RU2196184C2 - Method of processing scandium-containing solutions - Google Patents

Abstract

FIELD: technology of scandium recovery from solutions; applicable in selective recovery of scandium from wastes of production of aluminum (red mud), titanium (used melts), zirconium, tin, tungsten, uranium. SUBSTANCE: method of processing scandium-containing solutions from leaching of wastes and/or middlings of production processes includes sorption from sulfuric acid solution on anionite treated with sulfuric acid solution; sorption of scandium by phosphorus-containing ionite; subsequent washing of ionite; desorption of scandium and processing of eluate. Sorption is carried out on slightly-basic anionite treated with solution of sulfuric acid with concentration of 150-500 g/cu.dm. Slightly basic anionite is based on polyethylene-polyamines, 3-chlorine-1,2-epoxypropane and ammonia with general formula

Description

 The invention relates to the field of chemistry and metallurgy, and specifically to the technology for extracting scandium from various solutions, and can be used for the selective extraction of scandium from waste products from aluminum (red mud), titanium (spent melts), zirconium, tin, tungsten, uranium.

 A known method of processing scandium-containing solutions (see Sorption and separation of hydrolyzed scandium ions from some associated metal ions. Journal of Applied Chemistry, 1976, v. 45, S. 1191). A known method is as follows. Processing scandium-containing solutions is carried out by sorption by carboxylic cation exchangers. The initial solution is treated with an alkaline reagent to a pH of 3.0-4.5 and sent to ion exchange recovery. After sorption, the ion exchangers in the column are washed with 0.5-2.0 n. a solution of chloride, perchlorate or sodium sulfate (ammonium). Scandium is desorbed 0.3-3.0 n. a solution of nitric, hydrochloric, phosphoric or nitric acid.

 The reasons that impede the achievement of the following technical result when using this known method include the fact that according to the known method, it is necessary to pre-neutralize the initial solutions to a pH of 3.0-4.5, which complicates the technology, leads to an additional consumption of reagents. On the other hand, neutralized solutions are very unstable and quickly hydrolyze; a precipitate appears in the solution, which adsorbs a significant amount of scandium in the presence of significant amounts of titanium in the initial solution. This results in a loss of more than 50% of scandium.

 A known method of processing scandium-containing solutions, which consists in the following. A nitric acid solution containing scandium and associated metals is brought into contact (passing through a sorption column) with a phosphorus-containing ion exchanger, which is used as a macroporous phosphoric acid cation exchanger based on styrene and divinylbenzene. In this case, scandium is selectively extracted from the solution - it is sorbed by cation exchange resin, while other metals mostly remain in the filtrate. After sorption, the cation exchange resin is washed successively with water and 1-3 N hydrochloric acid solution. Then carry out the desorption of scandium 0.5-1.0 N. ammonium fluoride solution (see. Study of the ion-exchange separation of scandium from related elements / News of universities. Non-ferrous metallurgy, 1975, 2, P. 88-90).

 The known method makes it possible to selectively extract scandium from solutions containing 5-10 times the amount of yttrium, lanthanum, aluminum, iron (II), calcium, manganese (II) and other related metals.

 The reasons that impede the achievement of the technical result indicated below include the unsatisfactory performance of the process and the lack of selectivity when extracting scandium from solutions containing a significant amount of titanium.

The known method (RF Patent 2062810, IPC ⁶ C 22 V 59/00, 3/24, Method for the selective extraction of scandium from hydrochloric acid solutions. Published on June 27, 1996, Bull. 18), which consists in the sorption of scandium from hydrochloric acid solutions (3-350 g / dm ³ phosphorus-containing ampholytes, which are used as chloride N- / 2-hydroxypropyl / -N '- / 2-hydroxypyridinium propyl / -N "/ - methylenephosphoniumpolyethylenepolyamine, followed by washing of the ampholyte with acid, water, desorption of scandium fluoride or carbonate solutions.

 The reasons that impede the achievement of the technical result indicated below include the poor selectivity of the ampholyte used in the processing of scandium-containing solutions in which a significant amount of titanium is present, and therefore the low degree of purification of scandium from titanium.

