CN111606356B - Method for preparing artificial scheelite - Google Patents
Method for preparing artificial scheelite Download PDFInfo
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- CN111606356B CN111606356B CN202010565977.3A CN202010565977A CN111606356B CN 111606356 B CN111606356 B CN 111606356B CN 202010565977 A CN202010565977 A CN 202010565977A CN 111606356 B CN111606356 B CN 111606356B
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- tungsten
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- mother liquor
- dihydrogen phosphate
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- C01G41/00—Compounds of tungsten
Abstract
The invention discloses a novel precipitator and a method for preparing artificial scheelite, wherein the novel precipitator is composed of calcium oxide and calcium dihydrogen phosphate according to a mass ratio of 0.8-1.2: 2.0-2.5; the process for preparing artificial scheelite includes adding sodium tungstate solution at neutral pHCalcium oxide, and adjusting the PH to 10-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 800-1200 kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor; continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution; and (4) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and precipitating tungsten through reaction, wherein the dosage of the calcium chloride is 0.15-0.30 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate. The precipitant can replace part of calcium chloride to prepare artificial scheelite.
Description
Technical Field
The invention relates to the field of metallurgy, in particular to a novel precipitator and a method for preparing artificial scheelite.
Background
At present, the industrial method for processing APT crystallization mother liquor mainly comprises three methods: 1. CaCl2Artificial scheelite is precipitated → acid decomposed and partially molybdenum removed → crude tungstic acid → returns to the main process; 2. molybdenum removal → precipitation of artificial scheelite → returning to heat ball milling for alkali decomposition; 3. secondary crystallization, and precipitating artificial scheelite in the mother solution. CaCl2The artificial scheelite precipitating process is one traditional process for recovering APT crystal mother liquid and has the advantages of simple process and high selectivity. However, there are also disadvantages in that CaCl is used due to the weak acidity of the calcium chloride solution2The gradual addition of (2) results in the increase of acidity and the decrease of pH value of the crystallization mother liquor, so that the precipitation rate of the scheelite is low. In order to neutralize the alkalinity acidity, a large amount of sodium hydroxide is generally added into the mother liquor before adding the calcium chloride, so that a certain alkalinity is ensured and controlled. In the traditional method, the consumption of calcium chloride and alkali is very large, the cost for preparing the artificial white tungsten is increased, and the artificial white tungsten has high cost and is not suitable for industrial production.
Disclosure of Invention
In order to overcome the technical problems, the invention aims to provide a novel precipitator which can replace part of calcium chloride to prepare artificial scheelite.
The invention also provides a method for preparing the artificial scheelite by the novel precipitator.
The invention is realized by the following technical scheme:
the novel precipitator consists of calcium oxide and calcium dihydrogen phosphate according to a mass ratio of 0.8-1.2: 2.0-2.5.
Preferably, the novel precipitator is composed of calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1: 2.1.
The invention provides a method for preparing artificial scheelite by using a novel precipitator, which comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 0.8-1.2: 2.0-2.5 for later use;
(2) in thatAdding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 10-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 800-1200 kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and performing reaction to precipitate tungsten, wherein the dosage of the calcium chloride is 0.15-0.30 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
Further, the method for preparing the artificial white tungsten by the novel precipitator provided by the invention comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1: 2.0-2.1 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 1000kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and performing reaction to precipitate tungsten, wherein the dosage of the calcium chloride is 0.17-0.25 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
Further, in the above method, the mass ratio of the calcium oxide, the monocalcium phosphate and the calcium chloride is 5:10: 3.
According to the method, the tungsten deposition mother liquor in the step (2) and the tungsten deposition solution in the step (3) are heated by introducing steam at the temperature of 80-90 ℃, and preferably at the temperature of 90 ℃.
The reaction principle of the precipitator of the invention is as follows:
in the step (2), CaO is added to react with water to decompose in the feeding process of a neutral sodium tungstate solution with a pH value of (pH: 11-12), and Ca is adjusted to2+And
the reaction is carried out to generate the scheelite, when reaching the mother liquor WO3Almost all in
The shape exists, and the pH value meets the process requirement of 10-12.
