Method for removing phosphorus in crude sodium tungstate solution by using industrial gypsum and preparation method of ammonium paratungstate
阅读说明：本技术 一种用工业石膏去除粗钨酸钠溶液中磷的方法及仲钨酸铵的制备方法 (Method for removing phosphorus in crude sodium tungstate solution by using industrial gypsum and preparation method of ammonium paratungstate ) 是由 叶正华 于 2021-10-19 设计创作，主要内容包括：本发明公开了一种用工业石膏去除粗钨酸钠溶液中磷的方法,分别测定粗钨酸钠溶液中磷、钨的浓度,然后在常温～48℃下搅拌均匀；当粗钨酸钠溶液中磷钨比大于0.005时,分3次投入石膏,每隔30min投料一次；当粗钨酸钠溶液中磷钨比小于0.005时,一次性投入石膏；投料结束后,保持温度搅拌30～60min,过滤,即得除磷后的粗钨酸钠溶液。本发明还公开一种仲钨酸铵的制备方法,应用了上述除磷方法。本发明采用廉价的工业石膏作为除磷剂,除磷时间短,温度低,除磷效果优于传统除磷剂轻质碳酸钙；能够满足交前液上柱的磷钨比0.0007以下的要求,确保仲钨酸铵产品的杂质磷满足国标零级要求。(The invention discloses a method for removing phosphorus in a crude sodium tungstate solution by using industrial gypsum, which comprises the steps of respectively measuring the concentrations of phosphorus and tungsten in the crude sodium tungstate solution, and then uniformly stirring at normal temperature to 48 ℃; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is more than 0.005, adding gypsum for 3 times, and adding once every 30 min; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is less than 0.005, gypsum is added at one time; and (3) after the feeding is finished, keeping the temperature, stirring for 30-60 min, and filtering to obtain the dephosphorized crude sodium tungstate solution. The invention also discloses a preparation method of the ammonium paratungstate, and the dephosphorization method is applied. The invention adopts cheap industrial gypsum as the phosphorus removing agent, has short phosphorus removing time and low temperature, and has phosphorus removing effect superior to that of the light calcium carbonate of the traditional phosphorus removing agent; can meet the requirement that the phosphorus-tungsten ratio of the liquid before the cross-linking on the column is less than 0.0007, and ensure that the impurity phosphorus of the ammonium paratungstate product meets the national standard zero-order requirement.)
1. A method for removing phosphorus in a crude sodium tungstate solution by using industrial gypsum is characterized by comprising the following steps:
taking a crude sodium tungstate solution, respectively measuring the concentrations of phosphorus and tungsten in the crude sodium tungstate solution, and then uniformly stirring at the normal temperature to 48 ℃; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is more than 0.005, adding gypsum for 3 times, and adding once every 30 min; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is less than 0.005, gypsum is added at one time; and (3) after the feeding is finished, keeping the temperature, stirring for 30-60 min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
2. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 1, wherein: in the crude sodium tungstate solution, the concentration of tungsten is 15-250 g/L.
3. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 1, wherein: the industrial gypsum is industrial titanium white gypsum, industrial phosphogypsum or scheelite gypsum; and SO in the industrial gypsum3The content of (A) is more than or equal to 35 percent.
4. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 1, wherein: the actual total feeding amount of the industrial gypsum is 1.2-1.5 times of the theoretical total feeding amount.
5. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 1, wherein: when the gypsum is added in 3 times, 1/3 which is the actual total dosage of the gypsum is added in each time.
6. The method for preparing ammonium paratungstate, which applies the method for removing phosphorus in the crude sodium tungstate solution by using the industrial gypsum as described in any one of claims 1 to 5, is characterized by comprising the following steps:
s1: crushing and grinding scheelite into powder, adding water to prepare ore pulp, sequentially adding sodium hydroxide and trisodium phosphate, uniformly stirring to obtain mixed pulp, decomposing at 192-210 ℃ and 0.8-1.0 MPa, diluting, press-filtering and washing to obtain filtrate to obtain a crude sodium tungstate solution;
s2: removing phosphorus in the crude sodium tungstate solution by using industrial gypsum;
s3: and (2) sequentially adsorbing the dephosphorized crude sodium tungstate solution by using cation exchange resin and anion exchange resin, then desorbing the adsorbed tungstate ions by using an desorbing agent containing ammonium chloride to obtain a desorption solution, evaporating and crystallizing the desorption solution to obtain high-purity ammonium paratungstate crystals, filtering and drying to obtain the ammonium paratungstate product.
7. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 6, wherein: in the mixed slurry obtained in the step S1, the concentration of sodium hydroxide is 155-200 g/L, and the concentration of trisodium phosphate is 25-65 g/L.
8. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 6, wherein: the weight ratio of the particles with the particle size not smaller than 325 meshes in the ore pulp obtained in the step S1 is more than or equal to 96 percent.
9. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 6, wherein: in the crude sodium tungstate solution in the step S1, the phosphorus-tungsten ratio is 0.001-0.02.
10. The method for removing phosphorus from a crude sodium tungstate solution by using industrial gypsum as claimed in claim 6, wherein: in the resolving agent in the step S3, the concentration of ammonium chloride is 4-5 mol/L, and the concentration of ammonia water is 1-3 mol/L.
Technical Field
The invention belongs to the technical field of chemical product preparation, and particularly relates to a method for removing phosphorus in a crude sodium tungstate solution by using industrial gypsum and a preparation method of ammonium paratungstate.
Background
In the scheelite decomposing process by phosphorus, phosphoric acid or trisodium phosphate is added to decompose tungsten in the scheelite completely as much as possible, the phosphorus-tungsten ratio in the decomposed sodium tungstate solution is often more than 0.0007, and in order to meet the phosphorus content requirement in the product, the quality requirement can be met only by controlling the phosphorus-tungsten ratio to be less than 0.0007 before the product is loaded on an ion exchange column. In the industry, industrial-grade light calcium carbonate is used as a phosphorus removal agent for phosphorus removal, the phosphorus removal temperature is 60-80 ℃, calcium carbonate is added and stirred until the phosphorus-tungsten ratio is less than 0.0007, calcium carbonate needs to be repeatedly added when the phosphorus-tungsten ratio does not meet the standard, the time consumption is long, the addition amount of the calcium carbonate is 1.6-2 times of the theoretical calculation amount, the price of the industrial-grade light calcium carbonate is 1200 yuan/t, and taking the case that five thousandths of the phosphorus-tungsten ratio is reduced to 0.0007, the phosphorus removal consumes 50 kilograms/ton of light calcium carbonate, and the phosphorus removal cost is high.
The industry also has a process for removing phosphorus by using ammonium magnesium salt, the prices of industrial-grade ammonium salt and magnesium salt are more than thousand yuan, and the phosphorus removal cost is more than 60 yuan/ton.
Disclosure of Invention
The invention aims to provide a method for removing phosphorus in a crude sodium tungstate solution by using industrial gypsum, which aims to solve the problems of high phosphorus removal cost and poor effect in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for removing phosphorus in a crude sodium tungstate solution by using industrial gypsum comprises the following steps:
taking a crude sodium tungstate solution, respectively measuring the concentrations of phosphorus and tungsten in the crude sodium tungstate solution, and then uniformly stirring at the normal temperature to 48 ℃; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is more than 0.005, adding gypsum for 3 times, and adding once every 30 min; when the phosphorus-tungsten ratio in the crude sodium tungstate solution is less than 0.005, gypsum is added at one time; and (3) after the feeding is finished, keeping the temperature, stirring for 30-60 min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Further, in the crude sodium tungstate solution, the concentration of tungsten is 15-250 g/L.
Further, the industrial gypsum is industrial titanium white gypsum, industrial phosphogypsum or scheelite gypsum; and SO in the industrial gypsum3The content of (A) is more than or equal to 35 percent.
Furthermore, the actual total feeding amount of the industrial gypsum is 1.2-1.5 times of the theoretical total feeding amount.
Further, when the gypsum was added in 3 portions, 1/3 which is the actual total amount of the gypsum was added in each portion.
