CN112961063A

CN112961063A - Method for preparing glycine metal complex salt and device for implementing same

Info

Publication number: CN112961063A
Application number: CN202110250881.2A
Authority: CN
Inventors: 李显扬; 应国海; 耿海涛
Original assignee: Bozun Investment Group Co Ltd
Current assignee: Bozun Investment Group Co Ltd
Priority date: 2021-03-08
Filing date: 2021-03-08
Publication date: 2021-06-15

Abstract

The present invention relates to a process for the preparation of a glycine metal complex salt, a composition for use in the process and an apparatus for carrying out the process. Wherein the method comprises contacting a hydantoin method glycine crystallization mother liquor with a zirconium raw material to perform a hydrolysis reaction, and then mixing an aqueous glycine solution with an inorganic metal salt to perform a complex reaction, thereby obtaining a glycine metal complex salt. The method has the advantages that the zirconium is utilized to hydrolyze impurities (such as hydantoin, hydantoin acid, hydantoin amide, glycine dipeptide, diketopiperazine, glycine tripeptide and the like) in the glycine mother liquor, so that the impurities can be effectively converted, and the feed-grade glycine metal complex salt is obtained.

Description

Method for preparing glycine metal complex salt and device for implementing same

Technical Field

The invention belongs to the field of organic complex preparation, and particularly relates to a method for preparing glycine metal complex salt by utilizing a hydantoin method glycine mother liquor, a composition used for the method, and a device for implementing the method.

Background

The trace elements are very important nutritional additives, and the trace element additives commonly used in feed and premix at present mainly comprise inorganic salts such as sulfate, chloride, oxide and the like, and have a plurality of defects, such as: in animal nutrition, due to the complex chemical reaction in the digestion process, insoluble precipitate is easily formed under the influence of phosphate (such as calcium hydrophosphate, calcium dihydrogen phosphate), phytic acid and other components in the feed, the biological value is reduced, and the absorption and utilization are influenced; in feed processing, inorganic salt generally contains crystal water and is easy to absorb moisture and agglomerate; the inorganic salt has strong destructive effect on vitamins, grease and the like; some feed factories adopt high-manganese and high-zinc feed, the yield is low, and the environment is seriously polluted.

The test result of glycine chelated (complexed) metal compound for broiler shows that the weight gain speed of the test group is increased by 5.28% compared with that of the control group, the feed conversion rate is increased by 2.59%, and 2100 yuan can be added to one feeder which is fed with 1500 per batch and 5 batches of 5 annual feeders. The results of experiments on the laying hens in the Decka by Sundecheng et al (1995) show that the total egg weight and the laying rate of the experimental group are respectively improved by 21.02% and 12.80% compared with those of the control group, and the feed-egg ratio and the soft-breaking rate are respectively reduced by 20.74% and 31.79%; the metabolism test also shows that the absorption utilization rates of the iron, copper, manganese and zinc elements in the test group are respectively improved by 71.65%, 93.07%, 188.08% and 107.42% compared with the control group.

The ferrous glycine chelate can obviously improve the reproductive performance of sows, improve the body conditions of the sows, reduce the elimination rate of the sows during the birth, prevent the anemia and diarrhea of piglets and reduce the death rate of the piglets. The feed added with glycine chelated iron (500ppm) is fed 21-28 days before the birth of the sow, so that the postpartum piglets do not need to be supplemented with iron, the death rate of the piglets is obviously reduced, the weaning weight is larger, and the breeding rate of the weaning piglets can reach 94%. The experimental study of the compound amino acid chelate and the ecological preparation feed additive on the fattening pigs shows that the daily gain ratio is improved by 17.82 percent compared with the control, the feed conversion ratio is reduced by 14.43 percent, and the economic benefit is improved by 70.38 percent.

The glycine chelated (complexed) metal compound has obvious effects on promoting the growth of fish, improving the feed conversion rate and the survival rate of fish, and is an ideal nutritional feed additive suitable for the nutritional needs of fish. A feeding test of Zhao Yuanfeng et al (1994) on carps shows that the weight gain of a comparison group added with glycine chelated (complexed) metal compounds is improved by 37.2-68.1%, and the bait coefficient is reduced to 1.4-1.7 from 2.4 of the comparison group. Liaijie et al (1994) add glycine chelating (complexing) metal compounds, Cu 2Mg, Zn 30Mg, Mn 12Mg, Fe 150Mg, Co 2Mg and Mg 400Mg, into each kilogram of feed, can accelerate the growth of tilapia, and improve the weight gain rate by 17.84-25.84% compared with inorganic trace elements; for crucian carp, the digestibility of trace elements can be improved, the Cu and Co are 41-58%, the Fe and Zn are 14-16%, and the Mn is 5-7%.

Therefore, the glycine chelating (complexing) metal compound has stable chemical performance, high biological value, no toxicity, no stimulation, good palatability, no incompatibility with vitamins, antibiotics and the like, has certain functions of sterilizing and improving immunologic function, has curative effects on enteritis, dysentery and anemia, and has stable chemical properties. As a feed additive, the compound feed additive has the double functions of supplementing trace elements and amino acids, can reduce the feed consumption and improve the feed conversion utilization rate, and has obvious economic benefit.

The direct hydantoin method is an important production method of glycine, and the method takes hydroxyacetonitrile and ammonium bicarbonate as raw materials, the hydroxyacetonitrile, ammonia, carbon dioxide and water are subjected to high-temperature high-pressure reaction according to the feeding molar ratio of 1:6:3:46, a glycine aqueous solution is generated after ammonia and carbon dioxide are discharged, and a glycine product and a glycine mother solution are obtained through decoloration, concentration, cooling and crystallization. The process is the cleanest production process at present, only hydroxyl acetonitrile and water are consumed in the production process of the glycine, the production cost is low, no inorganic salt is generated, and the separation and purification of the glycine are simple. However, there is a problem that some organic impurities such as hydantoin acid, hydantoin acid amide, glycine dipeptide, glycine tripeptide, 2, 5-diketopiperazine, glycinamide and unreacted hydantoin, which are generated in the glycine production process, are structurally shown as follows, and are generated because hydroxyacetonitrile is firstly reacted with ammonia to generate aminoacetonitrile, then cyclization is performed under the action of carbon dioxide, and then the hydantoin ring is unstable and decomposed into glycine, carbon dioxide and ammonia under high temperature and high pressure; in this process, incomplete decomposition of the hydantoin ring produces impurities such as hydantoin acid, hydantoin acid amide, glycine dipeptide, glycine tripeptide, 2, 5-diketopiperazine, glycinamide, and the like, thereby affecting the recycling of the glycine mother liquor:

in order to obtain feed-grade and food-grade glycine, the crude glycine product needs to be subjected to recrystallization treatment, and although a high-quality glycine product can be obtained, the recrystallization mother liquor cannot be recycled for multiple times, mainly because impurities such as hydantoin acid, hydantoin acid amide, glycine dipeptide, glycine tripeptide, 2, 5-diketopiperazine, glycine amide and the like are also carried in the crude glycine product. These impurities remain in the recrystallization mother liquor during recrystallization, and as the recrystallization mother liquor is reused, the impurities will accumulate to the limit and affect the circulation of the mother liquor. In order to prevent the quality of the glycine product from being affected, the recrystallization mother liquor needs to be periodically extracted for treatment. In industrial processes, in order to prevent the accumulation of these impurities, a part of glycine crystallization mother liquor is generally extracted and incinerated, and the amount of the mother liquor extracted and incinerated is generally about 10% of the mass of the mother liquor, which inevitably results in a great amount of glycine loss. Impurities such as hydantoin acid, hydantoin acid amide, glycine dipeptide, glycine tripeptide, 2, 5-diketopiperazine, glycine amide (also called "glycine amide") present in a glycine mother liquor are converted to glycine under certain conditions (such as high temperature or alkaline conditions), however, the conversion under high temperature conditions is not complete, and even the following reversible reactions occur:

although some impurities can be completely hydrolyzed and converted into glycine under alkaline conditions, the part of mother liquor treated by alkali liquor cannot be recycled to the original reaction system, and acidification crystallization treatment is often needed, so that a large amount of inorganic sodium salt and saline wastewater which is difficult to treat are by-produced, and the production cost of glycine is increased. At least in the present case, the treatment by incineration is directly effective, but it would result in waste of resources, environmental pollution and thus increase of the production cost of glycine.

