Preparation method of environment-friendly low-nitrogen high-purity potassium persulfate

Abstract

The invention provides a preparation method of environment-friendly low-nitrogen high-purity potassium persulfate, and belongs to the technical field of chemical reagents, and the preparation method specifically comprises the following steps: (1) adding distilled water into a reaction container, stirring at a certain rotating speed, heating to a certain temperature, and adding a proper amount of industrial-grade potassium persulfate; (2) adding a proper amount of nitrite into the reaction tank, enabling the nitrite to react with ammonium salt in potassium persulfate, cooling, crystallizing, filtering, washing and drying; and (3) pouring crystals obtained by the reaction into a recrystallization tank, dissolving, cooling and crystallizing, filtering, washing with ethanol, and drying. Through chemical and physical methods, the purity of the industrial-grade potassium persulfate is greatly improved, the industrial-grade potassium persulfate reaches the standard, and the yield is high. The water body total nitrogen detection standard can be reached by a one-time chemical method, the operation is simple and convenient, and recrystallization can be carried out for many times to reach a higher standard.

Description

Technical Field

[0001] The invention relates to the technical field of chemical reagents, and in particular to a method for preparing environmentally friendly, low-nitrogen, high-purity potassium persulfate. Background Art

[0002] Potassium persulfate is a white crystalline inorganic compound, odorless, deliquescent, combustion-supporting, and irritating. It is a key reagent for determining total nitrogen in water environment in the national standard "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry" (HJ636-2012), and specifies the detection method. Total ammonia is the total ammonia content of all ammonia-containing compounds in water, and is an important indicator of the degree of pollution and eutrophication of water.

[0003] With the rapid development of industry, people's living standards have significantly improved. Domestic sewage, solution drainage, and industrial wastewater are directly discharged into water bodies, which greatly increases the content of organic nitrogen and inorganic nitrogen compounds in water bodies, leading to the massive reproduction of plankton and the consumption of dissolved oxygen in water bodies, causing water pollution. With the strengthening of environmental protection management, the frequency of determination of total nitrogen content in water bodies has increased, which has led to a significant increase in the use of potassium persulfate as a key reagent for detection.

[0004] Since ammonium sulfate or ammonium bisulfate is used as the starting raw material in the production of industrial potassium persulfate, the ammonium salt content in industrial potassium persulfate is relatively high. The total nitrogen in potassium persulfate exists in the form of ammonium salt, so potassium persulfate needs to be purified by nitrogen reduction.

[0005] At present, domestic ordinary potassium persulfate has insufficient purity and high impurity content, and the existing method for purifying potassium persulfate requires multiple recrystallization purification. Although the method is simple to operate, it has high labor costs, long time consumption, low recovery rate, low crystallization efficiency, poor economic benefits, and the product is difficult to meet the quality requirement of total nitrogen content TN ≤ 0.0005%; although imported high-purity potassium persulfate can meet the requirements of total nitrogen determination, its price is high, which is several times or even dozens of times that of domestic products. The use of existing commercially available high-purity potassium persulfate will significantly increase the cost of determining total nitrogen. Therefore, it is urgent to carry out technical research and development of potassium persulfate import substitution.

[0006] Chinese patent CN 112758896A proposes a method of removing chemical impurities by adding hydrogen peroxide. However, the disadvantage is that the use of hydrogen peroxide, a dangerous chemical, greatly increases the production and application costs, and the operation is complicated and cannot be applied to actual production. Chinese patent CN 110668471A proposes a method of removing chemical impurities by adding anhydrous ethanol to assist the crystallization of persulfate. However, the disadvantage is that the removal rate of ammonium ions is low, and the purification conditions are more stringent, which greatly increases the production and application costs. Summary of the invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art. The purpose of the present invention is to provide a method for preparing environmentally friendly, low-nitrogen, high-purity potassium persulfate, by adopting a purification method combining chemistry and physics, so that the total nitrogen content of industrial-grade potassium persulfate after purification is less than 0.0005%, which meets the national standard for the detection of total nitrogen content in water bodies.

[0008] To achieve the purpose of the present invention, the following technical scheme is adopted: a method for preparing environmentally friendly low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add distilled water to a reaction vessel, stir at a certain speed and heat to a certain temperature, then add an appropriate amount of industrial grade potassium persulfate; (2) adding an appropriate amount of nitrite to a reaction vessel, allowing it to react with the ammonium salt in potassium persulfate, cooling to crystallize, filtering, washing, and drying; (3) The crystals obtained by the reaction are poured into a recrystallization tank for dissolution, cooling and crystallization. After filtering, they are washed and dried with ethanol.