The invention also provides a preparation method of ammonium paratungstate, which applies the method for removing phosphorus in the crude sodium tungstate solution by using industrial gypsum and comprises the following steps:
s1: crushing and grinding scheelite into powder, adding water to prepare ore pulp, sequentially adding sodium hydroxide and trisodium phosphate, uniformly stirring to obtain mixed pulp, decomposing at 192-210 ℃ and 0.8-1.0 MPa, diluting, press-filtering and washing to obtain filtrate to obtain a crude sodium tungstate solution;
s2: removing phosphorus in the crude sodium tungstate solution by using industrial gypsum;
s3: and (2) sequentially adsorbing the dephosphorized crude sodium tungstate solution by using cation exchange resin and anion exchange resin, then desorbing the adsorbed tungstate ions by using an desorbing agent containing ammonium chloride to obtain a desorption solution, evaporating and crystallizing the desorption solution to obtain high-purity ammonium paratungstate crystals, filtering and drying to obtain the ammonium paratungstate product.
Further, in the mixed slurry of step S1, the concentration of sodium hydroxide is 155-200 g/L, and the concentration of trisodium phosphate is 25-65 g/L.
Further, the weight ratio of particles with the particle size not smaller than 325 meshes in the ore pulp in the step S1 is more than or equal to 96%.
Further, in the crude sodium tungstate solution in the step S1, the phosphorus-tungsten ratio is 0.001-0.02.
Further, the concentration of ammonium chloride in the resolving agent in the step S3 is 4-5 mol/L, and the concentration of ammonia water is 1-3 mol/L.
The concentration of phosphorus and tungsten is mass concentration, and the unit is g/L; the phosphorus-tungsten ratio is the mass concentration ratio of phosphorus to tungsten.
The main chemical component of the industrial gypsum is CaSO4·2H2O, by using Ca in gypsum in the presence of alkali2+With PO in solution4 3-Reacting to remove the phosphorus in the solution. The reaction equation is as follows:
5Ca2++3PO4 3-+OH-→Ca5(PO4)3OH↓
the theoretical total dosage of gypsum is calculated according to the following formula:
wherein:
mgypsum plasterIs the theoretical total feed amount of the industrial gypsum, g;
cp is phosphorus concentration, g/L;
v is the volume of the solution, L;
Φso3is the content of sulfur trioxide in gypsum.
The invention has the following beneficial effects:
(1) the calcium carbonate is only suitable for removing phosphorus from a solution with the tungsten concentration of more than 50g/L in a crude sodium tungstate solution, the phosphorus-tungsten ratio limit of phosphorus removal is 0.0005, and the limitation is large. The invention adopts cheap industrial gypsum as the phosphorus removing agent, has short phosphorus removing time and low temperature, has phosphorus removing effect superior to that of the light calcium carbonate of the traditional phosphorus removing agent, and can greatly reduce the phosphorus removing cost; the method can be used for removing phosphorus from the high-concentration crude sodium tungstate solution and also can be used for removing phosphorus from the low-concentration crude sodium tungstate solution, and the phosphorus-tungsten ratio can be reduced to be below 0.0003, so that the limitation is broken, and the application range is expanded.
(2) The preparation method of ammonium paratungstate adopts industrial gypsum to remove phosphorus in the crude sodium tungstate during the preparation process, so that a good phosphorus removal effect can be achieved, the production cost of ammonium paratungstate is reduced, and the production efficiency is improved; the high-purity ammonium paratungstate product can be prepared by combining the scheelite treatment and ion exchange technology.
Detailed Description
In order to facilitate a better understanding of the invention, the following examples are given to illustrate, but not to limit the scope of the invention.