Therefore, there is a need in the art to develop a method for producing valuable organic complex products by comprehensively utilizing glycine mother liquor obtained by a direct hydantoin process, which can prevent impurities from accumulating in the mother liquor to affect the recycling of the mother liquor, and can fully recover glycine and glycine derivatives and other impurities in the mother liquor to avoid direct incineration treatment, thereby achieving the purpose of fully utilizing waste.

Disclosure of Invention

In view of the above technical problems, the present inventors have found that impurities (such as hydantoin, hydantoin acid, hydantoin amide, glycine dipeptide, diketopiperazine, glycine tripeptide) in a glycine mother liquor can be efficiently converted into glycine by utilizing the effect of zirconium on the hydrolysis reaction of these impurities. In view of the above, the present invention provides a method for preparing a feed-grade glycine metal complex salt containing trace elements using a glycine crystallization mother liquor, a composition for the method, and an apparatus for performing the method.

In one aspect, the present invention provides a method for preparing a glycine metal complex salt, wherein the method comprises the steps of:

(1) contacting a hydantoin method glycine crystallization mother liquor with a zirconium raw material, and then heating and preserving heat to perform hydrolysis reaction to obtain a glycine aqueous solution, wherein the zirconium raw material comprises zirconium, zirconium-containing alloy, zirconium salt, zirconium oxide or any mixture thereof;

(2) removing ammonia and carbon dioxide from the glycine aqueous solution obtained in the step (1), and then performing decolorization and reduced pressure concentration treatment to obtain a concentrated glycine aqueous solution;

(3) and (3) mixing the concentrated glycine aqueous solution obtained in the step (2) with an inorganic metal salt, heating and stirring to perform a complex reaction to obtain a glycine complex metal salt aqueous solution, and then concentrating and drying the glycine complex metal salt aqueous solution to obtain a glycine metal complex salt.

In another aspect, the present invention provides a composition for use in the above method, wherein the composition comprises a hydantoin process glycine crystallization mother liquor and a zirconium raw material comprising zirconium, a zirconium-containing alloy, a zirconium salt, zirconium oxide, or any mixture thereof.

In another aspect, the present invention provides a feed additive, wherein the feed additive comprises a glycine metal complex salt prepared by the above method.

In yet another aspect, the present invention provides an apparatus for carrying out the above method, wherein the apparatus comprises a hydrolysis reactor, a stripping column, a decolorization kettle, a concentration kettle, a complexation kettle, and a drying system, which are connected in series in fluid communication.

Advantageous effects

Zirconium is introduced into a reaction system to effectively convert impurities in the glycine mother liquor into glycine, so that the hydantoin method glycine mother liquor can be used for preparing feed-grade glycine metal complex salt, and compared with the traditional process for preparing the complex salt by using commercial grade glycine, the method has the advantages of low production cost and comprehensive utilization of waste; the method has the advantages of cleanness, environmental protection, high yield, high product stability, high recovery rate of the glycine in the mother liquor, no generation of three wastes and the like. The purity of the glycine metal complex salt prepared by the method of the invention reaches more than 95%, the recovery and utilization rate of glycine reaches more than 99%, and the obtained glycine metal complex salt meets the feed grade requirement. The device has the advantages of simple operation, easy maintenance of equipment and the like.

Drawings

FIG. 1 is a schematic diagram of an exemplary apparatus for producing a glycine metal complex salt of the present invention.

Each symbol in fig. 1 represents: 1 hydrolysis reactor, 2 stripping tower, 3 decoloration cauldron, 4 concentration cauldron, 5 complex reaction cauldron, 6 spray drying system.

FIG. 2 is an infrared spectrum of a glycine and glycine-complexed zinc sulfate product prepared in example 1 (referred to as "glycine-complexed zinc").

FIG. 3 is an infrared spectrum of a glycine and glycine-complexed copper sulfate product (referred to as "glycine-complexed copper") prepared in example 2.

FIG. 4 is an infrared spectrum of a glycine and ferrous glycine complex sulfate product (referred to as "ferrous glycine complex") prepared in example 3.

FIG. 5 is an infrared spectrum of a glycine and manganese glycine complex sulfate product prepared in example 4 (abbreviated as "manganese glycine complex").

FIG. 6 is an infrared spectrum of a glycine and glycine complex cobalt sulfate product (referred to as "cobalt glycine complex") prepared in example 5.

Detailed Description

The solution of the invention will be described below in connection with various exemplary embodiments, but the scope of protection of the invention is not limited thereto.

In the present invention, unless otherwise indicated, the terms "glycine crystallization mother liquor", "hydantoin process glycine mother liquor", "mother liquor" and "glycine mother liquor" are used interchangeably to refer to the raffinate after synthesis and isolation of a glycine product using the direct hydantoin process and/or the glycine recrystallization mother liquor.

In the present invention, unless otherwise specified, the terms "chelated metal compound", "complexed metal compound", "metal complex" and "metal chelate" are used interchangeably to refer to a complex formed by coordination of a metal ion with glycine. In the present invention, unless otherwise specified, the terms "glycine metal complex salt" and "glycine metal complex salt" are used interchangeably to refer to the glycine complex salt, e.g., sulfate salt, produced by the process of the present invention.

In the present invention, the term "atmospheric pressure" means 1 standard atmospheric pressure unless otherwise specified.

The inventor finds that zirconium can promote impurities (such as hydantoin, hydantoin acid, hydantoin amide, glycinamide, glycine dipeptide, diketopiperazine and glycine tripeptide) in the hydantoin method glycine mother liquor to be completely converted into glycine products through hydrolysis reaction. It is known in the art that glycine undergoes a dynamic equilibrium reaction at elevated temperatures, where partial conversion of glycine to glycine dimers (i.e., glycine dipeptides) and trimers (i.e., glycine tripeptides) and the like, is favored by higher temperatures. However, the present inventors have found that this conversion can be prevented in the presence of zirconium or zirconium ions, and even that glycine dimers, trimers, etc. obtained by the conversion can be promoted to be hydrolyzed into glycine in the presence of zirconium or zirconium ions.

As an example, the present inventors have also found that if adding zirconium material to the material of the hydrolysis reactor of glycine crystallization mother liquor, it is not only advantageous to enhance the resistance of the reactor to corrosion of the reactor by carbon dioxide and ammonia under high temperature and pressure conditions, but also to directly affect the effect of the hydrolysis reaction (making the equilibrium of the hydrolysis reaction proceed to the left, facilitating the formation of glycine product), so that impurities in the mother liquor, such as hydantoin, hydantoin acid, hydantoin amide, glycine dipeptide, diketopiperazine, glycine tripeptide, etc., can be completely and effectively converted into glycine product.

