CN104498714B - Ferrum, aluminum, calcium, the method for titana matter is removed from containing scandium solution separates - Google Patents

Abstract

The present invention proposes a method for separating and removing impurities of iron, aluminum, calcium and titanium from a scandium-containing solution, comprising steps: (1) reduction: adding a reducing agent to the scandium-containing solution to reduce Fe(III) to Fe(II ); (2) adding a complexing agent to complex Sc(Ⅲ) in the scandium-containing solution after step (1) reduction; (3) adding an alkali to the scandium-containing solution after the complexation, and adjusting the pH value of the solution to 1 ‑7; (4) The scandium-containing solution is mixed with a strongly acidic ion-exchange resin, or it flows through an exchange column equipped with a strongly acidic cation-exchange resin, and impurity ions are adsorbed to obtain a pure scandium solution. The present invention adopts the method of ion exchange to effectively remove impurities such as iron, aluminum, calcium and other impurities from the solution containing scandium; it can also remove some impurities such as titanium, zirconium, magnesium and manganese at the same time, providing an effective solution for the preparation of high-purity scandium. impurity removal method.

Description

Method for separating and removing impurities of iron, aluminum, calcium and titanium from scandium-containing solution

technical field

The invention belongs to the field of chemical metallurgy, and in particular relates to a method for removing impurities from scandium-containing solutions.

Background technique

Since the 1990s, many countries, including China, have set off an upsurge in the production and research of scandium. Russia has developed many practical industrial scandium-containing aluminum alloys, which have been applied in many high-tech sectors. In Western countries, the application of scandium in power supplies has made great progress, and scandium sodium lamps have been increasingly widely used. At present, the latest trend in the development of scandium is the research and development of cost reduction and comprehensive application including military-to-civilian conversion.

There are more than 800 kinds of scandium-containing minerals in nature, and traces of scandium can be found in almost all by-products of granite pegmatite mines. However, there are very few ores with a scandium oxide grade greater than 0.05%. my country is rich in scandium resources, especially high-yield minerals in my country, such as bauxite and phosphorite deposits, South China porphyry and quartz vein type tungsten deposits, South China rare earth deposits, Baiyun Obo rare earth iron deposits in Inner Mongolia, and Panzhihua vanadium-titanium magnets in Sichuan Mineral deposits and so on contain scandium. Therefore, the extraction of scandium basically uses red mud in the alumina industry, leaching slag in tungsten metallurgy, acid hydrolysis wastewater in the process of producing titanium dioxide by sulfuric acid method, and soot in the chlorination process of high-titanium slag as raw materials.

Due to the high content of Fe, Al, Ti and other substances in these raw materials, they exist in the form of impurities in scandium oxide or scandium-containing solution during the preparation of scandium oxide, thus affecting the purity of the product scandium compound.

At present, the method of separating these impurities from scandium compounds or scandium-containing solutions is mainly extraction method, such as the invention of patent No. 201310237363.2, which uses P204 to extract scandium. Although P204 has a strong extraction ability for scandium, the selectivity is very poor. It is also extracted, which makes the impurity removal process more complicated, the number of extraction and separation stages is huge, and the final scandium oxide purity is only 90%-95%, and with the output of industrial wastewater with high COD content, the processing cost is relatively high.

There is also a technique of removing impurities by precipitation, such as the invention of patent application No. 201110186520.2, which can obtain 99.99% high-purity scandium by calcining the filter cake after multiple dissolution-filtration-precipitation-rinsing-filtration, and effectively separate impurities, but more Secondary precipitation-dissolution-filtration results in greater loss of scandium, low yield of scandium and a large amount of waste water.

Contents of the invention

Aiming at the deficiencies in the art, the present invention aims to provide an effective method for removing impurity iron from crude scandium oxide. By ion exchange, the removal rate of iron can reach 98%, the removal rate of aluminum can reach 99.9%, and the removal rate of calcium can reach 98%. The removal rate is close to 99%. The method is simple in operation, low in cost and good in effect.