CaO+H2O→Ca2++2OH-：
In the step (3) of the present invention
The pH value is 4-6, when the tungsten-precipitating mother liquor with high alkalinity is continuously added into the tungsten-precipitating mother liquor in the step (1), the pH value of the mother liquor is reduced,
solubility increases with decreasing PH; ca2+And
reaction to produce scheelite and Ca in mother liquid2+Is promoted by the consumption of
Decomposition of (3). The tungsten powder can be fully dissolved by continuously adding the tungsten powder, and the tungsten precipitation time is prolonged.
Step (4) of the present invention is performed in step (3)
After the solubility is balanced, calcium chloride is added to dissolve the calcium chloride and the calcium chloride is not dissolved
Along with Cl in mother liquor-Increase in concentration further dissolves, Ca2+And
reacting to generate scheelite;
CaCl2→Ca2++2Cl-，
under the condition of normal temperature: the precipitation equilibrium constant Ksp of calcium tungstate, calcium oxide and calcium dihydrogen phosphate is as follows:
in the invention, in the step (4), steam is introduced to heat the tungsten precipitation solution in the step (2), calcium chloride is added, and when the temperature is 80-90 ℃,
increase in temperature, CaWO4The solubility of the compound is reduced along with the rise of the temperature, which is beneficial to accelerating the precipitation reaction and improving the precipitation rate.
The invention has the beneficial effects that:
1. the precipitator can precipitate tungsten of a sodium tungstate solution step by step and can ensure complete precipitation, wherein calcium oxide mainly adjusts the pH value and can only precipitate partial scheelite, calcium dihydrogen phosphate utilizes calcium and can only precipitate partial scheelite; calcium chloride is used to precipitate un-precipitated tungsten in the sodium tungstate solution. Therefore, each component and step cannot be reduced, and the complete tungsten precipitation of the sodium tungstate solution is ensured.
2. The precipitant of the present invention can reduce the amount of calcium chloride used, but cannot completely replace calcium chloride due to CaO and Ca (H)2PO4)2Excessive white tungsten can cause low grade of the generated white tungsten and more impurities, the quality of the white tungsten can be met only by the preparation of the special proportion, the dosage of calcium chloride is reduced, the use of alkali such as sodium hydroxide is avoided, and the production cost is reduced. According to the existing production condition, 60 tons of calcium chloride are saved every month, the conversion is 6.3 ten thousand yuan, and the cost is savedThe caustic soda flakes are 20 tons, the conversion is 4.5 ten thousand yuan, the consumption of CaO is 20 tons, the conversion is 7000 yuan, and the monthly direct income is about 10.1 ten thousand yuan. The cost of auxiliary materials after the project is implemented is reduced, especially the by-product Ca (H) of the process2PO4)2The recycling of the process can generate obvious comprehensive benefits.
Detailed Description
The following detailed description of specific embodiments of the invention is provided, but it should be understood that the scope of the invention is not limited to the specific embodiments.
Example 1
A method for preparing artificial scheelite by using a novel precipitator comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 0.8:2.0 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 1000kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and performing reaction to precipitate tungsten, wherein the dosage of the calcium chloride is 0.25 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
And (3) introducing steam for heating, and controlling the temperature at 90 ℃.
Example 2
A method for preparing artificial scheelite by using a novel precipitator comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1:2.1 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 1000kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and performing reaction to precipitate tungsten, wherein the dosage of the calcium chloride is 0.2 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
And (3) introducing steam for heating, and controlling the temperature at 80 ℃.
Example 3
A method for preparing artificial scheelite by using a novel precipitator comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1.2:2.5 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 800kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution obtained in the step (3), and performing reaction to precipitate tungsten, wherein the dosage of the calcium chloride is 0.25 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
And (3) introducing steam for heating, and controlling the temperature at 90 ℃.
Example 4
A method for preparing artificial scheelite by using a novel precipitator comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1:2.5 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 1200kg:10M3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (3) adding calcium chloride into the tungsten precipitation solution to perform reaction and precipitate tungsten, wherein the dosage of the calcium chloride is 0.30 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
And (3) introducing steam for heating, and controlling the temperature at 90 ℃.
