RU2677571C1 - Eudialyte concentrate opening method - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to the rare metals metallurgy. Eudialyte concentrate processing method includes the concentrate preliminary mechanical activation and the subsequent hydrometallurgical processing. Pre-processing is carried out to the total amount of absorbed by eudialyte energy in the form of the coherent scattering surface and micro deformations regions of at least 800 kJ/mol. Hydrometallurgical processing is carried out in two stages, at that, in the first stage alkaline treatment is carried out with 40 % NaOH solution at a temperature of 120 °C, L:S of not more than 10:1 and the treatment duration of at least 8 hours, and the obtained after alkaline treatment in the second stage precipitate is treated with the hydrochloric acid C=30–36 % at a temperature of 90 °C, L:S = 10:1, for 1 h.EFFECT: enabling the alkaline treatment temperature reduction.1 cl, 2 tbl

Description

The invention relates to the metallurgy of rare metals.

Eudialyte is a promising source of raw materials for the production of rare earth metals (REM) of moderate and heavy groups.

The difficulty of opening determined by the high content of SiO ₂ (40-60%) in the composition, which leads to the opening in the acid form silica gel with high adsorption surface on which ions are sorbed REM and Zr and their extraction does not exceed 80% of the solution.

Pyrometallurgical methods for the processing of eudialyte concentrate make it possible to obtain refractory materials with the extraction of refractory rare metals (RM), but high-value rare-earth metals are not recoverable (A.S. No. 1333670 (USSR) Method for producing fused refractories / Kononov M.E., Kulakov A.N. ., Pakhomovsky Y.O., Masloboev V.A. // Bull. 32 from 08.30.87).

There is a known hydrometallurgical method for producing liquid glass by the interaction of eudialyte with alkali solutions (NaOH and KOH) under hydrothermal conditions (Govorukhina OA, Masloboev V.A. Interaction of eudialyte with solutions of NaOH and KOH under hydrothermal conditions. - In the book: Chemical- metallurgical processing of mineral and technogenic raw materials of the Kola Peninsula, apatity, ed. of the Kola Branch of the Academy of Sciences of the USSR, 1988, pp. 29-30). In this case, zirconium remains in the solid phase, and the extraction of silicon into the solution was 45%.

The disadvantage of this method is: increased energy consumption.

Also known is the hydrometallurgical method of alkaline treatment of eudialyte concentrate at a temperature of 150 ° C and a pressure of 5-7 atm for 6 hours with its preliminary grinding to a particle size of less than 20 μm, however, the extraction of SiO ₂ in solution did not exceed 33% (Melnik N.A., Avsaragov Kh.B. Distribution of radioactivity during the enrichment of eudialyte luarvites and radiation assessment of the technological scheme / In collection Chemical and Metallurgical Processing of Mineral and Technogenic Raw Materials of the Kola Peninsula. - Apatity: USSR Academy of Sciences, 1988. - P. 25-28.)

Preliminary fine grinding proved to be ineffective for deeply changing the structure of eudialyte and increasing its reactivity, which did not allow to obtain a significant result.

The disadvantage of this method is: the complexity of the equipment, its high cost and increased energy consumption.

The last hydrometallurgical method of alkaline treatment of eudialyte concentrate using preliminary grinding to a particle size of less than 20 microns is accepted by us as a prototype.

The technical result of the invention is to reduce energy consumption (by lowering the temperature of alkaline processing) and complex processing of raw materials with the separation of the bulk of silicon from valuable components (REM and RM).

The technical result is achieved by the fact that in the method of processing eudialyte concentrate, including preliminary mechanical activation and subsequent hydrometallurgical treatment, in order to increase the reactivity of the material being processed, the preliminary processing is carried out to the total amount of energy absorbed by eudialyte in the form of the surface of coherent scattering and microstrains ΔE _S + ΔE _ε not less than 800 kJ / mol, and the subsequent hydrometallurgical treatment is carried out in two stages. At the same time, in the first stage, alkaline treatment with a 40% NaOH solution at a temperature of 120 ° C, a ratio of W: T no more than 10: 1 and a duration of at least 8 hours. The precipitate obtained after alkaline treatment in the second stage is subjected to acid treatment with C _CHI = 30-36% at a temperature of 90 ° C, W: T = 10: 1, for 1 hour.

