A production and purification process for food-grade hydrated chromium trichloride

Abstract

The present invention discloses a production and purification process for food-grade hydrated chromium trichloride, comprising: S1, cleaning a reactor, adding chromium chloride and pure water into the reactor and introducing protective gas, heating to dissolve, and insulating the reaction; S2, adding an antidote and hydrochloric acid during the insulating reaction process to carry out a detoxification reaction, and removing the antidote after the reaction; S3, filtering the reaction material, and collecting the filtrate for crystallization; S4, centrifuging after crystallization; S5, low-temperature vacuum drying to obtain food-grade hydrated chromium trichloride. The process of the present invention mainly obtains food-grade chromium trichloride hexahydrate through processes such as dissolution, inert gas protection detoxification, charge reduction filter bag detoxification filtration, recrystallization, centrifugation, and low-temperature rotary vacuum drying, thereby solving the problems of unstable quality, foreign matter impurities, elemental impurities, uneven particle size distribution, inconsistent product appearance color, and the possible presence of highly toxic hexavalent chromium in the current industrialized production of health products, food and drug additives.

Description

Technical Field

[0001] The invention relates to the technical field of production and purification technology of food mineral additives, and in particular to a production and purification technology of food-grade hydrated chromium trichloride. Background Art

[0002] Chromium (Cr) is an essential trace element for humans and mammals. Trivalent chromium influences the metabolism of lipids, carbohydrates, proteins, and nucleic acids through its synergistic effects on the glucose tolerance factor (GTF) and by enhancing insulin sensitivity. Trivalent chromium preparations have been widely used in human health supplements, medicines, and foods. Since the 1990s, the role of chromium trichloride in animal nutrition has garnered increasing attention. Special organic complexes of chromium can penetrate cell membranes and directly act on cellular tissues, enhancing insulin activity and improving glucose metabolism. These compounds are permitted by health authorities for inclusion in health foods. Numerous experimental studies have demonstrated that chromium promotes animal growth, increases milk production in dairy cows, increases milk fat, lactose, and total solids, and reduces the feed-to-milk ratio. Adding organic chromium additives to animal feeds, such as aquaculture feed and pig feed, can significantly promote growth and enhance feed efficacy.

[0003] Conventional industrial production of chromium chloride hexahydrate is mainly produced through processes such as dissolution, recrystallization, and drying. Because the product still contains a large amount of elemental impurities, mechanical impurities, and some highly toxic hexavalent chromium, the industrially produced chromium trichloride hexahydrate has defects such as short shelf life, easy hardening, unstable quality, the presence of foreign impurities and elements, inconsistent product color, and uneven particle size distribution. As a result, when used in health care products or food and medicines, drastic fluctuations in physical and chemical phenomena occur, causing unstable quality of health care products or food and medicines, and even toxicity. Summary of the Invention

[0004] The present invention aims to provide a stable and reliable production and purification process for food-grade chromium trichloride hydrate, which addresses the defects of currently industrially produced chromium trichloride hexahydrate, such as short shelf life, easy hardening, unstable quality, presence of foreign matter, impurities and elements, inconsistent product color, and uneven particle size distribution. The process proposed by the present invention solves the problems of unstable quality, presence of foreign matter, impurities, elemental impurities, uneven particle size distribution, inconsistent product appearance color, and possible presence of highly toxic hexavalent chromium in chromium trichloride hexahydrate, which are health products and food and drug additives.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0007] S1, cleaning the reactor, then adding chromium chloride and pure water into the reactor and introducing protective gas, heating to dissolve, and keeping the temperature to react;

[0008] S2, adding an antidote and hydrochloric acid during the insulation reaction to carry out a detoxification reaction, and removing the antidote after the reaction;

[0009] S3, filtering the reaction mass, and collecting the filtrate for crystallization;

[0010] S4, centrifugation after crystallization;

[0011] S5. Low-temperature vacuum drying to obtain food-grade hydrated chromium trichloride.

[0012] Specifically, the production and purification process for food-grade chromium trichloride hexahydrate provided by the present invention solves the problems faced by conventional industrial production of chromium trichloride hexahydrate through processes such as dissolution, detoxification under inert gas protection, detoxification filtration using a charge reduction filter bag, recrystallization, centrifugation, and low-temperature rotary vacuum drying.

[0013] The process of the present invention needs to be dust-free, and all tools and equipment must be confirmed to be free of wear and tear before and after use.

