Preparation method of electronic-grade tartaric acid solution

Abstract

The invention belongs to the technical field of preparation of electronic-grade tartaric acid, and particularly relates to a preparation method of an electronic-grade tartaric acid solution, which comprises the following steps: (1) dissolving tartaric acid to prepare a tartaric acid solution, cooling the solution to 20 DEG C, crystallizing, separating out, filtering and drying to prepare recrystallized tartaric acid; (2) preparing the recrystallized tartaric acid into a tartaric acid solution, dropwise adding the tartaric acid solution into the calcium hydroxide suspension, reacting for 2 hours to obtain a calcium tartrate solid, washing the calcium tartrate solid at 60-80 DEG C for 3 times, filtering and drying to obtain calcium tartrate; (3) preparing a 50% calcium tartrate suspension from the calcium tartrate prepared in the step (2), dropwise adding an electronic-grade concentrated sulfuric acid solution into the calcium tartrate suspension, and reacting to prepare a tartaric acid solution; and (4) performing ion exchange on the tartaric acid solution prepared in the step (3) through secondary resin to obtain the electronic-grade tartaric acid solution. The method is low in cost and easy to operate, and the maximum removal rate of metal ions reaches 99.99%.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of electronic-grade tartaric acid, and particularly relates to a method for preparing an electronic-grade tartaric acid solution. Background Art

[0002] Electronic-grade reagents refer to high-purity chemical reagents used in the electronics industry. Their electrical impurity content is extremely low, and they are one of the key basic chemical materials indispensable in the manufacturing processes of ultra-large-scale integrated circuits, new displays, solar cells, etc. With the development of the semiconductor and electronics industries, the purity requirements for electronic-grade reagents are getting higher and higher, and the cleanliness requirements are getting stricter, because the purity and cleanliness of electronic-grade reagents are the key factors for the stable and reliable performance of electronic products.

[0003] L(+)-tartaric acid, with the molecular formula C 4 H 6 O 6 , is a white crystalline powder with a sour taste, soluble in water and ethanol, and insoluble in chloroform. Tartaric acid has a wide range of uses. In the food industry, it can be used as a food additive, antioxidant, stabilizer, and clarifying agent, etc.; in the pharmaceutical industry, it can be used as a complexing agent, chemical resolution agent, and its derivatives, etc.; in addition, it can also be used as a photographic developer, and can complex with a variety of metal ions, and is used as a cleaning agent and polishing agent for metal surfaces.

[0004] The purification methods of electronic-grade reagents mainly include distillation, rectification, continuous rectification, salt fusion rectification, azeotropic rectification, sub-boiling distillation, isothermal distillation, vacuum distillation, sublimation, chemical treatment, gas absorption, etc. The removal of metal ions in the preparation process of electronic-grade tartaric acid is particularly crucial. The present invention provides a method for preparing an electronic-grade tartaric acid solution, achieving the purpose of removing metal ions. Summary of the Invention

[0005] Aiming at the problems and deficiencies existing in the prior art, the purpose of the present invention is to provide a method for preparing an electronic-grade tartaric acid solution, particularly a method in which tartaric acid reacts with calcium hydroxide to form calcium tartrate, and after washing with water, reacts with electronic-grade concentrated sulfuric acid to form tartaric acid to remove metal ions.

[0006] Based on the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing an electronic-grade tartaric acid solution, comprising the following steps:

[0008] (1) Dissolve L(+)-tartaric acid with a purity of 99.7% in ultrapure water at 90 - 100 °C to prepare a tartaric acid solution. The concentration of the tartaric acid solution is equal to or slightly less than the saturation concentration of the tartaric acid solution at the corresponding dissolution temperature. Then cool the solution to 20 °C to crystallize out tartaric acid solid, filter and dry to obtain recrystallized tartaric acid;

[0009] (2) Dissolve the recrystallized tartaric acid obtained in step (1) in ultrapure water to prepare a tartaric acid solution. Drop the tartaric acid solution into the calcium hydroxide suspension and react for 2 h to obtain calcium tartrate solid. Wash the calcium tartrate solid with ultrapure water 3 times at 60 - 80 °C, filter and dry to obtain calcium tartrate;

[0010] (3) Prepare a 50% calcium tartrate suspension with the calcium tartrate obtained in step (2) using ultrapure water. Drop the electronic grade concentrated sulfuric acid solution into the calcium tartrate suspension and react to prepare a tartaric acid solution;

[0011] (4) Pass the tartaric acid solution prepared in step (3) through a two-stage resin for ion exchange to obtain an electronic grade tartaric acid solution.

