Preparation method of co-producing chromium trichloride hexahydrate and ferric chloride hexahydrate
By adopting the co-production process of chromium trioxide, iron powder and hydrochloric acid, the preparation process of chromium trichloride hexahydrate and ferric chloride hexahydrate is simplified, and the problems of many raw materials, high costs and environmental protection in traditional processes are solved, so as to achieve the goal of achieving many kinds of raw materials, high costs and environmental protection in traditional processes. It has efficient and environmentally friendly preparation effect.
Patent Information
- Application Number
- CN202211582726.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-09
- Publication Date
- 2024-12-31
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the preparation process of traditional ferric chloride hexahydrate and chromium chloride hexahydrate, there are problems such as many types of raw materials, high costs, complex reaction steps, and unenvironmental protection, resulting in low preparation efficiency and serious pollution.
Using chromium trioxide, iron essence powder and hydrochloric acid as raw materials, the preparation of co-production of chromium trichloride hexahydr and ferric chloride hexahydr is achieved through dissolution, reaction, filtration, concentration and cleaning, and the process flow is simplified. , reduces costs and improves yield and purity by controlling temperature and concentration conditions.
The efficient preparation of chromium trichloride hexahydrate and ferric chloride hexahydrate has been achieved, the process steps are simplified, production costs are reduced, and the process is safe and environmentally friendly, and it meets the requirements of sustainable development.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate, and in particular to a method for co-producing chromium trichloride hexahydrate and ferric chloride hexahydrate. Background Art
[0002] Chromium trichloride hexahydrate is used in the chemical industry to manufacture chromium fluoride and other chromium salts; in organic synthesis, it is used to manufacture chromium-containing catalysts and catalysts for olefin polymerization; in the pigment industry, it is used to manufacture various chromium-containing pigments; in the printing and dyeing industry, it is used as a mordant for textile printing and dyeing and as a tanning intermediate; in the ceramic industry, it is used in ceramics and glazes; in the electroplating industry, trivalent chromium is used in plating solutions.
[0003] Ferric chloride hexahydrate is mainly used for metal etching and sewage treatment. The etching includes etching of copper, stainless steel, aluminum and other materials. It has the advantages of good effect and low price for the treatment of low oil content raw water, but it brings the disadvantage of yellowing water color. It is also used for printing and dyeing roller engraving, electronic industry circuit board and fluorescent digital tube production. It is used in the construction industry to prepare concrete to enhance the strength, corrosion resistance and waterproofness of concrete. It can also be prepared with ferrous chloride, calcium chloride, aluminum chloride, aluminum sulfate, hydrochloric acid, etc. to make concrete waterproofing agent. It is used in the inorganic industry to make other iron salts and inks. It is used as an oxidant in the dye industry for dyeing with indicin dye. It is used as a mordant in the printing and dyeing industry. It is used as a chlorination extractor in the metallurgical industry to extract gold and silver. It is used as a catalyst, oxidant and chlorinating agent in the organic industry. It is used as a hot colorant for glassware in the glass industry. It is used as a coagulant for recovering glycerol from soap waste liquid in the soap making industry.
[0004] With the continuous consumption of fossil energy and the increasingly serious environmental pollution, renewable energy such as solar energy and wind energy are widely used. However, the instability and discontinuity of these renewable energy power generation restricts their further development. In order to improve the power quality and reliability of renewable energy power generation, large-scale energy storage technology is one of the effective solutions. High-purity chromium trichloride hexahydrate and high-purity ferric chloride hexahydrate are mainly used as electrolytes for energy storage iron-chromium liquid flow batteries.