In one embodiment, the present invention relates to a method for preparing a glycine metal complex salt, wherein the method comprises the steps of:

In some preferred embodiments, in step (1), the total nitrogen content of the glycine crystallization mother liquor is 3.0 wt% to 5.5 wt%. In a further preferred embodiment, the glycine crystallization mother liquor comprises the following components in percentage by mass: 15 to 26 parts of glycine, 0.5 to 3.5 parts of glycine dipeptide, 0.5 to 0.8 part of glycine tripeptide, 0.5 to 2.0 parts of hydantoin, 0.2 to 0.6 part of diketopiperazine, 0.1 to 1.0 part of glycinamide, 0.05 to 0.3 part of hydantoin, 0.05 to 0.2 part of hydantoin amide, less than 50ppm of ammonia, and the balance of water.

In a further preferred embodiment, the process further comprises producing the hydantoin process glycine crystallization mother liquor by: feeding hydroxyl acetonitrile, ammonia, carbon dioxide and water according to a molar feeding ratio of 1:6:3 (44-46), wherein the reaction temperature is 140-160 ℃, and the reaction time is 2-3 hours; after the reaction is finished, removing carbon dioxide and ammonia which do not participate in the reaction by steam stripping to obtain a dilute glycine solution (preferably, the glycine content of the dilute glycine solution is 7.0 wt% -15 wt%), decoloring, concentrating, cooling and crystallizing to obtain crude glycine with light yellow crystals, and separating the crude glycine to obtain a crystallization mother liquor which is used as the hydantoin-method glycine crystallization mother liquor.

In a further preferred embodiment, the process further comprises producing the hydantoin process glycine crystallization mother liquor by: adding water into the crude glycine product for recrystallization, separating the recrystallized glycine to obtain a recrystallization mother liquor, and taking the single recrystallization mother liquor or the mixture of the recrystallization mother liquor and the crystallization mother liquor as the hydantoin-process glycine crystallization mother liquor.

In some preferred embodiments, in step (1), the zirconium feedstock may be in the form of reactor linings, chunks, powders, and the like.

In some preferred embodiments, in step (1), the zirconium-containing alloy is an alloy having a zirconium content of 5 wt% to 30 wt%. Preferably, the zirconium-containing alloy may be, for example, a zirconium iron alloy, a zirconium cobalt alloy, a zirconium copper alloy, a zirconium tin alloy, a zirconium aluminum alloy, a zirconium niobium alloy, or any mixture thereof, and the like, but is not limited thereto.

In some preferred embodiments, in step (1), the zirconium salt is an inorganic zirconium salt; preferably, the inorganic zirconium salt includes, but is not limited to, zirconium sulfate, zirconium chloride, zirconium carbonate (e.g., zirconium basic carbonate), zirconium nitrate, zirconium phosphate, zirconium acetate, or any mixture thereof.

In some preferred embodiments, in the step (1), the amount of the zirconium raw material added is 20 to 500ppm of the mass of the hydantoin-process glycine crystallization mother liquor, based on the mass of the zirconium element.

In some preferred embodiments, in the step (1), the hydrolysis reaction is carried out by heating to 150-170 ℃ and maintaining the temperature for 30-90 min with stirring at a speed of 60-200 r/min.

In some preferred embodiments, in step (1), the pressure of the hydrolysis reaction is 1.2 to 3.0 MPa.

In some preferred embodiments, in step (2), the aqueous glycine solution of step (1) is subjected to a stripping treatment to remove ammonia and carbon dioxide.

In the present invention, stripping is carried out using conventional operating conditions known in the art.

In some preferred embodiments, in step (2), the decolorizing treatment is performed with activated carbon or a nanofiltration membrane, preferably activated carbon. In a further preferred embodiment, the amount of the activated carbon is 0.2 wt% to 1.0 wt% of the total mass of glycine in the aqueous glycine solution. In a further preferred embodiment, the temperature of the decolorization treatment is 40 to 70 ℃ and the time is 20 to 40 min.

The concentration under reduced pressure in the above-mentioned step (2) of the present invention is a conventional operation in the art. In the present invention, a small amount of ammonia and excess water produced can be removed by the concentration-compression treatment.

In some preferred embodiments, in step (3), the inorganic metal salt is a sulfate salt, such as zinc sulfate, ferrous sulfate, copper sulfate, manganese sulfate, an anhydrous compound or hydrate of cobalt sulfate, or any mixture thereof.

In some preferred embodiments, in step (3), the feeding molar ratio of the metal ion in the inorganic metal salt to glycine is 1: 1.

In some preferred embodiments, in step (3), the temperature of the complexation reaction is 80 ℃ to 100 ℃ (preferably 80 ℃ to 95 ℃) for 1 hour to 2 hours.

In some preferred embodiments, in step (3), the concentration of the aqueous glycine complex metal salt solution is from 35 wt% to 60 wt%, preferably from 40 wt% to 60 wt%.

In some preferred embodiments, in step (3), the glycine metal complex salt contains any one or more of zinc, iron, copper, manganese and cobalt.

In some embodiments, in step (3), the glycine metal complex salt is glycine complex sulfate.

In a further preferred embodiment, the chemical structure of the glycine metal complex salt is as follows:

wherein M is any one or more selected from zinc, iron, copper, manganese and cobalt; n is 1 to 10.

In some preferred embodiments, the method comprises the steps of:

(i) enabling a hydantoin-method glycine crystallization mother liquor to be in contact with a zirconium raw material in a reactor lining form, heating to 150-170 ℃ under stirring at a speed of 60-200 r/min, and preserving heat for 30-90 min to perform hydrolysis reaction, wherein the pressure of the hydrolysis reaction is 1.2-3.0 MPa, and obtaining a glycine aqueous solution after the reaction;

(ii) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide to obtain a feed liquid I, adding active carbon into the feed liquid I to carry out decoloring treatment, wherein the adding amount of the active carbon is 0.2-1.0 wt% of the total mass of the glycine, the temperature of the decoloring treatment is 40-70 ℃, the time is 20-40 min, removing the active carbon after the decoloring treatment is finished, and carrying out reduced pressure concentration treatment on the decolored feed liquid to obtain a concentrated glycine aqueous solution;

(iii) adding metal sulfate into the concentrated glycine aqueous solution obtained in the step (ii), heating to 80-100 ℃ under stirring to perform a complexing reaction for 1-2 hours to obtain a glycine complex metal salt aqueous solution with the concentration of 35-60 wt%, dissolving the glycine complex metal salt, concentrating and drying to obtain glycine metal complex sulfate.

In some preferred embodiments, the process is one or more of a batch, semi-continuous, or continuous process, preferably a semi-continuous or continuous process.

The method comprehensively utilizes the glycine mother liquor synthesized by the direct hydantoin method and the glycine recrystallization mother liquor thereof, can realize the comprehensive utilization of wastes, and the purity of the prepared glycine metal complex salt reaches more than 95 percent, the recovery and utilization rate of the glycine reaches more than 99 percent, and the obtained glycine metal complex salt reaches the feed grade requirement.

In one embodiment, the present invention relates to a composition for use in the above process, wherein the composition comprises a hydantoin process glycine crystallization mother liquor and a zirconium feedstock comprising zirconium, a zirconium-containing alloy, a zirconium salt, zirconium oxide, or any mixture thereof.

In some preferred embodiments, the zirconium feedstock may be in the form of reactor liners, chunks, powders, and the like.