[0012] According to the above preparation method, preferably, the following preparatory work needs to be done before preparation:

[0013] ① Conduct experiments in an electronic grade thousand-class clean laboratory (the number of particles ≥ 0.3 um is less than 1000) to determine that the air in the clean room has no interference with the experimental metal ions;

[0014] ② Determine that the chromatography column soaked in ultrapure water has no interference with the experimental metal ions;

[0015] ③ Determine that the use of electronic grade sulfuric acid has no interference with the experimental metal ions;

[0016] ④ Determine that the use of PFA and PTFE material equipment has no interference with the experimental metal ions;

[0017] ⑤ Detect the status of the detection instrument and prepare the required standard curve.

[0018] According to the above preparation method, preferably, in step (2), the reaction temperature of the tartaric acid solution and the calcium hydroxide suspension is 10 - 30 °C.

[0019] More preferably, in step (2), the reaction temperature of the tartaric acid solution and the calcium hydroxide suspension is 20 °C.

[0020] According to the above preparation method, preferably, in step (3), the reaction temperature of the electronic grade concentrated sulfuric acid and calcium tartrate is 40 - 60 °C; the molar ratio of the electronic grade concentrated sulfuric acid to calcium tartrate is 1:(1.02 - 1.20); the concentration of the electronic grade concentrated sulfuric acid solution is 5% - 50%.

[0021] More preferably, in step (3), the reaction temperature of electronic-grade concentrated sulfuric acid and calcium tartrate is 50 °C; the molar ratio of the electronic-grade concentrated sulfuric acid to calcium tartrate is 1:1.10; the concentration of the electronic-grade concentrated sulfuric acid solution is 50%.

[0022] According to the above preparation method, preferably, in step (2), the dissolution temperature of tartaric acid is 10 - 30 °C, and the concentration of the tartaric acid solution is 40%.

[0023] More preferably, in step (2), the dissolution temperature of tartaric acid is 20 °C, and the concentration of the tartaric acid solution is 40%.

[0024] According to the above preparation method, preferably, the preparation step of the calcium hydroxide suspension is to dissolve solid calcium hydroxide in ultrapure water at 10 - 30 °C to prepare a 25% calcium hydroxide suspension.

[0025] More preferably, the preparation step of the calcium hydroxide suspension is to dissolve solid calcium hydroxide in ultrapure water at 20 °C to prepare a 25% calcium hydroxide suspension.

[0026] According to the above preparation method, preferably, in step (4), before the tartaric acid solution passes through the secondary resin, it also includes activated resin treatment: the resin column is purged and replaced with 99.999% nitrogen and then filled with resin. First, backwash the chromatography column with a 1.5% electronic-grade sulfuric acid solution, and then rinse it with ultrapure water until it is neutral.

[0027] According to the above preparation method, preferably, in step (4), the height-to-diameter ratio of the resin in the chromatography column is 16:1, and the diameter is 25 mm; the volume of the electronic-grade sulfuric acid solution used for backwashing the chromatography column is three times the volume of the resin.

[0028] According to the above preparation method, preferably, in step (4), the temperature of the tartaric acid solution passing through the secondary resin is 10 - 30 °C; the flow rate of the tartaric acid solution through the resin is 3 - 10 Bv / h.

[0029] More preferably, in step (4), the temperature of the tartaric acid solution passing through the secondary resin is 30 °C; the flow rate of the tartaric acid solution through the resin is 3 Bv / h.

[0030] According to the above preparation method, preferably, in step (4), the resin is an electronic-grade strongly acidic cation exchange resin (washed with ultrapure water with a volume of <1 ppt and the metal ions are less than 50 ppt), and the loading amount of the resin is 200 g.

[0031] According to the above preparation method, preferably, both the filtration and drying steps are carried out under the protection of 99.999% nitrogen; the ultrapure water is all ultrapure water with metal ions < 1 ppt.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The present invention uses the ion exchange resin method combined with primary recrystallization and the process of washing the calcium tartrate formed to prepare electronic grade tartaric acid. This method not only has low cost and is easy to operate, but also the content of metal ions in the product is all lower than 0.5 ppb, and the removal rate of metal ions reaches up to 99.99%, which can be used for the cleaning and surface treatment of electronic components.

