Search

CN-117324123-B - Phosphogypsum flotation impurity removal and whitening process

CN117324123BCN 117324123 BCN117324123 BCN 117324123BCN-117324123-B

Abstract

The invention relates to a phosphogypsum flotation impurity removal and whitening process, belongs to the technical field of phosphorus chemical industry solid waste treatment, and solves the problems of long process flow, complex operation, limited whiteness and limited increase range of calcium sulfate dihydrate purity of the existing phosphogypsum impurity removal and whitening process. A process for removing impurities and whitening phosphogypsum by floatation includes such steps as mixing phosphogypsum with water, adding a certain amount of floatation agent A, stirring the ore pulp at high speed for a certain time, introducing the ore pulp to floatation equipment for reverse floatation, introducing the bottom flow of reverse floatation to stirring tank, adding a certain amount of floatation agent B, introducing the ore pulp in stirring tank to floatation equipment for reverse floatation again, and filtering. Short technological process, less floatation agent consumption and meeting the first grade standard of GB/T23456-2018 phosphogypsum.

Inventors

  • CAO YIJUN
  • PENG WEIJUN
  • FAN GUIXIA
  • HUANG YUKUN
  • LI GUOSHENG
  • LI HUIYONG
  • LI JINGCHAO

Assignees

  • 郑州大学

Dates

Publication Date
20260508
Application Date
20220624

Claims (10)

  1. 1. The phosphogypsum flotation impurity-removing whitening process is characterized by comprising the following steps of: Mixing phosphogypsum and water according to a certain mass percentage, adding a certain amount of flotation reagent A, stirring and pulping to obtain ore pulp, wherein the raw materials of the flotation reagent A comprise, by weight, 40-60 parts of vinyl trimethoxy silane, 30-45 parts of acetic acid solution and 10-15 parts of alkyl trimethyl ammonium bromide; step two, stirring and scrubbing ore pulp at a high speed for a certain time; step three, after scrubbing, guiding ore pulp into flotation equipment for primary reverse flotation; Introducing reverse flotation underflow into a stirring tank, and adding a certain amount of flotation reagent B, wherein the flotation reagent B is one or more of dodecylamine hydrochloride, hexadecylamine hydrochloride, octadecylamine hydrochloride, dodecylamine acetate, hexadecylamine acetate and octadecylamine acetate; introducing ore pulp in the stirring tank into flotation equipment for primary positive flotation again to obtain a foam product; and step six, filtering and dehydrating the foam product to obtain phosphogypsum concentrate.
  2. 2. The process according to claim 1, wherein in the first step, the mass fraction of the acetic acid solution is 0.5-5.0%.
  3. 3. The process of claim 1, wherein in step one, the alkyl trimethylammonium bromide comprises one or more of dodecyl trimethylammonium bromide, tetradecyl trimethylammonium bromide, hexadecyl trimethylammonium bromide, and octadecyl trimethylammonium bromide.
  4. 4. The process according to claim 1, wherein in the first step, the amount of the flotation reagent A is 90-250g/t in terms of phosphogypsum mass ratio.
  5. 5. The process according to claim 1, wherein in the second step, the phosphogypsum mass percentage in the pulp is 35-65%.
  6. 6. The process according to claim 1, wherein in the second step, the high-speed stirring speed is 4000 to 8000rpm.
  7. 7. The process according to claim 1, wherein in the second step, the high-speed stirring time is 10-60min.
  8. 8. The process according to claim 1, wherein in the third step, the concentration of the reverse flotation slurry is 18-35%, and the reverse flotation time is 3-8min.
  9. 9. The process according to claim 1, wherein in the fourth step, the amount of the flotation reagent B is 80-300g/t in terms of phosphogypsum mass ratio.
  10. 10. The process according to claim 1, wherein in the fifth step, the forward flotation time is 4-9min.