Concrete case for removing phosphorus in crude sodium tungstate solution by using industrial gypsum
Case 1
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten in the solution is measured to be 120g/L, the concentration of phosphorus is measured to be 1.1g/L, and the phosphorus-tungsten ratio is measured to be 0.0092; heating to 40 ℃ under the condition of stirring, adding the scheelite gypsum with the sulfur trioxide content of 38.4% for 3 times, and adding 1.48g every 30 min; and after the feeding is finished, keeping the temperature at 40 ℃, stirring for 30min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Case 2
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten in the solution is measured to be 30.4g/L, the concentration of phosphorus is measured to be 0.25g/L, and the phosphorus-tungsten ratio is measured to be 0.0082; heating to 25 ℃ under the condition of stirring, adding industrial titanium white gypsum with the sulfur trioxide content of 39.5% for 3 times, and adding 0.35g every 30 min; and after the feeding is finished, keeping the temperature at 25 ℃, stirring for 60min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Case 3
300mL of tungsten crude sodium tungstate solution is put into a 500mL beaker, and the tungsten concentration, the phosphorus concentration and the phosphorus-tungsten ratio in the solution are measured to be 209g/L, 1.12g/L and 0.0053 respectively; heating to 48 ℃ under the condition of stirring, adding industrial phosphogypsum with the sulfur trioxide content of 38.0% for 3 times, and adding 1.77g every 30 min; and after the feeding is finished, keeping the temperature at 48 ℃, stirring for 30min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Case 4
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten in the solution is measured to be 20.5g/L, the concentration of phosphorus is measured to be 0.021g/L, and the phosphorus-tungsten ratio is measured to be 0.001; under the condition of normal temperature, 0.10g of scheelite gypsum with sulfur trioxide content of 40.0 percent is added at one time; and (3) after the feeding is finished, keeping the normal temperature, stirring for 40min, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Second, comparison example of dephosphorization of crude sodium tungstate solution
Comparative example 1
Basically the same as in case 2, except that 3 plunges were replaced by one plunge.
Comparative example 2
Essentially the same as in case 2, except that the industrial phosphogypsum with a sulphur trioxide content of 38.0% was replaced by light calcium carbonate with a content of 99%.
Comparative example 3
Essentially the same as in case 4, except that scheelite gypsum having a sulfur trioxide content of 40.0% was replaced with light calcium carbonate having a sulfur trioxide content of 99%.
Comparative example 4
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten and the concentration of phosphorus in the solution are measured to be 120g/L and 1.1g/L respectively; heating to 90 ℃ under the stirring condition, and adding 2.90g of light calcium carbonate with the content of 99 percent at one time; and (3) after the feeding is finished, preserving heat, stirring for 3 hours, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Comparative example 5
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten and the concentration of phosphorus in the solution are measured to be 30.4g/L and 0.25g/L respectively; heating to 85 ℃ under the condition of stirring, and adding 0.80g of light calcium carbonate with the content of 99% at one time; and (3) after the feeding is finished, preserving heat, stirring for 3 hours, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Comparative example 6
300mL of crude sodium tungstate solution is put into a 500mL beaker, and the concentration of tungsten and the concentration of phosphorus in the solution are measured to be 209g/L and 1.12g/L respectively; heating to 95 ℃ under the condition of stirring, and adding 2.92g of light calcium carbonate with the content of 99 percent at one time; and (3) after the feeding is finished, preserving heat, stirring for 3 hours, and filtering to obtain the dephosphorized crude sodium tungstate solution.
Third, comparative experiment
Comparing the phosphorus removal methods of examples 1-4 and comparative examples 1-6, the crude sodium tungstate solution after phosphorus removal was sampled and analyzed, and the concentrations of phosphorus and tungsten were determined according to the requirements of GB/T10116-2007 ammonium paratungstate standard and the regulations of GB/T4324, and the results are shown in Table 1.
Table 1 results of measuring the concentrations of phosphorus and tungsten in the dephosphorized crude sodium tungstate solution of each case and comparative example
Experimental groups
Phosphorus concentration/g/L
Concentration of tungsten/g/L
Phosphorus to tungsten ratio
Case 1
0.035
119.5
0.00029
Case 2
0.0075
30.1
0.00025
Case 3
0.054
208.2
0.00026
Case 4
0.0061
20.3
0.00030
Comparative example 1
0.022
29.9
0.00072
Comparative example 2
0.028
29.8
0.00093
Comparative example 3
0.017
20.1
0.00085
Comparative example 4
0.071
118.8
0.00060
Comparative example 5
0.023
29.5
0.00080
Comparative example 6
0.135
208.3
0.00065
(1) As can be seen from the data of cases 1 to 4, the phosphorus-tungsten ratio in the crude sodium tungstate solution can be controlled to be less than 0.0007 by using the phosphorus removal method provided by the invention, and the quality requirement can be met.