The technical scheme that realizes the object of the present invention is:

A method for separating and removing impurities of iron, aluminum, calcium and titanium from a scandium-containing solution, comprising the steps of:

(1) Reduction: determine the content of Fe(III) in the scandium-containing solution, add a reducing agent to the scandium-containing solution, and reduce Fe(III) to Fe(II); the reducing agent is ascorbic acid, iron powder, thiosulfuric acid One or more of sodium, hydrazine hydrate, and ammonium sulfide, and the amount of the reducing agent added is 1 to 4 times the theoretical amount required to reduce Fe(III) to Fe(II).

(2) Complexation: adding a complexing agent to complex Sc(III) into the scandium-containing solution after reduction in step (1);

(3) Adjust PH: add alkali to the scandium-containing solution after complexation, and adjust the pH value of the solution to 1-7;

(4) Resin adsorption of iron, aluminum, calcium, titanium and other impurities: the scandium-containing solution after reduction, complexation and pH adjustment is mixed with a strong acidic ion exchange resin, or it flows through an exchange system equipped with a strong acidic cation exchange resin Impurities such as iron, titanium, calcium, and titanium are adsorbed by the resin to obtain pure scandium solution.

In the technical solution of the present invention,

During the reduction process, Fe(Ⅲ) in the solution is reduced to Fe(II); an appropriate amount of complexing agent is added to the reduced scandium-containing solution to complex Sc(Ⅲ), and the cation scandium is converted into a complex anion, thereby avoiding the resin from Scandium adsorption. If there is precipitation during the pH adjustment process, it needs to be filtered, and the filtrate is carried out to the next step. In the process of ion exchange resin adsorption of iron, aluminum, calcium, titanium and other impurities, most of the iron, aluminum, calcium and some magnesium, manganese, zirconium and other impurities in the form of cations are adsorbed by the strongly acidic cation exchange resin, and scandium because Exist in the solution with complex anions, so as to obtain pure scandium solution.

Wherein, the scandium-containing solution is a hydrochloric acid solution containing one or more ions of Sc(III), Fe(III), Fe(II), Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Ti ⁴⁺ , sulfuric acid solution, nitric acid solution or mixtures thereof.

Specifically, the scandium-containing solution is an intermediate product of scandium-containing mineral metallurgy, or a solution similar to its composition, such as red mud in the alumina industry, leaching slag in tungsten metallurgy, acid hydrolysis in the process of producing titanium dioxide by sulfuric acid Wastewater and dust from the chlorination process of high-titanium slag are used as raw materials; or a solution similar to the composition of the leachate obtained from the metallurgical process, which contains Sc(Ⅲ) 0.1-10.86g/L, Fe(Ⅲ) 0.1-6.0g/L , Al 0.1-2.0g/L, Ca 0.1-1.0g/L, Ti 5-20g/L.

Preferably, the reducing agent in the step (1) is one or more of ascorbic acid, sodium thiosulfate, hydrazine hydrate, and ammonium sulfide, and the amount added is 1 to 1.5 times the theoretical amount of complexed scandium.

Wherein, the complexing agent used in the step (2) is one of EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), HEDTA (hydroxyethylethylenediaminetetraacetic acid), DTPA, DCTA, lactic acid One or more kinds, the amount added is 1-2 times of the theoretical complexed Sc(III) amount.

Preferably, the alkali for adjusting the pH in the step (3) is one or more of sodium hydroxide, sodium carbonate, and ammonia water, and the pH is adjusted to 2-4.

Wherein, the resin in the step (4) is a strongly acidic styrene-based cation exchange resin, selected from D001, D003, gel-type 001×7 (732), 001×3, 001×4 resins with large pores .

When the ion exchange column is filled with resin for ion exchange, the treatment capacity and flow rate of the scandium-containing solution can be determined according to the column volume, adsorption capacity and contact time. For example, in step (4), the volume ratio when the scandium-containing solution and the strong acidic cation exchange resin are mixed and adsorbed is 10-50:1; -30mL/h.

Further, sulfuric acid, hydrochloric acid, nitric acid or a mixed solution thereof with a concentration of 1-3 mol/L is used as a desorbent for the resin adsorbed with impurities in the step (4), and the desorbed resin can be returned for adsorption.

The beneficial effects of the present invention are:

1. The method of ion exchange is used to effectively remove impurities such as iron, aluminum, calcium and other impurities from scandium oxide;

2. The method of the present invention can also simultaneously remove some impurities such as titanium, zirconium, magnesium, manganese, etc., providing an effective impurity removal method for the preparation of high-purity scandium.