Description

Phosphogypsum flotation impurity removal and whitening process Technical Field The invention belongs to the technical field of phosphorus chemical solid waste treatment, and particularly relates to a phosphogypsum flotation impurity removal and whitening process. Background Phosphogypsum is mainly produced in the phosphorus chemical industry, is a solid byproduct produced in the process of preparing phosphoric acid by a wet method, and mainly comprises calcium sulfate dihydrate (CaSO 4·2H2 O), and is a good regenerated gypsum resource. According to statistics, 5-6 tons (dry basis) of phosphogypsum are produced per 1 ton of phosphoric acid production, and the real amount is about 7 tons. Phosphogypsum contains various forms of phosphorus and fluorine substances, organic matters, siO 2, alkali metal salts, radioactive elements and other impurities besides the main component CaSO 4·2H2 O, and the impurities have great influence on the environment and the usability of the phosphogypsum, so that purification and impurity removal are necessary steps for recycling the phosphogypsum. The flotation method has low cost, simple operation, easy realization of large-scale, industrialization, automation and the like, and is applied to the aspects of phosphogypsum impurity removal and whitening. Zhang Lizhen et al use dodecanol as a collector, adopt 'coarse and fine' forward flotation to upgrade and reduce impurities of phosphogypsum, obtain concentrate (inorganic salt industry, 2021,53 (06), 171-173+184) with a mass fraction of dihydrate gypsum (CaSO 4·2H2 O) of 97.5% and a mass fraction of silicon dioxide of 1.17%, and remove most silicate impurities, but have low organic matter removal rate and limited whiteness increase range. Patent CN202111600207.9 discloses a method for purifying phosphogypsum by floatation, washing, decoloring and purifying, which uses etherdiamine as a collector, and adopts three times of reverse floatation to obtain concentrate with the purity of calcium sulfate dihydrate of 95.81% and the whiteness of 56.57%, but has the problems of long floatation process, large dosage of medicament, limited increase range of the purity of the calcium sulfate dihydrate and the like. Patent CN201510930935.4 discloses a method for preparing phosphogypsum flotation collector, which applies phosphogypsum flotation to obtain concentrate with calcium sulfate dihydrate content of 95.28% and silicon dioxide content of 2.87% through primary roughing and primary concentration. However, the preparation of the collecting agent is complex, the whiteness improvement amplitude of phosphogypsum is not obvious, and the subsequent high-end building material application is affected, so that the development of the phosphogypsum impurity removal and whitening process which has the advantages of short process flow, simple and convenient operation and larger whiteness and calcium sulfate dihydrate purity increase amplitude has very important significance. Disclosure of Invention In view of the analysis, the invention aims to provide a phosphogypsum flotation impurity removal and whitening process, which is used for solving the problems of long process flow, complex operation, limited whiteness and limited increase range of purity of calcium sulfate dihydrate in the existing phosphogypsum impurity removal and whitening process. The main purpose of the invention is realized by the following technical scheme: a phosphogypsum flotation impurity removal and whitening process comprises the following steps: Mixing phosphogypsum and water according to a certain mass percentage, adding a certain amount of flotation reagent A, stirring and pulping to obtain ore pulp, wherein the raw materials of the flotation reagent A comprise, by weight, 40-60 parts of vinyl trimethoxy silane, 30-45 parts of acetic acid solution and 10-15 parts of alkyl trimethyl ammonium bromide; step two, stirring and scrubbing ore pulp at a high speed for a certain time; step three, after scrubbing, guiding ore pulp into flotation equipment for primary reverse flotation; Introducing reverse flotation underflow into a stirring tank, and adding a certain amount of flotation reagent B, wherein the flotation reagent B is one or more of dodecylamine hydrochloride, hexadecylamine hydrochloride, octadecylamine hydrochloride, dodecylamine acetate, hexadecylamine acetate and octadecylamine acetate; introducing ore pulp in the stirring tank into flotation equipment for primary positive flotation again to obtain a foam product; and step six, filtering and dehydrating the foam product to obtain phosphogypsum concentrate. Further, in the first step, the mass fraction of the acetic acid solution is 0.5-5.0%. Further, in the first step, the alkyl trimethyl ammonium bromide includes one or more of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide and octadecyl trimethyl ammonium bromide. Further, in the first step, the amount