A method for efficiently decomposing scheelite at room temperature
By using sodium oxalate-tartaric acid-hydrochloric acid composite decomposition agent in sedraelite at room temperature, the problems of high energy consumption and low decomposition efficiency under heating conditions in the prior art are solved, and efficient decomposition and simplified treatment are achieved Process reduces environmental and operational risks, improves energy efficiency and safety.
Patent Information
- Application Number
- CN202411272828.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2044-09-11
AI Technical Summary
The existing sedraelite decomposition technology relies on heating conditions, resulting in high energy consumption and limited decomposition efficiency, and the decomposition slag treatment after decomposition is difficult, and the environmental impact and operational safety are poor.
After fine grinding activation and alkaline water washing, sodium oxalate-tartaric acid-hydrochloric acid composite decomposition agent is used to decompose sedosyl ore at room temperature. Calcium tungstate is decomposed through the synergistic action of sodium oxalate and hydrochloric acid to form a highly solubility network. The compound achieves efficient complexing and dissolution of tungsten, and adjusts the pH value of the decomposition residue by washing with weak acidic water to reduce the generation of strong alkaline residue.
It realizes efficient decomposition without heating, reduces energy consumption and equipment operation costs, simplifies the follow-up processing process of decomposition slag, reduces environmental impact and operation risks, improves the energy efficiency ratio of the decomposition process, and creates a safer and healthier working environment. .
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Figure CN118773456B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of tungsten smelting, and in particular to a method for efficiently decomposing scheelite at room temperature. Background Art
[0002] Tungsten in scheelite mainly exists in the form of calcium tungstate. Since the combination of tungsten and calcium is very stable, decomposition usually needs to be completed by heating and pressurization, especially when sodium salt or sodium alkali is used as the decomposition agent, the decomposition temperature is often ≥150℃, the pressure is ≥0.5MPa, and the consumption of the decomposition agent is 2 to 6 times the theoretical amount. At the same time, the slag after decomposition is strongly alkaline, which is difficult to handle, seriously limiting the decomposition efficiency. To this end, researchers have developed an acid decomposition process and made important progress, but there are still shortcomings. The hydrochloric acid / nitric acid heating decomposition method has high decomposition efficiency, but it must be decomposed at 90℃~100℃, resulting in very high consumption of hydrochloric acid / nitric acid, difficulty in acid mist treatment, and serious corrosion to equipment. The recovery rate of sulfuric acid heating decomposition method and sulfuric acid-hydrogen peroxide decomposition method is poor, because tungsten exists in the slag in the form of tungstic acid, and a large part of it is dissolved in the solution, resulting in low recovery rate. The sulfur-phosphorus mixed acid heating decomposition method has pioneering results and good decomposition effect, but it still needs to be completed at 50°C. At the same time, due to the introduction of phosphorus as a chelating agent for tungsten, a more sophisticated phosphorus removal process is required later, and the operation requires more precision. The phytic acid-sulfuric acid decomposition method has also achieved certain results, but in order to achieve a better decomposition effect, a heating process is still required. In summary, the current decomposition of scheelite depends on heating conditions, has high energy consumption, and the decomposition efficiency is limited. Therefore, the development of a process for efficient decomposition at room temperature is the key to solving the above problems. Summary of the invention
[0003] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for efficiently decomposing scheelite at room temperature, comprising the following steps:
[0004] S1: Fine grinding and activation: Use a ball mill to finely grind and activate the scheelite, further reduce the particle size of the scheelite, increase the contact area with the decomposer, and use ball milling to destroy the film formed on the surface of the mineral particles due to flotation, improve the decomposition efficiency, collect the milled scheelite particles, and enter the next step.
[0005] S2: Alkaline water washing: Place the ball-milled scheelite particles in step S1 in a glass beaker, add alkaline water I containing NaOH for stirring and washing, and use alkaline water I to remove the residual flotation agent in the scheelite to prevent the residual flotation agent from wrapping the scheelite and affecting decomposition. After the alkaline water washing is completed, an alkaline water washing slurry is obtained, and the washing water I is collected and processed to enter the next step.