 Of the known analogues, the closest to the claimed invention in terms of features and purpose is a known method for processing scandium-containing solutions, including sorption from sulfuric acid solutions treated with a solution of sulfuric acid anion exchange resin, sorption extraction of scandium with phosphorus-containing ion exchanger, followed by washing of the ion exchanger, desorption of scandium and processing of the eluate (see AS 1572036 USSR, С 22 В 59/00, publ. 10.07.00), adopted as a prototype.

 The disadvantage of the prototype method is the unsatisfactory performance of the process and the relatively low selectivity in the processing of scandium solutions containing a significant amount of titanium. This disadvantage is due to the low sorption capacity for titanium of the anion exchangers used in the known method.

 The claimed technical solution is aimed at solving the problem of increasing the productivity and selectivity of extracting scandium from solutions.

 The technical result that can be obtained by implementing the claimed invention is to increase the sorption load on the ion exchanger for titanium and to increase the degree of purification of scandium from titanium.

Другая особенность состоит в том, что сорбцию ведут из растворов, содержащих 150-500 г/дм³ H₂SO₄.The specified technical result in the implementation of the claimed invention is achieved by the fact that in the known method of processing scandium-containing solutions, including sorption from sulfuric acid solutions treated with sulfuric acid anion exchange resin, sorption extraction of scandium with phosphorus-containing ion exchanger, followed by washing the ion exchanger and desorption of scandium and processing of the eluate, the feature is that that from the initial sulfate solution, sorption is carried out on a solution of sulfuric acid treated with a concentration of 150-500 g / dm ³ H ₂ SO ₄ s lab-based anion exchange resin based on polyethylene polyamines, 3-chloro-1,2-epoxypropane and ammonia of the general formula

Another feature is that sorption is carried out from solutions containing 150-500 g / dm ³ H ₂ SO ₄ .

 A feature is also that the desorption from weakly basic anion exchange resin is carried out with a solution of hydrochloric acid.

 Ceteris paribus, the above new techniques, modes of implementation and the new substances used ensure the achievement of a technical result in the implementation of the claimed invention.

An analysis of the totality of the features of the claimed invention and new methods for their implementation and the result achieved in this case shows that there is a definite causal relationship between them, which consists in the following. The results of research and experimental tests showed that the implementation of the processing of scandium-containing solutions according to the proposed method, that is, by sequential sorption from solutions containing 150-500 g / dm ³ H ₂ SO ₄ , first on a weakly basic anion exchange resin of a definite composition and structure (as indicated above), pre-treated with a solution of H ₂ SO ₄ (150-500 g / dm ³ ), and then on a phosphorus-containing ion exchanger provides an increase in the process productivity and selectivity of scandium extraction by increasing the degree of scandium source from titanium. With a different sequence of operations, modes, acidity of solutions, etc. the above technical result is not achieved.

 The analysis of the prior art in relation to the totality of all the essential features of the claimed technical solution shows that the proposed method meets the criterion of "novelty."

 Verification of compliance of the claimed invention with the requirements of "inventive step" in relation to the totality of essential features indicates that the proposed method does not follow for experts explicitly from the prior art.

 Information confirming the possibility of carrying out the invention to obtain the above technical result is given in the examples and are as follows.

Examples of the method
Example 1 (Experiments 1.1 and 1.2)
Processing scandium-containing solutions was carried out by a known and proposed method. In experiments 1.1 and 1.2. we compared the productivity of the process determined by the sorption load of anion exchangers on titanium during sorption from H ₂ SO ₄ solutions with a concentration of 150-500 g / dm ³ , 100 mEq. Ti ⁴⁺ / dm ³ , 100 mEq Sc ³⁺ / dm ³ anion exchangers of various types:
1.1.) By a known method (prototype) - anion exchange resin based on 1,4,7,11,14-pentase-9,16-diol-4-polycyclotetradecane-1,7-diammonium dichloride;
1.2. ) according to the proposed method - anion exchange resin based on polyethylene polyamines 3-chloro-1,2-epoxypropane and ammonia.

