A method for preparing zirconium carbonate with high zirconium dioxide content

Abstract

A method for preparing zirconium carbonate with a high zirconium dioxide content comprises the following steps: (1) dissolving zirconium oxychloride in pure water to obtain a zirconium oxychloride solution; (2) 2‑ mol / ZrO2mol=0.6-0.8, adding anhydrous sodium sulfate to the zirconium oxychloride solution to react and generate zirconium sulfate; performing solid-liquid separation and washing the separated zirconium sulfate; (3) adding zirconium sulfate to pure water and dissolving it to obtain a zirconium sulfate solution; pressing CO3 2‑ mol / ZrO2mol=0.75-0.82, and a sodium carbonate solution is prepared to react and generate zirconium carbonate; solid-liquid separation and washing of the zirconium carbonate; (4) zirconium carbonate is added to pure water and dissolved to obtain a zirconium carbonate solution; concentrated nitric acid is added to the zirconium carbonate solution to adjust the acidity and remove sodium ions until the pH value of the zirconium carbonate solution is maintained at 3.2-4.2; solid-liquid separation and washing of the zirconium carbonate are performed to obtain the desired zirconium carbonate product. The method of the present invention can stably prepare a zirconium carbonate product with a high ZrO2 content and a high CO2 content, and the yield is high.

Description

Technical Field

[0001] The invention relates to the technical field of new material preparation technology, and in particular to a method for preparing zirconium carbonate with high zirconium dioxide content. Background Art

[0002] Zirconium carbonate molecular formula ZrOCO 3 . nH 2 O , also known as basic zirconium carbonate ZrO2CO2.nH2O, is an important zirconium compound. In the prior art, the liquid phase step-by-step precipitation synthesis method is widely used to prepare zirconium carbonate, which has the advantages of simple process control, relatively stable product quality, and good activity. The liquid phase step-by-step precipitation synthesis method uses zirconium oxychloride as a raw material, prepares it into an aqueous solution of a certain concentration, adds concentrated sulfuric acid or sodium sulfate to the solution, heats and hydrolyzes it to generate basic zirconium sulfate, and then adds sodium carbonate solution under certain conditions to convert it into a zirconium carbonate product.

[0003] In certain application areas (for example, when used as a raw material for CeO2-ZrO2 composite oxide, a carrier material for automobile exhaust three-way catalytic purifiers), users require zirconium carbonate to have a high zirconium dioxide (ZrO2) content, but commercially available zirconium carbonate is difficult to meet the demand. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing zirconium carbonate with high zirconium dioxide content, by which zirconium carbonate products with high ZrO2 content and high CO2 content can be stably prepared with high yield. The technical scheme adopted is as follows:

[0005] A method for preparing zirconium carbonate with a high zirconium dioxide content, characterized in that it comprises the following steps in sequence:

[0006] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:2.5-3.0; then, the materials in the reaction kettle are heated to 45-50° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0007] (2) According to SO4 2- mol / ZrO2mol=0.6-0.8, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 90-95°C while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0008] When the temperature of the material in the reaction kettle drops to 50-60°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with pure water at 45-55°C until the chloride content in the zirconium sulfate is less than 200ppm;

[0009] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 45-50° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 45-50° C.;

[0010] Then press CO3 2- mol / ZrO2mol=0.75-0.82, and then add the sodium carbonate solution to the zirconium sulfate solution. After the sodium carbonate solution is added, continue to stir for 20-30 minutes. During this process, sodium carbonate and zirconium sulfate undergo a replacement reaction to generate zirconium carbonate.

[0011] Then, the solid-liquid separation is performed by using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 45-55°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0012] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained, and stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution to adjust the acidity and remove sodium ions, until the pH value of the zirconium carbonate solution is maintained at 3.2-4.2; after the pH value of the zirconium carbonate solution remains stable, solid-liquid separation is performed using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 45-55° C. to obtain the desired zirconium carbonate product.

[0013] Preferably, in the above step (1), the weight ratio of zirconium oxychloride to pure water is 1:3.