[0014] Furthermore, a production and purification process for food-grade hydrated chromium trichloride includes the following steps: step S1, cleaning a reactor, then adding chromium chloride and pure water into the reactor and introducing a protective gas, heating the reactor to 75-95° C. for dissolution, and then keeping the temperature to react for 2-8 hours; wherein the mass ratio of the chromium chloride to the pure water is 1:(0.15-0.45).

[0015] Furthermore, a production and purification process for food-grade hydrated chromium trichloride: step S1, the mass ratio of the chromium chloride to the pure water is 1: (0.15-0.3); the temperature is raised to 85-95° C. for dissolution, and then the temperature is kept for reaction for 2-4 hours.

[0016] Furthermore, a production and purification process for food-grade hydrated chromium trichloride: In step S1, the process of cleaning the reactor is: cleaning the reactor 3-5 times with 1-10wt% hydrochloric acid solution and deionized water in sequence.

[0017] Furthermore, a production and purification process for food-grade hydrated chromium trichloride is provided: in step S1, the chromium chloride is analytically pure, chemically pure, or premium pure; the pure water is grade II pure water; and the protective gas is nitrogen. Preferably, the raw material chromium chloride is chemically pure or premium pure.

[0018] Furthermore, a production and purification process for food-grade hydrated chromium trichloride is provided: Step S2, adding an antidote and hydrochloric acid during the heat-insulating reaction process, conducting the detoxification reaction for 1-3 hours, and then introducing excess oxygen to eliminate the antidote; wherein: the antidote is chromium dichloride; the mass ratio of the antidote to the chromium chloride is 1:(1500-10000); and the mass-to-volume ratio of the antidote to the hydrochloric acid is 0.03-0.1 g / mL. If hexavalent chromium is not detected in the raw chromium chloride, the antidote need not be added.

[0019] The detoxification reaction for eliminating hexavalent chromium is preferably carried out by keeping the temperature for 1-3 hours. After the detoxification reaction is completed, excess oxygen is introduced to oxidize the divalent chromium in the detoxifier into trivalent chromium.

[0020] The detoxification principle of the present invention is embodied by the following two groups of reaction formulas:

[0021] (1) 3CrCl2+CrCl6=4CrCl3;

[0022] (2)4CrCl2+O2+4HCl=4CrCl3+2H20.

[0023] Furthermore, a production and purification process for food-grade hydrated chromium trichloride: Step S3, filtering the reaction material 2-5 times with a charged filter bag at 70-80° C., and collecting the filtrate into a crystallization kettle and cooling it to 25-45° C. for crystallization.

[0024] Furthermore, a production and purification process for food-grade hydrated chromium trichloride: the pore size of the filter bag in step S3 is 250-400 mesh.

[0025] Preferably, the filter bag material selected in the present invention is a high temperature resistant and strong acid resistant material. After charging, the filter bag has an electric charge detoxification and can be used to reduce hexavalent chromium.

[0026] Furthermore, a production and purification process for food-grade hydrated chromium trichloride is provided: Step S4: after crystallization, while the viscous state is still present, transfer the hydrated chromium trichloride to an acid-resistant centrifuge and centrifuge at 30-100 Hz for 20-40 minutes. Specifically, the acid-resistant centrifuge is a centrifuge with inner and outer walls sprayed with tetrafluoroethylene or acid-resistant material.

[0027] Furthermore, a production and purification process for food-grade hydrated chromium trichloride is provided: Step S5, low-temperature vacuum drying to obtain food-grade hydrated chromium trichloride; wherein: the vacuum drying temperature is 55-65° C., the vacuum pressure is -0.1 MPa, and the drying time is 30-50 hours.

[0028] The beneficial effects achieved by the present invention are:

[0029] (1) The present invention provides a stable and reliable production and purification process for food-grade hydrated chromium trichloride. The process of the present invention mainly obtains high-quality food-grade mineral additive hexahydrate chromium trichloride through processes such as dissolution, inert gas protection detoxification, charge reduction filter bag detoxification filtration, recrystallization, centrifugation, and low-temperature rotary vacuum drying. It solves the problems of unstable quality, presence of foreign matter impurities, elemental impurities, uneven particle size distribution, inconsistent product appearance color, and possible presence of highly toxic hexavalent chromium in the current industrialized production of health products and food and drug additives.

