阅读说明：本技术 一种采用焦亚硫酸钾母液生产食品级亚硫酸钾的方法 (Method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor ) 是由 徐德良 孙军 马忠堂 何国勇 于 2020-05-23 设计创作，主要内容包括：本发明公开了一种采用焦亚硫酸钾母液生产食品级亚硫酸钾的方法。本发明提供采用焦亚硫酸钾母液生产食品级亚硫酸钾的方法,采用附加值很低的焦亚硫酸钾母液生产,其生产过程不需要加热赶净CO<Sub>2</Sub>、无需生产后期的加热蒸发,利用自身反应热完全满足反应温度的要求,使生产能耗大大降低、生产成本也大幅度降低。(The invention discloses a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor. The invention provides a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor, which adopts the potassium metabisulfite mother liquor with low additional value to produce, and the production process does not need to heat to drive off CO 2 The method does not need heating evaporation in the later production stage, and utilizes the self reaction heat to completely meet the requirement of reaction temperature, thereby greatly reducing the production energy consumption and the production cost.)

1. A method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor is characterized by comprising the following steps:

1) adding potassium hydroxide into the potassium metabisulfite mother liquor under a stirring state, and adjusting the pH value of the solution to 4-8;

2) adding a heavy metal impurity removing agent into the reaction primary solution obtained in the step 1), and stirring for 20-40 min at the temperature of 60-90 ℃ to generate small heavy metal group particles;

3) continuously adding an auxiliary agent into the solution obtained in the step 2) under the stirring state, adsorbing and coagulating the heavy metal group small particles into large particles for precipitation, and standing under the heat preservation state for precipitation and aging;

4) filtering the liquid obtained in the step 3) to obtain a filtrate; adding potassium hydroxide into the obtained filtrate to make K in the solution⁺The content of the potassium sulfite reaches 200-500 g/L, and then the potassium sulfite reacts with sulfur dioxide until the pH value is 8.0-10.0 to generate a potassium sulfite solution;

5) and 4) carrying out spray drying on the solution obtained in the step 4) under the protection of inert gas to obtain a food-grade potassium sulfite product.

2. The method for producing food-grade potassium sulfite by using potassium metabisulfite mother liquor according to claim 1, wherein the heavy metal impurity removing agent is an inorganic heavy metal impurity removing agent or an organic heavy metal impurity removing agent; the inorganic heavy metal impurity removing agent is potassium sulfide, sodium sulfide, ammonium sulfide or hydrogen sulfide, and the addition amount of the inorganic heavy metal impurity removing agent is 0.003-0.008% of the total mass of the material; the organic heavy metal impurity removing agent is thioacetamide, dithiocarbamate or triaphobilintriazine salt; the addition amount of the organic heavy metal impurity removing agent is 0.001-0.005% of the total mass of the material.

3. The method for producing the food-grade potassium sulfite by adopting the potassium metabisulfite mother liquor as claimed in claim 1, wherein the auxiliary agent is any one or a compound of two of calcium sulfate, calcium sulfite, diatomite, activated clay, activated carbon, polyacrylamide and sodium polyacrylate; wherein, the adding amount of the calcium sulfate, the calcium sulfite, the diatomite, the activated clay and the activated carbon is 0.02 to 0.05 percent of the total mass of the materials; the addition amount of the polyacrylamide and the sodium polyacrylate is 0.0001-0.0005 percent of the total mass of the materials.

4. The method for producing food-grade potassium sulfite by using the potassium metabisulfite mother liquor according to claim 1, wherein in the step 3), the auxiliary agent is added in a specific manner that the auxiliary agent is added at a temperature of 60-80 ℃ and in a stirring state, and the stirring operation lasts for 15 min; and after stirring, keeping the temperature of the mixture at the temperature of 60-80 ℃ and standing the mixture for 45-60 min.

5. The method for producing the food-grade potassium sulfite by using the potassium metabisulfite mother liquor as claimed in claim 1, wherein the reaction temperature in the step 4) is 60-90 ℃.

6. The method for producing food-grade potassium sulfite by using potassium metabisulfite mother liquor according to claim 1, wherein the inert gas in the step 5) is nitrogen; the atmosphere condition is that the nitrogen content (V/V) is 90-95%.

7. The method for producing the food-grade potassium sulfite by using the potassium metabisulfite mother liquor according to the claim 1, wherein the spray drying is carried out under the protection of inert gas in the step 5), and the inlet temperature is 200-280 ℃ and the outlet temperature is 105-125 ℃.

8. The method for producing food-grade potassium sulfite by using potassium metabisulfite mother liquor according to claim 7, wherein the step 5) of spray drying under the protection of inert gas comprises the following specific steps:

5.1) heating the nitrogen, feeding the heated nitrogen into a spray dryer, and controlling the air intake rate to be 2100m³/h～2300m³H, air output 2800m³/h～3200m³/h；

And 5.2) when the air inlet temperature is 200-280 ℃ and the air outlet temperature is 105-125 ℃, starting a centrifugal nozzle and a feed pump, controlling the feed rate of the potassium sulfite solution to be 160-200 kg/h, and pumping the materials into a spray dryer for drying.

Technical Field

The invention relates to a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor, belonging to the technical field of chemical processes.

Background

The finished product of the food-grade potassium sulfite is white crystalline powder, is odorless, is oxidized into sulfate in the air, is easy to dissolve in water and is difficult to dissolve in ethanol; the water solution is alkaline and is decomposed when meeting acid and releases sulfur dioxide; has strong reducibility and low toxicity! Preservative, antioxidant, bleaching agent and reducing agent for food industry.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor.