[0014] Preferably, in the above step (2), according to SO4 2- Add anhydrous sodium sulfate to the zirconium oxychloride solution at a ratio of mol / ZrO2mol=0.7.

[0015] Preferably, the heating rate in step (2) is >5°C / min. More preferably, the heating rate in step (2) is 5-7°C / min.

[0016] Preferably, the weight percent concentration of the sodium carbonate solution in step (3) is 14-15%. More preferably, the weight percent concentration of the sodium carbonate solution in step (3) is 15%.

[0017] Preferably, in the above step (3), the flow rate of the sodium carbonate solution is controlled to be 450-500 ml / min by a metering pump.

[0018] Preferably, the weight percentage concentration of concentrated nitric acid in step (4) is 8.0-8.5%. More preferably, the weight percentage concentration of concentrated nitric acid in step (4) is 8.5%.

[0019] Preferably, in the above step (4), the flow rate of concentrated nitric acid is controlled by a metering pump to be 750-800 ml / min.

[0020] Preferably, in the above step (4), concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions until the pH value of the zirconium carbonate solution is maintained at 4.2.

[0021] The purpose of washing the zirconium carbonate in the above step (4) is to remove residual sulfate and chloride. The washing end point is usually when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm.

[0022] Preferably, in the above steps (1), (2), (3) and (4), the materials in the reaction kettle are heated by circulating a graphite heater.

[0023] In step (1) and step (2), the number of moles of ZrO2 is calculated based on the ZrO2 content of zirconium oxychloride.

[0024] The present invention is based on the traditional liquid phase fractionation method, through process optimization (such as controlling SO4 2- mol / ZrO2mol、CO3 2- mol / ZrO2mol and other process parameters), the high-quality zirconium carbonate prepared stably has a zirconium dioxide content of 45.0-49.0wt% (much higher than the standard level of first-class zirconium carbonate 38-42w / % (HG / T 3785-2014)), a carbon dioxide content of ≥7.0wt%, and a direct zirconium yield of ≥95%. In short, the present invention has the advantages of high zirconium dioxide content, high carbon dioxide content, and high direct zirconium yield.

[0025] In addition, the preparation method of the present invention has the great advantages of energy saving and consumption reduction, easy operation, and easy to realize industrialization. DETAILED DESCRIPTION

[0026] Example

[0027] In this embodiment, the preparation method of zirconium carbonate with high zirconium dioxide content comprises the following steps in sequence:

[0028] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:2.5; then, the materials in the reaction kettle are heated to 50° C. while stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0029] (2) According to SO4 2- mol / ZrO2mol=0.8, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 90°C (heating rate of 5°C / min) while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0030] When the temperature of the material in the reaction kettle drops to 50°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 45°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0031] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 45° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 45° C.;

[0032] Then press CO3 2- mol / ZrO2mol=0.75, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 14%), and add the sodium carbonate solution to the zirconium sulfate solution (use a metering pump to control the flow rate of the sodium carbonate solution to be 500ml / min), and continue to stir for 20min after the sodium carbonate solution is added. During this process, sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0033] Then, the solid-liquid separation is performed by using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 45°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0034] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.0%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 800 ml / min), until the pH value of the zirconium carbonate solution is maintained at 3.6; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 45° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0035] The zirconium carbonate product obtained in Example 1 has a zirconium dioxide content of 45.21 wt / %, a CO2 content of 7.5 wt / %; and a direct zirconium yield of 95.0%. Example

[0036] In this embodiment, the preparation method of zirconium carbonate with high zirconium dioxide content comprises the following steps in sequence:

[0037] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:2.8; then the materials in the reaction kettle are heated to 50° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0038] (2) According to SO4 2- mol / ZrO2mol=0.625, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 95°C (heating rate of 7°C / min) while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0039] When the temperature of the material in the reaction kettle drops to 60°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 55°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0040] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 50° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 50° C.;

