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CN-115925003-A - Production process of high-efficiency high-concentration polymeric ferric sulfate

CN115925003ACN 115925003 ACN115925003 ACN 115925003ACN-115925003-A

Abstract

The application provides a production process of high-efficiency high-concentration polymeric ferric sulfate, and relates to the technical field of flocculant manufacturing processes. The method comprises the following steps of mixing concentrated sulfuric acid with water to obtain sulfuric acid diluent; heating ferrous sulfate heptahydrate at 100-300 ℃ until dehydration and oxidation are carried out to generate an oxidation mixture; mixing the sulfuric acid diluent with the oxidation mixture, adding sodium dihydrogen phosphate, uniformly stirring, introducing oxygen and a catalyst, adding the catalyst in batches, and fully reacting to obtain a mother solution; performing synergistic concentration on the mother liquor until the density is more than 1.45g/cm 3 Stopping concentration, and then carrying out aeration, curing and filtering to obtain the high-efficiency high-concentration polymeric ferric sulfate. The application adopts the disodium hydrogen phosphate to inhibit the phenomenon that hydroxide ions and iron generate precipitates in the reaction, thereby improving the production efficiency, reducing the reaction time, having low requirements on the conditions required by the reaction, generating small pollutants and having high quality of the prepared products.

Inventors

  • WU GUOMING
  • CHEN ZHUOLING
  • Yan Shanhu

Assignees

  • GUANGDONG DEXIN TECH CO LTD

Dates

Publication Date
20230407
Application Date
20221221
Priority Date
20221221

Claims (10)

  1. 1. The production process of the high-efficiency high-concentration polymeric ferric sulfate is characterized by comprising the following steps of: s1, mixing concentrated sulfuric acid with water to obtain sulfuric acid diluent; s2, heating ferrous sulfate heptahydrate at 100-300 ℃ until dehydration and oxidation are carried out to generate an oxidation mixture; s3, mixing the sulfuric acid diluent with the oxidation mixture, adding sodium dihydrogen phosphate, uniformly stirring, introducing oxygen and a catalyst, adding the catalyst in batches, and fully reacting to obtain a mother solution; s4, performing synergistic concentration on the mother liquor until the density of the mother liquor is more than 1.45g/cm 3 Stopping concentration, aerating, aging, and filteringAnd obtaining the high-efficiency high-concentration polymeric ferric sulfate.
  2. 2. The process for producing high-efficiency high-concentration polymeric ferric sulfate as claimed in claim 1, wherein the catalyst comprises a main catalyst which is KNO 2 And NaNO 2 At least one of (1).
  3. 3. The process for producing high-efficiency high-concentration polymeric ferric sulfate as claimed in claim 2, wherein the catalyst in S3 further comprises a cocatalyst, and the cocatalyst is NaI.
  4. 4. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 3, wherein the mass ratio of the main catalyst to the cocatalyst is 1.6-2: 0.2 to 0.4.
  5. 5. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the sulfuric acid diluent is 30-35% by volume of sulfuric acid.
  6. 6. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the molar ratio of the ferrous sulfate heptahydrate to the sulfuric acid diluent is 1:0.4 to 0.5.
  7. 7. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the input amount of the catalyst is 2.5-3% of the mass of ferrous sulfate heptahydrate.
  8. 8. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the specific conditions of the reaction in the S3 are as follows: the pH value is 1.6-2, the temperature is 46-54 ℃, and the pressure is 0.13-0.15 MPa.
  9. 9. The process for producing high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the reaction in S3 is stopped until the concentration of ferrous ions in the solution is lower than 0.1%.
  10. 10. The production process of high-efficiency high-concentration polymeric ferric sulfate according to claim 1, wherein the specific operations of aeration, curing and filtering in S4 are as follows: and standing the mother solution for 24 hours, filtering the mother solution by a sieve of 80-100 meshes, adding polyacrylamide accounting for 0.5-0.8 percent of the mass percent of the mother solution into the mother solution, standing the mother solution for 48 hours, and filtering the mother solution by a sieve of 200-300 meshes to obtain the final high-efficiency high-concentration polymeric ferric sulfate.