Evaluation of the amount of energy absorbed during mechanical activation allows not only to evaluate, but also to control the reactivity of the target phase of the activated material not by the degree or speed of its reaction, that is, at the final stage of processing, but by the degree of its structural changes immediately after extraction from the mechanical activator.

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

where ΔE _d is the amount of energy stored in the form of a change in the interplanar spacings of the crystal lattice of the compound:

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

E _latt is the energy of the crystal lattice of the compound.

ΔE _s is the amount of energy stored in the form of the surface of coherent scattering regions (CSR):

E _surƒ - surface energy of the compound before activation;

V _mol is the molar volume of the compound;

D _i , D ₀ are the sizes of the coherent scattering regions of the compound after mechanical activation and before it, respectively.

ΔЕ _ε is the amount of energy stored in the form of microdeformations:

E _Y is the Young's modulus of the compound;

ε ₁ , ε ₀ - the root mean square microdeformation of the compound after mechanical activation and before it, respectively

Pre-treatment of eudialyte concentrate is carried out to the total amount of energy absorbed by eudialyte in the form of the surface of the regions of coherent scattering and microstrains - ΔE _S + ΔЕ _ε , not less than 800 kJ / mol.

Preliminary mechanical activation provides increased reactivity of the concentrate and the extraction of silicon in a solution of at least 60% at the first stage of hydrometallurgical treatment - alkaline (NaOH) processing.

Alkaline treatment conditions: C _NaOH = 40%; temperature 120 ° C, W: T not more than 10: 1 and the processing time not less than 8 hours provide an increase in the rate of filtration of the pulp from 0.07-0.14 to 0.7-4.5 dm ³ / (m ² min), that is, 1-2 orders of magnitude.

The second stage of hydrometallurgical treatment - the treatment of the first stage sediment with hydrochloric acid C _HCI = 30-36% at a temperature of 90 ° C, W: T = 10: 1, a duration of 1 hour ensures the extraction of rare-earth metals and zirconium into solution from 90 to 94%.

Eudialyte concentrate with a grain size of 73.6% fraction less than 250 microns, containing,%: 49.9 SiO ₂ ; 9.81 ZrO ₂ ; 1.99 TiO ₂ ; 1.96 MnO; 1.837 REM ₂ O ₃ ; 0.626 Nb ₂ O ₅ .

Activation was carried out in an LAIR-0.015 centrifugal planetary mill with acceleration of 25 and 35 g.

M _W : M _to - the ratio of the mass of grinding media and the mass of the loaded concentrate.

τ _MA - the duration of mechanical activation.

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

τ _{Щ / О} - duration of alkaline treatment.

τ _{K / O} is the duration of acid treatment.

Examples of practical implementation are presented in table 1 - alkaline (NaOH) hydrometallurgical treatment of eudialyte concentrate and in table 2 - two-stage hydrometallurgical treatment of eudialyte concentrate.

The data presented show that the total amount of energy absorbed by eudialyte in the form of coherent scattering and microstrains is correlated with the extraction of silicon into the solution during alkaline hydrometallurgical treatment of eudialyte concentrate and the extraction of rare-earth metals into solution during the two-stage hydrometallurgical treatment of the concentrate. 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 processing eudialyte concentrate, including preliminary mechanical activation of the concentrate and subsequent hydrometallurgical treatment, characterized in that the pretreatment is carried out to the total amount of energy absorbed by eudialyte in the form of a surface of coherent scattering and microstrains ΔE _S + ΔE _{ε of} at least 800 kJ / mol, and the subsequent hydrometallurgical treatment is carried out in two stages, while in the first stage, alkaline treatment is carried out with a 40% NaOH solution at a temperature of 120 ° C, G: T not more than 10: 1 and the processing time not less than 8 hours, and the precipitate obtained after alkaline treatment in the second stage is subjected to treatment with hydrochloric acid With _HCl = 30-36% at a temperature of 90 ° C, W: T = 10: 1, for 1 hour