[0006] S3: Filtration and washing: The alkaline water washing slurry obtained in step S2 is filtered using a cyclone separator and washed with weakly acidic water I to elute the residual alkali remaining in the residue. After washing, the filtrate II and washing water II are collected and processed, and the filter residue I enters the next step.
[0007] S4: Decomposition at room temperature: Add the filter residue I obtained in step S3 after washing with weakly acidic water I into a glass beaker, and then add the decomposing agent sodium oxalate-tartaric acid-hydrochloric acid. The amount of sodium oxalate is 100% to 200% of the theoretical amount of calcium in scheelite converted into calcium oxalate, and the amount of tartaric acid is 100% to 200% of the theoretical amount of WO in scheelite. 3 100% to 150% of the theoretical amount of complex is added, the concentration of hydrochloric acid is 0.5% to 1%, the liquid-solid mass ratio is 2:1 to 5:1, and decompose at room temperature for 2h to 5h. When the decomposition is completed, enter the next step.
[0008] S5: Filtration and washing: The slurry decomposed at room temperature in step S4 is filtered by a cyclone separator and washed with pure water to clean the tungsten-containing liquid and residual acid remaining in the slag. After washing, the filtrate III and washing water III are collected and processed, and the filter residue II enters the next stage.
[0009] S6: Alkaline water washing: The filter residue II obtained in step S5 is placed in a glass beaker, and alkaline water II containing NaOH is added for stirring and washing. The alkaline water II is used to further dissolve the tungsten that may remain in the filter residue II in the form of tungstic acid, so as to achieve the purpose of improving the tungsten recovery rate. The alkaline water washing is completed and enters the next step.
[0010] S7: Filtration and washing: The slurry obtained after washing in step S6 is filtered using a cyclone separator, and washed with weakly acidic water II. After washing, the filtrate IV and washing water IV are collected and processed, and the filter residue III is collected to complete the room temperature decomposition of the scheelite.
[0011] Furthermore, in step S1, the proportion of mineral particle size -325 mesh after ball milling is ≥98%.
[0012] Furthermore, the NaOH content of the alkaline water I in step S2 and the alkaline water II in step S6 is 0.5% to 1.5%.
[0013] Furthermore, in step S2, the liquid-solid mass ratio is 2:1 to 4:1, the stirring time is 4 h to 8 h, and the stirring speed is 60 r / min to 90 r / min.
[0014] Furthermore, in step S3, the weakly acidic water I is sulfuric acid or hydrochloric acid with a concentration in the range of 0.05 mol / L to 0.2 mol / L, and the amount of the weakly acidic water I is 100% to 300% of the mass of the added scheelite particles.
[0015] Furthermore, the amount of pure water used in step S5 is 100% to 200% of the mass of the added scheelite particles.
[0016] Furthermore, in step S6, the liquid-solid mass ratio is 2:1 to 4:1, the stirring time is 1 h to 2 h, and the stirring speed is 60 r / min to 90 r / min.
[0017] Furthermore, in step S7, the weakly acidic water II is sulfuric acid or hydrochloric acid with a concentration in the range of 0.1% to 0.5%, and the amount of the weakly acidic water II is 100% to 150% of the mass of the added scheelite particles.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1. Efficient decomposition without heating. The present invention uses a sodium oxalate-tartaric acid-hydrochloric acid composite decomposition agent. First, under the synergistic effect of sodium oxalate and hydrochloric acid, calcium tungstate in scheelite is decomposed to form calcium oxalate and tungstic acid. Tartaric acid and tungstic acid form a highly soluble tungsten complex [WO 4 (C 4 H 6 O 6 )] 2- , achieving efficient complex dissolution of tungsten, and achieving efficient decomposition of calcium tungstate at room temperature without heating, achieving a high decomposition rate of calcium tungstate, which not only reduces energy consumption, but also reduces equipment operating costs and improves the energy efficiency of the entire decomposition process.