(2) It can be known from the data of case 2 and comparative example 1 that when the phosphorus-tungsten ratio of the crude sodium tungstate solution is greater than 0.005, the phosphorus-tungsten ratio in the dephosphorized crude sodium tungstate solution is increased by 0.00047 and the dephosphorizing effect is greatly reduced by replacing 3 times of investment with one-time investment on the basis of no change of other conditions.
(3) It can be seen from the data of cases 2 and 4 and comparative examples 2 and 3 that, on the basis of no change in other conditions, the gypsum is replaced by the precipitated calcium carbonate, and the phosphorus-tungsten ratio in the dephosphorized crude sodium tungstate solution increases by 0.00068 and 0.00060 respectively, so that the dephosphorizing effect of the precipitated calcium carbonate with the content of 99% is not as good as that of the gypsum with the content of sulfur trioxide of 38.0% no matter under normal temperature or higher temperature of 48 ℃.
(3) According to comparative examples 4-6, the suitable condition for removing the phosphorus by the light calcium carbonate is 85-95 ℃, and the stirring time is 3 hours; the data of comparative examples 4-6 show that the phosphorus-tungsten ratio in the dephosphorized crude sodium tungstate solution is within 0.0006-0.0008; in the phosphorus removal method of cases 1-4 of the invention, the temperature condition is normal temperature to 48 ℃, which is far lower than the temperature required by light calcium carbonate phosphorus removal, thereby greatly reducing energy consumption; the phosphorus removal time of cases 1-4 of the invention is 30-60 min, the time consumption is shorter, the speed is faster, and the phosphorus removal efficiency is improved; in the cases 1 to 4 of the invention, the phosphorus-tungsten ratio of the dephosphorized crude sodium tungstate solution is 0.00025 to 0.00030, which is far lower than that of the comparative examples 4 to 6, so that the dephosphorizing effect is optimized; in addition, the price of the industrial gypsum is lower than 200 yuan/ton and lower than that of light calcium carbonate, so the industrial gypsum is more economical and practical and greatly reduces the cost.
Preparation examples of ammonium paratungstate
Example 1
A preparation method of ammonium paratungstate comprises the following steps:
s1: crushing and grinding scheelite into powder, and adding water to prepare ore pulp, wherein the weight ratio of particles with the particle size not less than 325 meshes in the ore pulp is 96%; sequentially adding sodium hydroxide and trisodium phosphate, and uniformly stirring to obtain mixed slurry, wherein the concentration of the sodium hydroxide is 155g/L, and the concentration of the trisodium phosphate is 25 g/L; decomposing at 192 deg.C under 1.0MPa, diluting, press filtering, washing, and collecting filtrate to obtain crude sodium tungstate solution;
s2: putting 300mL of crude sodium tungstate solution into a 500mL beaker, measuring that the tungsten concentration in the solution is 20.5g/L, the phosphorus concentration is 0.021g/L, the phosphorus-tungsten ratio is 0.001, and adding 0.10g of scheelite acid gypsum with the sulfur trioxide content of 40.0 percent at one time under the normal temperature condition; after the feeding is finished, stirring for 40min at normal temperature, and filtering to obtain a dephosphorized crude sodium tungstate solution;
s3: and (2) sequentially adsorbing the dephosphorized crude sodium tungstate solution by using cation exchange resin and anion exchange resin, then resolving adsorbed tungstate ions by using resolving agents with the concentrations of ammonium chloride and ammonia water of 4.5mol/L and 2mol/L respectively to obtain resolving liquid, evaporating and crystallizing the resolving liquid to obtain high-purity ammonium paratungstate crystals, filtering and drying to obtain the ammonium paratungstate product.