In some preferred embodiments, the zirconium-containing alloy is an alloy having a zirconium content of 5 wt% to 30 wt%. Preferably, the zirconium-containing alloy may be, for example, a zirconium iron alloy, a zirconium cobalt alloy, a zirconium copper alloy, a zirconium tin alloy, a zirconium aluminum alloy, a zirconium niobium alloy, or any mixture thereof, and the like, but is not limited thereto.

In some preferred embodiments, the zirconium salt is an inorganic zirconium salt; preferably, the inorganic zirconium salt includes, but is not limited to, zirconium sulfate, zirconium chloride, zirconium carbonate (e.g., zirconium basic carbonate), zirconium nitrate, zirconium phosphate, zirconium acetate, or any mixture thereof.

In some preferred embodiments, the amount of the zirconium raw material is 20 to 500ppm of the mass of the hydantoin-process glycine crystallization mother liquor based on the mass of zirconium element.

In one embodiment, the present invention relates to a feed additive, wherein the feed additive comprises a glycine metal complex salt prepared by the above method.

In some preferred embodiments, the glycine metal complex salt contains any one or more of zinc, iron, copper, manganese and cobalt.

In some preferred embodiments, the glycine complex metal salt is a glycine complex sulfate salt.

In some embodiments, the feed additive further comprises a feedinglogically acceptable adjuvant. For the auxiliary materials acceptable in the feed science, those skilled in the art can easily select suitable materials according to the relevant records in the prior art (e.g., < feed additive item catalog (2013) >, etc.).

In one embodiment, the present invention relates to an apparatus for carrying out the above process, wherein the apparatus comprises a hydrolysis reactor, a stripping column, a decolorization tank, a concentration tank, a complexation tank, and a drying system connected in series in fluid communication.

In some preferred embodiments, the hydrolysis reactor and the concentration tank are each provided with a pressure assist device.

In some preferred embodiments, the hydrolysis reactor, the concentration kettle, the complexation kettle, and the drying system are respectively provided with temperature regulation auxiliary devices.

In some preferred embodiments, the drying system may be a spray drying system, a forced air drying oven, a vacuum drying oven, or the like.

Next, with reference to the content of fig. 1, an exemplary aspect of the present invention is explained as follows, however, the scope of the present invention is not limited thereto:

the device for preparing the glycine metal complex salt comprises a hydrolysis reactor (1), a stripping tower (2), a decoloring kettle (3), a concentration kettle (4), a complexing reaction kettle (5) and a spray drying system (6) which are sequentially connected in a fluid communication manner. Wherein, hydrolysis reactor (1) and concentrated cauldron (4) all be equipped with pressure auxiliary device, hydrolysis reactor (1), concentrated cauldron (4), complex reation kettle (5) and spray drying system (6) all be equipped with temperature regulation auxiliary device.

Introducing the hydantoin-method glycine crystallization mother liquor into a hydrolysis reactor (1) lined with a zirconium material, heating while stirring, and keeping the temperature to perform hydrolysis reaction. After the reaction, cooling and depressurizing to normal pressure to obtain the glycine aqueous solution. Stripping the glycine aqueous solution through a stripping tower (2) to remove ammonia and carbon dioxide to obtain a feed liquid I; and (3) feeding the obtained feed liquid I into a decoloring kettle (3), adding activated carbon for decoloring, removing the activated carbon after decoloring, and transferring the decolored feed liquid into a concentration kettle (4) for carrying out reduced pressure concentration treatment to obtain feed liquid II. And transferring the obtained feed liquid II into a complex reaction kettle (5), adding metal sulfate, heating under stirring to perform complex reaction to obtain glycine complex metal salt water solution, and directly feeding the water solution into a spray drying system (6) for spray drying treatment to obtain glycine metal complex salt.

Exemplary aspects of the present invention may be illustrated by the following numbered paragraphs, but the scope of the present invention is not limited thereto:

1. a method of preparing a glycine metal complex salt, wherein the method comprises the steps of:

2. The method of paragraph 1 wherein, in step (1), the total nitrogen content of the glycine crystallization mother liquor is from 3.0 wt% to 5.5 wt%.

3. The method as described in

paragraph

1 or 2, wherein the glycine crystallization mother liquor comprises the following components in percentage by mass: 15 to 26 parts of glycine, 0.5 to 3.5 parts of glycine dipeptide, 0.5 to 0.8 part of glycine tripeptide, 0.5 to 2.0 parts of hydantoin, 0.2 to 0.6 part of diketopiperazine, 0.1 to 1.0 part of glycinamide, 0.05 to 0.3 part of hydantoin, 0.05 to 0.2 part of hydantoin amide, less than 50ppm of ammonia, and the balance of water.

4. The method of any of paragraphs 1-3, wherein the method further comprises producing the hydantoin-process glycine crystallization mother liquor by: feeding hydroxyl acetonitrile, ammonia, carbon dioxide and water according to a molar feeding ratio of 1:6:3 (44-46), wherein the reaction temperature is 140-160 ℃, and the reaction time is 2-3 hours; after the reaction is finished, removing carbon dioxide and ammonia which do not participate in the reaction through steam stripping to obtain a dilute glycine solution, decoloring, concentrating, cooling and crystallizing to obtain a crude glycine with a light yellow crystal, and separating the crude glycine to obtain a crystallization mother liquor as the hydantoin-method glycine crystallization mother liquor.

5. The method of paragraph 4 wherein the method further comprises producing the hydantoin process glycine crystallization mother liquor by: adding water into the crude glycine product for recrystallization, separating the recrystallized glycine to obtain a recrystallization mother liquor, and taking the single recrystallization mother liquor or the mixture of the recrystallization mother liquor and the crystallization mother liquor as the hydantoin-process glycine crystallization mother liquor.

6. The method of any of paragraphs 1-5, wherein, in step (1), the zirconium feedstock is in the form of a reactor lining, a briquette, or a powder.

7. The method of any of paragraphs 1-6, wherein, in step (1), the zirconium-containing alloy is an alloy having a zirconium content of 5 wt% to 30 wt%.

8. The method of paragraph 7, wherein the zirconium-containing alloy is a zirconium iron alloy, a zirconium cobalt alloy, a zirconium copper alloy, a zirconium tin alloy, a zirconium aluminum alloy, a zirconium niobium alloy, or any mixture thereof.

9. The method of any of paragraphs 1-8, wherein the zirconium salt is an inorganic zirconium salt.

10. The method of paragraph 9 wherein the inorganic zirconium salt comprises zirconium sulfate, zirconium chloride, zirconium carbonate, zirconium nitrate, zirconium phosphate, zirconium acetate or any mixture thereof.

11. The method according to any one of paragraphs 1 to 10, wherein in step (1), the amount of the zirconium raw material added is 20 to 500ppm by mass of the hydantoin-process glycine crystallization mother liquor, based on the mass of the zirconium element.

12. The method as described in any of paragraphs 1 to 11, wherein the hydrolysis reaction is carried out by heating to 150 ℃ to 170 ℃ and holding the temperature for 30 to 90min in step (1) with stirring at a speed of 60 to 200 r/min.

13. The method according to any one of paragraphs 1 to 12, wherein in step (1), the pressure of the hydrolysis reaction is 1.2 to 3.0 MPa.

14. The method of any one of paragraphs 1 to 13, wherein in step (2), the aqueous glycine solution of step (1) is subjected to a stripping treatment to remove ammonia and carbon dioxide.

15. The method of any of paragraphs 1-14, wherein in step (2), the decolorizing treatment is performed with activated carbon or a nanofiltration membrane.

16. The method of paragraph 15 wherein the amount of activated carbon is 0.2 wt% to 1.0 wt% of the total mass of glycine in the aqueous glycine solution.