3. The recovery rate of scandium in the method of the present invention is high, and the loss of scandium in the whole process is very little.

4. The method of the present invention has simple operation and low cost.

Description of drawings

Fig. 1 is the process flow diagram of the inventive method;

detailed description

The present invention is illustrated with the following preferred embodiments, but they are not used to limit the scope of the present invention.

The feed solutions of Examples 1-6 were prepared with crude scandium oxide.

Embodiment 1: Separation effect in different scandium-containing solution systems

(1) Prepare scandium chloride solution respectively. The components in the form of hydrochloride in the solution are: Sc(Ⅲ) 0.82g/L, Fe(Ⅲ) 0.65g/L, Al 0.68g/L, Ca 0.51g/L L; scandium sulfate solution, the components in the form of sulfate in the solution are: Sc(Ⅲ) 0.86g/L, Fe(Ⅲ) 0.75g/L, Al 0.65g/L, Ca 0.55g/L; scandium nitrate solution , the components existing in the form of nitrate in the solution are: Sc(Ⅲ) 0.88g/L, Fe(Ⅲ) 0.68g/L, Al 0.60g/L, Ca 0.50g/L;

(2) Add 1.05 times the theoretical amount of ascorbic acid to reduce Fe(Ⅲ) to Fe(Ⅱ);

(3) Add 2.0 times the theoretical amount of EDTA to complex Sc(Ⅲ);

(4) the sodium hydroxide solution of 4mol/L is used to regulate three kinds of material liquid pHs and is 3.0;

(5) Measure 100ml of feed liquid and 10ml of processed D001 macroporous resin into a 250ml Erlenmeyer flask, and oscillate and absorb at room temperature. The adsorption results are shown in Table 1.

Table 1 The adsorption rate of scandium and iron, aluminum and calcium at different pH values

solution system Scandium chloride solution Scandium Sulfate Solution Scandium nitrate solution Fe adsorption rate 91.2% 90.3% 89.3% Al adsorption rate 93.5% 94.5% 94.1% Ca adsorption rate 92.6% 91.6% 93.1% Sc adsorption rate 1.4% 1.7% 1.6%

Embodiment 2: different cation exchange resin adsorption separation effect

(1) Six parts of scandium chloride solutions with the same composition were prepared. The components existing in the form of hydrochloride in the solution were: Sc(Ⅲ) 0.82g/L, Fe(Ⅲ) 0.65g/L, Al 0.68g/L, Ca 0.51g/L;.

(2) Add 1.5 times the theoretical amount of ascorbic acid to reduce Fe(III) to Fe(II).

(3) Add 1.1 times the theoretical amount of EDTA to complex Sc.

(4) Adjust the pH value of the solution to 3.0 with 26% ammonia water. .

(5) Measure 100ml of the solution in a graduated cylinder and place it in six 250ml Erlenmeyer flasks, add 10ml of treated 001×3, 001×4, 001×7, D001, D003 and D115 resins respectively, and shake and absorb at room temperature.

The adsorption results are shown in Table 2.

Table 2 The adsorption rates of scandium, iron, aluminum and calcium by resins of different grades

resin 001×3 001×4 001×7 D001 D003 D115 Fe adsorption rate 94.4% 93.6% 93.2% 90.1% 88.8% 55.8% Al adsorption rate 96.9% 97.1% 96.5% 92.8% 95.0% 56.1% Ca adsorption rate 96.0% 95.5% 95.6% 93.3% 95.2% 59.6% Sc adsorption rate 3.8% 2.1% 1.6% 1.4% 1.5% 3.3%

Separation effect under different pH value conditions of embodiment 3

(1) Prepare six parts of scandium chloride solutions with the same composition. The components in the form of hydrochloride in the solution are: Sc(Ⅲ) 1.55g/L, Fe(Ⅲ) 0.25g/L, Al 0.38g/L, Ca 0.46g/L, Ca 0.205g/l;.