Example 2
A preparation method of ammonium paratungstate comprises the following steps:
s1: crushing and grinding scheelite into powder, and adding water to prepare ore pulp, wherein the weight ratio of particles with the particle size not less than 325 meshes in the ore pulp is 97%; sequentially adding sodium hydroxide and trisodium phosphate, and uniformly stirring to obtain mixed slurry, wherein the concentration of the sodium hydroxide is 185g/L, and the concentration of the trisodium phosphate is 65 g/L; decomposing at 200 deg.C under 0.9MPa, diluting, press filtering, washing, and collecting filtrate to obtain crude sodium tungstate solution;
s2: putting the coarse 300mL sodium tungstate solution into a 500mL beaker, measuring the tungsten concentration of the solution to be 5.8g/L, the phosphorus concentration to be 0.035g/L and the phosphorus-tungsten ratio to be 0.006, and then uniformly stirring at 25 ℃; feeding industrial titanium white gypsum with the sulfur trioxide content of 39.5% for 3 times, wherein the feeding is performed once every 30min, and 0.06g is not fed again; after the feeding is finished, keeping the temperature, stirring for 60min, and filtering to obtain a dephosphorized crude sodium tungstate solution;
s3: and (2) sequentially adsorbing the dephosphorized crude sodium tungstate solution by using cation exchange resin and anion exchange resin, then resolving adsorbed tungstate ions by using resolving agents with the concentrations of ammonium chloride and ammonia water of 4.5mol/L and 2mol/L respectively to obtain resolving liquid, evaporating and crystallizing the resolving liquid to obtain high-purity ammonium paratungstate crystals, filtering and drying to obtain the ammonium paratungstate product.
Example 3
A preparation method of ammonium paratungstate comprises the following steps:
s1: crushing and grinding scheelite into powder, and adding water to prepare ore pulp, wherein the weight ratio of particles with the particle size not less than 325 meshes in the ore pulp is 98%; sequentially adding sodium hydroxide and trisodium phosphate, and uniformly stirring to obtain mixed slurry, wherein the concentration of the sodium hydroxide is 200g/L, and the concentration of the trisodium phosphate is 35 g/L; decomposing at 210 ℃ and 0.8MPa, diluting, filter-pressing and washing, and taking filtrate to obtain a crude sodium tungstate solution;
s3: putting 300mL of crude sodium tungstate solution into a 500mL beaker, measuring that the tungsten concentration in the solution is 6.5g/L, the phosphorus concentration is 0.026g/L, the phosphorus-tungsten ratio is 0.004, heating to 48 ℃ under the stirring condition, and adding 0.07g of industrial phosphogypsum with the sulfur trioxide content of 38.0 percent for 2 times; after the feeding is finished, stirring for 30min at normal temperature, and filtering to obtain a dephosphorized crude sodium tungstate solution;
s3: and (2) sequentially adsorbing the dephosphorized crude sodium tungstate solution by using cation exchange resin and anion exchange resin, then resolving adsorbed tungstate ions by using resolving agents with the concentrations of ammonium chloride and ammonia water of 4.5mol/L and 2mol/L respectively to obtain resolving liquid, evaporating and crystallizing the resolving liquid to obtain high-purity ammonium paratungstate crystals, filtering and drying to obtain the ammonium paratungstate product.
Fifthly, purity determination of ammonium paratungstate product
The results of sampling and analyzing the ammonium paratungstate product obtained by the method for preparing ammonium paratungstate of examples 1 to 3, and measuring the purity of ammonium paratungstate according to the method of GB T10116-2007 ammonium paratungstate standard are shown in Table 2.
TABLE 2 purity of ammonium paratungstate products obtained in examples 1 to 3
As can be seen from Table 2, the purity of the obtained ammonium paratungstate product can reach the GB/T10116-2007 APT-0 grade by adopting the preparation method of ammonium paratungstate.
The above description should not be taken as limiting the invention to the embodiments, but rather, as will be apparent to those skilled in the art to which the invention pertains, numerous simplifications or substitutions may be made without departing from the spirit of the invention, which shall be deemed to fall within the scope of the invention as defined by the claims appended hereto.