[0020] 2. Simplify the subsequent treatment process of decomposition slag. Using weakly acidic water to wash the decomposition slag produced after the decomposition of scheelite can adjust the pH value of the decomposition slag to 6-9, avoiding the production of strongly alkaline decomposition slag. This step not only reduces the potential impact on the environment, but also reduces the subsequent treatment cost and operation difficulty.
[0021] 3. Environmentally friendly and safe operation. This method does not require heating or the use of strong acids or alkalis to decompose scheelite, which reduces the generation of acid mist. This improvement not only reduces the impact on the health of operators, but also reduces the risk of corrosion to equipment, creating a safer and healthier working environment for users. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the specific implementation of the present invention or the technical solution in the prior art, the drawings required for describing the specific implementation or the prior art will be briefly introduced below. Obviously, the drawings described below are only one implementation of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0023] Figure 1The present invention is a flowchart of a method for decomposing scheelite at room temperature according to an embodiment of the present invention.
[0024] Figure 2 This is the final energy chromatography analysis result diagram of the decomposition slag in Example 1.
[0025] Figure 3 This is the final energy chromatography analysis result of the decomposition slag in Example 2.
[0026] Figure 4 This is the final energy chromatography analysis result of the decomposition slag in Example 3. DETAILED DESCRIPTION
[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the technical scheme in the specific implementation mode of the present invention is clearly and completely described below to further illustrate the present invention. Obviously, the specific implementation mode described is only a part of the implementation mode of the present invention, rather than all styles.
[0028] Embodiment 1
[0029] like Figure 1 As shown, a method for efficiently decomposing scheelite at room temperature comprises the following steps:
[0030] S1: Fine grinding and activation: Weigh 50g of scheelite (synthetic scheelite). 3 The content is 45.61%, the Ca content is 13.12%. The scheelite is finely ground and activated with a ball mill. The grinding time is 20 minutes. The mineral particle size after ball milling is -325 mesh, accounting for 99.52% (water sieve test). The scheelite particles after ball milling are collected and enter the next step.
[0031] S2: Alkaline water washing: Place the ball-milled scheelite particles in step S1 in a container, add alkaline water containing 10.81 g / L NaOH, with a liquid-to-solid mass ratio of 4:1, and stir and wash for 4 hours at a stirring speed of 60 r / min. After the alkaline water washing is completed, an alkaline water-washed slurry is obtained, and the washing water I is collected and processed to enter the next step.
[0032] S3: Filtration and washing: The alkaline water washing slurry obtained in step S2 is filtered using a cyclone separator and washed with weakly acidic water I. The weakly acidic water I is dilute hydrochloric acid with a concentration of 0.05 mol / L. The amount of weakly acidic water I is 100% of the mass of the added scheelite particles. After the washing is completed, the filtrate II and washing water II are collected and processed, and the filter residue I enters the next step.
[0033] S4: Decomposition at room temperature: Add the filter residue I obtained in step S3 after washing with weakly acidic water I into a glass beaker, and then add the decomposing agent sodium oxalate-tartaric acid-hydrochloric acid. The amount of sodium oxalate is 150% of the theoretical amount of calcium in scheelite converted into calcium oxalate, and the amount of tartaric acid is 150% of the theoretical amount of WO in scheelite converted into calcium oxalate. 3 120% of the theoretical amount of complex is added, the concentration of hydrochloric acid is 1%, the liquid-solid mass ratio is 4:1, decompose at room temperature for 4 hours, the decomposition is completed, and enter the next step.
[0034] S5: Filtration and washing: The slurry decomposed at room temperature in step S4 is filtered using a cyclone separator, and then washed with pure water. The amount of pure water used is 200% of the mass of the added scheelite particles. After washing, the filtrate III and washing water III are collected and processed, and the filter residue II enters the next stage.
[0035] S6: Alkaline water washing: Place the filter residue II obtained in step S5 in a container, add alkaline water containing 10.81 g / L NaOH, with a liquid-to-solid mass ratio of 3:1, and stir and wash for 1 hour at a stirring speed of 60 r / min. After the alkaline water washing is completed, proceed to the next step.
