A method for preparing high-purity nano-scheelene tungstic acid

Abstract

The present invention belongs to the technical field of tungsten smelting, and specifically relates to a method for preparing high-purity nano-white tungstic acid, wherein a tungstate solution is prepared for use; hydrochloric acid is prepared for use, and the volume of the hydrochloric acid is 1.2 to 2.0 times the volume of the tungstate solution; the prepared hydrochloric acid is slowly dripped into the prepared tungstate solution; and high-purity nano-white tungstic acid is obtained after filtering. By precisely controlling the addition sequence and addition speed of the raw materials, not only can the purity of the obtained product reach the high-purity standard, the purity of the high-purity nano-white tungstic acid is ≥99.9%, and stable nano-white tungstic acid can be prepared, and the industrialization prospect is broad.

Description

Technical Field

[0001] The invention belongs to the technical field of tungsten smelting, and specifically relates to a method for preparing high-purity nano-scheelene tungstic acid. Background Art

[0002] Tungstic acid is an inorganic acid composed of three chemical elements: transition metal tungsten, non-metallic oxygen and hydrogen. It is a compound composed of positive monovalent hydrogen ions and negative divalent tungstate ions. It is an important raw material for the production of tungsten oxide and tungstate. According to the different ratios of tungsten trioxide and water, its color is also different, and there are two types: yellow and white. According to the different colors, they are named yellow tungstic acid and white tungstic acid, respectively, and the two are slightly different in physical and chemical properties and production processes. White tungstic acid is a microcrystalline white powder with a ratio of tungsten trioxide to water greater than 1.3. It is a monomeric compound or a polymeric compound and a hydrated tungsten oxide. The appearance of white tungstic acid is a microcrystalline white powder, which is easily soluble in phosphoric acid solution, has certain acidity, high chemical activity, weak thermal stability (heating easily removes part of the water, but still has activity), strong photosensitivity (blue when seeing light) and oxidizability. It should be noted that when it is not stored properly, it will be converted into light yellow tungstic acid and lose its activity at the same time. The existing technology cannot or cannot stably prepare white nano tungstic acid. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the main purpose of the present invention is to propose a method for preparing high-purity nano white tungstic acid. By accurately controlling the addition sequence and addition speed of the raw materials, not only the purity of the obtained product can reach the high-purity standard, but also stable nano white tungstic acid can be prepared, and the industrialization prospect is broad.

[0004] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0005] A method for preparing high-purity nano-scheelite tungstic acid, wherein the purity of the high-purity nano-scheelite tungstic acid is ≥99.9%, comprising the following steps:

[0006] S1. Take tungstate solution for later use;

[0007] S2. Take hydrochloric acid for use, the volume of the hydrochloric acid being 1.2 to 2.0 times the volume of the tungstate solution;

[0008] S3. The reserved hydrochloric acid is slowly added dropwise to the reserved tungstate solution, stirring while adding dropwise;

[0009] S4. After filtration, high-purity nano-white tungstic acid is obtained.

[0010] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, in the step S1, the tungstate solution is a solution with a concentration C of 50 to 300 g / L in terms of tungsten trioxide.

[0011] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, in the step S2, the concentration H of the hydrochloric acid is adjusted according to the concentration C of the tungstate solution.

[0012] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, when the tungstate solution is a solution with a concentration C of 50 g / L ≤ C ≤ 100 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 1.2 mol / L ≤ H < 2.3 mol / L.

[0013] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, when the tungstate solution is a solution with a concentration C of 100 g / L < C ≤ 150 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 2.3 mol / L ≤ H < 3.8 mol / L.

[0014] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, when the tungstate solution is a solution with a concentration C of 150 g / L < C ≤ 200 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 3.8 mol / L ≤ H < 5.0 mol / L.

[0015] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, when the tungstate solution is a solution with a concentration C of 200 g / L < C ≤ 250 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 5.0 mol / L ≤ H < 6.1 mol / L.

[0016] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, when the tungstate solution is a solution with a concentration C of 250 g / L < C ≤ 350 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 6.1 mol / L ≤ H < 7.9 mol / L.

[0017] As a preferred embodiment of the method for preparing high-purity nano tungstic acid according to the present invention, in the step S2, the dropping time is 1.0 to 2.0 h, and the stirring speed during dropping and stirring is 200 to 400 r / min.

[0018] A high-purity nano tungstic acid is prepared by the above method for preparing high-purity nano tungstic acid.