Sorption was carried out under static conditions until the establishment of ion-exchange equilibrium (3-7 days). The ratio of the mass of the anion exchange resin and the solution in all experiments is 1: 100. Before sorption, the anion exchangers were preliminarily washed with a solution of H ₂ SO ₄ (150-500 g / dm ³ ) in an amount of 3-5 volumes of acid per 1 volume of anion exchange resin. Under the indicated conditions, which are strictly identical for the known and proposed methods, the following results were obtained on the sorption load (and, therefore, on the performance of the process of extracting titanium from scandium-containing solutions) on anion exchange resins on titanium (IV) ions (see table).

The data obtained show that, according to the proposed method, under comparable conditions, the sorption load on anion exchange resin for titanium in the processing of scandium-containing solutions (150-500 g / dm ³ H ₂ SO ₄ ) of scandium-containing solutions is 1.5-3.0 times higher than by the known method , in this regard, on the one hand, by the proposed method, the process productivity is higher in terms of the volume of processed solutions, and on the other hand, the degree of selective extraction of titanium from the solution is higher and, as a result, the residual titanium concentration in the filtrate after sorption on anion exchange resin and, therefore, a higher degree of purification of scandium from titanium.

Example 2
The processing of production wastes — sulfate solutions containing 1.2 g / dm ^{3 of} titanium, 0.15 g / dm ^{3 of} scandium and 250 g / dm ³ H ₂ SO ₄ , was carried out by sorption methods under dynamic conditions at 80 ^o C. The volume of processed solutions 0.5 dm ³ .

затем - через сорбционную колонку с 5 г фосфорсодержащего ионита - аминофосфорнокислого амфолита, в качестве которого используют хлористый N-/2-оксипропил/-N'-/2-оксипиридинийпропил/-N"/-метиленфосфонийполиэтиленполиамин.Experience 2.1. According to the proposed method. The solution was first passed through a sorption column with 20 g of weakly basic anion exchange resin based on polyethylene polyamides, 3-chloro-1,2-epoxypropane and ammonia (pretreated before sorption with a solution of sulfuric acid with a concentration of 250 g / dm ³ until the anion exchange resin was saturated with sulfuric acid) of the general formula

then - through a sorption column with 5 g of phosphorus-containing ion exchanger - amphosphate ampholyte, which is used as chloride N- / 2-hydroxypropyl / -N '- / 2-hydroxypyridinium propyl / -N "/ - methylenephosphonium-polyethylene-polyamine.

 After sorption, washing of ion exchangers in columns, desorption of sorbed metals and processing of eluates was carried out.

Under these conditions, the following results were obtained:
The degree of extraction of scandium was 97.3%;
- degree of titanium extraction (total)> 99.9% (no titanium ions were detected in the filtrate after the second column);
- degree of purification of scandium from titanium α = 54.4, i.e. conditions are provided for the selective extraction of scandium from sulfuric acid solutions containing a significant amount of titanium.

Experience 2.2. In parallel experiments performed under conditions identical to that described in example 2.1, but without first passing the initial sulfate (250 g / dm ³ H ₂ SO ₄ ) solution containing 0.15 g / dm ³ scandium and 1.2 g / dm ³ titanium through a column with anion exchange resin, i.e. immediately by directly passing the solution through a sorption column with aminophosphate ampholyte, the following data were obtained:
- the degree of extraction of Sc 66%;
- the degree of extraction of Ti 75%;
- the degree of purification of Sc from Ti, calculated as the quotient of dividing the ratio (mass or concentration) of Sc and Ti in the initial solution by the specified ratio in the eluate α = 0.9. Those. selective sorption of Sc did not occur during sorption-desorption; moreover, some enrichment of the eluate in titanium was observed (α <1).

Example 3
The experiments were carried out according to the proposed method under conditions identical to example 2.1, but at a concentration of sulfuric acid in the initial solution of 150 g / l.

Prior to sorption, the weakly basic anion exchange resin in the column was pretreated with a solution of sulfuric acid with a concentration of 150 g / l until the resin was completely saturated with sulfuric acid: until the concentrations of sulfuric acid in the starting and filtrate were equal (C / C ₀ = 1).

 The degree of extraction of scandium 96.7%; the degree of extraction of titanium in the first stage of sorption of 97.5%; total (after two columns) degree of titanium recovery> 99.9%; the degree of purification of scandium from titanium α = 33.2.