[0034] (2) Among them, the reaction of tartaric acid with calcium hydroxide to form calcium tartrate, and then reacting with electronic grade concentrated sulfuric acid after washing to form tartaric acid to remove metal ions has the advantage that metal ions in tartaric acid can be removed more efficiently, making the metal ion content all lower than 5 ppb. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a process flow chart of the preparation method of the electronic grade tartaric acid solution of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail through embodiments in conjunction with the drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Example 1

[0038] After replacing the dissolution tank with 99.999% nitrogen, 300 g of L(+)-tartaric acid and 100 g of ultrapure water with metal ions < 1 ppt were weighed and put into the dissolution tank, and dissolved at 100 °C to form a 75% tartaric acid solution. After fully dissolving, it was slowly cooled to 20 °C for crystallization to precipitate, and filtered and dried using a suction filter under the protection of 99.999% nitrogen to obtain recrystallized tartaric acid.

[0039] Take an appropriate amount of L(+)-tartaric acid raw material and recrystallized tartaric acid, dissolve them with ultrapure water with metal ions < 1 ppt, measure the metal ion content by ICP-MS, and measure the purity by HPLC, as shown in Table 1.

[0040] Table 1 Metal ion content and tartaric acid purity

[0041]

[0042] According to Table 1, tartaric acid was fully dissolved at 100 °C to prepare a tartaric acid solution with a mass concentration of 75%. During the process of cooling to 20 °C, the solution was in a supersaturated state, and crystals gradually precipitated. It can be seen from Table 1 that the removal rate of metal impurity ions before and after recrystallization reached 52-60%, and the purity of tartaric acid was increased to 99.85%. However, there is still a certain gap from the requirements of electronic-grade tartaric acid.

[0043] Example 2

[0044] Weigh 200 g of the recrystallized tartaric acid from Example 1 and 300 g of ultrapure water with metal ions <1 ppt and put them into a dissolution tank to dissolve at 10 °C to make a 40% tartaric acid solution. Weigh 98 g of calcium hydroxide solid and 300 g of ultrapure water with metal ions <1 ppt and put them into reaction tank 1 to make a 25% calcium hydroxide suspension at 10 °C. The 40% tartaric acid solution was added dropwise to the 25% calcium hydroxide suspension at 10 °C under stirring conditions, and reacted at 10 °C for 2 h to prepare calcium tartrate solid, which was filtered and dried using a suction filter under the protection of 99.999% nitrogen. 250 g of the dried calcium tartrate solid and 500 g of ultrapure water with metal ions <1 ppt were put into reaction tank 2 and washed 3 times with water at 60 °C. After washing, it was filtered and dried using a suction filter under the protection of 99.999% nitrogen to prepare calcium tartrate.

[0045] Take the washing liquid from the 3 times of water washing, and measure the metal ion content by ICP-MS, as shown in Table 2.

[0046] Table 2 Metal ion content

[0047] Metal impurity ions ppb Na Mg Al K Ca Cr Fe Co Ni First washing liquid 2832.96 14.32 3.05 11.37 5472.88 28.60 280.46 6.64 3.25 Second washing liquid 76.92 1.92 1.01 3.09 986.53 5.98 46.57 2.22 1.08 Third washing liquid 4.29 1.02 0.17 1.06 94.29 1.95 2.05 0.16 0.09

[0048] According to Table 2, the 40% tartaric acid solution was added dropwise to the 25% calcium hydroxide suspension at 10 °C under stirring conditions to prepare calcium tartrate. After washing 3 times with water at 60 °C, it can be seen from Table 2 that after calcium tartrate and multiple water washings, a large amount of metal ions can be removed.

[0049] Example 3

[0050] Weigh 200 g of tartaric acid after recrystallization in Example 1, and put 300 g of ultrapure water with metal ions <1 ppt into the dissolution tank to dissolve it at 20 °C to make a 40% tartaric acid solution. Weigh 98 g of calcium hydroxide solid, and put 300 g of ultrapure water with metal ions <1 ppt into Reaction Tank 1 to make a 25% calcium hydroxide suspension at 20 °C. The 40% tartaric acid solution is added dropwise to the 25% calcium hydroxide suspension at 20 °C under stirring conditions, and react for 2 h at 20 °C to prepare calcium tartrate solid, and filter and dry it using a suction filter under the protection of 99.999% nitrogen. 250 g of the dried calcium tartrate solid and 500 g of ultrapure water with metal ions <1 ppt are put into Reaction Tank 2 and washed 3 times at 70 °C. After washing, filter and dry it using a suction filter under the protection of 99.999% nitrogen to obtain calcium tartrate.