[0005] In the traditional preparation of ferric chloride hexahydrate, scrap iron containing a large amount of iron oxide is generally taken, dissolved in hydrochloric acid, and then an excess of chlorine (cheap but polluting) and an excess of hydrogen peroxide (expensive but non-polluting) are introduced, and the liquid after the reaction is filtered, burned, and cooled to prepare ferric chloride hexahydrate. The specific reaction equation is as follows: Fe2O3+6HCl=2FeCl3+3H2O; Fe+2HCl=FeCl2+H2↑; 2FeCl2+Cl2=2FeCl3; 6FeCl2+H2O2=4FeCl3+2Fe(OH)3↓. Although chlorine is cheap and easy to obtain, it is seriously polluting and toxic; therefore, using it to prepare ferric chloride is not scientific and does not belong to sustainable development.
[0006] In the traditional preparation of chromium trichloride hexahydrate, sodium chromate, methanol and hydrochloric acid are generally used for reaction. After neutralization, chromium hydroxide is obtained. The chromium hydroxide is then reacted with hydrochloric acid to obtain a chromium trichloride hexahydrate aqueous solution. After evaporation concentration, crystallization and centrifugal drying, chromium trichloride hexahydrate is obtained. The specific reaction equation is as follows: 2Na2CrO4+CH3OH+4HCl=4NaCl+2Cr(OH) 3↓ +CO2+H2O; Cr(OH)3+3HCl+H2O=CrCl3·6H2O; however, the preparation steps are complicated and the cost is high.
[0007] Therefore, in the traditional preparation of ferric chloride hexahydrate and chromium chloride hexahydrate, there are disadvantages such as a large variety of raw materials, high cost, multiple reaction processes, and complex preparation, and they cannot be produced simultaneously with high efficiency. Summary of the invention
[0008] The technical problem to be solved by the present invention is to provide a preparation method for the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate, and chromium trichloride hexahydrate and ferric chloride hexahydrate are prepared simultaneously and efficiently, with simple steps, time-saving, labor-saving, green and environmentally friendly, and cost-saving.
[0009] The preparation method of the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate of the present invention comprises the following steps:
[0010] (1) dissolving chromium trioxide in water to obtain a chromium trioxide solution;
[0011] (2) then adding iron ore concentrate and hydrochloric acid, reacting at a temperature of 30°C to 35°C, and continuing the reaction for 60min to 90min after the addition is completed;
[0012] (3) cooling the reaction solution to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; the obtained filtrate is further heated to 45° C. to 50° C., concentrated to a specific gravity of 1.25 g / mL to 1.27 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, stopping the concentration, cooling to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a reaction mother liquor, and combining the chromium trichloride hexahydrate crystals;
[0013] (4) heating the reaction mother liquor obtained in step (3) to 45° C. to 50° C., concentrating it to a specific gravity of 1.28 g / mL to 1.30 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, stopping the concentration, cooling it to below 0° C., and filtering to obtain ferric chloride hexahydrate crystals;
[0014] (5) The chromium trichloride hexahydrate obtained in step (3) is crystallized, washed with water, and dried to obtain a chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystallized in step (4) is washed with hydrochloric acid to obtain a ferric chloride hexahydrate product.
[0015] The molar ratio of chromium trioxide, iron ore concentrate and hydrochloric acid is 1:1:6 to 1:1.05:7.2.
[0016] The mass of water added in step (1) is 65% to 75% of the mass of chromium trioxide.
[0017] The CrO3 content in the chromium trioxide in step (1) is 96.5% to 99.8%.
[0018] The addition rate of the iron ore concentrate in step (2) is 1 g / min to 2.5 g / min, and the addition rate of the hydrochloric acid is 6 g / min to 15 g / min.
[0019] The Fe content in the iron ore concentrate of step (2) is 98% to 99.9%.
[0020] The concentration of hydrochloric acid in step (2) is 10 mol / L to 12 mol / L.
[0021] The water temperature for washing the chromium chloride hexahydrate crystals in step (5) is 0°C to 5°C, and the washing is repeated multiple times.
[0022] The drying temperature in step (5) is 40°C to 45°C.