17. The method according to any one of paragraphs 1 to 16, wherein the temperature of the decoloring is 40 to 70 ℃ and the time is 20 to 40 min.

18. The method of any of paragraphs 1-17, wherein, in step (3), the inorganic metal salt is a sulfate salt.

19. The method of paragraph 18 wherein the sulfate is zinc sulfate, ferrous sulfate, copper sulfate, manganese sulfate, an anhydrous compound or hydrate of cobalt sulfate, or any mixture thereof.

20. The method of any of paragraphs 1-19, wherein in step (3) the metal ion to glycine feed molar ratio in the inorganic metal salt is 1: 1.

21. The method according to any one of paragraphs 1 to 20, wherein in step (3), the temperature of the complexation reaction is 80 ℃ to 100 ℃ for 1 to 2 hours.

22. The method of any of paragraphs 1-21, wherein in step (3), the concentration of the glycine complexing metal salt aqueous solution is from 35 wt% to 60 wt%.

23. The method of any of paragraphs 1-22, wherein in step (3) the glycine metal complex salt comprises any one or more of zinc, iron, copper, manganese and cobalt.

24. The method of any of paragraphs 1-23, wherein in step (3) the glycine metal complex salt is a glycine complex sulfate.

25. The method of any of paragraphs 1-24, wherein the chemical structure of the glycine metal complex salt is as follows:

26. The method of any of paragraphs 1-25, wherein the method comprises the steps of:

27. The method of any of paragraphs 1-26, wherein the method is one or more of a batch, semi-continuous, or continuous operating method.

28. A composition for use in the method of any of paragraphs 1-27, wherein the composition comprises a hydantoin process glycine crystallization mother liquor and a zirconium feedstock comprising zirconium, a zirconium-containing alloy, a zirconium salt, zirconium oxide, or any mixture thereof.

29. The composition of paragraph 28 wherein the zirconium feedstock is in the form of a reactor lining, a briquette, a powder.

30. The composition of paragraph 28 or 29 wherein the zirconium-containing alloy is an alloy having a zirconium content of from 5 wt% to 30 wt%.

31. The composition of any of paragraphs 28-30 wherein the zirconium-containing alloy is a zirconium iron alloy, a zirconium cobalt alloy, a zirconium copper alloy, a zirconium tin alloy, a zirconium aluminum alloy, a zirconium niobium alloy, or any mixture thereof.

32. The composition of any of paragraphs 28-31 wherein the zirconium salt is an inorganic zirconium salt.

33. The composition of paragraph 32 wherein the inorganic zirconium salt comprises zirconium sulfate, zirconium chloride, zirconium carbonate, zirconium nitrate, zirconium phosphate, zirconium acetate, or any mixture thereof.

34. The composition of any of paragraphs 28 to 33 wherein the amount of the zirconium raw material is 20 to 500ppm based on the mass of the hydantoin-process glycine crystallization mother liquor, based on the mass of zirconium element.

35. A feed additive, wherein the feed additive comprises a glycine metal complex salt prepared by the method of any one of paragraphs 1-27.

36. The feed additive of paragraph 35 wherein the glycine metal complex salt contains any one or more of zinc, iron, copper, manganese and cobalt.

37. The feed additive of paragraphs 35 or 36 wherein the glycine complexing metal salt is glycine complex sulfate.

38. A feed additive as described in any of paragraphs 35-37 wherein the chemical structure of the glycine metal complex salt is as follows:

39. A feed additive according to any of paragraphs 35-38, wherein said feed additive further comprises a feedinglogically acceptable adjuvant.

40. An apparatus for performing the method of any of paragraphs 1-27, wherein the apparatus comprises a hydrolysis reactor, a stripping column, a decolorization tank, a concentration tank, a complexation tank, and a drying system connected in series in fluid communication.

41. An apparatus as in paragraph 40 wherein the hydrolysis reactor and the concentration vessel are each provided with a pressure assist device.

42. An apparatus as in paragraphs 40 or 41 wherein said hydrolysis reactor, concentration vessel, complexation vessel and drying system are each provided with a temperature regulation aid.

43. An apparatus as in any of paragraphs 40-42, wherein the drying system is a spray drying system, a forced air drying oven, or a vacuum drying oven.

Examples

Hereinafter, preferred embodiments of the present invention will be described in detail. The preferred examples, which are not to be construed as limiting the invention, are generally conventional in the art and are provided for the purpose of illustration only. Therefore, those skilled in the art can make insubstantial modifications and adaptations to the embodiments of the present invention based on the above disclosure, and still fall within the scope of the present invention. In the following examples, the total nitrogen content in the glycine crystallization mother liquor was measured by Kjeldahl method, and ion chromatography (Switzerland cation chromatography, Mrtrossrp C4250 column, analytical conditions were that eluent was 1.7mol/L HNO₃Aqueous solution, flow rate of 1.0ml/min, sample injection volume of 20 microliter) to analyze the content of impurities such as glycine, glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like in the glycine crystallization mother liquor.

Unless otherwise indicated, each of the reagents, materials and devices employed in the following examples and comparative examples are commercially available reagents, materials and devices known in the art. Unless otherwise indicated, the various operations hereinafter are conventional operations known in the art, as may be found, for example, in the following descriptions: wangzkui et al, "principles of chemical industry (fifth edition), chemical industry publishers, 1 month in 2018; yellow portrait, et al, "general theory of fine chemical industry (second edition), chemical industry publishers, 3 months 2015; chang et al, Fine chemical engineering principles and technology, Sichuan scientific and technical Press, 10 months in 2005.

Example 1

700 g of glycine mother liquor having a total nitrogen content of 3.36 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant zirconium-lined reactor having a feed and a stirrer: glycine 15.0 wt%, glycine dipeptide 1.0 wt%, hydantoin 0.5 wt%, diketopiperazine 0.6 wt%, glycine tripeptide 0.5 wt%, glycinamide 0.1 wt%, hydantoin acid 0.2 wt%, hydantoin acid amide 0.1 wt%, ammonia 40 ppm. Wherein the amount of the zirconium material is 20ppm of the mass of the glycine mother liquor based on the mass of the zirconium element. Immediately heating to 150 ℃ under stirring at a speed of 60r/min, keeping the temperature for 0.5 hour to perform hydrolysis reaction (pressure is 2.0MPa), then cooling to about 100 ℃ and depressurizing to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 688 g of glycine aqueous solution, wherein the glycine aqueous solution is yellowish brown, the glycine content in the aqueous solution is 18.31 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 1.4 g of activated carbon into the glycine aqueous solution, stirring the mixture for 20min at the temperature of 40 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure to a glycine content of 32 wt% to obtain a concentrated glycine aqueous solution having a weight of 393.67 g (molar amount of glycine: 1.68 mol).

To the concentrated glycine aqueous solution obtained above and introduced into the complexation reaction kettle was added 307.65 g (1.68mol) of 98 wt% zinc sulfate monohydrate, followed by heating to 90 ℃ with stirring and reacting at that temperature for 2 hours to obtain 701.32 g of a glycine-complexed zinc sulfate aqueous solution containing 56.64 wt% of glycine-complexed zinc sulfate. The aqueous solution is directly concentrated to be anhydrous in a complex reaction kettle, then poured into a porcelain plate, put into a blast drying oven to be dried (105 ℃) to constant weight, ground and sieved to obtain 457.72 g of white powdery glycine complex zinc sulfate product, wherein the purity of the glycine complex zinc sulfate product is 98%, the yield is more than or equal to 99.9%, and the recovery rate of glycine is more than or equal to 99.9%. The infrared spectrum of the glycine and glycine complexed zinc sulfate product prepared in this example is shown in figure 2.

