A method for separating niobium oxide and scandium oxide from Baiyunebo tailings

Abstract

The application discloses a method for separating niobium oxide and scandium oxide from Baiyunebo tailings, which comprises the following steps: normal-pressure acid leaching, precipitating rare earth complex salt by adopting sodium sulfate on the leaching solution, removing iron and titanium in the organic phase by using hydrochloric acid-hydrogen peroxide washing liquid, and obtaining the co-precipitation alkali cake of niobium hydroxide and scandium hydroxide by back-extracting the organic phase by sodium hydroxide, and the alkali cake is reacted with a mixed solution of oxalic acid and ammonia water, so that three products of rare earth sulfate complex salt, niobium oxide and scandium oxide can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for separating niobium oxide and scandium oxide from Baiyunebo tailings. BACKGROUND

[0002] Scandium (Sc) is a rare and dispersed rare earth element, which is rarely present in nature in the form of associated minerals in other minerals. In the extraction of elements from various ores, scandium is generally not involved in the reaction in the process, so it is finally concentrated in the slag discharged during the production of these elements. Due to the characteristics of high chemical activity, good electrical conductivity, high melting point, low specific gravity, soft quality and easy cutting, scandium has been widely used in important fields such as electric light source, aerospace, electronic industry, nuclear technology and superconducting technology. With the increasing application range of scandium and its compounds, the demand for scandium is increasing.

[0003] Niobium (Nb) is a transition metal element located in the V sub-group. Niobium is a soft and ductile metal with high melting point and boiling point. It is mainly used as an alloy additive for steel, such as niobium iron (FeNb). Niobium oxide (Nb2O5) is an important niobium product. Part of the niobium oxide can be used for glass, ceramic capacitors, piezoelectric elements and catalysts. Meanwhile, niobium oxide can also be used to produce other niobium products, such as niobium metal, niobium alloy, vacuum-grade niobium iron and niobium nickel, niobium carbide and potassium niobate crystals and other niobium compounds.

[0004] Rare earths are a total of seventeen metal elements including lanthanide series elements and scandium and yttrium in the periodic table. There are 250 kinds of rare earth minerals in nature. Among the more than 250 kinds of rare earth minerals and minerals containing rare earth elements found today, only more than 10 kinds of industrial minerals suitable for current smelting conditions. Rare earths are known as the "industrial gold" due to their excellent photoelectric and electromagnetic physical properties, and can be combined with other materials to form new materials with different properties and a wide variety of types. Its most notable function is to greatly improve the quality and performance of other products, so it is widely used in military, metallurgy, petroleum and chemical industry, glass and ceramic industry.

[0005] The Baotou Baiyunebo mine has scandium reserves of 140,000 tons and niobium reserves of 6.6 million tons. Scandium and niobium are indispensable elements for the development of advanced science and technology and the preparation of advanced materials in China. Scandium oxide is rich in Baotou steel tailings, which is a high-grade raw material among various scandium resources in China.

[0006] The title is "comprehensive utilization of sc in baotou tailings", introduce the sulfuric acid system of high pressure leaching, P204 system extraction leaching liquid, washing organic phase, back extraction of sc and nb, P350 system purification of crude sc liquid, sc liquid oxalic acid precipitation, sc oxide calcination and other tests, explore the complete process parameters. The invention improves the steps of pressurized acid leaching, extraction and back extraction compared with the previous process, saves raw materials, simplifies the process, so it has stronger process adaptability.

[0007] The original method uses pressurized acid leaching method, which has high requirement for equipment and has potential safety hazard; The two-step acid leaching method is used to wash the organic phase, which has high raw material consumption; At the same time, the rare earth in the tailings cannot be effectively recycled and utilized. SUMMARY

[0008] In order to solve the above technical problems, the purpose of the present application is to provide a method for separating niobium oxide and scandium oxide from baotou tailings.

[0009] In order to solve the above technical problems, the present application adopts the following technical scheme:

[0010] The method for separating niobium oxide and scandium oxide from baotou tailings of the present application grinds and filters the baotou tailings slurry, adds excess Na2SO4 to the leaching solution after normal pressure acid leaching, filters the precipitate after reaction, and can obtain product rare earth sulfate double salt;

[0011] The filtrate obtained after filtration enters the extraction system, and hydrochloric acid-hydrogen peroxide mixed solution is used to wash and remove impurities from the organic phase. After the impurity removal is completed, NaOH is used for back extraction, and ammonium oxalate solution and scandium oxalate precipitate are obtained by adding oxalic acid-ammonia mixed solution to the back extraction product. The scandium oxalate is calcined to obtain finished product scandium oxide. The ammonium oxalate can be precipitated by adjusting the PH value of the solution, and the subsequent purification process is carried out.