Example 4
The same as in example 2.1 (according to the proposed method), but the concentration of sulfuric acid in the initial solution and for the treatment of anion exchange resin is 500 g / l. The degree of extraction of titanium (total) 99.9%, the degree of extraction of scandium 97.0%; the degree of purification of scandium from titanium α = 98.0.

 In examples 5-8 shows the results of experiments in which the process parameters differ from those recommended by the proposed method.

Example 5
The same as in example 2.1 (according to the proposed method), but the concentration of sulfuric acid in the initial solution and during the treatment of anion exchange resin is 50 g / l.

 Compared to optimal conditions, the degree of purification of scandium from titanium decreased from 54.4 to 1.3. At the same time, scandium losses at the sorption stage increased from 2.7 to 12.

Example 6
The same as in example 2.1 (according to the proposed method), but the concentration of sulfuric acid in the initial solution and during the processing of anion exchange resin 700 g / l (14.3 g-equiv / l).

 The degree of purification compared with optimal conditions (example 2.1) decreased by more than 30 times and amounted to only 1.8. At the same time, the degree of extraction of scandium also decreased from 96-99% to 85%.

Example 7
Same as in example 2.1 (according to the proposed method), but the anion exchange resin was not treated with sulfuric acid before sorption.

 When the solution was passed through a column with anion exchange resin, scandium and titanium did not separate: both metals precipitated in the intergranular space and the anion exchange phase in the form of sparingly soluble compounds (hydroxides, hydroxosulfates). Thus, there was no selective isolation of scandium in this case.

Example 8
The same as in example 2.1 (by the proposed method), but highly basic anion exchange resin was used as anion exchange resin. The solution, as in example 2.1 (according to the proposed method), was sequentially passed first through a column with anion exchange resin, and then through a column with phosphorus-containing ion exchanger. The separation of scandium and titanium in this case did not occur: scandium and titanium were sorbed on a phosphorus-containing ion exchanger (the strongly basic anion exchange resin did not absorb titanium). The degree of purification of scandium from titanium is 0.9, i.e. there was no selective extraction of scandium.

Example 9
Recycled wastes from the production of titanium dioxide - hydrolytic sulfuric acid, containing, g / l: Ti 3.2; Sc 0.025; H ₂ SO ₄ 170.

The initial solution was passed at 70 ^{° C.} first through a sorption column with weakly basic anion exchange resin (based on polyethylene polyamides, 3-chloro-1,2-epoxypropane and ammonia), a pre-treated solution (170 g / l) of sulfuric acid until the resin was completely saturated, then through sorption column with phosphorus-containing ion exchanger (macroporous phosphoric acid cation exchanger based on styrene and 12% divinylbenzene).

The volume of processed solutions is 500 dm ³ . The mass of ion exchangers in the columns: anion exchange resin 50 g; cation exchanger 10 g. The rate of transmission of solutions 1 cm ³ / (min • cm ² ).

After sorption, the ion exchangers in the columns were washed with water and metals were desorbed: from anion exchange resin (titanium) 6 N (220 g / l) with hydrochloric acid, and from cation exchange resin (scandium) 3 N with sodium carbonate. The eluates were neutralized to pH 4 ± 0.5, precipitated precipitates were separated from the mother liquors, washed, dried and calcined at 800 ^o C.

 Under these conditions, the degree of extraction of scandium is 99.5%. The degree of extraction of titanium (total - in two columns) 99.0%. The degree of purification of scandium from titanium is 40.0.

 As a result of the process, two concentrates were obtained: during the processing of hydrochloric acid eluate from a column with weakly basic anion exchange resin - titanium dioxide concentrate; when processing carbonate eluate from a column with cation exchange resin - scandium-containing concentrate.