[0019] As a preferred embodiment of the high-purity nano tungstic acid according to the present invention, the purity of the high-purity nano tungstic acid is ≥ 99.9%.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention provides a method for preparing high-purity nano-white tungstic acid, which comprises the following steps: taking a tungstate solution for standby; taking hydrochloric acid for standby, wherein the volume of the hydrochloric acid is 1.2 to 2.0 times the volume of the tungstate solution; slowly dropping the standby hydrochloric acid into the standby tungstate solution; and filtering to obtain high-purity nano-white tungstic acid. By precisely controlling the order and speed of adding the raw materials, not only can the purity of the obtained product reach the high-purity standard, the purity of the high-purity nano-white tungstic acid is ≥99.9%, but also stable nano-white tungstic acid can be prepared, and the industrialization prospect is broad. DETAILED DESCRIPTION

[0022] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] The main purpose of the present invention is to provide a method for preparing high-purity nano white tungstic acid. By accurately controlling the addition sequence and addition speed of the raw materials, not only can the purity of the obtained product reach the high-purity standard, but also stable nano white tungstic acid can be prepared, and the industrialization prospect is broad.

[0024] According to one aspect of the present invention, the present invention provides the following technical solution:

[0025] A method for preparing high-purity nano-scheelite tungstic acid, wherein the purity of the high-purity nano-scheelite tungstic acid is ≥99.9%, comprising the following steps:

[0026] S1. Take tungstate solution for later use;

[0027] S2. Take hydrochloric acid for use, the volume of the hydrochloric acid being 1.2 to 2.0 times the volume of the tungstate solution;

[0028] S3. The reserved hydrochloric acid is slowly added dropwise to the reserved tungstate solution, stirring while adding dropwise;

[0029] S4. After filtration, high-purity nano-white tungstic acid is obtained.

[0030] Preferably, in the step S1, the tungstate solution is a solution with a concentration C of 50 to 300 g / L in terms of tungsten trioxide. Specifically, in terms of tungsten trioxide, the concentration C can be, for example but not limited to, any one of 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L or the range between any two of them. In the system where the tungstate is only ammonium tungstate, except for a sudden increase in temperature, when stored in alkali, the critical concentration of the stable alkali is 2 mol / L to ensure stability.

[0031] Preferably, in the step S2, the volume of the hydrochloric acid is 1.2 to 2.0 times the volume of the tungstate solution; specifically, the volume of the hydrochloric acid can be, for example but not limited to, any one of 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times the volume of the tungstate solution or the range between any two of them;

[0032] Preferably, in the step S2, the concentration H of the hydrochloric acid is adjusted according to the concentration C of the tungstate solution:

[0033] When the tungstate solution is a solution with a concentration C of 50 g / L ≤ C ≤ 100 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 1.2 mol / L ≤ H < 2.3 mol / L;

[0034] When the tungstate solution is a solution with a concentration C of 100 g / L < C ≤ 150 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 2.3 mol / L ≤ H < 3.8 mol / L;

[0035] When the tungstate solution is a solution with a concentration C of 150 g / L < C ≤ 200 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 3.8 mol / L ≤ H < 5.0 mol / L;

[0036] When the tungstate solution is a solution with a concentration C of 200 g / L < C ≤ 250 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 5.0 mol / L ≤ H < 6.1 mol / L;

[0037] When the tungstate solution is a solution with a concentration C of 250 g / L < C ≤ 350 g / L in terms of tungsten trioxide, the hydrochloric acid concentration H is 6.1 mol / L ≤ H < 7.9 mol / L.

[0038] Preferably, in the step S2, the dropping time is 1.0 to 2.0 h, and the stirring speed during dropping is 200 to 400 r / min. Specifically, the dropping time can be, for example but not limited to, any one of 1.0 h, 1.25 h, 1.5 h, 1.75 h, 2.0 h or the range between any two of them; the stirring speed can be, for example but not limited to, any one of 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min or the range between any two of them.

[0039] Preferably, in the step S2, the specific operation of slowly dropping the spare hydrochloric acid into the spare tungstate solution is as follows: put the spare hydrochloric acid into a separatory funnel and slowly drop the hydrochloric acid into the spare tungstate solution.

[0040] A high-purity nano tungstic acid is prepared by the method for preparing high-purity nano tungstic acid described above; the purity of the high-purity nano tungstic acid is ≥99.9%.

[0041] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0042] Example 1

[0043] A method for preparing high-purity nano tungstic acid includes the following steps:

[0044] S1. Prepare a tungstate solution with a concentration C of 250 g / L in terms of tungsten trioxide.

[0045] S2. In terms of tungsten trioxide, the tungstate solution has a concentration C in the range of 200 g / L < C ≤ 250 g / L, and the hydrochloric acid concentration H should be 5.0 mol / L ≤ H < 6.1 mol / L. In this example, 6 mol / L hydrochloric acid is prepared for use, and the volume of the hydrochloric acid is 2.0 times the volume of the tungstate solution.