[0012] Further, it specifically includes the following steps:

[0013] ①The baotou tailings slurry with particle size of about 45-75μm is first concentrated, and then ground to particle size of 5-45μm;

[0014] ②The ground scandium-containing material is pressure filtered, and the water content after pressure filtration is about 20-40%;

[0015] ③The mixture is injected into the reaction kettle, and high temperature normal pressure acid leaching is carried out in high temperature sulfuric acid system. After acid leaching, the solution is diluted with water to a sulfuric acid concentration of 5.8-6.2mol / L (preferably 6.0mol / L);

[0016] ④After dilution, the solution is added with excess Na2SO4, and after reaction, the precipitate is filtered to obtain the product rare earth sulfate double salt;

[0017] ⑤The filtered solution enters the extraction system, and 3-5 mol / L HCl and 1%-5% H2O2 are added to the organic phase during the washing process of the solution.

[0018] ⑥After the reaction, the original impurities such as iron and titanium in the solution are basically removed. After washing with hydrochloric acid and hydrogen peroxide, the niobium and scandium in the organic phase are back-extracted with NaOH to obtain the products scandium hydroxide and niobium hydroxide;

[0019] ⑦Next, the scandium hydroxide and niobium hydroxide are reacted with oxalic acid-ammonia mixed solution, and the reaction can obtain solid precipitate scandium oxalate [Sc(C3O4)3nH2O] with a purity higher than 95% and solution niobium ammonium oxalate C2H5NNbO4.

[0020] Sc(OH)3+ 3HCl → ScCl3+ 3H2O

[0021] ScCl3+ 3H2C2O4 → Sc2(C2O4)3+ 6HCl

[0022] ⑧Scandium oxalate is calcined to obtain finished product scandium oxide with a purity of 99.9%;

[0023] Sc2(C2O4)3→ Sc2O3+ 3CO2↑+ 3CO2↑

[0024] ⑨Ammonium niobium oxalate forms a precipitate by adjusting the pH value of the solution, and 99.9% niobium oxide can be obtained through multi-stage purification and other processes.

[0025] Further, in step ③, the high-temperature sulfuric acid system is 150-200℃, and the mineral acid ratio ranges from 1:2 to 1:5 according to the change of the mineral.

[0026] Further, in step ④, the amount of Na2SO4 added is 1.1-1.5 times.

[0027] Further, in step ⑤, the extraction system is P 204 : TBP: kerosene = 20-25%: 3-5%: 70-77%.

[0028] Further, in step ⑤, the concentration of H2O2 varies according to the content of titanium, with a ratio of 1:1 and a number of stages of 10-30.

[0029] Further, the overall process effect: rare earth leaching rate > 85%, recovery rate > 80%; Sc leaching rate > 60%, recovery rate > 50%; Nb leaching rate > 85%, recovery rate > 70%.

[0030] Compared with the prior art, the present application has the beneficial technical effects of:

[0031] The required equipment for the reaction is low, the safety is improved, the process flow is simplified, the raw materials required for the reaction are saved, and the rare earth in the tailings is effectively recycled and utilized to increase the product types. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will be further described below in conjunction with the description of the accompanying drawings.

[0033] Figure 1 The flow chart for separating niobium oxide and scandium oxide from Baiyunebo tailings according to the present application. DETAILED DESCRIPTION

[0034] As shown in the figure, a method for separating niobium oxide and scandium oxide from Baiyunebo tailings Figure 1

[0035] ①The Baiyunebo tailings slurry with a particle size of about 45 μm-75 μm is first concentrated, and then ground to a particle size of 5 μm-45 μm.

[0036] ②The ground scandium-containing material is subjected to pressure filtration, and the water content after pressure filtration is about 20-40%.

[0037] ③The mixture is injected into a reaction kettle, and high-temperature atmospheric acid leaching is carried out under a high-temperature sulfuric acid system (150℃-200℃, the mineral acid ratio ranges from 1:2 to 1:5 according to the change of the mineral). After acid leaching, the solution is diluted with water to a sulfuric acid concentration of 6 mol / L.

[0038] ④After dilution, an excess of Na2SO4 (1.1-1.5 times) is added, and after reaction, the precipitate is filtered to obtain the product rare earth sulfate double salt.

[0039] ⑤The filtered solution enters the extraction system (P 204 and TBP two extractants, and solvent oil as the extraction solvent, P 204 : TBP: kerosene = 20-25%: 3-5%: 70-77%), 3-5 mol / L of HCl and 1%-5% of H2O2 (the concentration changes according to the content of titanium, the ratio is 1:1, and the order is 10-30) are added to the organic phase during the washing process of the organic phase solution.

[0040] ​The originally existing iron element, titanium element and other impurities in the solution are basically removed after the reaction is completed. The niobium element and scandium element in the organic phase after washing with hydrochloric acid and hydrogen peroxide are back-extracted using NaOH, and the product scandium hydroxide and niobium hydroxide are obtained.