[0051] Take the washing liquid from the 3 - time water washing, and measure the metal ion content by ICP - MS, as shown in Table 3.

[0052] Table 3 Metal Ion Content

[0053] Metal impurity ions ppb Na Mg Al K Ca Cr Fe Co Ni First washing liquid 2843.46 14.94 4.01 13.09 5547.11 30.29 298.57 7.03 3.67 Second washing liquid 74.62 2.03 0.98 3.79 1098.24 5.87 32.27 1.21 0.94 Third washing liquid 3.98 1.09 0.21 1.12 98.74 2.01 2.24 0.20 0.11

[0054] Example 4

[0055] Weigh 200 g of tartaric acid after recrystallization in Example 1, and put 300 g of ultrapure water with metal ions <1 ppt into the dissolution tank to dissolve it at 30 °C to make a 40% tartaric acid solution. Weigh 98 g of calcium hydroxide solid, and put 300 g of ultrapure water with metal ions <1 ppt into Reaction Tank 1 to make a 25% calcium hydroxide suspension at 30 °C. The 40% tartaric acid solution is added dropwise to the 25% calcium hydroxide suspension at 30 °C under stirring conditions, and react for 2 h at 30 °C to prepare calcium tartrate solid, and filter and dry it using a suction filter under the protection of 99.999% nitrogen. 250 g of the dried calcium tartrate solid and 500 g of ultrapure water with metal ions <1 ppt are put into Reaction Tank 2 and washed 3 times at 80 °C. After washing, filter and dry it using a suction filter under the protection of 99.999% nitrogen to obtain calcium tartrate.

[0056] Take the washing liquid from the 3 - time water washing, and measure the metal ion content by ICP - MS, as shown in Table 4.

[0057] Table 4 Metal Ion Content

[0058] Metal impurity ions ppb Na Mg Al K Ca Cr Fe Co Ni First washing liquid 2850.92 12.05 3.66 13.42 5700.45 30.06 292.55 6.65 3.05 Second washing liquid 66.35 5.96 1.02 3.06 939.27 6.25 35.87 2.03 1.01 Third washing liquid 4.69 1.15 0.25 1.07 89.92 1.99 2.45 0.53 0.14

[0059] Examples 2 - 4 explored the influence of the water washing temperature on the removal of metal ions from calcium tartrate by water washing. From the data in Tables 2 - 4, it can be seen that the water washing temperature has little influence on the removal of metal ions from calcium tartrate by water washing.

[0060] Example 5

[0061] Weigh 250 g of calcium tartrate solid after being washed three times with water and dried in Example 2. Put 250 g of ultrapure water with metal ions <1 ppt into reaction tank 3 to make a 50% calcium tartrate suspension. Take 132.6 g of electronic grade concentrated sulfuric acid (metal ions <0.1 ppb), and put 2519.4 g of ultrapure water with metal ions <1 ppt into a PFA bottle to make a 5% electronic grade concentrated sulfuric acid solution. The 5% electronic grade concentrated sulfuric acid solution is added dropwise to the 50% calcium tartrate suspension at room temperature under stirring conditions. After the addition is complete, react for 2 h at 40 °C to prepare a tartaric acid solution, and filter the tartaric acid solution using a suction filter under the protection of 99.999% nitrogen.

[0062] For the tartaric acid solution prepared by the reaction, measure the metal ion content by ICP-MS, as shown in Table 5.

[0063] Table 5 Metal ion content

[0064]

[0065] Example 6

[0066] Weigh 250 g of calcium tartrate solid after being washed three times with water and dried in Example 3. Put 250 g of ultrapure water with metal ions <1 ppt into reaction tank 3 to make a 50% calcium tartrate suspension. Take 143 g of electronic grade concentrated sulfuric acid (metal ions <0.1 ppb), and put 429 g of ultrapure water with metal ions <1 ppt into a PFA bottle to make a 25% electronic grade concentrated sulfuric acid solution. The 25% electronic grade concentrated sulfuric acid solution is added dropwise to the 50% calcium tartrate suspension at room temperature under stirring conditions. After the addition is complete, react for 2 h at 50 °C to prepare a tartaric acid solution, and filter the tartaric acid solution using a suction filter under the protection of 99.999% nitrogen.