Example 5
Table over 12018 years, with the gradual use of new precipitants, process auxiliaries were consumed:
TABLE 2 cost accounting
It can be seen from tables 1 and 2 that, through continuous process trial operation, the consumption of calcium chloride is greatly reduced, and the cost of preparing the artificial white tungsten by using the novel precipitator instead of calcium chloride is greatly reduced, for example, according to the accounting of the existing production condition, 60 tons of calcium chloride are saved every month, the conversion is 6.3 ten thousand yuan, 20 tons of caustic soda flakes are saved, the conversion is 4.5 ten thousand yuan, 20 tons of calcium oxide is consumed, the conversion is 7000 yuan, and the direct profit is about 10.1 ten thousand yuan every month. The cost of the auxiliary materials after the project is implemented is reduced, and particularly, the recycling of the process by-product monocalcium phosphate generates remarkable comprehensive benefits.
EXAMPLE 6 screening test of tungsten deposition reaction temperature
TABLE 3 influence of temperature on precipitation Rate
| Step (ii) of | Temperature of | Precipitation rate |
| Step (1) | 60 | 95％ |
| Step (2) | 80 | 98％ |
| Step (3) | 90 | 99％ |
As can be seen from Table 3, the precipitation rate is as high as 99% at 90 deg.C, and the tungsten precipitation reaction temperature of 90 deg.C is preferred for energy saving and consumption reduction.
EXAMPLE 7 Ca (H) of novel precipitant2PO4)2CaO and CaCl2Proportioning screening
TABLE 4 Ca (H) of novel precipitant2PO4)2CaO and CaCl2Proportioning screening
| Serial number | CaO(g) | Ca(H2PO4)2(g) | CaCl2(g) | Precipitation rate | Quality of artificial scheelite |
| 1 | 0 | 0 | 166 | 97％ | 52％ |
| 2 | 30 | 50 | 50 | 97％ | 51％ |
| 3 | 20 | 30 | 20 | 98％ | 53％ |
| 4 | 40 | 80 | 24 | 99％ | 54％ |
From Table 4, it can be seen that although the complete use of calcium chloride gives good precipitation and artificial scheelite quality, the present invention aims to reduce the amount of calcium chloride used. From the serial numbers 2-4, it can be seen that the use of calcium oxide and calcium dihydrogen phosphate is increased, and the use of calcium chloride is decreased, so that the precipitation rate and the quality of the artificial scheelite are improved. In sequence No. 3, when the dosage of calcium chloride is reduced to 30 percent of the total amount (the total amount of calcium oxide, calcium dihydrogen phosphate and calcium chloride), the precipitation rate reaches 98 percent, and the quality of the scheelite is improved to 53 percent. In sequence number 4, the dosage of calcium chloride is continuously reduced to 17%, the precipitation rate and the quality of white tungsten reach the best, and the content of calcium oxide: calcium dihydrogen phosphate: the calcium chloride is 40:80:24, the effect is best, and the effect is better than that of the calcium chloride which is completely used.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives.
Claims (8)
1. A method for preparing artificial scheelite is characterized in that: the method comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 0.8-1.2: 2.0-2.5 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 10-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 800-1200 kg:10m3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (4) adding calcium chloride into the tungsten precipitation solution obtained in the step (3) to react and precipitate tungsten, wherein the dosage of the calcium chloride is 0.15-0.30 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
2. A method of making artificial scheelite according to claim 1, characterised in that: the method comprises the following steps:
(1) taking calcium oxide and calcium dihydrogen phosphate according to the mass ratio of 1: 2.0-2.1 for later use;
(2) adding calcium oxide in the feeding process of the sodium tungstate solution with neutral pH, and adjusting the pH to 11-12, wherein the volume ratio of the mass of the calcium oxide to the volume of the sodium tungstate solution is 1000kg:10m3Reacting and precipitating tungsten to obtain tungsten precipitation mother liquor;
(3) continuously adding calcium dihydrogen phosphate into the tungsten precipitation mother liquor obtained in the step (2), and performing reaction to precipitate tungsten to obtain a tungsten precipitation solution;
(4) and (4) adding calcium chloride into the tungsten precipitation solution obtained in the step (3) to react and precipitate tungsten, wherein the dosage of the calcium chloride is 0.17-0.25 times of the total mass of the calcium oxide and the calcium dihydrogen phosphate.