The invention provides the following technical scheme:

a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor comprises the following steps:

1) adding potassium hydroxide into the potassium metabisulfite mother liquor under a stirring state, and adjusting the pH value of the solution to 4-8;

2) adding a heavy metal impurity removing agent into the reaction primary solution obtained in the step 1), and stirring for 20-40 min at the temperature of 60-90 ℃ to generate small heavy metal group particles;

3) continuously adding an auxiliary agent into the solution obtained in the step 2) under the stirring state, adsorbing and coagulating the heavy metal group small particles into large particles for precipitation, and standing under the heat preservation state for precipitation and aging; the step is favorable for better removing heavy metals and other harmful impurities in the potassium metabisulfite mother liquor.

4) Filtering the liquid obtained in the step 3) to obtain a filtrate; adding potassium hydroxide into the obtained filtrate to make K in the solution⁺The content of the potassium sulfite reaches 200-500 g/L, and then the potassium sulfite reacts with sulfur dioxide until the pH value is 8.0-10.0 to generate a potassium sulfite solution;

5) and 4) carrying out spray drying on the solution obtained in the step 4) under the protection of inert gas to obtain a food-grade potassium sulfite product.

Preferably, the heavy metal impurity removing agent is an inorganic heavy metal impurity removing agent or an organic heavy metal impurity removing agent;

the inorganic heavy metal impurity removing agent is potassium sulfide, sodium sulfide, ammonium sulfide or hydrogen sulfide, and the addition amount of the inorganic heavy metal impurity removing agent is 0.003-0.008% of the total mass of the material;

the organic heavy metal impurity removing agent is thioacetamide, dithiocarbamate or triaphobilintriazine salt; the addition amount of the organic heavy metal impurity removing agent is 0.001-0.005% of the total mass of the material.

Preferably, the auxiliary agent is any one or a compound of two of calcium sulfate, calcium sulfite, diatomite, activated clay, activated carbon, polyacrylamide and sodium polyacrylate; wherein, the adding amount of the calcium sulfate, the calcium sulfite, the diatomite, the activated clay and the activated carbon is 0.02 to 0.05 percent of the total mass of the materials; the addition amount of the polyacrylamide and the sodium polyacrylate is 0.0001-0.0005 percent of the total mass of the materials.

Preferably, in the step 3), the specific manner of adding the auxiliary agent is to add the auxiliary agent at the temperature of 60-80 ℃ and in a stirring state, and the stirring operation lasts for 15 min; and after stirring, keeping the temperature of the mixture at the temperature of 60-80 ℃ and standing the mixture for 45-60 min.

Preferably, the reaction temperature in step 4) is 60 ℃ to 90 ℃.

Preferably, the inert gas in step 5) is nitrogen; the atmosphere condition is that the nitrogen content (V/V) is 90-95%.

Preferably, in the step 5), spray drying is carried out under the protection of inert gas, wherein the inlet temperature is 200-280 ℃, and the outlet temperature is 105-125 ℃.

Further preferably, the spray drying in step 5) under the protection of inert gas comprises the following specific steps:

5.1) heating the nitrogen, feeding the heated nitrogen into a spray dryer, and controlling the air intake rate to be 2100m³/h～2300m³H, air output 2800m³/h～3200m³/h；

And 5.2) when the air inlet temperature is 200-280 ℃ and the air outlet temperature is 105-125 ℃, starting a centrifugal nozzle and a feed pump, controlling the feed rate of the potassium sulfite solution to be 160-200 kg/h, and pumping the materials into a spray dryer for drying.

The invention has the beneficial effects that:

1. according to the method for producing the food-grade potassium sulfite by using the potassium metabisulfite mother liquor, the mother liquor generated in the production of the potassium metabisulfite is utilized to produce the food-grade potassium sulfite; because the added value of the potassium metabisulfite mother liquor is low, the food-grade potassium sulfite is produced by utilizing the mother liquor, the cost of the food-grade potassium sulfite product is greatly reduced, and the economic benefit of an enterprise is increased;

in addition, the production practice shows that the contents of heavy metals and other harmful impurities can be enriched after the potassium metabisulfite mother liquor is reused for many times, and the heavy metal impurity removing agent and the auxiliary agent are added to reduce the contents of the heavy metals and other harmful impurities in the potassium metabisulfite mother liquor, so that the contents of the heavy metals and other harmful impurities in a potassium sulfite product are obviously reduced, the heavy metals in the obtained food-grade potassium sulfite finished product are reduced to be below 3(mg/kg), arsenic is reduced to be below 0.5(mg/kg), and selenium is reduced to be below 0.5(mg/kg), and the standard specification index requirements are far lower;

2. the method for producing the food-grade potassium sulfite by adopting the potassium metabisulfite mother liquor innovatively adopts a spray drying process technology under the protection of inert gas, does not need cooling crystallization, centrifugation, crushing and screening, and does not generate the mother liquor;

the potassium sulfite is prevented from contacting with air in a large area in the drying process and being oxidized into potassium sulfate; and potassium sulfite crystals collide and rub with each other during airflow drying, so that a potassium sulfite product is agglomerated; the production process is reduced, the production process flow is simplified, and the drying energy consumption is low; to obtain (K)₂SO₃) The content can reach more than 98 percent, and the product is stable and has certain economic and social benefits;

3. the invention provides a method for producing food-grade potassium sulfite by adopting potassium metabisulfite mother liquor, which adopts the potassium metabisulfite mother liquor with low additional value to produce, and the production process does not need to heat to drive off CO₂The method does not need heating evaporation in the later production stage, and utilizes the self reaction heat to completely meet the requirement of reaction temperature, thereby greatly reducing the production energy consumption and the production cost.

Drawings

FIG. 1 is a production flow chart for producing food grade potassium sulfite by using potassium metabisulfite mother liquor according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.