare-earth metals in a nitric acid solution is 99%. In non-activated laparitis, under the same opening conditions, it amounted to 1.5%.

When the amount of energy absorbed in the form of changes in the crystal lattice parameters of loparite is 73.4 kJ / mol and the total amount of energy absorbed in the form of coherent scattering and microstrains to 5.8 kJ / mol of loparite is reduced, the degree of rare-earth metal extraction is reduced to 76% (in those leaching conditions).

A decrease in the amount of energy absorbed in the form of a change in the parameters of the crystal lattice of loparite to 21 kJ / mol and the total amount of energy absorbed in the areas of coherent scattering and microdeformation to 3.9 kJ / mol of loparite is accompanied by a decrease in the degree of extraction of rare-earth metals to 26.5% (in those leaching conditions).

Loparite concentrate with a particle size of 89.9% fraction (-0.100 + 0.010) mm, containing,%: 21.67 Ti; was subjected to mechanical activation. 27.44 REE; 5.73 Nb; 5.29 Ca; 5.12 Na; 1.02 Si; 0.49 Ta; 0.43 Th.

Activation was carried out in a centrifugal planetary mill brand LAIR-0.015.

The assimilated amount of energy of the change in the parameters of the crystal lattice of the loparite and the total amount of energy corresponding to the surface of the areas of coherent scattering and microstrains can be estimated during machining on periodically taken samples of loparite concentrate or can be predicted in advance by conducting trial mechanical activation under various conditions.

Specific examples of execution are presented in the table. Designations in the table:

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 machining (activation).

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

E _latt = 16675.5 kJ / mol (determined by the Fersman method); V _mol = 37.91 cm ³ / mol.

E _surf = 1.39 J / m ² and E _Y = 199.26 GPa (determined by the method described in the work of Zuev V.V., Aksenova G.A., Mochalov N.A. et al. Study of the specific energies of crystalline lattices of minerals and inorganic crystals to evaluate their properties / Ore dressing. 1999. No. 1-2. S.48-53).

The data presented show that the amount of absorbed energy in the form of regions 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.

Table The ratio of the amount of absorbed energy and the degree of extraction of rare-earth metals solution Sample No. Mechanical Activation Modes XRD structural characteristics of loparite The amount of absorbed energy, kD w / mol Leaching modes The extraction of rare-earth metals in solution,% Ms: Mk Z,% τ _a , min Lattice options Di, Å ε _i ,% ΔE _d (ΔE _s + ΔE _ε ) T: F t, ° C τ _high, h

, %

% Ref. - - - a = 5,494 > 5000 0.10 - - 1: 6 99 6 thirty 1,52 c = 7.783 one 20: 1 fifteen 0.5 a = 5,495 3510 0.11 17.5 0.9 1: 6 99 6 thirty 5.06 c = 7.772 2 20: 1 fifteen 2,5 a = 5.484 633 0.28 73,4 5.8 1: 6 99 6 thirty 76.13 c = 7,777 3 80: 1 60 0.5 a = 5,495 1093 0.14 4.0 3.0 1: 6 99 6 thirty 11.31 c = 7,782 four 80: 1 60 2,5 a = 5,486 381 0.39 74.1 9.9 1: 6 99 6 thirty 99.7 c = 7.771 5 5: 1 fifteen 2,5 a = 5,493 1571 0.14 12.5 2.1 1: 6 99 6 thirty 9.59 c = 7,780 6 20: 1 60 2,5 a = 5,494 857 0.17 21.0 3.9 1: 6 99 6 thirty 26.53 c = 7,777 7 80: 1 60 2.0 a = 5.484 355 0.17 73,4 9.1 1: 6 99 6 thirty 92.10 c = 7,777

Claims (1)

A method for opening loparite concentrates, including preliminary machining of loparite concentrates and subsequent processing of activated loparite concentrates with 30% HNO ₃ solution at a temperature of 99 ° C, characterized in that the activated loparite concentrates with the acquired amount of energy of changing the parameters of the crystal lattice of the loparite are no less than 73 kJ / mol and the stored total amount of energy corresponding to the surface of the regions of coherent scattering and microdefault rmacy, not less than 9.5 kJ / mol of loparite.