[0046] S3. Put the prepared 6 mol / L hydrochloric acid into a separatory funnel and slowly drop it into the tungstate solution with a concentration C of 250 g / L, and stir while dropping, with a stirring speed of 300 r / min and a dropping time of 2.0 h.

[0047] S4. After the dropping is completed, filter to obtain high-purity nano tungstic acid, and the purity of the high-purity nano tungstic acid is 99.95%.

[0048] Example 2

[0049] A method for preparing high-purity nano tungstic acid includes the following steps:

[0050] S1. Prepare a tungstate solution with a concentration C of 50 g / L in terms of tungsten trioxide.

[0051] S2. In terms of tungsten trioxide, the concentration C of the tungstate solution ranges from 50 g / L to 100 g / L, and the concentration H of hydrochloric acid should be 1.2 mol / L ≤ H < 2.3 mol / L. In this example, hydrochloric acid with a concentration of 2 mol / L is prepared for use, and the volume of the hydrochloric acid is 1.5 times the volume of the tungstate solution;

[0052] S3. Put the prepared 2 mol / L hydrochloric acid into a separatory funnel and slowly drip it into the tungstate solution with a concentration C of 50 g / L. Stir while dripping, with a stirring speed of 200 r / min and a dripping time of 1.5 h;

[0053] S4. After the dripping is completed, filter to obtain high-purity nano tungstic acid, and the purity of the high-purity nano tungstic acid is 99.90%.

[0054] Example 3

[0055] A method for preparing high-purity nano tungstic acid includes the following steps:

[0056] S1. Prepare a tungstate solution with a concentration C of 120 g / L in terms of tungsten trioxide;

[0057] S2. In terms of tungsten trioxide, the concentration C of the tungstate solution ranges from 100 g / L < C ≤ 150 g / L, and the concentration H of hydrochloric acid should be 2.3 mol / L ≤ H < 3.8 mol / L. In this example, hydrochloric acid with a concentration of 3 mol / L is prepared for use, and the volume of the hydrochloric acid is 1.2 times the volume of the tungstate solution;

[0058] S3. Put the prepared 3 mol / L hydrochloric acid into a separatory funnel and slowly drip it into the tungstate solution with a concentration C of 120 g / L. Stir while dripping, with a stirring speed of 400 r / min and a dripping time of 1.0 h;

[0059] S4. After the dripping is completed, filter to obtain high-purity nano tungstic acid, and the purity of the high-purity nano tungstic acid is 99.92%.

[0060] Example 4

[0061] A method for preparing high-purity nano tungstic acid includes the following steps:

[0062] S1. Prepare a tungstate solution with a concentration C of 180 g / L in terms of tungsten trioxide;

[0063] S2. In terms of tungsten trioxide, the concentration C of the tungstate solution ranges from 150 g / L < C ≤ 200 g / L, and the concentration H of hydrochloric acid should be 3.8 mol / L ≤ H < 5.0 mol / L. In this example, hydrochloric acid with a concentration of 4 mol / L is prepared for use, and the volume of the hydrochloric acid is 2.0 times the volume of the tungstate solution;

[0064] S3. Place the spare 4 mol / L hydrochloric acid into the separatory funnel and slowly drip it into the tungstate solution with a concentration C of 180 g / L. Stir while dripping, with a stirring speed of 300 r / min and a dripping time of 2.0 h.

[0065] S4. After the dripping is completed, filter to obtain high-purity nano-calcium tungstate, and the purity of the high-purity nano-calcium tungstate is 99.96%.

[0066] Example 5

[0067] A method for preparing high-purity nano-calcium tungstate, comprising the following steps:

[0068] S1. Take a tungstate solution with a concentration C of 280 g / L in terms of tungsten trioxide for standby.

[0069] S2. In terms of tungsten trioxide, the concentration C of the tungstate solution is in the range of 250 g / L < C ≤ 350 g / L, and the hydrochloric acid concentration H should be 6.1 mol / L ≤ H < 7.9 mol / L. In this example, 7 mol / L hydrochloric acid is taken for standby, and the volume of the hydrochloric acid is 2.0 times the volume of the tungstate solution.

[0070] S3. Place the standby 7 mol / L hydrochloric acid into the separatory funnel and slowly drip it into the tungstate solution with a concentration C of 280 g / L. Stir while dripping, with a stirring speed of 300 r / min and a dripping time of 2.0 h.

[0071] S4. After the dripping is completed, filter to obtain high-purity nano-calcium tungstate, and the purity of the high-purity nano-calcium tungstate is 99.95%.

[0072] Comparative Example 1

[0073] A method for preparing tungstic acid, comprising the following steps:

[0074] S1. Take a tungstate solution with a concentration C of 250 g / L in terms of tungsten trioxide for standby.