[0067] For the tartaric acid solution prepared by the reaction, measure the metal ion content by ICP-MS, as shown in Table 6.

[0068] Table 6 Metal ion content

[0069]

[0070] Example 7

[0071] Weigh 250 g of the calcium tartrate solid after being washed three times with water and dried in Example 4. Put 250 g of ultrapure water with metal ions < 1 ppt into the reaction tank 3 to make a 50% calcium tartrate suspension. Take 156 g of electronic grade concentrated sulfuric acid (metal ions < 0.1 ppb) and 156 g of ultrapure water with metal ions < 1 ppt and put them into a PFA bottle to make a 50% electronic grade concentrated sulfuric acid solution. The 50% electronic grade concentrated sulfuric acid solution is added dropwise to the 50% calcium tartrate suspension under normal temperature and stirring conditions. After the addition is completed, react at 60 °C for 2 h to prepare a tartaric acid solution, and filter the tartaric acid solution using a suction filter under the protection of 99.999% nitrogen.

[0072] For the tartaric acid solution prepared by the reaction, measure the metal ion content by ICP-MS, as shown in Table 7.

[0073] Table 7 Metal ion content

[0074]

[0075] From the data in Table 5 - Table 7, it can be seen that tartaric acid is recrystallized, then reacts with calcium hydroxide to form calcium tartrate, and after washing with water, it reacts with electronic grade concentrated sulfuric acid to form tartaric acid. The concentration of metal ions in the tartaric acid can be significantly reduced. This is because the combination of recrystallization and washing the calcium tartrate precipitate made from calcium hydroxide with water can effectively remove the impurities in the tartaric acid, enabling it to meet the standards required by the electronics industry faster.

[0076] Example 8

[0077] After purging and displacing the resin column with 99.999% nitrogen, fill the resin (height-diameter ratio 16:1, diameter 25 mm). The resin used is electronic grade strongly acidic cation exchange resin (washed with an equal volume of ultrapure water with metal ions < 1 ppt, metal ions less than 50 ppt). The loading amount of the resin is 200 g. Backwash the chromatography column with a 1.5% electronic grade sulfuric acid solution three times the volume of the resin, and then wash it with ultrapure water with metal ions < 1 ppt until it is neutral. At 10 °C, place the tartaric acid solution prepared in Example 5 in the storage tank 1 and slowly enter the pretreated secondary resin through a pump for ion exchange, with the flow rate controlled at 5 Bv / h, and collect the distillate in the storage tank 2.

[0078] According to the SJ / T11637-2016 electronics industry standard, take an appropriate amount of the product and measure the metal ion content by ICP-MS, as shown in Table 8.

[0079] Table 8 Metal ion content

[0080]

[0081] According to Table 8, at 10°C, the tartaric acid solution was passed through the secondary resin with a flow rate controlled at 5 Bv / h. The removal rate of metal impurity ions before and after passing through the resin both reached over 97.90%. This is because the metal ions in tartaric acid underwent ion exchange with the resin, reducing its metal ion content to meet the UP-S grade standard required by the electronics industry.

[0082] Example 9

[0083] The resin column was purged and replaced with 99.999% nitrogen and then filled with resin (aspect ratio 16:1, diameter 25 mm). The resin used was an electronic-grade strongly acidic cation exchange resin (eluted with ultrapure water with a volume equivalent and metal ions less than 50 ppt). The resin loading was 200 g. The chromatography column was backwashed with a 1.5% electronic-grade sulfuric acid solution with a volume three times that of the resin, and then rinsed with ultrapure water with metal ions less than 1 ppt until neutral. At 20°C, the tartaric acid solution prepared in Example 6 was placed in storage tank 1 and slowly entered the pretreated secondary resin through a pump for ion exchange with a flow rate controlled at 5 Bv / h. The distillate was collected in storage tank 2.

[0084] According to the SJ / T11637-2016 electronics industry standard, an appropriate amount of the product was taken for ICP-MS measurement of metal ion content, as shown in Table 9.