[0030] (2) The whole process of the present invention is simple and easy to operate. The system process solves the problem of unstable quality in conventional production processes, avoids the appearance of impurities, maintains the uniform particle size distribution of chromium chloride hexahydrate crystals, and is non-agglomerated, making it easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 The present invention provides a flow chart of a production and purification process of food-grade hydrated chromium trichloride. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0036] S1. The reactor was cleaned three times with a 2 wt% hydrochloric acid solution and deionized water, and then 12 kg of secondary pure water and 50 kg of chemically pure chromium trichloride (wherein the hexavalent chromium content was approximately 0.001%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.24. Then, protective nitrogen was introduced, the temperature was raised to 90°C for dissolution, and the reaction was kept at this temperature for 4 hours;

[0037] S2, add 5.0g of antidote (chromium dichloride) and 50ml of hydrochloric acid during the insulation reaction, carry out detoxification reaction for 1 hour, and pass excess oxygen into the reaction after the reaction to eliminate the antidote;

[0038] S3, cooling to 70 ° C, then filtering the reaction mass three times with a 300-mesh charged filter bag, and collecting the filtrate into a crystallization kettle and cooling to 25 ° C for crystallization;

[0039] S4. After crystallization, transfer the viscous liquid into an acid-resistant centrifuge and centrifuge at 35 Hz for 20 minutes;

[0040] S5. Finally, the mixture was dried under a rotary vacuum at 60° C. and -0.1 MPa for 48 hours to obtain food-grade chromium chloride hexahydrate (CrCl 3 ·6H 2 O).

[0041] Among them: Cr 6+ , Cr 2+ Not detected, CrCl3·6H2O content>99.9%, Fe%<0.01%, insoluble matter<0.003%, sulfate<0.01%, matter not precipitated by ammonia water<0.03%; clear and transparent after dissolution without impurities.

[0042] The process flow of the production and purification process of a food-grade hydrated chromium trichloride of above-described embodiment 1 is as follows: Figure 1 shown.

[0043] Example 2

[0044] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0045] S1. The reactor was cleaned three times with a 2 wt% hydrochloric acid solution and deionized water, and then 17 kg of secondary pure water and 50 kg of chemically pure chromium trichloride (wherein the hexavalent chromium content was approximately 0.001%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.34. Then, protective nitrogen was introduced, the temperature was raised to 95°C for dissolution, and the reaction was kept at this temperature for 2 hours;

[0046] S2, add 5.0g of antidote (chromium dichloride) and 60ml of hydrochloric acid during the insulation reaction, carry out detoxification reaction for 2 hours, and pass excess oxygen into after the reaction to eliminate the antidote;

[0047] S3, cooling to 80 ° C, then filtering the reaction mass with a 400-mesh charged filter bag 5 times, and collecting the filtrate into a crystallization kettle and cooling to 45 ° C for crystallization;

[0048] S4. After crystallization, transfer the viscous liquid into an acid-resistant centrifuge and centrifuge at 50 Hz for 20 minutes;

[0049] S5. Finally, the mixture was dried under a rotary vacuum at 65° C. and -0.1 MPa for 30 hours to obtain food-grade chromium chloride hexahydrate (CrCl 3 ·6H 2 O).

[0050] Among them: Cr 6+ , Cr 2+ Not detected, CrCl3·6H2O content>100%, Fe%<0.005%, insoluble matter<0.003%, sulfate<0.01%, matter not precipitated by ammonia water<0.03%; clear and transparent after dissolution without impurities.

[0051] Example 3

[0052] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0053] S1. The reactor was cleaned five times with a 5 wt% hydrochloric acid solution and deionized water, and then 10 kg of secondary pure water and 50 kg of analytical grade chromium trichloride (wherein the hexavalent chromium content was approximately 0.002%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.2. Then, protective nitrogen was introduced, the temperature was raised to 85°C for dissolution, and the reaction was kept at this temperature for 3 hours;

[0054] S2, add 5.0g of antidote (chromium dichloride) and 60ml of hydrochloric acid during the insulation reaction, carry out detoxification reaction for 3 hours, and pass excess oxygen into after the reaction to eliminate the antidote;

[0055] S3, cooling to 70 ° C, then filtering the reaction mass with a 350 mesh charged filter bag 4 times, and collecting the filtrate into a crystallization kettle and cooling to 35 ° C for crystallization;

[0056] S4. After crystallization, transfer the viscous liquid into an acid-resistant centrifuge and centrifuge at 80 Hz for 30 minutes;

[0057] S5. Finally, the mixture was dried under a rotary vacuum at 65° C. and -0.1 MPa for 30 hours to obtain food-grade chromium chloride hexahydrate (CrCl 3 ·6H 2 O).