[0023] In step (5), the hydrochloric acid temperature for washing the ferric chloride hexahydrate crystals is 0°C to 5°C, the mass concentration is 3% to 6%, and the washing is performed multiple times.
[0024] Specifically, the method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate comprises the following steps:
[0025] (1) adding deionized water having a CrO3 content of 96.5% to 99.8% and a mass ratio of 65% to 75% of chromium trioxide into a reactor, and adding chromium trioxide under stirring to obtain a chromium trioxide aqueous solution;
[0026] (2) then adding iron ore concentrate having an Fe content of 98% to 99.9% at a rate of 1 g / min to 2.5 g / min and adding 10 mol / L to 12 mol / L hydrochloric acid at a rate of 6 g / min to 15 g / min, reacting at a temperature of 30° C. to 35° C., and continuing the reaction for 60 min to 90 min after the addition is completed; the molar ratio of the above chromium trioxide, iron ore concentrate and hydrochloric acid is 1:1:6 to 1:1.05:7.2;
[0027] (3) cooling the reaction liquid to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; the obtained filtrate is further heated to 45° C. to 50° C., concentrated to a specific gravity of 1.25 g / mL to 1.27 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, the concentration is stopped, the temperature is lowered to below 0° C., and the chromium trichloride hexahydrate crystals and the reaction mother liquor are filtered to obtain the chromium trichloride hexahydrate crystals and the reaction mother liquor, and the chromium trichloride hexahydrate crystals are combined; after four consecutive concentration and crystallization and separation, the chromium trichloride hexahydrate content in the reaction liquid mother liquor can be reduced to below 0.01%;
[0028] (4) heating the reaction mother liquor obtained in step (3) to 45° C. to 50° C., concentrating it to a specific gravity of 1.28 g / mL to 1.30 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, stopping the concentration, cooling it to below 0° C., and filtering to obtain ferric chloride hexahydrate crystals;
[0029] (5) The chromium trichloride hexahydrate crystals obtained in step (3) are rinsed three times with clean water at 0°C to 5°C, and dried under hot air at 40°C to 45°C to obtain a chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystals obtained in step (4) are rinsed three times with hydrochloric acid at a mass concentration of 3% to 6% at 0°C to 5°C to obtain a ferric chloride hexahydrate product.
[0030] The preparation method of the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate of the present invention adopts chromium trioxide, refined iron powder and hydrochloric acid as raw materials, and simultaneously produces ferric chloride hexahydrate and chromium trichloride hexahydrate. After the reaction is completed, according to the different crystallization temperatures of the products, chromium trichloride hexahydrate and ferric chloride hexahydrate are obtained by concentration and crystallization, filtration and drying. The reaction formula of the present invention is as follows:
[0031] CrO3+H2O=H2CrO4
[0032] H2CrO4+Fe+6HCl=CrCl3+FeCl3+4H2O.
[0033] Compared with the prior art, the present invention has the following beneficial effects:
[0034] (1) The preparation method of the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate of the present invention has the advantages of easy raw materials, simple preparation method, convenient operation and reduced production cost;
[0035] (2) The preparation method of the present invention uses environmentally friendly raw materials, is safe, and is a green reaction for sustainable development;
[0036] (3) The preparation method of the present invention is used to prepare chromium trichloride hexahydrate and ferric chloride hexahydrate at the same time, with high efficiency and high yield. DETAILED DESCRIPTION
[0037] The present invention is further described below in conjunction with specific examples. The iron concentrate and chromium trioxide described below are both normal commercial products, the Fe content in the iron concentrate is 98% to 99.9%, and the CrO3 content in the chromium trioxide is 96.5% to 99.8%, both of which meet the requirements. Other reagents are also normal commercial products.