[0009] Preferably, recrystallization is performed twice or more in step (3). The crystallization temperatures used for the multiple recrystallizations in step (3) are different, with the first crystallization temperature being 10 to 30 degrees Celsius and the second crystallization temperature being 0 to 10 degrees Celsius.

[0010] Preferably, the industrial grade potassium persulfate used in step (1) has an ammonium salt mass fraction of 0.10-0.20%.

[0011] Preferably, in step (1), the mass ratio of distilled water to potassium persulfate is 5:1 to 7:1, and the stirring speed is 150 to 250 rpm.

[0012] Preferably, the reaction temperature in step (1) and / or step (2) is 30 to 60 degrees Celsius, and the reaction time is 0.5 to 3 hours.

[0013] Further preferably, the molar ratio of nitrite to ammonium in the sodium nitrite added in step (2) is 1:1 to 1.2.

[0014] Still more preferably, in step (3), distilled water is heated to 40-60 degrees Celsius for dissolution, and the drying temperature after recrystallization is 50 degrees Celsius for 4-8 hours.

[0015] Another technical solution of the present invention is the environmentally friendly low-nitrogen high-purity potassium persulfate prepared by the above-mentioned preparation method combining chemical reaction and physical crystallization.

[0016] Compared with the prior art, the present invention achieves the following technical effects: (1) Through chemical and physical methods, the purity of industrial-grade potassium persulfate is greatly improved to meet the standard with high yield.

[0017] (2) The chemical method can meet the total nitrogen detection standard in water bodies in one go. The operation is simple and convenient, and recrystallization can be performed multiple times to achieve higher standards. DETAILED DESCRIPTION

[0018] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments; in the following description, specific details such as specific configurations are provided only to help fully understand the embodiments of the present invention. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0020] Unless otherwise specified, the materials, practices and experimental equipment involved in the implementation cases of the present invention are all in line with commercially available products in the relevant chemical and biotechnology fields. Example 1

[0021] This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 10L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 50 degrees Celsius. Add 12.5g of sodium nitrite. The ammonium salt content is about 0.20% calculated as NH4, and the molar ratio of nitrite to ammonium is 1:1. Control the temperature to 50 degrees Celsius and react for 1 hour.

[0022] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for cooling and crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed and tested for indicators. 1.78 kg of product is obtained, and the yield is 89%. The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00034%, which met the requirements. Example 2

[0023] This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 10L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 50 degrees Celsius. Add 12.5g of sodium nitrite. The ammonium salt content is about 0.20% calculated as NH4, and the molar ratio of nitrite to ammonium is 1:1. Control the temperature to 50 degrees Celsius and react for 0.5h.

[0024] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for cooling and crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly grade potassium persulfate product is weighed and the index is tested to obtain 1.72 kg of product with a yield of 86%.

[0025] The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00039%, which met the requirements.

[0026] Example 3 This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 12L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 50 degrees Celsius. Add 12.5g of sodium nitrite, the ammonium salt content calculated as NH4 is about 0.20%, and the molar ratio of nitrite to ammonium is 1:1. Control the temperature to 50 degrees Celsius and react for 1 hour.

[0027] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed and tested for indicators. 1.74 kg of product is obtained, and the yield is 87%. The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00031%, which met the requirements.

[0028] Example 4 This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 10L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 60 degrees Celsius. Add 12.5g of sodium nitrite, the ammonium salt content calculated as NH4 is about 0.20%, and the molar ratio of nitrite to ammonium is 1:1. Control the temperature to 60 degrees Celsius and react for 1 hour.

[0029] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for cooling and crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed.

[0030] (3) The obtained potassium persulfate is placed in a dissolution tank, 8L of distilled water is added, and the mixture is heated to 50 degrees Celsius and stirred thoroughly. The solution is then transferred to a crystallization tank and cooled outside the tank with ice water. The cooling temperature is controlled at about 5 degrees Celsius.

[0031] (4) After the crystals are obtained, they are filtered, washed twice with ice water, washed once with anhydrous ethanol, and placed in a drying oven at 50 degrees Celsius for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed and tested for indicators to obtain 1.76 kg of product with a yield of 88%.

[0032] The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00036%, which met the requirements.

[0033] Example 5 This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 10L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 60 degrees Celsius. Add 14.8g of sodium nitrite. The ammonium salt content is about 0.20% calculated as NH4, and the molar ratio of nitrite to ammonium is 1:1.2. Control the temperature to 60 degrees Celsius and react for 1 hour.