[0085] Table 9 Metal ion content

[0086]

[0087] According to Table 9, at 20°C, the tartaric acid solution was passed through the secondary resin with a flow rate controlled at 5 Bv / h. The removal rate of metal impurity ions before and after passing through the resin both reached over 97.95%. This is because the metal ions in tartaric acid underwent ion exchange with the resin, reducing its metal ion content.

[0088] Example 10

[0089] The resin column was purged and replaced with 99.999% nitrogen and then filled with resin (aspect ratio 16:1, diameter 25 mm). The resin used was an electronic-grade strongly acidic cation exchange resin (eluted with ultrapure water with a volume equivalent and metal ions less than 50 ppt). The resin loading was 200 g. The chromatography column was backwashed with a 1.5% electronic-grade sulfuric acid solution with a volume three times that of the resin, and then rinsed with ultrapure water with metal ions less than 1 ppt until neutral. At 30°C, the tartaric acid solution prepared in Example 7 was placed in storage tank 1 and slowly entered the pretreated secondary resin through a pump for ion exchange with a flow rate controlled at 5 Bv / h. The distillate was collected in storage tank 2.

[0090] According to the SJ / T 11637-2016 electronic industry standard, an appropriate amount of the product was taken for ICP-MS measurement of the metal ion content, as shown in Table 10.

[0091] Table 10 Metal Ion Content

[0092]

[0093] According to Table 10, at 30 °C, the tartaric acid solution was passed through the secondary resin, and the flow rate was controlled at 5 Bv / h. The removal rate of metal impurity ions before and after passing through the resin reached over 98.00%. This is because the metal ions in the tartaric acid underwent ion exchange with the resin, reducing its metal ion content.

[0094] Example 11

[0095] After the resin column was purged and replaced with 99.999% nitrogen, it was filled with resin (height-diameter ratio 16:1, diameter 25 mm). The resin used was an electronic-grade strongly acidic cation exchange resin (washed with ultrapure water with a volume equivalent to <1 ppt and having metal ions less than 50 ppt). The resin loading was 200 g. The chromatography column was backwashed with a 1.5% electronic-grade sulfuric acid solution with a volume three times that of the resin, and then rinsed with ultrapure water with metal ions <1 ppt until neutral. At 30 °C, the tartaric acid solution prepared in Example 7 was placed in storage tank 1 and slowly entered the pretreated secondary resin through a pump for ion exchange, with the flow rate controlled at 3 Bv / h. The distillate was collected in storage tank 2.

[0096] According to the SJ / T 11637-2016 electronic industry standard, an appropriate amount of the product was taken for ICP-MS measurement of the metal ion content, as shown in Table 11.

[0097] Table 11 Metal Ion Content

[0098]

[0099] According to Table 11, at 30 °C, the tartaric acid solution was passed through the secondary resin, and the flow rate was controlled at 3 Bv / h. The removal rate of metal impurity ions before and after passing through the resin reached over 98.00%. This is because the metal ions in the tartaric acid underwent ion exchange with the resin, reducing its metal ion content.

[0100] Example 12

[0101] The resin column is purged and replaced with 99.999% nitrogen and then filled with resin (aspect ratio 16:1, diameter 25 mm). The resin used is an electronic-grade strongly acidic cation exchange resin (washed with ultrapure water with a volume equivalent to <1 ppt and with metal ions less than 50 ppt). The loading amount of the resin is 200 g. The chromatography column is backwashed with a 1.5% electronic-grade sulfuric acid solution with a volume three times that of the resin, and then washed with ultrapure water with metal ions <1 ppt until neutral. At 30 °C, the tartaric acid solution prepared in Example 7 is placed in storage tank 1 and slowly enters the pretreated secondary resin through a pump for ion exchange, with the flow rate controlled at 10 Bv / h. The distillate is collected in storage tank 2.

[0102] According to the SJ / T 11637-2016 electronic industry standard, an appropriate amount of the product is taken and the metal ion content is measured by ICP-MS, as shown in Table 12.

[0103] Table 12 Metal ion content

[0104]

[0105] According to Table 12, at 30 °C, the tartaric acid solution is passed through the secondary resin with the flow rate controlled at 10 Bv / h. The removal rates of metal impurity ions before and after passing through the resin both reach over 97.00%. This is because the metal ions in the tartaric acid undergo ion exchange with the resin, reducing the metal ion content.