[0075] S2. Take 7 mol / L hydrochloric acid for standby, and the volume of the hydrochloric acid is 2.0 times the volume of the tungstate solution.

[0076] S3. Place the standby 7 mol / L hydrochloric acid into the separatory funnel and slowly drip it into the tungstate solution with a concentration C of 250 g / L. Stir while dripping, with a stirring speed of 300 r / min and a dripping time of 2.0 h.

[0077] S4. After the dripping is completed, filter to obtain yellow tungstic acid, and there is calcium tungstate in the yellow tungstic acid.

[0078] Comparative Example 2

[0079] A method for preparing tungstic acid comprises the following steps:

[0080] S1. Take a tungstate solution with a concentration C of 250 g / L in terms of tungsten trioxide for later use;

[0081] S2. Take 4 mol / L hydrochloric acid for use, the volume of the hydrochloric acid being 2.0 times the volume of the tungstate solution;

[0082] S3. The reserved concentration C of 250g / L tungstate solution was placed in a separatory funnel, and slowly added dropwise to the reserved 4mol / L hydrochloric acid, stirring while dropping, the stirring speed was 300r / min, and the dropping time was 2h;

[0083] S4. After the addition is completed, yellow tungstic acid is filtered to obtain yellow tungstic acid, which contains white tungstic acid.

[0084] Comparative Example 3

[0085] A method for preparing tungstic acid comprises the following steps:

[0086] S1. Take a tungstate solution with a concentration C of 250 g / L in terms of tungsten trioxide for later use;

[0087] S2. Take 4 mol / L hydrochloric acid for use, the volume of the hydrochloric acid being 2.0 times the volume of the tungstate solution;

[0088] S3. The reserved concentration C of 250g / L tungstate solution was quickly introduced into the reserved 7mol / L hydrochloric acid, and then stirred for 1h;

[0089] S4. After filtering, yellow tungstic acid is obtained, and white tungstic acid exists in the yellow tungstic acid.

[0090] Comparative Example 4

[0091] A method for preparing tungstic acid comprises the following steps:

[0092] S1. Take a tungstate solution with a concentration of 250g / L in terms of tungsten trioxide for later use;

[0093] S2. Take 4 mol / L hydrochloric acid for use, the volume of the hydrochloric acid being 2.0 times the volume of the tungstate solution;

[0094] S3. The reserved 4 mol / L hydrochloric acid was quickly added to the reserved concentration C of 250g / L tungstate solution, and then stirred for 1h;

[0095] S4. After filtering, white tungstic acid is obtained, and yellow tungstic acid exists in the white tungstic acid.

[0096] The present invention prepares a tungstate solution for use; prepares hydrochloric acid for use, wherein the volume of the hydrochloric acid is 1.2 to 2.0 times the volume of the tungstate solution; slowly drips the hydrochloric acid for use into the tungstate solution for use; and obtains high-purity nano-white tungstic acid after filtration. By precisely controlling the order and speed of adding the raw materials, not only can the purity of the obtained product reach the high-purity standard, the purity of the high-purity nano-white tungstic acid is ≥99.9%, but also stable nano-white tungstic acid can be prepared, and the industrialization prospect is broad.

[0097] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing high-purity nano-scheelite tungstic acid, characterized in that: The purity of the high-purity nano tungstic acid is ≥99.9%, and the method includes the following steps: S1. Prepare a tungstate solution for standby. The tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 50 - 300 g / L. S2. Prepare hydrochloric acid for standby. The volume of the hydrochloric acid is 1.2 - 2.0 times the volume of the tungstate solution. The concentration H of the hydrochloric acid is adjusted according to the concentration C of the tungstate solution: When the tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 50 g / L ≤ C ≤ 100 g / L, the hydrochloric acid concentration H is 1.2 mol / L ≤ H < 2.3 mol / L; When the tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 100 g / L < C ≤ 150 g / L, the hydrochloric acid concentration H is 2.3 mol / L ≤ H < 3.8 mol / L; When the tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 150 g / L < C ≤ 200 g / L, the hydrochloric acid concentration H is 3.8 mol / L ≤ H < 5.0 mol / L; When the tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 200 g / L < C ≤ 250 g / L, the hydrochloric acid concentration H is 5.0 mol / L ≤ H < 6.1 mol / L; When the tungstate solution is a solution with a concentration C (calculated as tungsten trioxide) of 250 g / L < C ≤ 350 g / L, the hydrochloric acid concentration H is 6.1 mol / L ≤ H < 7.9 mol / L; S3. Slowly add the standby hydrochloric acid dropwise to the standby tungstate solution while stirring during the dropping process; The dropping time is 1.0 - 2.0 h, and the stirring speed during the dropping process is 200 - 400 r / min; S4. Obtain high-purity nano tungstic acid after filtration.