[0036] S7: Filtration and washing: The slurry obtained after washing in step S6 is filtered using a cyclone separator and washed with weakly acidic water II. The weakly acidic water II is dilute hydrochloric acid with a concentration of 0.1%. The amount of weakly acidic water II is 150% of the mass of the added scheelite particles. After washing, the filtrate IV and washing water IV are collected and processed, and the filter residue III is collected. The filter residue III is placed in a blast drying oven and dried at 105°C for 5 hours to complete the room temperature decomposition of the scheelite. After the filter residue III is dried and cooled, the residue is weighed to 29.23g. After mixing evenly, a sample is taken to measure the WO in the sample. 3 The content of scheelite is 0.12% (weight method), and the decomposition rate of scheelite is 99.85%, and the slag pH value is 7.5. The final decomposition slag energy chromatography analysis results are shown in Figure 2 ,Depend on Figure 2 The test results show that the W content in the decomposition slag is 0.10%, which is generally consistent with the results of the gravimetric analysis.
[0037] Embodiment 2
[0038] S1: Fine grinding and activation: Weigh 50g of scheelite (synthetic scheelite). 3 The content is 36.71%, the Ca content is 20.70%, and the scheelite is finely ground and activated with a ball mill. The grinding time is 20 minutes. The mineral particle size after ball milling is -325 mesh, accounting for 99.52% (water sieve test). The scheelite particles after ball milling are collected and enter the next step.
[0039] S2: Alkaline water washing: Place the ball-milled scheelite particles in step S1 in a container, add alkaline water containing 15.17 g / L NaOH, with a liquid-to-solid mass ratio of 4:1, and stir and wash for 4 hours at a stirring speed of 90 r / min. After the alkaline water washing is completed, an alkaline water washed slurry is obtained, and the washing water I is collected and processed to enter the next step.
[0040] S3: Filtration and washing: The alkaline water washing slurry obtained in step S2 is filtered using a cyclone separator and washed with weakly acidic water I. The weakly acidic water I is dilute sulfuric acid with a concentration of 0.2 mol / L. The amount of weakly acidic water I is 150% of the mass of the added scheelite particles. After the washing is completed, the filtrate II and washing water II are collected and processed, and the filter residue I enters the next step.
[0041] S4: Decomposition at room temperature: Add the filter residue I obtained in step S3 after washing with weakly acidic water I into a glass beaker, and then add the decomposing agent sodium oxalate-tartaric acid-hydrochloric acid. The amount of sodium oxalate is 140% of the theoretical amount of calcium in scheelite converted into calcium oxalate, and the amount of tartaric acid is 100% of the theoretical amount of WO in scheelite. 3 150% of the theoretical amount of complex is added, the concentration of hydrochloric acid is 0.5%, the liquid-solid mass ratio is 4:1, and decompose at room temperature for 5 hours. When the decomposition is completed, enter the next step.
[0042] S5: Filtration and washing: The slurry decomposed at room temperature in step S4 is filtered using a cyclone separator, and then washed with pure water. The amount of pure water used is 200% of the mass of the added scheelite particles. After washing, the filtrate III and washing water III are collected and processed, and the filter residue II enters the next stage.
[0043] S6: Alkaline water washing: Place the filter residue II obtained in step S5 in a container, add alkaline water containing 15.71 g / L NaOH, with a liquid-to-solid mass ratio of 3:1, and stir and wash for 2 hours at a stirring speed of 90 r / min. After the alkaline water washing is completed, proceed to the next step.