Example 2

700 g of glycine mother liquor having a total nitrogen content of 3.36 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant zirconium-lined reactor having a feed and a stirrer: glycine 15.0 wt%, glycine dipeptide 0.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.5 wt%, glycine tripeptide 0.5 wt%, glycinamide 1.0 wt%, hydantoin acid 0.1 wt%, hydantoin acid amide 0.1 wt%, ammonia 30 ppm. Wherein the amount of the zirconium material is 500ppm of the mass of the glycine mother liquor in terms of the mass of the zirconium element. Immediately heating to 160 ℃ under stirring at a speed of 200r/min, keeping the temperature for 1.0 hour to perform hydrolysis reaction (pressure is 1.2MPa), then cooling to about 100 ℃ and depressurizing to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 688 g of glycine aqueous solution, wherein the glycine aqueous solution is yellowish brown, the glycine content in the aqueous solution is 18.31 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 6.88 g of activated carbon into the glycine aqueous solution, stirring the mixture for 30min at the temperature of 60 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure to a glycine content of 32 wt% to obtain a concentrated glycine aqueous solution having a weight of 393.67 g (molar amount of glycine: 1.68 mol).

To the concentrated glycine aqueous solution obtained above and introduced into the complexation reaction kettle was added 427.90 g (1.68mol) of 98 wt% copper sulfate pentahydrate, and then the temperature was raised to 90 ℃ with stirring, and the reaction was carried out at that temperature for 2 hours to obtain 821.57 g of a glycine-complexed copper sulfate aqueous solution in which the glycine-complexed copper sulfate content was 55.34 wt%. The aqueous solution is directly concentrated to be anhydrous in a complex reaction kettle, then poured into a porcelain plate, put into a blast drying oven to be dried (105 ℃) to constant weight, ground and sieved to obtain 459.21 g of blue powdery glycine complex copper sulfate product, wherein the purity of the glycine complex copper sulfate product is 99%, the yield is more than or equal to 99.9%, and the recovery rate of glycine is more than or equal to 99.9%. The infrared spectrum of the glycine and glycine complex copper sulfate product prepared in this example is shown in FIG. 3.

Example 3

700 g of glycine mother liquor having a total nitrogen content of 3.36 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant zirconium-lined reactor having a feed and a stirrer: glycine 15.0 wt%, glycine dipeptide 0.5 wt%, hydantoin 1.0 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.8 wt%, glycinamide 0.1 wt%, hydantoin acid 0.2 wt%, hydantoin acid amide 0.2 wt%, ammonia 45 ppm. Wherein the amount of the zirconium material is 100ppm of the mass of the glycine mother liquor based on the mass of the zirconium element. Immediately heating to 160 ℃ under the stirring condition at the speed of 150r/min, preserving the temperature for 1.5 hours to perform hydrolysis reaction (the pressure is 2.0MPa), then cooling to about 100 ℃ and relieving the pressure to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 688 g of glycine aqueous solution, wherein the aqueous solution is yellow brown, the mass percentage of glycine in the aqueous solution is 18.31 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 4.0 g of activated carbon into the glycine aqueous solution, stirring the mixture for 40min at the temperature of 70 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure to a glycine content of 32 wt% to obtain a concentrated glycine aqueous solution having a weight of 393.67 g (molar amount of glycine: 1.68 mol).

To the concentrated glycine aqueous solution obtained above introduced into the complex reaction kettle were added 291.29 g (1.68mol) of ferrous sulfate monohydrate 98 wt%, 6.3 g of citric acid and 3 g of reduced iron powder, followed by heating to 80 ℃ under stirring and reacting at that temperature for 1.0 hour to obtain 694.26 g of a glycine complex ferrous sulfate aqueous solution containing 54.91 wt%, and the reduced iron powder was filtered. Directly concentrating the filtrate in a complexing reaction kettle until the filtrate is anhydrous, then pouring the filtrate into a porcelain plate, putting the porcelain plate into a vacuum drying oven to dry (105 ℃) until the weight is constant, grinding and sieving to obtain 447.99 g of a faint yellow powdery glycine complex ferrous sulfate product, wherein the purity of the glycine complex ferrous sulfate product is 98.6%, the yield is more than or equal to 99.9%, and the recovery rate of glycine is more than or equal to 99.9%. The infrared spectrum of the glycine and glycine complex ferrous sulfate product prepared in this example is shown in figure 4.

Example 4

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant zirconium-lined reactor having a feed and a stirrer: 21.0 wt% of glycine, 3.5 wt% of glycine dipeptide, 2.0 wt% of hydantoin, 0.5 wt% of diketopiperazine, 0.8 wt% of glycine tripeptide, 0.1 wt% of glycinamide, 0.05 wt% of hydantoin acid amide and 30ppm of ammonia. Wherein the amount of the zirconium material is 300ppm of the mass of the glycine mother liquor based on the mass of the zirconium element. Heating to 160 ℃ immediately under the condition of stirring at the speed of 180r/min, keeping the temperature for 1.5 hours to perform hydrolysis reaction (the pressure is 3.0MPa), then cooling to about 100 ℃ and relieving the pressure to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 690 g of aqueous glycine solution, wherein the aqueous solution is yellowish brown, the mass percentage of glycine in the aqueous solution is 28.42 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 1.8 g of activated carbon into the glycine aqueous solution, stirring the mixture for 30min at the temperature of 50 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure to a glycine content of 32 wt% to obtain a concentrated glycine aqueous solution having a weight of 612.81 g (molar amount of glycine: 2.615 mol).

450.98 g (2.615mol) of 98 wt% manganese sulfate monohydrate was added to the above-obtained concentrated glycine aqueous solution introduced into the complexation reaction tank, and then the temperature was raised to 95 ℃ under stirring, and the reaction was carried out at that temperature for 2.0 hours to obtain 1063.79 g of a glycine complex manganese sulfate aqueous solution in which the content of glycine complex manganese sulfate was 55.56 wt%. The aqueous solution is directly concentrated to be anhydrous in a complexation reaction kettle, then poured into a porcelain plate, put into a blast drying oven to be dried (105 ℃) to constant weight, ground and sieved to obtain 692.05 g of a white grey powder glycine complexed manganese sulfate product, wherein the purity of the glycine complexed manganese sulfate product is 99%, the yield is more than or equal to 99.9%, and the recovery rate of glycine is more than or equal to 99.9%. The infrared spectrum of the glycine and glycine complexed manganese sulfate product prepared in this example is shown in figure 5.

Example 5

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant zirconium-lined reactor having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin acid 0.3 wt%, hydantoin acid amide 0.1 wt%, ammonia 40 ppm. Wherein the amount of the zirconium material is 400ppm of the mass of the glycine mother liquor based on the mass of the zirconium element. Immediately heating to 160 ℃ under the stirring state at the speed of 190r/min, preserving the temperature for 1.5 hours to perform hydrolysis reaction (the pressure is 2.8MPa), then cooling to about 100 ℃ and relieving the pressure to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 698 g of glycine aqueous solution, wherein the aqueous solution is yellow brown, the mass percentage of glycine in the aqueous solution is 28.10 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 3.5 g of activated carbon into the glycine aqueous solution, stirring the mixture for 40min at the temperature of 55 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure to a glycine content of 30 wt% to obtain a concentrated glycine aqueous solution having a weight of 653.80 g (molar amount of glycine: 2.615 mol).