Description

Production process of high-efficiency high-concentration polymeric ferric sulfate Technical Field The application relates to the technical field of flocculant manufacturing processes, in particular to a production process of high-efficiency high-concentration polymeric ferric sulfate. Background The polyferric sulfate is a novel, high-quality and high-efficiency ferric salt inorganic polymeric flocculant, has a huge molecular structure and strong adsorption capacity, and has a water purification effect superior to that of all traditional inorganic water purifiers. The polyferric sulfate has good coagulation property, stable chemical property, high sedimentation speed and wide applicable pH value range, and is widely used for purifying and treating domestic drinking water, various industrial water, industrial wastewater and municipal sewage. At present, the polymeric ferric sulfate is mainly in two forms of liquid (total iron is more than or equal to 11%) and solid (total iron is more than or equal to 19%). The solid product is obtained by converting the liquid product into the solid product through processes of drying, drying and the like on the basis of the liquid product, and a large amount of labor, fuel, equipment, packaging, carrying and other costs are increased in the process. If the high-efficiency high-concentration liquid product can be selected and used, the water treatment effect the same as that of the solid product is achieved in the aspect of water treatment, the cost of each item put into the drying process can be saved, meanwhile, the product can be sold far and even exported, the advantage of long-distance transportation of the solid product is not existed, and the economic benefit can be realized. The production method of polymeric ferric sulfate can be mainly divided into three types, namely a direct oxidation method, a conversion oxidation method and a catalytic oxidation method. The production of polymeric ferric sulfate by direct oxidation or conversion oxidation requires the consumption of a large amount of oxidant and excessive acid or alkali, the production cost is too high, the product quality (mainly including basicity and total iron content) is poor, and the separation cost of residues such as metal salts introduced by the oxidant in the production process is high, which affects the product quality without separation, so that the industrial production is difficult. At present, the production of polymeric ferric sulfate at home and abroad generally adopts a catalytic oxidation method, and NaNO is selected without exception 2 Or HNO 3 Etc. as a catalyst. Although the catalytic oxidation method is simple and easy, the oxidation time is too long (1.5% of NaNO) 2 As a catalyst, the reaction time is as long as 17 h), the efficiency of the equipment is low, and a large amount of nitrogen oxide is often discharged in the oxidation process, thereby polluting the environment. In addition, the existing methods for producing the polymeric ferric sulfate have great dependence on acidity (the adding amount of acid must be great to ensure that the ferric hydroxide precipitation does not occur in the final product mixture, and the adding amount of acid is increased to inevitably reduce the basicity of the polymeric ferric sulfate), so that the basicity of the product is greatly restricted. Disclosure of Invention The production process of the high-efficiency high-concentration polymeric ferric sulfate is optimized on the basis of direct oxidation and catalytic oxidation in the prior art, and the phenomenon that hydroxide ions and iron are precipitated in the reaction is inhibited by adopting disodium hydrogen phosphate, so that the production efficiency is improved, the reaction time is reduced, the requirements on conditions required by the reaction are low, the produced pollutants are small, and the quality of the prepared product is high. The technical problem to be solved by the application is achieved by adopting the following technical scheme. On the one hand, the embodiment of the application provides a production process of high-efficiency high-concentration polymeric ferric sulfate, which comprises the following steps: s1, mixing concentrated sulfuric acid with water to obtain sulfuric acid diluent; s2, heating ferrous sulfate heptahydrate at 100-300 ℃ until dehydration and oxidation are carried out to generate an oxidation mixture; s3, mixing the sulfuric acid diluent with the oxidation mixture, adding sodium dihydrogen phosphate, uniformly stirring, introducing oxygen and a catalyst, adding the catalyst in batches, and fully reacting to obtain a mother solution; s4, performing synergistic concentration on the mother liquor until the density of the mother liquor is more than 1.45g/cm 3 Stopping concentration, and then carrying out aeration, curing and filtering to obtain the high-efficiency high-concentration polymeric ferric sulfate. Because both direct oxidation and catalytic oxidat