Process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate

Abstract

The invention discloses a process for producing zinc thiosulfate through intermediate conversion of ammonium thiosulfate. The process comprises the following steps: S1, firstly, preparing ammonium thiosulfate, zinc hydroxide and sulfur dioxide; s2, mixing an ammonium thiosulfate solution and zinc hydroxide; s3, putting the mixed ammonium thiosulfate solution and zinc hydroxide into a reaction kettle, adding water, controlling temperature and stirring to generate a zinc thiosulfate solution and ammonium hydroxide, dissociating ammonium hydroxide into ammonia gas and water in water, and then reacting the ammonia gas with sulfur dioxide to generate ammonium thiosulfate for recycling; s4, carrying out filtering; and S5, performing packaging. Ammonia water and sulfur dioxide react to produce ammonium thiosulfate, the ammonium thiosulfate and zinc hydroxide are subjected to a replacement reaction to generate zinc thiosulfate, and meanwhile, the by-product ammonium thiosulfate generated by purifying waste gas sulfur dioxide is selected, so that the pollution to the environment is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of zinc thiosulfate production technology, and in particular to a process for producing zinc thiosulfate through intermediate conversion of ammonium thiosulfate. Background Art

[0002] Zinc thiosulfate, as an important inorganic chemical product, is widely used in medicine, food, agriculture and other fields.

[0003] The conventional method for producing zinc thiosulfate is to react zinc hydroxide with sulfur dioxide to generate zinc thiosulfate. Since the solubility of zinc hydroxide is extremely low, the production efficiency is extremely low and the energy consumption cost is very high. Therefore, the method of producing zinc thiosulfate using zinc hydroxide and sulfur dioxide has the problems of high production cost and great environmental pollution. Therefore, this scheme proposes a process for producing zinc thiosulfate through intermediate conversion of ammonium thiosulfate to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a process for producing zinc thiosulfate through intermediate conversion of ammonium thiosulfate to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate, comprising the following steps:

[0006] S1, firstly preparing raw materials, the raw materials include ammonium thiosulfate, zinc hydroxide and sulfur dioxide, and the ammonium thiosulfate is prepared by reaction, the purity of the ammonium thiosulfate is ≥57%, and the purity of the zinc hydroxide is ≥98%;

[0007] S2, mixing the raw materials, mixing 57% ammonium thiosulfate solution and 98% zinc hydroxide in a mass ratio of 1:1, and stirring evenly;

[0008] S3, performing a reaction preparation, placing the mixed ammonium thiosulfate solution and zinc hydroxide into a reactor, generating a zinc thiosulfate solution and ammonium hydroxide by adding water, controlling the temperature and stirring, and the ammonium hydroxide is dissociated into ammonia and water in water, and then the ammonia is reacted with sulfur dioxide to generate ammonium thiosulfate, which is reused;

[0009] S4, filtering the solution after the reaction of the ammonium thiosulfate solution and the zinc hydroxide, filtering out the unreacted zinc slag, separating the clear solution, and obtaining a finished zinc thiosulfate solution;

[0010] S5, packaging: measuring the finished zinc thiosulfate and packaging it in 200L-1000L plastic barrels.

[0011] Preferably, the preparation of ammonium thiosulfate comprises the following steps:

[0012] S101, preparing ammonia water and sulfur dioxide, wherein the concentration of the ammonia water is 25% to 30%;

[0013] S102, adding ammonia water and sulfur dioxide into a reaction container in a mass ratio of 2:1, and stirring and mixing at 50-80 r / min;

[0014] S103, performing a cold water bath reaction by controlling the reaction temperature at 10-15°C;

[0015] S104, after the reaction is completed, the product is centrifuged and filtered to obtain a solid product of ammonium thiosulfate;

[0016] S105, drying the product to obtain ammonium thiosulfate with a purity of ≥57%.

[0017] Preferably, the chemical reaction equation of ammonia water and sulfur dioxide is expressed as:

[0018] 2NH3·H2O+SO2=(NH4)2SO3+H2O (1).