[0058] Among them: Cr 6+ , Cr 2+ Not detected, CrCl3·6H2O content>100%, Fe%<0.01%, insoluble matter<0.003%, sulfate<0.01%, matter not precipitated by ammonia water<0.03%; clear and transparent after dissolution without impurities.

[0059] Example 4

[0060] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0061] S1. The reactor was cleaned five times with a 10 wt% hydrochloric acid solution and deionized water, and then 7.5 kg of secondary pure water and 50 kg of analytical grade chromium trichloride (wherein the hexavalent chromium content was approximately 0.002%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.15. Then, protective nitrogen was introduced, the temperature was raised to 75°C for dissolution, and the reaction was kept at this temperature for 6 hours;

[0062] S2, add antidote (chromium dichloride) 30.0g and 1000ml hydrochloric acid during the insulation reaction, carry out detoxification reaction for 2 hours, and pass into excess oxygen after the reaction to eliminate the antidote;

[0063] S3, cooling to 75 ° C, then filtering the reaction mass three times with a 250 mesh charged filter bag, and collecting the filtrate into a crystallization kettle and cooling to 30 ° C for crystallization;

[0064] S4. After crystallization, transfer the mixture to an acid-resistant centrifuge while it is still viscous and centrifuge it at 45 Hz for 30 minutes;

[0065] S5. Finally, the mixture was dried in a rotary vacuum at 55° C. and -0.1 MPa for 36 hours to obtain food-grade chromium trichloride hexahydrate (CrCl 3 ·6H 2 O).

[0066] Among them: Cr 6+ , Cr 2+ Not detected, CrCl3·6H2O content>99.3%, Fe%<0.01%, insoluble matter<0.002%, sulfate<0.01%, matter not precipitated by ammonia water<0.02%; clear and transparent after dissolution without impurities.

[0067] Example 5

[0068] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0069] S1. The reactor was cleaned three times with a 1.0 wt% hydrochloric acid solution and deionized water, and then 18 kg of secondary pure water and 50 kg of analytical grade chromium trichloride (wherein the hexavalent chromium content was approximately 0.003%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.36. Then, protective nitrogen was introduced, the temperature was raised to 80°C for dissolution, and the reaction was kept at this temperature for 5 hours;

[0070] S2, add 8.0g of antidote (chromium dichloride) and 100ml of hydrochloric acid during the insulation reaction, carry out detoxification reaction for 1 hour, and pass excess oxygen into after the reaction to eliminate the antidote;

[0071] S3, cooling to 75 ° C, then filtering the reaction mass three times with a 400-mesh charged filter bag, and collecting the filtrate into a crystallization kettle and cooling to 25 ° C for crystallization;

[0072] S4. After crystallization, transfer the mixture to an acid-resistant centrifuge while it is still viscous and centrifuge it at 55 Hz for 40 minutes;

[0073] S5. Finally, the mixture was dried under a rotary vacuum at 60° C. and −0.1 MPa for 40 hours to obtain food-grade chromium chloride hexahydrate (CrCl 3 ·6H 2 O).

[0074] Among them: Cr 6+ , Cr 2+ Not detected, CrCl3·6H2O content>99.0%, Fe%<0.01%, insoluble matter<0.004%, sulfate<0.001%, matter not precipitated by ammonia water<0.03%; clear and transparent after dissolution without impurities.

[0075] Example 6

[0076] A production and purification process for food-grade hydrated chromium trichloride, characterized in that the process comprises the following steps in sequence:

[0077] S1. The reactor was cleaned three times with a 5.0 wt% hydrochloric acid solution and deionized water, and then 15 kg of secondary pure water and 50 kg of analytical grade chromium trichloride (wherein the hexavalent chromium content was approximately 0.002%) were added to the cleaned reactor in a mass ratio of chromium chloride: pure water = 1:0.3. Then, protective nitrogen was introduced, the temperature was raised to 85°C for dissolution, and the reaction was kept at this temperature for 4 hours;

[0078] S2. Add 60 ml of hydrochloric acid during the heat-insulating reaction and react for 1 hour;

[0079] S3, cooling to 75 ° C, then filtering the reaction mass three times with a 300-mesh charged filter bag, and collecting the filtrate into a crystallization kettle and cooling to 25 ° C for crystallization;

[0080] S4. After crystallization, transfer the mixture to an acid-resistant centrifuge while it is still viscous and centrifuge it at 35 Hz for 30 minutes;

[0081] S5. Finally, the mixture was dried under a rotary vacuum at 60° C. and −0.1 MPa for 40 hours to obtain food-grade chromium chloride hexahydrate (CrCl 3 ·6H 2 O).