[0038] Example 1
[0039] The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate comprises the following steps:
[0040] (1) adding 65 g of deionized water into a reactor, and adding 100 g of chromium trioxide under stirring to obtain a chromium trioxide aqueous solution;
[0041] (2) Then, 56 g of iron ore concentrate was added at a rate of 1 g / min and 600 mL of 10 mol / L hydrochloric acid was added at a rate of 6 g / min, and the mixture was reacted at 30° C. After the addition was completed, the reaction was continued for 90 min;
[0042] (3) cooling the reaction solution to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; the obtained filtrate is further heated to 45° C., concentrated to a specific gravity of 1.25 g / mL under a vacuum degree of -0.08 MPa, the concentration is stopped, the temperature is lowered to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a reaction mother liquor, and the chromium trichloride hexahydrate crystals are combined;
[0043] (4) heating the reaction mother liquor obtained in step (3) to 45° C., concentrating it to a specific gravity of 1.28 g / mL under a vacuum degree of −0.08 MPa, stopping the concentration, cooling it to below 0° C., and filtering to obtain ferric chloride hexahydrate crystals;
[0044] (5) The chromium trichloride hexahydrate crystals obtained in step (3) were rinsed three times with clean water at 5° C. and dried under hot air at 45° C. to obtain 259.5 g of chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystals obtained in step (4) were rinsed three times with 5% hydrochloric acid at 5° C. to obtain 268.3 g of ferric chloride hexahydrate product.
[0045] The yield of chromium chloride hexahydrate was calculated to be 97.4%, and the purity was tested to be 99.4%; the yield of ferric chloride hexahydrate was 99.2%, and the purity was 99.1%.
[0046] Example 2
[0047] The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate comprises the following steps:
[0048] (1) adding 35 g of deionized water into a reactor, and adding 50 g of chromium trioxide under stirring to obtain a chromium trioxide aqueous solution;
[0049] (2) Then, 28 g of iron ore concentrate was added at a rate of 2.5 g / min and 292 mL of 12 mol / L hydrochloric acid was added at a rate of 15 g / min, and the mixture was reacted at 35° C. After the addition was completed, the reaction was continued for 60 min;
[0050] (3) cooling the reaction solution to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; the obtained filtrate is further heated to 50° C., concentrated to a specific gravity of 1.27 g / mL under a vacuum degree of -0.09 MPa, the concentration is stopped, the temperature is lowered to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a reaction mother liquor, and the chromium trichloride hexahydrate crystals are combined;
[0051] (4) heating the reaction mother liquor obtained in step (3) to 50° C., concentrating it to a specific gravity of 1.30 g / mL under a vacuum degree of -0.09 MPa, stopping the concentration, cooling it to below 0° C., and filtering to obtain ferric chloride hexahydrate crystals;
[0052] (5) The chromium trichloride hexahydrate crystals obtained in step (3) were rinsed three times with clean water at 0° C. and dried under hot air at 40° C. to obtain 131.2 g of chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystals obtained in step (4) were rinsed three times with hydrochloric acid with a mass concentration of 6% at 0° C. to obtain 133.8 g of ferric chloride hexahydrate product.
[0053] The yield of chromium chloride hexahydrate was calculated to be 98.5%, and the purity was tested to be 99.5%; the yield of ferric chloride hexahydrate was 98.9%, and the purity was 99.0%.