[0019] Preferably, the ammonium thiosulfate solution and zinc hydroxide are placed in a stirring container and stirred and mixed at a speed of 100-120 r / min for 3-5 min.

[0020] Preferably, the chemical reaction equation of the ammonium thiosulfate solution and zinc hydroxide is expressed as:

[0021] (NH4)2S2O3+Zn(OH)2=ZnS2O3+2NH3↑+2H2O (2).

[0022] Preferably, the temperature of the reaction of the ammonium thiosulfate solution and zinc hydroxide is controlled at 40-60°C.

[0023] Preferably, the stirring speed of the reaction of the ammonium thiosulfate solution and zinc hydroxide is 50-60 r / min, and the stirring reaction time is 2-3 hours, and the reaction generates a zinc thiosulfate solution with a concentration of 25%.

[0024] Preferably, after the reaction of the ammonium thiosulfate solution and zinc hydroxide is completed, the reaction mixture is filtered using a filter to remove unreacted zinc residue, and after filtering, the liquid under the filter is a clear zinc thiosulfate solution.

[0025] Preferably, during the filtration process, the filter is tilted and stirred at a speed of 10-15 r / min until the solution filtration is completed.

[0026] Preferably, the finished zinc thiosulfate is packaged in a storage barrel marked with a capacity display, and then the finished zinc thiosulfate is put into the barrel with a filter.

[0027] Technical effects and advantages of the present invention:

[0028] The invention firstly uses ammonia water and sulfur dioxide to react to produce ammonium thiosulfate, and then undergoes a substitution reaction with zinc hydroxide to generate zinc thiosulfate. The product has good stability, corrosion resistance and biocompatibility. Meanwhile, the by-product ammonium thiosulfate generated by purifying sulfur dioxide in waste gas is selected, which not only reduces pollution to the environment, but also reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the operating steps of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the 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 described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1, the present invention provides as follows Figure 1 The process for producing zinc thiosulfate through the intermediate conversion of ammonium thiosulfate shown includes the following steps:

[0032] S1, firstly preparing raw materials, the raw materials include ammonium thiosulfate, zinc hydroxide and sulfur dioxide, and the ammonium thiosulfate is prepared by reaction, the purity of the ammonium thiosulfate is ≥57%, and the purity of the zinc hydroxide is ≥98%;

[0033] It should be noted that ammonium thiosulfate is a chemical substance with the molecular formula (NH4)2S2O3. It is white crystals at room temperature and is easily soluble in water. It should be stored in a cool, dry warehouse and protected from moisture. It will decompose to form ammonium sulfite, sulfur, ammonia, hydrogen sulfide and water when heated to 150°C. It is unstable in the air, but stable in ammonia. It will completely decompose at 150°C. It is easily soluble in water, slightly soluble in acetone, and insoluble in alcohol and ether. Its aqueous solution will precipitate sulfur after being left for a long time. The concentrated aqueous solution will gradually decompose at above 50°C. It is used as a photographic fixer, metal cleaning agent, electroplating solution and reducing agent.

[0034] Zinc hydroxide is an inorganic compound with the chemical formula Zn(OH)2. It is composed of divalent zinc and two hydroxide ions. It is an amphoteric hydroxide. It is insoluble in water, but soluble in acid, alkali solutions and ammonia water. It should be stored in a ventilated and dry place to prevent moisture and heat. It should be protected from rain and sunlight during transportation. It should not be stored or transported together with acids or ammonium salts. It should be handled with care during loading and unloading to prevent damage to the packaging.

[0035] The chemical formula of sulfur dioxide is SO2. It is the simplest and most common sulfur oxide. It is a colorless, transparent gas with a pungent odor at room temperature and pressure. It is easily soluble in water, ethanol, and ether. It dissolves in water to form a dibasic medium-strong acid sulfurous acid (H2SO3) with bleaching properties. It can form colorless compounds when combined with organic pigments. Sulfur dioxide is one of the main pollutants in the atmosphere and is produced during volcanic eruptions, industrial production, and the combustion of fossil fuels (coal, oil, and natural gas).