[0082] Among them: Cr6+ % = 0.002%, CrCl3·6H2O content > 100%, Fe% < 0.01%, insoluble matter < 0.003%, sulfate < 0.01%, matter not precipitated by ammonia water < 0.03%; after dissolution, it is clear and transparent without impurities.

[0083] The antidote chromium dichloride was not added in the above-described embodiment 6.

[0084] As can be seen from the above-mentioned tests, the production and purification process of the food-grade mineral additive chromium trichloride hexahydrate proposed by the present invention obtains high-quality food-grade mineral additive chromium trichloride hexahydrate through the processes of dissolution, detoxification, impurity removal, crystallization, centrifugation, vacuum drying, etc. The entire process is simple and easy to operate, and the system flow solves the problem of unstable quality in the conventional industrial production process of chromium trichloride hexahydrate. The process of the present invention can avoid the occurrence of impurities, maintain the uniform particle size distribution of the chromium chloride hexahydrate crystals, and maintain the characteristics of non-agglomeration, thereby being convenient to use.

[0085] The above preferred embodiments of the present invention are only used to explain the present invention and are not used to limit the present invention. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A production and purification process for food-grade hydrated chromium trichloride, characterized in that: The process comprises the following steps in sequence: S1, cleaning the reactor, then adding chromium chloride and pure water into the reactor and introducing protective gas, heating to dissolve, and keeping the temperature to react; Wherein, the chromium chloride is of analytical grade, chemical grade or premium grade, and the pure water is grade II pure water; S2, adding an antidote and hydrochloric acid during the heat-insulating reaction process, carrying out the detoxification reaction for 1 to 3 hours, and then introducing excess oxygen to eliminate the antidote after the reaction; Wherein, the antidote is chromium dichloride, and the mass ratio of the antidote to chromium chloride is 1:(1500-10000); S3. Filter the reaction material 2 to 5 times with a charged filter bag at 70 to 80°C, and collect the filtrate into a crystallization kettle and cool it to 25 to 45°C for crystallization; S4. After crystallization, transfer the viscous solution into an acid-resistant centrifuge at 30-100 Hz and centrifuge for 20-40 minutes; S5. Low-temperature vacuum drying to obtain food-grade hydrated chromium trichloride.

2. A production and purification process for food-grade hydrated chromium trichloride according to claim 1, characterized in that, Step S1, cleaning the reactor, then adding chromium chloride and pure water into the reactor and introducing protective gas, heating to 75-95°C for dissolution, and then keeping the temperature to react for 2-8 hours; Wherein, the mass ratio of the chromium chloride to the pure water is 1:(0.15~ 0.45)。 3. A production and purification process for food-grade hydrated chromium trichloride according to claim 2, characterized in that, step S1. The mass ratio of the chromium chloride to pure water is 1: (0.15-0.3), the temperature is raised to 85-95° C. for dissolution, and the temperature is kept to react for 2-4 hours.

4. A production and purification process for food-grade hydrated chromium trichloride according to claim 1 or 2, characterized in that, The process of cleaning the reactor in step S1 is: cleaning the reactor 3 to 5 times with 1 to 10 wt % hydrochloric acid solution and deionized water in sequence.

5. A production and purification process for food-grade hydrated chromium trichloride according to claim 1 or 2, characterized in that, The protective gas in step S1 is nitrogen.

6. A production and purification process for food-grade hydrated chromium trichloride according to claim 1, characterized in that, The mass volume ratio of the antidote to hydrochloric acid in step S2 is 0.03 to 0.1 g / mL.

7. A production and purification process for food-grade hydrated chromium trichloride according to claim 1, characterized in that, The pore size of the filter bag in step S3 is 250-400 mesh.

8. A production and purification process for food-grade hydrated chromium trichloride according to claim 1, characterized in that, The vacuum drying temperature in step S5 is 55-65° C., the vacuum pressure is -0.1 MPa, and the drying time is 30-50 hours.

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