[0041] Then press CO3 2- mol / ZrO2mol=0.8, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 15%), and add sodium carbonate solution to zirconium sulfate solution (use metering pump to control the flow rate of sodium carbonate solution to 450ml / min), continue to stir for 30min after adding sodium carbonate solution, during which sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0042] Then, the solid-liquid separation is performed by using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 55°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0043] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.5%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 750 ml / min), until the pH value of the zirconium carbonate solution is maintained at 4.0; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 55° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0044] The zirconium carbonate obtained in Example 2 has a zirconium dioxide content of 45.41 wt / %, a CO2 content of 7.2 wt / %, and a direct zirconium yield of 95.8%. Example

[0045] In this embodiment, the preparation method of zirconium carbonate with high zirconium dioxide content comprises the following steps in sequence:

[0046] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:3.0; then, the materials in the reaction kettle are heated to 48° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0047] (2) According to SO4 2- mol / ZrO2mol=0.7, anhydrous sodium sulfate is added to the zirconium oxychloride solution, and the materials in the reactor are heated to 92°C (heating rate is 6°C / min) while stirring, and then the heating is stopped and the temperature is naturally lowered. During this process, zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0048] When the temperature of the material in the reaction kettle drops to 55°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 50°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0049] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 48° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 48° C.;

[0050] Then press CO3 2-mol / ZrO2mol=0.82, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 14.5%), and add sodium carbonate solution to zirconium sulfate solution (use metering pump to control the flow rate of sodium carbonate solution to 480ml / min), continue to stir for 25min after adding sodium carbonate solution, during which sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0051] Then, a suction filtration device is used to separate the solid and the liquid, and the separated zirconium carbonate is washed with pure water at 50°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0052] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.2%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 780 ml / min), until the pH value of the zirconium carbonate solution is maintained at 4.2; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 50° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0053] The zirconium carbonate obtained in Example 3 has a zirconium dioxide content of 48.7 wt / %, a CO2 content of 7.0 wt / %, and a direct zirconium yield of 96.6%.

[0054] Comparative Example 1

[0055] In this comparative example, the preparation method of zirconium carbonate comprises the following steps in sequence:

[0056] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:3.0; then, the materials in the reaction kettle are heated to 48° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0057] (2) According to SO4 2- mol / ZrO2mol=0.6, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 92°C (heating rate of 6°C / min) while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0058] When the temperature of the material in the reaction kettle drops to 55°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 50°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0059] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 48° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 48° C.;

[0060] Then press CO3 2- mol / ZrO2mol=0.5, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 14.5%), and add sodium carbonate solution to zirconium sulfate solution (use metering pump to control the flow rate of sodium carbonate solution to 480ml / min), continue to stir for 25min after adding sodium carbonate solution, during which sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0061] Then, a suction filtration device is used to separate the solid and the liquid, and the separated zirconium carbonate is washed with pure water at 50°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0062] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.2%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 780 ml / min), until the pH value of the zirconium carbonate solution is maintained at 4.2; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 50° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0063] The zirconium carbonate obtained in Comparative Example 1 has a zirconium dioxide content of 36.97 wt / %, a CO2 content of 6.5 wt / %, and a direct zirconium yield of 86.5%.

[0064] Comparative Example 2

[0065] In this comparative example, the preparation method of zirconium carbonate comprises the following steps in sequence:

[0066] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:3.0; then, the materials in the reaction kettle are heated to 48° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0067] (2) According to SO4 2-mol / ZrO2mol=0.55, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 92°C (heating rate of 6°C / min) while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0068] When the temperature of the material in the reaction kettle drops to 55°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 50°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0069] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 48° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 48° C.;

[0070] Then press CO3 2- mol / ZrO2mol=0.8, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 14.5%), and add sodium carbonate solution to zirconium sulfate solution (use metering pump to control the flow rate of sodium carbonate solution to 480ml / min), continue to stir for 25min after adding sodium carbonate solution, during which sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0071] Then, a suction filtration device is used to separate the solid and liquid, and the separated zirconium carbonate is washed with pure water at 50°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0072] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.2%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 780 ml / min), until the pH value of the zirconium carbonate solution is maintained at 5.0; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 50° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0073] The zirconium carbonate obtained in Comparative Example 2 had a zirconium dioxide content of 37.32 wt / %, a CO2 content of 6.6 wt / %, and a direct zirconium yield of 88.6%.