[0044] S7: Filtration and washing: The slurry obtained after washing in step S6 is filtered using a cyclone separator and washed with weakly acidic water II. The weakly acidic water II is dilute sulfuric acid with a concentration of 0.3%. The amount of weakly acidic water II is 120% of the mass of the added scheelite particles. After washing, the filtrate IV and washing water IV are collected and processed, and the filter residue III is collected. The filter residue III is placed in a blast drying oven and dried at 105°C for 5 hours to complete the room temperature decomposition of the scheelite. After the filter residue III is dried and cooled, the residue is weighed to 36.72g, and then mixed evenly and sampled to measure the WO in the sample. 3 The content of scheelite is 0.11% (weight method), and the decomposition rate of scheelite is 99.78%, and the slag pH value is 7.1. The final decomposition slag energy chromatography analysis results are shown in Figure 3 ,Depend on Figure 3 The test results show that the W content in the decomposition slag is 0.10%, which is generally consistent with the results of the gravimetric analysis.
[0045] Embodiment 3
[0046] S1: Fine grinding and activation: Weigh 50g of scheelite (synthetic scheelite). 3 The content is 27.93%, the Ca content is 24.64%. The scheelite is finely ground and activated with a ball mill. The grinding time is 20 minutes. The mineral particle size after ball milling is -325 mesh, accounting for 98.84% (water sieve test). The scheelite particles after ball milling are collected and proceed to the next step.
[0047] S2: Alkaline water washing: Place the ball-milled scheelite particles in step S1 in a container, add alkaline water containing 6.34 g / L NaOH, with a liquid-to-solid mass ratio of 4:1, and stir and wash for 5 hours at a stirring speed of 80 r / min. After the alkaline water washing is completed, an alkaline water washed slurry is obtained, and the washing water I is collected and processed to enter the next step.
[0048] S3: Filtration and washing: The alkaline water washing slurry obtained in step S2 is filtered using a cyclone separator and washed with weakly acidic water I. The weakly acidic water I is dilute sulfuric acid with a concentration of 0.2 mol / L. The amount of weakly acidic water I is 200% of the mass of the added scheelite particles. After the washing is completed, the filtrate II and washing water II are collected and processed, and the filter residue I enters the next step.
[0049] S4: Decomposition at room temperature: Add the filter residue I obtained in step S3 after washing with weakly acidic water I into a glass beaker, and then add the decomposing agent sodium oxalate-tartaric acid-hydrochloric acid. The amount of sodium oxalate is 150% of the theoretical amount of calcium in scheelite converted into calcium oxalate, and the amount of tartaric acid is 150% of the theoretical amount of WO in scheelite converted into calcium oxalate. 3 150% of the theoretical amount of complex is added, the concentration of hydrochloric acid is 0.8%, the liquid-solid mass ratio is 4:1, and decompose at room temperature for 5 hours. When the decomposition is completed, enter the next step.
[0050] S5: Filtration and washing: The slurry decomposed at room temperature in step S4 is filtered using a cyclone separator, and then washed with pure water. The amount of pure water used is 200% of the mass of the added scheelite particles. After washing, the filtrate III and washing water III are collected and processed, and the filter residue II enters the next stage.
[0051] S6: Alkaline water washing: Place the filter residue II obtained in step S5 in a container, add alkaline water containing 6.34 g / L NaOH, with a liquid-solid mass ratio of 4:1, and stir and wash for 2 hours at a stirring speed of 80 r / min. After the alkaline water washing is completed, enter the next step.
[0052] S7: Filtration and washing: The slurry obtained after washing in step S6 is filtered using a cyclone separator and washed with weakly acidic water II. The weakly acidic water II is dilute hydrochloric acid with a concentration of 0.4%. The amount of weakly acidic water II is 150% of the mass of the added scheelite particles. After washing, the filtrate IV and washing water IV are collected and processed, and the filter residue III is collected. The filter residue III is placed in a blast drying oven and dried at 105°C for 5 hours to complete the room temperature decomposition of the scheelite. After the filter residue III is dried and cooled, the residue is weighed to 39.33g, and then sampled after mixing evenly to measure the WO in the sample. 3 The content of scheelite is 0.18% (weight method), and the decomposition rate of scheelite is 99.49%, and the slag pH value is 6.5. The final decomposition slag energy chromatography analysis results are shown in Figure 4 ,Depend on Figure 4 The test results show that the W content in the decomposition slag is 0.15%, which is generally consistent with the results of the gravimetric analysis.