To the concentrated glycine aqueous solution obtained above and introduced into the complexation reaction kettle was added 749.81 g (2.615mol) of 98 wt% cobalt sulfate heptahydrate, and then the temperature was raised to 95 ℃ with stirring, and the reaction was carried out at that temperature for 2.0 hours to obtain 1403.61 g of a glycine complex cobalt sulfate aqueous solution in which the content of glycine complex cobalt sulfate was 42.85 wt%. Directly concentrating the aqueous solution in a complexing reaction kettle until the aqueous solution is anhydrous, then pouring the aqueous solution into a porcelain dish, putting the porcelain dish into a blast drying oven to dry (105 ℃) until the weight is constant, grinding and sieving to obtain 702.62 g of brick red powdery glycine complexing cobalt sulfate product, wherein the purity of the glycine complexing cobalt sulfate product is 99%, the yield is more than or equal to 99.9%, and the recovery rate of the glycine is more than or equal to 99.9%. The infrared spectrum of the glycine and glycine complexed cobalt sulfate product prepared in this example is shown in FIG. 6.

Example 6

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and 0.35 g of metallic zirconium powder were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and stirring device, the contents of the individual components being: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin acid 0.3 wt%, hydantoin acid amide 0.1 wt%, ammonia 20 ppm. Wherein the amount of the zirconium is 500ppm of the mass of the glycine mother liquor based on the mass of the zirconium element. Immediately heating to 160 ℃ under stirring at a speed of 200r/min, keeping the temperature for 1.5 hours to perform hydrolysis reaction (pressure is 2.2MPa), then cooling to about 100 ℃ and relieving pressure to normal pressure, pouring the reaction material into a beaker, cooling to room temperature to obtain 698 g of glycine aqueous solution, wherein the aqueous solution is yellowish brown, the glycine content in the aqueous solution is 28.10 wt% by ion chromatography, and impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like are not detected, which indicates that the impurities are completely converted into glycine.

And (3) carrying out steam stripping treatment on the obtained glycine aqueous solution to remove ammonia and carbon dioxide, then adding 2.2 g of activated carbon into the glycine aqueous solution, stirring the mixture for 40min at the temperature of 70 ℃, and then carrying out suction filtration to remove the activated carbon to obtain decolorized feed liquid, wherein the feed liquid is colorless transparent liquid. The decolorized feed solution was concentrated in a concentration kettle under reduced pressure until the glycine content was 35 wt%, to obtain a concentrated glycine aqueous solution having a weight of 560.39 g (molar amount of glycine: 2.615 mol).

To the concentrated glycine aqueous solution obtained above and introduced into the complexation reaction kettle was added 749.81 g (2.615mol) of 98 wt% cobalt sulfate heptahydrate, and then the temperature was raised to 95 ℃ with stirring, and the reaction was carried out at that temperature for 2.0 hours to obtain 1403.61 g of a glycine complex cobalt sulfate aqueous solution in which the content of glycine complex cobalt sulfate was 42.85 wt%. Directly concentrating the aqueous solution in a complexing reaction kettle until the aqueous solution is anhydrous, then pouring the aqueous solution into a porcelain dish, putting the porcelain dish into a blast drying oven to dry (105 ℃) until the weight is constant, grinding and sieving to obtain 702.62 g of brick red powdery glycine complexing cobalt sulfate product, wherein the purity of the glycine complexing cobalt sulfate product is 99%, the yield is more than or equal to 99.9%, and the recovery rate of the glycine is more than or equal to 99.9%.

Comparative example 1

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin 0.3 wt%, hydantoin 0.1 wt% (total impurities 3.8 wt%), ammonia 30 ppm. Immediately raising the temperature to 160 ℃ while stirring at a speed of 200r/min and keeping the temperature for 1.5 hours to perform hydrolysis reaction (pressure of 2.2MPa), then cooling to about 100 ℃ and depressurizing to normal pressure, pouring the reaction mass into a beaker, cooling to room temperature to obtain 700 g of glycine-containing aqueous solution, which is yellowish brown, and the glycine content of the aqueous solution is 20.8 wt% by ion chromatography, and the total content of impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like in the aqueous solution is 7.2 wt% by ion chromatography, which shows that glycine is partially condensed and dehydrated to compounds such as dipeptide, tripeptide and the like under high temperature conditions, and the impurities are not hydrolyzed to form glycine under the conditions of comparative example 1.

Comparative example 2

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin 0.3 wt%, hydantoin 0.1 wt% (total impurities 3.8 wt%), ammonia 20 ppm. Heating to 100 deg.C immediately while stirring at 200r/min, maintaining the temperature for 1.5 hr for hydrolysis (pressure of 2.2MPa), cooling to about 50 deg.C, depressurizing to normal pressure, pouring the reaction mixture into a beaker, cooling to room temperature to obtain 700 g of glycine-containing aqueous solution which is yellowish brown, and analyzing the glycine content in the aqueous solution to 23.0 wt% by ion chromatography, wherein the total content of impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like is 5.0 wt% by ion chromatography, and the glycine is condensed and dehydrated to be converted into compounds such as dipeptide, tripeptide and the like in a small amount under relatively low temperature conditions (within 100 deg.C), and the impurities are not hydrolyzed to form glycine under the conditions of comparative example 2.

Comparative example 3

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin 0.3 wt%, hydantoin 0.1 wt% (total impurities 3.8 wt%), ammonia 30 ppm. Heating to 80 deg.C immediately while stirring at 200r/min, maintaining the temperature for 1.5 hr for hydrolysis (pressure of 2.2MPa), cooling to about 50 deg.C, depressurizing to normal pressure, pouring the reaction mixture into a beaker, cooling to room temperature to obtain 700 g of aqueous glycine solution, which is yellowish brown, and analyzing the glycine content in the aqueous solution to 24.0 wt% by ion chromatography, wherein the total content of impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide, etc. in the aqueous solution is 4.0 wt% by ion chromatography, indicating that glycine has a small amount of condensation and dehydration at a relatively low temperature (within 90 deg.C) to convert into compounds such as dipeptide, tripeptide, etc., and these impurities are not hydrolyzed to form glycine under the conditions of comparative example 3.

Comparative example 4

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin 0.3 wt%, hydantoin 0.1 wt% (total impurities 3.8 wt%), ammonia 30 ppm. Immediately raising the temperature to 65 ℃ under the stirring condition at the speed of 200r/min, keeping the temperature for 1.5 hours to perform hydrolysis reaction (the pressure is 2.2MPa), then cooling to about 50 ℃ and relieving the pressure to normal pressure, pouring the reaction materials into a beaker, cooling to room temperature to obtain 700 g of glycine aqueous solution, wherein the aqueous solution is yellowish brown, the content of glycine in the aqueous solution is 24.2 wt% by ion chromatography, and the content of impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin acid amide and the like in the aqueous solution is 3.8 wt% in total by ion chromatography, which indicates that glycine does not undergo condensation dehydration under relatively low temperature conditions (within 80 ℃) to be converted into compounds such as dipeptide, tripeptide and the like, and the impurities are not hydrolyzed to form glycine under the conditions of comparative example 4.