[0074] Comparative Example 3

[0075] In this comparative example, the preparation method of zirconium carbonate comprises the following steps in sequence:

[0076] (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:3.0; then, the materials in the reaction kettle are heated to 48° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution;

[0077] (2) According to SO4 2- mol / ZrO2mol=0.625, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 92°C (heating rate of 6°C / min) while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate;

[0078] When the temperature of the material in the reaction kettle drops to 55°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with 50°C pure water until the chloride content in the zirconium sulfate is less than 200ppm;

[0079] (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 48° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 48° C.;

[0080] Then press CO3 2- mol / ZrO2mol=0.90, prepare sodium carbonate solution (weight percentage concentration of sodium carbonate solution is 14.5%), and add sodium carbonate solution to zirconium sulfate solution (use metering pump to control the flow rate of sodium carbonate solution to 480ml / min), continue to stir for 25min after adding sodium carbonate solution, during which sodium carbonate and zirconium sulfate undergo replacement reaction to generate zirconium carbonate;

[0081] Then, a suction filtration device is used to separate the solid and liquid, and the separated zirconium carbonate is washed with pure water at 50°C until the sulfate content in the zirconium carbonate is detected to be zero;

[0082] (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained and the stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution for acid adjustment to remove sodium ions (the weight percentage concentration of the concentrated nitric acid is 8.2%; the flow rate of the concentrated nitric acid is controlled by a metering pump to be 780 ml / min), until the pH value of the zirconium carbonate solution is maintained at 4.2; after the pH value of the zirconium carbonate solution remains stable, a suction filtration device is used for solid-liquid separation, and the separated zirconium carbonate is washed with pure water at 50° C. (the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm), to obtain the desired zirconium carbonate product.

[0083] The zirconium carbonate obtained in Comparative Example 3 has a zirconium dioxide content of 39.62 wt / %, a CO2 content of 6.8 wt / %, and a direct zirconium yield of 90.5%.

[0084] The test methods for the zirconium dioxide content and CO2 content of the zirconium carbonate products in the above Examples 1-3 and Comparative Examples 1-3 are as follows:

[0085] 1. Determination method of zirconium dioxide content

[0086] The method specified in Section 5.3 of the Industry Standard of the People’s Republic of China HG_T3785-2014 “Industrial Zirconium Carbonate” was used.

[0087] 2. Method for determining CO2 content

[0088] 1. Test conditions: condensation reflux device;

[0089] 2. Add 20g of sulfuric acid with a volume ratio concentration of 33.33% and 2g of zirconium carbonate product, and heat (65-85℃) for reaction (reaction time 60min);

[0090] 3. Cool down after the reaction and test the loss;

[0091] The loss is the total mass before the reaction minus the total mass after the reaction minus the mass of the water droplets collected at the bottom of the condenser, that is:

[0092] Loss = total mass before reaction - total mass after reaction - mass of water droplets collected at the bottom of the condenser;

[0093] Among them, the total mass before the reaction is the sum of the mass of sulfuric acid and zirconium carbonate products;

[0094] 4. The measured carbon dioxide content is: carbon dioxide content = loss amount ÷ zirconium carbonate product mass × 100%.

[0095] Note: During the test, a precision electronic balance is required to measure the weight (accurate to 4 decimal places); sulfuric acid, zirconium carbonate product, total mass after reaction, and mass of water droplets collected at the bottom of the condenser are all based on the actual weighing values ​​for calculating the loss. For example, if the amount of sulfuric acid is 20g and the actual weighing value on the precision electronic balance is 20.8826g when taking the amount, then 20.8826g is used as the standard for calculating the loss; if the sample of zirconium carbonate product is 2g and the actual weighing value on the precision electronic balance is 2.1839g when taking the amount, then 2.1839g is used as the standard for calculating the loss.