[0041] The scandium hydroxide and niobium hydroxide are then reacted with an oxalic acid-ammonia mixed solution, and the reaction can obtain scandium oxalate [Sc(C3O4)3nH2O] (solid precipitate) and ammonium niobium oxalate C2H5NNbO4 (solution) with a purity higher than 95%.

[0042] Sc(OH)3+3HCl→ScCl3+3H2O

[0043] ScCl3+3H2C2O4→Sc2(C2O4)3+6HCl

[0044] The scandium oxalate can be calcined to obtain finished scandium oxide with a purity of 99.9%.

[0045] Sc2(C2O4)3→Sc2O3+3CO2↑+3CO2↑

[0046] The ammonium niobium oxalate forms a precipitate by adjusting the PH value of the solution, and 99.9% niobium oxide can be obtained through a multi-stage purification process such as recrystallization.

[0047] The overall process can achieve the following effects:

[0048] The leaching rate of rare earth is greater than 85%, and the recovery rate is greater than 80%;

[0049] The leaching rate of scandium is greater than 60%, and the recovery rate is greater than 50%;

[0050] The leaching rate of niobium is greater than 85%, and the recovery rate is greater than 70%.

[0051] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for separating niobium oxide from scandium oxide from Baiyunebo tailings, characterized in that, The Baiyunebo tailings slurry is ground, filter-pressed, and subjected to high-temperature normal-pressure acid leaching in a high-temperature sulfuric acid system, and then an excess amount of Na2SO4 is added to the leaching solution, and the precipitate is filtered after reaction to obtain a product of rare earth sulfate double salt; wherein the high-temperature sulfuric acid system is at 150-200 DEG C; The filtrate obtained after filtration enters an extraction system, and a mixed solution of hydrochloric acid and hydrogen peroxide is used to wash and remove impurities from the organic phase, and then NaOH is used for back extraction, and a mixed solution of oxalic acid and ammonia water is added to the back-extracted product for reaction to obtain scandium oxalate precipitate and ammonium niobium oxalate solution, and the scandium oxalate is calcined to obtain finished scandium oxide; the ammonium niobium oxalate is precipitated by adjusting the pH value of the solution, and then subjected to subsequent purification processes.

2. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 1, characterized in that, Specifically comprising the following steps: ①The Baiyunebo tailings slurry with a particle size of 45-75 μm is first concentrated, and then ground to a particle size of 5-45 μm; ②The ground scandium-containing material is filter-pressed, and the water content after filter-pressing is 20-40%; ③The mixture is injected into a reaction kettle, and subjected to high-temperature normal-pressure acid leaching in a high-temperature sulfuric acid system, and then the solution is diluted with water to a sulfuric acid concentration of 5.8-6.2 mol / L after acid leaching; ④An excess amount of Na2SO4 is added to the diluted solution, and the precipitate is filtered after reaction to obtain a product of rare earth sulfate double salt; ⑤The filtered solution enters an extraction system, and 3-5 mol / L of HCl and 1-5% of H2O2 are added to the organic phase for reaction during the washing process of the organic phase; ⑥The original iron and titanium impurities in the solution are removed after reaction; The niobium and scandium elements in the organic phase washed with hydrochloric acid and hydrogen peroxide are back-extracted with NaOH to obtain scandium hydroxide and niobium hydroxide as products; ⑦Next, a mixed solution of oxalic acid and ammonia water is used to react with scandium hydroxide and niobium hydroxide, and solid scandium oxalate [Sc(C3O4)3 nH2O] with a purity higher than 95% and ammonium niobium oxalate C2H5NNbO4 solution are obtained; Sc(OH)3+3HCl → ScCl3+3H2O ScCl3+3H2C2O4→ Sc2(C2O4)3+6HCl ⑧The scandium oxalate is calcined to obtain finished scandium oxide with a purity of 99.9%; Sc2(C2O4)3→ Sc2O3+3CO2↑ +3CO2↑ ⑨The ammonium niobium oxalate is precipitated by adjusting the pH value of the solution, and 99.9% niobium oxide is obtained through a multi-stage purification process.

3. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 2, characterized in that, In step ③, the mineral acid ratio ranges from 1:2 to 1:5 depending on the mineral.

4. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 2, characterized in that, In step ④, the amount of Na2SO4 added is 1.1-1.5 times.

5. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 2, characterized in that, The step (v) the extraction system is: P 204 : TBP: kerosene = 20-25%: 3-5%: 70-77%.

6. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 2, characterized in that, In step ⑤, the concentration of H2O2 varies according to the content of titanium, with a ratio of 1:1 and a number of stages of 10-30.

7. The method for separating niobium oxide and scandium oxide from Baiyunebo tailings according to claim 2, characterized in that, Overall process effect: rare earth leaching rate > 85%, recovery rate > 80%; scandium leaching rate > 60%, recovery rate > 50%; niobium leaching rate > 85%, recovery rate > 70%.

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