[0036] Specifically, the preparation of ammonium thiosulfate includes the following steps:

[0037] S101, preparing ammonia water and sulfur dioxide, wherein the concentration of the ammonia water is 25% to 30%;

[0038] It should be noted that ammonia water is an aqueous solution of gaseous ammonia. Its main component is NH3·H2O, that is, monohydrated ammonia. It is colorless, transparent and has a pungent odor. The density of ammonia water is lower than that of water. It is unstable, volatile, and easily decomposed by light or heat. Ammonia water itself is a non-combustible liquid with no explosion hazard. The ammonia gas separated from water has a strong pungent odor and is irritating and corrosive to the eyes, nose and skin of the human body, and is also combustible and explosive.

[0039] Concentrated ammonia water usually contains 28% to 29% ammonia. The gas molecules in the ammonia water undergo weak hydrolysis to produce hydroxide ions (OH-) and ammonium ions (NH4+), so it is weakly alkaline. It has the general properties of an alkali and can react with acidic substances and various metal ions such as copper and zinc to produce insoluble weak bases or amphoteric hydroxides.

[0040] S102, adding ammonia water and sulfur dioxide into a reaction container in a mass ratio of 2:1, and stirring and mixing at 50-80 r / min;

[0041] S103, performing a cold water bath reaction by controlling the reaction temperature at 10-15°C;

[0042] Furthermore, the chemical reaction equation of ammonia and sulfur dioxide is expressed as:

[0043] 2NH3·H2O+SO2=(NH4)2SO3+H2O (1).

[0044] S104, after the reaction is completed, the product is centrifuged and filtered to obtain a solid product of ammonium thiosulfate;

[0045] S105, drying the product to obtain ammonium thiosulfate with a purity of ≥57%.

[0046] S2, mixing the raw materials, mixing 57% ammonium thiosulfate solution and 98% zinc hydroxide in a mass ratio of 1:1, and stirring evenly;

[0047] Specifically, the ammonium thiosulfate solution and zinc hydroxide are placed in a stirring container and stirred and mixed at a speed of 100-120 r / min for 3-5 minutes.

[0048] S3, performing a reaction preparation, placing the mixed ammonium thiosulfate solution and zinc hydroxide into a reactor, generating a zinc thiosulfate solution and ammonium hydroxide by adding water, controlling the temperature and stirring, and the ammonium hydroxide is dissociated into ammonia and water in water, and then the ammonia is reacted with sulfur dioxide to generate ammonium thiosulfate, which is reused;

[0049] It should be noted that the mixed raw materials are placed in a reactor, water required for the reaction is added, the reaction temperature is controlled between 40-60°C, and the stirring speed is controlled at 50-60r / min. Under this condition, ammonium thiosulfate reacts with zinc hydroxide to generate a 25% zinc thiosulfate solution, and the generated ammonia reacts with sulfur dioxide to generate ammonium thiosulfate, which is reused.

[0050] The use of ammonium thiosulfate, a by-product generated by purifying sulfur dioxide in waste gas, not only reduces pollution to the environment, but also reduces production costs, and improves economic benefits by more than 30%.

[0051] Specifically, the chemical reaction equation of ammonium thiosulfate solution and zinc hydroxide is expressed as:

[0052] (NH4)2S2O3+Zn(OH)2=ZnS2O3+2NH3↑+2H2O (2).

[0053] Furthermore, the reaction temperature of the ammonium thiosulfate solution and zinc hydroxide is controlled at 40-60° C., the stirring speed of the ammonium thiosulfate solution and zinc hydroxide is 50-60 r / min, and the stirring reaction time is 2-3 hours, and the reaction generates a zinc thiosulfate solution with a concentration of 25%.