Comparative example 5

700 g of glycine mother liquor having a total nitrogen content of 5.23 wt.% and consisting of the following constituents were introduced into a 1000ml pressure-resistant reactor (material 316L) having a feed and a stirrer: glycine 24.2 wt%, glycine dipeptide 1.5 wt%, hydantoin 0.5 wt%, diketopiperazine 0.2 wt%, glycine tripeptide 0.6 wt%, glycinamide 0.6 wt%, hydantoin 0.3 wt%, hydantoin 0.1 wt% (total impurities 3.8 wt%), ammonia 30 ppm. 209.2 g of 50% by weight aqueous sodium hydroxide solution (2.615mol) were then added. Heating to 120 ℃ immediately under stirring at a speed of 200r/min, keeping the temperature for 1.5 hours to perform hydrolysis reaction (pressure is 2.2MPa), cooling to about 50 ℃ and depressurizing to normal pressure, pouring the reaction mixture into a beaker, cooling to room temperature to obtain 905 g of sodium glycinate aqueous solution, wherein the aqueous solution is brown yellow, the content of glycine in the aqueous solution is 20.73 wt% by ion chromatography, impurities such as glycine dipeptide, hydantoin, diketopiperazine, glycine tripeptide, glycinamide, hydantoin amide and the like in the aqueous solution are detected by ion chromatography, hydantoin, diketopiperazine, hydantoin acid amide and hydantoin acid amide are not detected, but glycine dipeptide and glycine tripeptide are detected, the total content of the two is 0.93 wt%, when the glycine mother solution is hydrolyzed by adding sodium hydroxide with an equal molar amount (based on the total nitrogen amount in the mother solution) under heating, impurities in the glycine mother liquor are not all completely converted into glycine.

Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

2. The method as claimed in claim 1, wherein, in the step (1), the total nitrogen content of the glycine crystallization mother liquor is 3.0-5.5 wt%;

preferably, the glycine crystallization mother liquor comprises the following components in percentage by mass: 15-26 parts of glycine, 0.5-3.5 parts of glycine dipeptide, 0.5-0.8 part of glycine tripeptide, 0.5-2.0 parts of hydantoin, 0.2-0.6 part of diketopiperazine, 0.1-1.0 part of glycinamide, 0.05-0.3 part of hydantoin, 0.05-0.2 part of hydantoin amide, less than 50ppm of ammonia and the balance of water;

preferably, the method further comprises producing the hydantoin process glycine crystallization mother liquor by: feeding hydroxyl acetonitrile, ammonia, carbon dioxide and water according to a molar feeding ratio of 1:6:3 (44-46), wherein the reaction temperature is 140-160 ℃, and the reaction time is 2-3 hours; after the reaction is finished, removing carbon dioxide and ammonia which do not participate in the reaction through steam stripping to obtain a dilute glycine solution, decoloring, concentrating, cooling and crystallizing to obtain a crude glycine with a light yellow crystal, and separating the crude glycine to obtain a crystallization mother liquor as the hydantoin-method glycine crystallization mother liquor;

preferably, the method further comprises producing the hydantoin process glycine crystallization mother liquor by: adding water into the crude glycine product for recrystallization, separating the recrystallized glycine to obtain a recrystallization mother liquor, and taking the single recrystallization mother liquor or the mixture of the recrystallization mother liquor and the crystallization mother liquor as the hydantoin-process glycine crystallization mother liquor;

preferably, in step (1), the zirconium feedstock is in the form of a reactor lining, a briquette or a powder;

preferably, in step (1), the zirconium-containing alloy is an alloy having a zirconium content of 5 wt% to 30 wt%; preferably, the zirconium-containing alloy is a zirconium-iron alloy, a zirconium-cobalt alloy, a zirconium-copper alloy, a zirconium-tin alloy, a zirconium-aluminum alloy, a zirconium-niobium alloy, or any mixture thereof;

preferably, the zirconium salt is an inorganic zirconium salt; preferably, the inorganic zirconium salt comprises zirconium sulfate, zirconium chloride, zirconium carbonate, zirconium nitrate, zirconium phosphate, zirconium acetate, or any mixture thereof;

preferably, in the step (1), the adding amount of the zirconium raw material is 20-500 ppm of the mass of the hydantoin-process glycine crystallization mother liquor based on the mass of zirconium element;

preferably, in the step (1), the hydrolysis reaction is carried out by heating to 150-170 ℃ and keeping the temperature for 30-90 min with stirring at the speed of 60-200 r/min;

preferably, in the step (1), the pressure of the hydrolysis reaction is 1.2-3.0 MPa.

3. The process according to claim 1 or 2, wherein, in step (2), the glycine aqueous solution of step (1) is subjected to a stripping treatment to remove ammonia and carbon dioxide;

preferably, in the step (2), activated carbon or a nanofiltration membrane is used for the decolorization treatment;

preferably, the using amount of the activated carbon is 0.2-1.0 wt% of the total mass of the glycine in the glycine aqueous solution;

preferably, the temperature of the decoloring treatment is 40-70 ℃, and the time is 20-40 min.

4. The method according to any one of claims 1 to 3, wherein, in step (3), the inorganic metal salt is a sulfate; preferably, the sulfate is zinc sulfate, ferrous sulfate, copper sulfate, manganese sulfate, an anhydrous compound or hydrate of cobalt sulfate, or any mixture thereof;

preferably, in the step (3), the feeding molar ratio of the metal ions in the inorganic metal salt to the glycine is 1: 1;

preferably, in the step (3), the temperature of the complexation reaction is 80-100 ℃ and the time is 1-2 hours;

preferably, in the step (3), the concentration of the glycine complex metal salt aqueous solution is 35 to 60 wt%;

preferably, in step (3), the glycine metal complex salt contains any one or more of zinc, iron, copper, manganese and cobalt;

preferably, in step (3), the glycine metal complex salt is glycine complex sulfate;

preferably, the chemical structure of the glycine metal complex salt is as follows:

5. The method according to any one of claims 1-4, wherein the method comprises the steps of:

6. The process of any one of claims 1-5, wherein the process is one or more of a batch, semi-continuous, or continuous operating process.

7. A composition for use in the method of any one of claims 1-6, wherein the composition comprises a hydantoin process glycine crystallization mother liquor and a zirconium feedstock comprising zirconium, a zirconium-containing alloy, a zirconium salt, zirconium oxide, or any mixture thereof;

preferably, the zirconium feedstock is in the form of a reactor lining, a cake, a powder;

preferably, the zirconium-containing alloy is an alloy having a zirconium content of 5 wt% to 30 wt%; preferably, the zirconium-containing alloy is a zirconium-iron alloy, a zirconium-cobalt alloy, a zirconium-copper alloy, a zirconium-tin alloy, a zirconium-aluminum alloy, a zirconium-niobium alloy, or any mixture thereof;

preferably, the amount of the zirconium raw material is 20 to 500ppm of the mass of the hydantoin-process glycine crystallization mother liquor, based on the mass of zirconium element.

8. A feed additive, wherein the feed additive comprises a glycine metal complex salt prepared by the method of any one of claims 1-6;

preferably, the glycine metal complex salt contains any one or more of zinc, iron, copper, manganese and cobalt;

preferably, the glycine complex metal salt is a glycine complex sulfate;

wherein M is any one or more selected from zinc, iron, copper, manganese and cobalt; n is 1 to 10;

preferably, the feed additive further comprises a feedinglogically acceptable auxiliary material.

9. An apparatus for carrying out the method of any one of claims 1-6, wherein the apparatus comprises a hydrolysis reactor, a stripping column, a decolorization tank, a concentration tank, a complexation tank, and a drying system connected in series in fluid communication.

10. The apparatus of claim 9, wherein the hydrolysis reactor and the concentration tank are respectively provided with a pressure auxiliary device;

preferably, the hydrolysis reactor, the concentration kettle, the complexation reaction kettle and the drying system are respectively provided with a temperature regulation auxiliary device;

preferably, the drying system is a spray drying system, a forced air drying oven or a vacuum drying oven.