[0054] Example 3
[0055] The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate comprises the following steps:
[0056] (1) adding 105 g of deionized water into a reactor, and adding 150 g of chromium trioxide under stirring to obtain a chromium trioxide aqueous solution;
[0057] (2) Then, 88.2 g of iron ore concentrate was added at a rate of 2 g / min and 1080 mL of 10 mol / L hydrochloric acid was added at a rate of 9 g / min, and the mixture was reacted at 35° C. After the addition was completed, the reaction was continued for 70 min;
[0058] (3) cooling the reaction solution to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; the obtained filtrate is further heated to 45° C., concentrated to a specific gravity of 1.26 g / mL under a vacuum degree of -0.08 MPa, the concentration is stopped, the temperature is lowered to below 0° C., filtering to obtain chromium trichloride hexahydrate crystals and a reaction mother liquor, and the chromium trichloride hexahydrate crystals are combined;
[0059] (4) heating the reaction mother liquor obtained in step (3) to 45° C., concentrating it to a specific gravity of 1.29 g / mL under a vacuum degree of −0.08 MPa, stopping the concentration, cooling it to below 0° C., and filtering to obtain ferric chloride hexahydrate crystals;
[0060] (5) The chromium trichloride hexahydrate crystals obtained in step (3) were rinsed three times with clean water at 3° C. and dried under hot air at 45° C. to obtain 394.5 g of chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystals obtained in step (4) were rinsed three times with 3% hydrochloric acid at 3° C. to obtain 400.8 g of ferric chloride hexahydrate product.
[0061] The yield of chromium chloride hexahydrate was calculated to be 98.7%, and the purity was tested to be 99.2%; the yield of ferric chloride hexahydrate was 98.8%, and the purity was 98.9%.
[0062] Of course, the above contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the embodiments of the present invention. The present invention is not limited to the above examples, and equal changes and improvements made by ordinary technicians in the technical field within the essential scope of the present invention should all fall within the scope of the patent coverage of the present invention.
Claims
1. A method for preparing chromium trichloride hexahydrate and ferric chloride hexahydrate by co-production, characterized in that: The following steps are involved: (1) dissolving chromium trioxide in water to obtain a chromium trioxide solution; (2) Then, add iron ore concentrate and hydrochloric acid, react at a temperature of 30°C to 35°C, and continue to react for 60min to 90min after the addition is completed; the addition rate of iron ore concentrate is 1g / min to 2.5g / min, and the addition rate of hydrochloric acid is 6g / min to 15g / min; the molar ratio of chromium trioxide, iron ore concentrate and hydrochloric acid is 1:1:6 to 1:1.05:7.2; (3) Cooling the reaction solution to below 0°C, filtering to obtain chromium trichloride hexahydrate crystals and a filtrate; heating the obtained filtrate to 45°C to 50°C, concentrating to a specific gravity of 1.25 g / mL to 1.27 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, stopping the concentration, cooling to below 0°C, filtering to obtain chromium trichloride hexahydrate crystals and a reaction mother liquor, and combining the chromium trichloride hexahydrate crystals; (4) heating the reaction mother liquor obtained in step (3) to 45°C to 50°C, concentrating it to a specific gravity of 1.28 g / mL to 1.30 g / mL under a vacuum degree of -0.08 MPa to -0.09 MPa, stopping the concentration, cooling it to below 0°C, and filtering to obtain ferric chloride hexahydrate crystals; (5) The chromium trichloride hexahydrate crystals obtained in step (3) are washed with water and dried to obtain a chromium trichloride hexahydrate product; the ferric chloride hexahydrate crystals obtained in step (4) are washed multiple times with hydrochloric acid having a mass concentration of 3% to 6% at 0°C to 5°C to obtain a ferric chloride hexahydrate product; The water temperature for washing the chromium chloride hexahydrate crystals in step (5) is 0°C to 5°C, and the washing is repeated multiple times.
2. The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate according to claim 1, characterized in that: The mass of water added in step (1) is 65% to 75% of the mass of chromium trioxide.
3. The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate according to claim 1, characterized in that: The CrO3 content in the chromium trioxide in step (1) is 96.5%~99.8%.
4. The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate according to claim 1, characterized in that: The Fe content in the iron ore concentrate of step (2) is 98% to 99.9%.
5. The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate according to claim 1, characterized in that: The concentration of hydrochloric acid in step (2) is 10 mol / L to 12 mol / L.
6. The method for preparing the co-production of chromium trichloride hexahydrate and ferric chloride hexahydrate according to claim 1, characterized in that: The drying temperature in step (5) is 40°C to 45°C.