[0054] S4, filtering the solution after the reaction of the ammonium thiosulfate solution and the zinc hydroxide, filtering out the unreacted zinc slag, separating the clear solution, and obtaining a finished zinc thiosulfate solution;

[0055] Specifically, after the reaction of the ammonium thiosulfate solution and zinc hydroxide is completed, the reaction mixture is filtered using a filter to remove unreacted zinc residue. After filtering, the liquid under the filter is a clear zinc thiosulfate solution.

[0056] Furthermore, during the filtration process, the filter was tilted and stirred at a speed of 10-15 r / min until the solution was filtered.

[0057] It should be noted that when filtering, prepare the filtering equipment, then set up a clean collection container at the discharge end of the filter, and slowly pour the reaction mixture into the filter. A stirring device can be used to help guide the flow to ensure that the liquid flows slowly and evenly into the filter to prevent solid matter from being washed into the collection container. During the filtering process, observe that the solid zinc slag (precipitate) in the filter is retained, while the clear liquid flows into the collection container. If the filtration speed is slow, increase the filtration speed by stirring to assist filtration; after the filtration is completed, ensure that the solids in the filter are completely precipitated and no liquid remains. The filter can be gently tilted to help the last liquid flow out; mark the collected clear zinc thiosulfate solution in the collection container, and record the experimental date and related information; after the filtration is completed, remove the filter, handle the filter paper and residual zinc slag, and dispose of them according to waste disposal regulations.

[0058] S5, packaging: measuring the finished zinc thiosulfate and packaging it in 200L-1000L plastic barrels.

[0059] Specifically, the finished zinc thiosulfate is packaged in a storage barrel marked with a capacity display, and then the finished zinc thiosulfate is put into the barrel with a filter.

[0060] It should be noted that when measuring and packaging the finished zinc thiosulfate in 200L-1000L plastic barrels, ensure that the working environment is clean and tidy, meet safety and hygiene standards, and prepare the necessary equipment and tools, including measuring equipment (such as electronic scales, liquid flow meters, etc.), plastic barrels with capacity markings and funnels; at the same time, select suitable plastic barrels according to the properties of the finished zinc thiosulfate, ensure that the barrel material can resist chemical corrosion and meet relevant safety standards; use a funnel to carefully pour the measured zinc thiosulfate into the plastic barrel to avoid spilling, and pay attention to avoid foaming when filling the barrel to ensure that the liquid flows smoothly into the barrel; after filling, ensure that the barrel cover is well sealed to prevent leakage and contamination; check whether the barrel cover and barrel body are intact to ensure that there is no damage; label each barrel with the product name, specifications, production date, expiration date and precautions; store the packed plastic barrels in an appropriate environment to avoid direct sunlight and high temperature to ensure the stability and safety of the product.

[0061] Example 2: Experiment on generating zinc thiosulfate by reaction of zinc hydroxide and ammonium thiosulfate:

[0062] 1. Experimental equipment;

[0063] pH value tester, electronic balance, constant temperature heating stirrer, washing bottle, medium speed filter paper, glass rod, brown burette, thermometer, electromagnetic stirring bar, conical flask and 250ml volumetric flask.

[0064] 2. Experimental steps;

[0065] Zinc hydroxide and ammonium thiosulfate react to form zinc thiosulfate. The reaction equation is as follows:

[0066]

[0067] The content of ammonium thiosulfate used is calculated as 60%, and the amount of ammonium thiosulfate used is:

[0068] 74.7 / 0.6＝124.5 ( 克 ) (4);

[0069] Therefore, zinc hydroxide is calculated and checked according to the analysis, and the experiment is as follows:

[0070] 53-55 grams of zinc hydroxide (slightly in excess) react with 124.5 grams of 60% ammonium thiosulfate to produce 89.4 grams of zinc thiosulfate.

[0071] 3. Detection method;

[0072] 1) HG / T2328-2006, mainly detects thiosulfate ions;

[0073] 2) HG / T2326-2005, mainly detects zinc ions;

[0074] 3) Density, determined by weight method;

[0075] 4) pH value: measured with a Mettler acidometer.