(2) Add 1.5 times the theoretical amount of ascorbic acid to reduce Fe(III) to Fe(II);

(3) Add 1.5 times the theoretical amount of EDTA to complex Sc;

(4) adjust the pH of six solutions with 26% ammonia water to be 0, 1.0, 2.0, 3.0, 4.0, 5.0 respectively;

(5) Measure 100ml of feed solution and 10ml of treated D001 resin into a 250ml Erlenmeyer flask by measuring cylinder, and shake and absorb at room temperature.

The results are shown in Table 3.

Table 3 The adsorption rate of scandium and iron, aluminum and calcium at different pH values

pH 0 1.0 2.0 3.0 4.0 5.0 Fe adsorption rate 45.8% 90.2% 92.5% 93.6% 94.8% 94.5% Al adsorption rate 36.8% 93.5% 96.0% 96.1% 96.6% 97.8% Ca adsorption rate 22.1% 92.4% 94.8% 95.7% 96.6% 96.3% Ti adsorption rate 28.4% 88.4% 89.2% 94.8% 95.1% 96.2% Sc adsorption rate 0.4% 1.3% 1.3% 1.6% 2.1% 2.8%

The separation effect of scandium and impurity during different reducing agent and consumption of embodiment 4

(1) Prepare seven scandium chloride solutions with the same composition. The components that exist in the form of hydrochloride in the solution are: Sc(Ⅲ) 0.82g/L, Fe(Ⅲ) 0.65g/L, Al 0.68g/L, Ca 0.51g/L;

(2) Adding reducing agents of different types and qualities to reduce ferric iron to ferrous iron.

(3) Add 1.5 times the theoretical amount of EDTA complexed scandium;

(4) Regulating feed liquid pH with sodium hydroxide solution is 3.0;

(5) Measure 100ml of feed liquid and 10ml of treated resin 001×7 in a measuring cylinder and put them in a 250ml conical flask, and oscillate and absorb at room temperature;

The results show that the adsorption rates of 001×7 resin on Fe, Al, Ca and Sc are shown in Table 4.

Table 4 The adsorption rate of scandium and iron, aluminum, and calcium under different types and masses (unit: multiple of theoretical amount)

Example 5: The separation effect of scandium and impurities when different complexing agents are complexed

(1) Six parts of scandium chloride solutions with the same composition were prepared. The components existing in the form of hydrochloride in the solution were: Sc(Ⅲ) 0.5175g/L, Fe(Ⅲ) 0.636g/L, Al 0.68g/L, Ca 0.51g/L;

(2) Add 1.5 times the theoretical amount of ascorbic acid to reduce Fe(III) to Fe(II);

(3) Add 1 times the theoretical amount of different complexing agents to complex scandium;

(4) Regulating feed liquid pH with sodium hydroxide solution is 3.0;

(5) Measure 100ml of feed liquid and 10ml of treated 001×7 resin in a graduated cylinder, place them in a 250ml Erlenmeyer flask, and oscillate at room temperature for adsorption.

The results are shown in Table 5.

Table 5 The adsorption rate of scandium and iron, aluminum and calcium under the complexing conditions of different complexing agents

complexing agent EDTA HEDTA DCTA DTPA NTA lactic acid Fe adsorption rate 93.2% 92.8% 93.3% 93.3% 93.8% 91.4% Al adsorption rate 96.5% 96.6% 97.0% 97.5% 96.0% 92.6% Ca adsorption rate 95.6% 95.1% 96.8% 94.2% 95.5% 92.8% Sc adsorption rate 4.5% 4.8% 5.5% 6.6% 6.5% 12.8%

Embodiment 6: exchange column adsorption experiment

(1) Feed liquid: Scandium chloride solution, the components in the form of hydrochloride in the solution are Sc(Ⅲ) 10.86g/L, Fe(Ⅲ)+Fe(Ⅱ) 0.403g/L, Al 0.51g/L , Ca 0.55g/L, Ti 0.60g/L, Mn 0.82g/L, Zr 0.34g/L.

(2) Add ascorbic acid which reduces Fe(III) to 1.2 times the theoretical amount of Fe(II) for reduction.

(3) Add 1.2 times the theoretical amount of complexed scandium EDTA for complexation.

(4) Regulate feed liquid pH with 4mol/L sodium hydroxide solution to be 3.0.