Example 10
Scandium was extracted from sulfuric acid solutions (200-400 g / dm ³ ) formed during the complex processing of dump slag of ferro-tungsten production (initial content of scandium 0.035%); tailings of wet magnetic separation of titanium-magnetites (initial content of scandium 0.015%) and red mud of alumina production (initial content of scandium 0.01%). These wastes were processed according to well-known technological schemes, including the operations of heat treatment of waste, leaching in solutions of mineral acids, decontamination of the resulting pulp, precipitation from solutions of rare rare metal concentrate (CRMK), i.e., the primary concentration of scandium and the separation of scandium from the bulk of Fe, Mn and other metals, dissolving ChRMK in sulfuric acid to obtain sulfate (200-400 g / dm ³ H ₂ SO ₄ ) scandium solution (0.2-1.5 g / dm ³ Sc) containing titanium and other metals - impurities: Fe , Cr, Al, Mn, Zr and others. Received e solutions were processed according to the proposed method — first, by sequentially passing these solutions through sorption columns with a low basic ion exchanger based on polyethylene polyamine 3-chloro-1,2-epoxypropane and ammonia, which had been pretreated before sorption with a solution of H ₂ SO ₄ with the same concentration from which then conducted sorption (i.e. 200-400 g / dm ^3), then the filtrate was passed through a column with porous phosphorus ion exchangers (cation exchangers and / or ampholytes), after sorption resins in columns and carrying out the desorption washed iju metal ions, in particular, from the anion exchanger, desorption conducted hydrochloric acid solution (titanium, small amounts of impurities of other metals) and of phosphorus-containing ion exchangers stripped scandium or carbonate, or a fluoride-containing solution (Na ₂ CO _3, Na ₂ CO ₃ + NH ₄ Cl, (NH ₄ ) ₂ CO ₃ , KF, KF HF, etc.).

The soluble scandium compounds were precipitated from the resulting eluates, the precipitates were washed, dried and calcined to obtain scandium concentrates containing from 60 to 90% S ₂ O ₃ .

Under these conditions, when processing the above production waste:
- the degree of extraction of titanium on the anion exchange resin is ≥95-98%;
- degree of extraction of scandium ≥98%;
- the degree of purification of scandium from titanium - (0.5-2.0) (10 ² .

 The results of this series of experiments showed that the developed method is very versatile and can be used in the complex processing of various scandium-containing waste and industrial products.

Example 11
Waste from the production of titanium tetrachloride, in particular intermediate products resulting from the integrated processing of spent melts of titanium chlorination plants, was subjected to processing.

A hydrated precipitate containing scandium, titanium, and impurities of other metals (Fe, Cr, Mn, Zr Na, K, Mg, Ca, etc.) was dissolved in sulfuric acid. The concentration of sulfuric acid in the solution was brought up to 400 g / DM ³ . The resulting solution (0.2 g / dm ³ scandium; 0.6 g / dm ³ titanium) was passed at 80 ^° C through sorption columns: first through a column with weakly basic anion exchange resin pretreated with H ₂ SO ₄ (400 g / dm ³ ) , for the extraction of thiatane (degree of extraction of titanium 98%; the degree of extraction of scandium 1.5%), then through a column with phosphorus-containing ion exchanger - for the extraction of scandium (degree of extraction of scandium 98%).

 After sorption, the ion exchangers in the columns were washed with water and desorption was carried out: from anion exchange resin - titanium (and impurities of other metals) 3 N. hydrochloric acid solution, and from cation exchange resin - scandium (and impurities of other metals) 3 n. ammonium carbonate solution.

 The eluates were processed by known methods (neutralization, precipitation, filtration, washing, drying, calcination) to obtain titanium dioxide and scandium oxide concentrates.

 Under these conditions, the degree of purification of scandium from titanium is 65.0%.

 Thus, the described method provides an increase in the productivity of the process by increasing the sorption load and selectivity of extracting scandium from sulfate solutions by increasing the degree of purification of scandium from titanium.

Claims (2)

1. A method of processing scandium-containing solutions from leaching of waste products and industrial products, including sorption from an initial sulfuric acid solution on an anion exchange resin treated with a solution of sulfuric acid, sorption extraction of scandium with a phosphorus-containing ion exchanger, followed by washing of the ion exchanger, desorption of scandium and processing of the eluate, characterized in that from the initial sulfate carry out sorption on a solution of sulfuric acid with a concentration of 150-500 g / dm ³ H ₂ SO ₄ weakly basic anion exchange resin based on polyethylene oliamines, 3-chloro-1,2-epoxypropane and ammonia of the general formula

2. The method according to p. 1, characterized in that the sorption is carried out from solutions containing 150-500 g / DM ³ sulfuric acid.  3. The method according to p. 1, characterized in that the desorption from weakly basic anion exchange resin is carried out with a solution of hydrochloric acid.

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