3. A method of making artificial scheelite according to claim 2, characterised in that: the mass ratio of the calcium oxide to the calcium dihydrogen phosphate to the calcium chloride is 5:10: 3.
4. A method of making artificial scheelite according to claim 1, characterised in that: and (3) introducing steam into the tungsten deposition mother liquor in the step (2) and the tungsten deposition solution in the step (3) for heating, wherein the temperature is 80-90 ℃.
5. The method for preparing artificial scheelite according to claim 4, wherein the method comprises the following steps: and (3) introducing steam into the tungsten deposition mother liquor in the step (2) and the tungsten deposition solution in the step (3) for heating at the temperature of 90 ℃.
6. A method of making artificial scheelite according to claim 1, characterised in that: in the step (2), calcium oxide is added to react and decompose when meeting water in the feeding process of the sodium tungstate solution with neutral pH, the pH value is adjusted to 11-12, and Ca is added2+With WO4 2-The reaction is carried out to generate the scheelite, when reaching the mother liquor WO3Almost all of WO4 2-The shape exists, and the pH value reaches 10-12 required by the process; the reaction process is as follows:
CaO+H2O→Ca2++2OH-；Ca2++WO4 2-→CaWO4。
7. a method of making artificial scheelite according to claim 1, characterised in that: ca (H) in the step (3)2PO4)2The pH value is 4-6, when the tungsten-precipitating mother liquor is continuously added into the tungsten-precipitating mother liquor in the step (2) with higher alkalinity, the pH value of the mother liquor is reduced, and Ca (H) is added2PO4)2Solubility increases with decreasing pH; ca2+With WO4 2-Reaction to produce scheelite and Ca in mother liquid2+The consumption of Ca (H) is promoted2PO4)2Decomposition of (2); the reaction process is as follows:
Ca(H2PO4)2→2HPO4 2-+Ca2++2H+；Ca2++WO4 2-→CaWO4。
8. a method of making artificial scheelite according to claim 1, characterised in that: in the step (4), Ca (H) in the step (3)2PO4)2After the solubility is balanced, calcium chloride is added to the dissolved, undissolved Ca (H)2PO4)2Along with Cl in mother liquor-Increase in concentration further dissolves, Ca2+With WO4 2-Reacting to generate scheelite; the reaction process is as follows:
CaCl2→Ca2++2Cl-；Ca2++WO4 2-→CaWO4。
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4397821A (en) * | 1982-01-04 | 1983-08-09 | Amax Inc. | Precipitation of synthetic scheelite |
| CN102080157B (en) * | 2010-12-24 | 2012-06-13 | 中南大学 | Method for decomposing scheelite |
| CN102021327B (en) * | 2010-12-24 | 2012-07-25 | 中南大学 | Method for decomposing scheelite by using phosphoric acid |
| RU2532767C1 (en) * | 2010-12-24 | 2014-11-10 | Централ Саус Юниверсити | Method of extracting tungsten from scheelite |
| US8834725B2 (en) * | 2011-01-31 | 2014-09-16 | Chevron U.S.A. Inc. | Method for treating acid mine drainage |
| CN102912129A (en) * | 2012-11-14 | 2013-02-06 | 中湘钨业股份有限公司 | Method for recycling tungsten in liquids after tungsten smelting exchanges |
| CN102910648A (en) * | 2012-11-14 | 2013-02-06 | 中湘钨业股份有限公司 | Method for recycling tungsten and ammonia in one step from ammonium paratungstate crystallization mother solution smelt through tungsten |
| CN110563041A (en) * | 2019-10-25 | 2019-12-13 | 中南大学 | Method for deeply purifying ammonium tungstate solution |
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