(5) 300ml of the above-mentioned feed solution flows through a glass exchange column equipped with 20ml 001×7 resin, the flow rate of the feed solution is 20ml/h, and room temperature.

(6) After the adsorption is completed, rinse the loaded resin in the column with pure water at a flow rate of 10ml/h for 3 hours, then use a 2mol/L hydrochloric acid solution absorbent to control the flow rate of the desorption solution to 10ml/h, and desorb for 3 hours.

The process is shown in Figure 1. The experimental results are shown in Table 6.

Table 6 Exchange column adsorption removal effect of impurities such as iron, aluminum, calcium, titanium, etc.

Embodiment 7: exchange column adsorption

(1) Feed liquid: chlorinated fume in the process of titanium smelting, dissolved in 2mol/L hydrochloric acid solution, the components in the form of hydrochloride in the solution are Sc(Ⅲ)2.02g/L, Fe(Ⅲ)+Fe( Ⅱ) 5.12g/L, Al 1.35g/L, Ca 0.45g/L, Ti 15.30g/L, Mn 2.24g/L, Zr 1.15g/L.

(2) Adding 1.2 times the theoretical amount of ascorbic acid to reduce Fe(III) to Fe(II) for reduction.

(3) Add 1.2 times the theoretical amount of complexed scandium EDTA for complexation.

(4) Regulate feed liquid pH with 4mol/L sodium hydroxide solution to be 3.0.

(5) 300ml of the above-mentioned feed solution flows through a glass exchange column equipped with 20ml 001×7 resin, the flow rate of the feed solution is 20ml/h, and room temperature.

(6) After the adsorption is completed, rinse the loaded resin in the column with pure water at a flow rate of 10ml/h for 3 hours, then use a 2mol/L hydrochloric acid solution absorbent to control the flow rate of the desorption solution to 10ml/h, and desorb for 3 hours.

The experimental results are shown in Table 7.

Table 7 Effect of adsorption removal of impurities such as iron, aluminum, titanium, and titanium by exchange column

The above embodiments are only descriptions of preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. On the premise of not departing from the design spirit of the present invention, ordinary engineers and technicians in the field may make various modifications to the technical solutions of the present invention. and improvements, all should fall within the scope of protection determined by the claims of the present invention.

Claims (3)

1. A method for separating and removing iron, aluminum, calcium, and titanium impurities from scandium-containing solution, characterized in that, comprising steps: (1) Reduction: Determine the content of Fe(III) in the scandium-containing solution, add a reducing agent to the scandium-containing solution, and reduce Fe(III) to Fe(II); the reducing agent is ascorbic acid, sodium thiosulfate, hydration One of hydrazine and ammonium sulfide, the amount added is 1 to 1.5 times the theoretical amount required for reducing iron; (2) complexation: add complexing agent complexation Sc(Ⅲ) in the scandium-containing solution after reduction in step (1); the complexing agent used is EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), One or more of HEDTA (hydroxyethylethylenediaminetetraacetic acid), DTPA, DCTA, and lactic acid, the amount added is 1 to 2 times the amount of theoretical complexed Sc(Ⅲ); (3) Regulate PH: Add alkali to the scandium-containing solution after complexation, the alkali is one or more of sodium hydroxide, sodium carbonate, and ammonia water, and the pH is adjusted to 2 to 4; (4) Resin adsorption of iron, aluminum, calcium, and titanium impurities: after reduction, complexation, and pH adjustment, the scandium-containing solution is mixed with a strong acidic ion exchange resin, or it flows through an exchange column equipped with a strong acidic cation exchange resin , to obtain pure scandium solution; the resin is a strongly acidic styrenic cation exchange resin selected from D001, D003, gel-type 001×7 (732), 001×3, and 001×4 resins with large pores A sort of. 2. The method according to claim 1, wherein the scandium-containing solution contains Sc(III), Fe(III), Fe(II), Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Ti Hydrochloric acid solution, sulfuric acid solution, nitric acid solution or mixtures of one or more ions in ⁴⁺ . 3. method according to claim 1, it is characterized in that, the sulfuric acid, hydrochloric acid, nitric acid or its mixed solutions of 1～3mol/L are used as desorption agent in the resin after absorbing impurity in the described step (4), The desorbed resin can be returned to adsorption for use.