[0106] The experimental data of Examples 8-12 show that at 10-30 °C, the prepared tartaric acid solution is passed through the secondary electronic-grade strongly acidic cation exchange resin to remove metal ions, with the flow rate controlled at 3-10 Bv / h. The highest removal rate of metal ions reaches 99.99%. Among them, in Example 11, at 30 °C and with the flow rate controlled at 3 Bv / h, the removal rate of metal ions of the tartaric acid solution passed through the secondary electronic-grade strongly acidic cation exchange resin is the highest.

[0107] The above examples are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Those skilled in the art can modify or equivalently replace the technical solutions of the present invention according to the idea of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an electronic grade tartaric acid solution, characterized in that: The following steps are involved: (1) dissolving L(+)-tartaric acid with a purity of 99.7% in ultrapure water at 90-100° C. to prepare a tartaric acid solution, wherein the concentration of the tartaric acid solution is equal to or slightly less than the saturated concentration of the tartaric acid solution at the corresponding dissolution temperature, then cooling the solution to 20° C. to crystallize tartaric acid solid, filtering and drying to prepare recrystallized tartaric acid; (2) dissolving the tartaric acid recrystallized in step (1) in ultrapure water to prepare a tartaric acid solution, adding the tartaric acid solution dropwise to a calcium hydroxide suspension, reacting for 2 hours to obtain a calcium tartrate solid, washing the calcium tartrate solid with ultrapure water for three times at 60-80° C., filtering, and drying to prepare calcium tartrate; (3) The calcium tartrate prepared in step (2) is prepared into a 50% calcium tartrate suspension with ultrapure water, and an electronic grade concentrated sulfuric acid solution is added dropwise to the calcium tartrate suspension to react and prepare a tartaric acid solution; (4) The tartaric acid solution prepared in step (3) is subjected to ion exchange by passing it through a secondary resin to obtain an electronic grade tartaric acid solution.

2. The preparation method of electronic grade tartaric acid solution according to claim 1, characterized in that, In step (2), the reaction temperature of the tartaric acid solution and the calcium hydroxide suspension is 10-30°C.

3. The preparation method of electronic grade tartaric acid solution according to claim 1, characterized in that, In step (3), the reaction temperature of electronic grade concentrated sulfuric acid and calcium tartrate is 40-60°C; the molar ratio of the electronic grade concentrated sulfuric acid to calcium tartrate is 1:(1.02-1.20); and the concentration of the electronic grade concentrated sulfuric acid solution is 5%-50%.

4. The method for preparing an electronic grade tartaric acid solution according to claim 1 or 2, characterized in that: In step (2), the dissolution temperature of tartaric acid is 10-30°C, and the concentration of the tartaric acid solution is 40%.

5. The preparation method of electronic grade tartaric acid solution according to claim 1 or 4, characterized in that, The preparation step of the calcium hydroxide suspension is to dissolve solid calcium hydroxide in ultrapure water at 10-30° C. to prepare a 25% calcium hydroxide suspension.

6. The method for preparing electronic grade tartaric acid solution according to claim 1, characterized in that: In step (4), the tartaric acid solution also includes an activated resin treatment before passing through the secondary resin: the resin column is purged and replaced with 99.999% nitrogen and then filled with resin, and the chromatography column is first backwashed with 1.5% electronic grade sulfuric acid solution and then rinsed with ultrapure water until neutral.

7. The method for preparing electronic grade tartaric acid solution according to claim 6, characterized in that: In step (4), the height-to-diameter ratio of the chromatography column resin is 16:1, and the diameter is 25 mm; the volume of the electronic grade sulfuric acid solution used for backwashing the chromatography column is three times the volume of the resin.

8. The method for preparing the electronic grade tartaric acid solution according to claim 1 or 7, characterized in that: In step (4), the temperature of the tartaric acid solution passing through the secondary resin is 10-30°C; the flow rate of the tartaric acid solution passing through the resin is 3-10 Bv / h.

9. The method for preparing electronic grade tartaric acid solution according to claim 8, characterized in that: In step (4), the resin is an electronic grade strongly acidic cation exchange resin, and the resin loading amount is 200 g.

10. The method for preparing the electronic grade tartaric acid solution according to claim 1 or 9, characterized in that: The filtering and drying steps are all carried out under the protection of 99.999% nitrogen; the ultrapure water is ultrapure water with metal ions <1ppt.

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