[0053] The above describes the main technical features and basic principles of the present invention and the related advantages. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the concept or basic features of the present invention. Therefore, no matter from which point of view, the above specific embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.
[0054] In addition, it should be understood that although the present specification is described according to various implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A method for efficiently decomposing scheelite at room temperature, characterized in that: The following steps are involved: S1: Fine grinding and activation: Use a ball mill to finely grind and activate the scheelite, collect the milled scheelite particles, and proceed to the next step; S2: Alkaline water washing: the scheelite particles ball-milled in step S1 are placed in a glass beaker, and alkaline water I containing NaOH is added for stirring and washing. After the alkaline water washing is completed, an alkaline water washing slurry is obtained, and the washing water I is collected and processed to enter the next step; S3: Filtration and washing: The alkaline water washing slurry obtained in step S2 is filtered using a cyclone separator and washed with weakly acidic water I. After washing, the filtrate II and washing water II are collected and processed, and the filter residue I enters the next step; S4: Decomposition at room temperature: add the filter residue I obtained in step S3 after washing with weakly acidic water into a container, and then add the decomposing agent sodium oxalate-tartaric acid-hydrochloric acid, the amount of sodium oxalate is 100% to 200% of the theoretical amount of calcium in scheelite converted into calcium oxalate, the amount of tartaric acid is 100% to 150% of the theoretical amount of WO3 in scheelite to form a complex, the concentration of hydrochloric acid is 0.5% to 1%, the liquid-solid mass ratio is 2:1 to 5:1, decompose at room temperature for 2h to 5h, the decomposition is completed, and enter the next step; S5: Filtration and washing: The slurry decomposed at room temperature in step S4 is filtered using a cyclone separator and washed with pure water. After washing, the filtrate III and washing water III are collected and processed, and the filter residue II enters the next step; S6: Alkaline water washing: the filter residue II obtained in step S5 is placed in a container, and alkaline water II containing NaOH is added for stirring and washing. After the alkaline water washing is completed, the next step is entered; S7: Filtration and washing: The slurry obtained after washing in step S6 is filtered using a cyclone separator, and washed with weakly acidic water II. After washing, the filtrate IV and washing water IV are collected and processed, and the filter residue III is collected to complete the room temperature decomposition of the scheelite.
2. The method for decomposing scheelite at room temperature and efficiently according to claim 1, characterized in that: The proportion of mineral particles with a particle size of -325 mesh after ball milling in step S1 is ≥98%.
3. The method for decomposing scheelite at room temperature and efficiently according to claim 1 is characterized in that: The NaOH content of the alkaline water I in step S2 and the alkaline water II in step S6 is 0.5% to 1.5%.
4. The method for decomposing scheelite at room temperature and efficiently according to claim 1 is characterized in that: In step S2, the liquid-to-solid mass ratio is 2:1-4:1, the stirring time is 4h-8h, and the stirring speed is 60r / min-90r / min.
5. The method for decomposing scheelite at room temperature and efficiently according to claim 1, characterized in that: In step S3, the weakly acidic water I is sulfuric acid or hydrochloric acid with a concentration in the range of 0.05 mol / L to 0.2 mol / L, and the amount of the weakly acidic water I is 100% to 300% of the mass of the added scheelite particles.
6. The method for decomposing scheelite at room temperature and efficiently according to claim 1 is characterized in that: The amount of pure water used in step S5 is 100% to 200% of the mass of the added scheelite particles.
7. The method for decomposing scheelite at room temperature and efficiently according to claim 1, characterized in that: In step S6, the liquid-to-solid mass ratio is 2:1-4:1, the stirring time is 1h-2h, and the stirring speed is 60r / min-90r / min.
8. The method for decomposing scheelite at room temperature and efficiently according to claim 1, characterized in that: In step S7, the weakly acidic water II is sulfuric acid or hydrochloric acid with a concentration in the range of 0.1% to 0.5%, and the amount of the weakly acidic water II is 100% to 150% of the mass of the added scheelite particles.