[0076] 4. Experimental data;

[0077] This experiment carried out reaction experiments from the aspects of raw material ratio, reaction temperature and reaction time. The specific reaction data are shown in Table 1 below:

[0078] Table 1 Experimental data results

[0079]

[0080] 5. Experimental conclusion;

[0081] According to the test results, it conforms to the general rule that the amount of water added determines the product content. In the experiment, the product content ranged from 25% to 39%, and the zinc ion content ranged from 3.86% to 7.76%. The actual production should determine the raw material ratio in combination with the product yield.

[0082] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate, characterized in that: The production process includes the following steps: S1, firstly preparing raw materials, the raw materials include ammonium thiosulfate, zinc hydroxide and sulfur dioxide, and the ammonium thiosulfate is prepared by reaction, the purity of the ammonium thiosulfate is ≥57%, and the purity of the zinc hydroxide is ≥98%; S2, mixing the raw materials, mixing 57% ammonium thiosulfate solution and 98% zinc hydroxide in a mass ratio of 1:1, and stirring evenly; S3, performing a reaction preparation, placing the mixed ammonium thiosulfate solution and zinc hydroxide into a reactor, generating a zinc thiosulfate solution and ammonium hydroxide by adding water, controlling the temperature and stirring, and the ammonium hydroxide is dissociated into ammonia and water in water, and then the ammonia is reacted with sulfur dioxide to generate ammonium thiosulfate, which is reused; S4, filtering the solution after the reaction of the ammonium thiosulfate solution and the zinc hydroxide, filtering out the unreacted zinc slag, separating the clear solution, and obtaining a finished zinc thiosulfate solution; S5, packaging: measuring the finished zinc thiosulfate and packaging it in 200L-1000L plastic barrels.

2. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 1, characterized in that: The preparation of the ammonium thiosulfate comprises the following steps: S101, preparing ammonia water and sulfur dioxide, wherein the concentration of the ammonia water is 25% to 30%; S102, adding ammonia water and sulfur dioxide into a reaction container in a mass ratio of 2:1, and stirring and mixing at 50-80 r / min; S103, performing a cold water bath reaction by controlling the reaction temperature at 10-15°C; S104, after the reaction is completed, the product is centrifuged and filtered to obtain a solid product of ammonium thiosulfate; S105, drying the product to obtain ammonium thiosulfate with a purity of ≥57%.

3. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 2, characterized in that: The chemical reaction equation of the ammonia water and sulfur dioxide is expressed as: 2NH3·H2O+SO2=(NH4)2SO3+H2O (1).

4. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 1, characterized in that: The ammonium thiosulfate solution and zinc hydroxide are placed in a stirring container and stirred and mixed at a speed of 100-120 r / min for 3-5 minutes.

5. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 1, characterized in that: The chemical reaction equation of the ammonium thiosulfate solution and zinc hydroxide is expressed as: (NH4)2S2O3+Z n (OH)2=ZnS2O3+2NH3↑+2H2O (2)。 6. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 5, characterized in that: The reaction temperature of the ammonium thiosulfate solution and zinc hydroxide is controlled at 40-60°C.

7. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 6, characterized in that: The stirring speed of the reaction of the ammonium thiosulfate solution and zinc hydroxide is 50-60 r / min, and the stirring reaction time is 2-3 hours, and the reaction generates a zinc thiosulfate solution with a concentration of 25%.

8. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 1, characterized in that: After the reaction of the ammonium thiosulfate solution and zinc hydroxide is completed, the reaction mixture is filtered using a filter to remove unreacted zinc residue. After filtering, the liquid under the filter is a clear zinc thiosulfate solution.

9. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 8, characterized in that: During the filtration process, the filter is tilted and stirred at a speed of 10-15 r / min until the solution filtration is completed.

10. The process for producing zinc thiosulfate by intermediate conversion of ammonium thiosulfate according to claim 1, characterized in that: The finished zinc thiosulfate is packaged in a storage barrel marked with a capacity display, and then the finished zinc thiosulfate is put into the barrel with a filter.

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