[0096] The data of Examples 1-3 and Comparative Examples 1-3 are summarized in Table 1:

[0097] Table 1

[0098]

[0099] From the experimental data of the above embodiments and comparative examples, it can be seen that by optimizing SO4 2- mol / ZrO2mol、CO3 2- mol / ZrO2mol, pH value of zirconium carbonate solution and other process parameters can prepare high-quality zirconium carbonate, increase the zirconium dioxide content and carbon dioxide content of the zirconium carbonate product, and increase the direct yield of zirconium.

Claims

1. A method for preparing zirconium carbonate with a high zirconium dioxide content, characterized in that The steps are as follows: (1) In a reaction kettle, zirconium oxychloride is added to pure water, and the weight ratio of zirconium oxychloride to pure water is 1:2.5-3.0; then, the materials in the reaction kettle are heated to 45-50° C. under stirring to dissolve the zirconium oxychloride in the pure water to obtain a zirconium oxychloride solution; (2) According to SO4 2- mol / ZrO2mol=0.6-0.8, add anhydrous sodium sulfate to the zirconium oxychloride solution, heat the materials in the reactor to 90-95°C while stirring, then stop heating and cool naturally, during which zirconium oxychloride and sodium sulfate react to form zirconium sulfate; When the temperature of the material in the reaction kettle drops to 50-60°C, use a suction filtration device to separate the solid and liquid, and wash the separated zirconium sulfate with pure water at 45-55°C until the chloride content in the zirconium sulfate is less than 200ppm; (3) In a reaction kettle, the zirconium sulfate obtained in step (2) is added to pure water, and the materials in the reaction kettle are heated to 45-50° C. while stirring to dissolve the zirconium sulfate in the pure water to obtain a zirconium sulfate solution, and the temperature of the zirconium sulfate solution is maintained at 45-50° C.; Then press CO3 2- mol / ZrO2mol=0.75-0.82, and then add the sodium carbonate solution to the zirconium sulfate solution. After the sodium carbonate solution is added, continue to stir for 20-30 minutes. During this process, sodium carbonate and zirconium sulfate undergo a replacement reaction to generate zirconium carbonate. Then, the solid-liquid separation is performed by using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 45-55°C until the sulfate content in the zirconium carbonate is detected to be zero; (4) In a reaction kettle, the zirconium carbonate obtained in step (3) is added to pure water, stirred to dissolve the zirconium carbonate, and a zirconium carbonate solution is obtained, and stirring is continued; then concentrated nitric acid is added to the zirconium carbonate solution to adjust the acidity and remove sodium ions, until the pH value of the zirconium carbonate solution is maintained at 3.2-4.2; after the pH value of the zirconium carbonate solution remains stable, solid-liquid separation is performed using a suction filtration device, and the separated zirconium carbonate is washed with pure water at 45-55° C. to obtain the desired zirconium carbonate product.

2. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (2), the heating rate is >5°C / min.

3. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: The heating rate in step (2) is 5-7°C / min.

4. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: The weight percentage concentration of the sodium carbonate solution in step (3) is 14-15%.

5. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (3), the flow rate of the sodium carbonate solution is controlled to 450-500 ml / min by a metering pump.

6. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: The weight percentage concentration of concentrated nitric acid in step (4) is 8.0-8.5%.

7. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (4), the flow rate of concentrated nitric acid is controlled to 750-800 ml / min by a metering pump.

8. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (4), the zirconium carbonate is washed, and the washing end point is when the sulfate content in the washing waste liquid is detected to be less than 20 ppm and the chloride content is less than 20 ppm.

9. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (1), step (2), step (3) and step (4), the materials in the reaction kettle are heated by circulating the graphite heater.

10. The method for preparing zirconium carbonate with high zirconium dioxide content according to claim 1, characterized in that: In step (1), the weight ratio of zirconium oxychloride to pure water is 1:3; In step (2), press SO4 2- mol / ZrO2mol=0.7, add anhydrous sodium sulfate to the zirconium oxychloride solution; In step (4), concentrated nitric acid is added to the zirconium carbonate solution to adjust the acidity and remove sodium ions until the pH value of the zirconium carbonate solution is maintained at 4.2.

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