[0034] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for cooling and crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed.

[0035] (3) The obtained potassium persulfate is placed in a dissolution tank, 8L of distilled water is added, and the mixture is heated to 50 degrees Celsius and stirred thoroughly. The solution is then transferred to a crystallization tank and cooled outside the tank with ice water. The cooling temperature is controlled at about 5 degrees Celsius.

[0036] (4) After the crystals are obtained, they are filtered, washed twice with ice water, washed once with anhydrous ethanol, and placed in a drying oven at 50 degrees Celsius for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed and tested for indicators to obtain 1.72 kg of product with a yield of 86%.

[0037] The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00024%, which met the requirements.

[0038] Example 6 This embodiment provides an environmentally friendly method for preparing low-nitrogen high-purity potassium persulfate, which specifically comprises the following steps: (1) Add 10L of distilled water to the reaction vessel, stir at 200 rpm, and heat to 50 degrees Celsius. Then add 2kg of industrial potassium persulfate and keep the temperature at 60 degrees Celsius. Add 14.5g of sodium nitrite, the ammonium salt content calculated as NH4 is about 0.20%, and the molar ratio of nitrite to ammonium is 1:1.2. Control the temperature to 60 degrees Celsius and react for 2 hours.

[0039] (2) After the reaction is completed, the solution is transferred to a crystallization tank and cooled to 25 degrees Celsius with cooling water for cooling and crystallization. After the crystallization is completed, the solution is filtered. The obtained crystals are washed twice with ice water and once with ethanol, and then placed in an oven at 50 degrees Celsius for drying for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed.

[0040] (3) The obtained potassium persulfate is placed in a dissolution tank, 8L of distilled water is added, and the mixture is heated to 50 degrees Celsius and stirred thoroughly. The solution is then transferred to a crystallization tank and cooled outside the tank with ice water. The cooling temperature is controlled at about 5 degrees Celsius.

[0041] (4) After the crystals are obtained, they are filtered, washed twice with ice water, washed once with anhydrous ethanol, and placed in a drying oven at 50 degrees Celsius for 5 hours. After drying, the environmentally friendly potassium persulfate product is weighed and tested for indicators to obtain 1.78 kg of product with a yield of 89%.

[0042] The total ammonia content was measured according to the general test method of analytical pure index test of "Chemical Reagent Potassium Persulfate (Potassium Persulfate)" (GB / T 641-2011), and the total nitrogen content was 0.00024%, which met the requirements.

[0043] Those skilled in the art to which the present application belongs may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but they will not deviate from the inventive concept of the present application or exceed the scope defined by the attached claims.

Claims

1. A method for preparing environmentally friendly, low-nitrogen, high-purity potassium persulfate, characterized in that: The steps include: (1) Add distilled water to a reaction vessel, stir at a certain speed and heat to a certain temperature, then add an appropriate amount of industrial grade potassium persulfate; (2) adding an appropriate amount of nitrite to a reaction vessel, allowing it to react with the ammonium salt in potassium persulfate, cooling to crystallize, filtering, washing, and drying; (3) The crystals obtained by the reaction are poured into a recrystallization tank for dissolution, cooling and crystallization. After filtering, they are washed and dried with ethanol.

2. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 1, characterized in that , in step (3), recrystallization is performed twice or more.

3. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 2, characterized in that In step (3), the crystallization temperatures used for multiple recrystallizations are different, the first crystallization temperature is 10 to 30 degrees Celsius, and the second crystallization temperature is 0 to 10 degrees Celsius.

4. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 3, characterized in that The industrial grade potassium persulfate used in step (1) has an ammonium salt mass fraction of 0.10-0.20%.

5. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 4, characterized in that In step (1), the mass ratio of distilled water to potassium persulfate is 5:1 to 7:1, and the stirring speed is 150 to 250 rpm.

6. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 5, characterized in that The reaction temperature in step (1) and / or step (2) is 30 to 60 degrees Celsius, and the reaction time is 0.5 to 3 hours.

7. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 6, characterized in that , the molar ratio of nitrite to ammonium in the sodium nitrite added in step (2) is 1:1 to 1.

2.

8. The method for preparing an environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 7, characterized in that In step (3), the drying temperature after recrystallization is 50 degrees Celsius and the time is 4 to 8 hours.

9. Environmentally friendly, low-nitrogen, high-purity potassium persulfate prepared by the preparation method according to any one of claims 1 to 8.

10. The environmentally friendly, low-nitrogen, high-purity potassium persulfate according to claim 9, characterized in that: Prepared by combining chemical reaction with physical crystallization.