CN-118306958-B - Method for preparing fibrous hydroxyapatite from phosphogypsum

CN118306958BCN 118306958 BCN118306958 BCN 118306958BCN-118306958-B

Abstract

The invention provides a method for preparing fibrous hydroxyapatite by using phosphogypsum, which comprises the steps of mixing phosphogypsum with a purifying agent, uniformly stirring, filtering the obtained suspension, dropwise adding filtrate into a phosphorus source solution under the stirring condition, slowly dropwise adding an ammonia water solution into the solution, regulating the pH value of the mixed solution to be alkaline, continuously stirring to obtain the mixed solution, adding a morphology control agent into the obtained mixed solution, uniformly stirring, performing hydrothermal reaction, and filtering the filtrate after the hydrothermal reaction is finished to obtain filter residues, namely fibrous hydroxyapatite. The method has the advantages of simple process, low cost and energy consumption, high purity of the obtained hydroxyapatite, high crystallinity and clear fibrous morphology.

Inventors

Jiang Shanzhu
WANG ZHAOBO
QIN YANGJIE
LI ZHONGJUN
DENG HUA
CHI RUAN
XI BENJUN

Assignees

湖北三峡实验室

Dates

Publication Date: 20260508
Application Date: 20240313

Claims (7)

1. A method for preparing fibrous hydroxyapatite by using phosphogypsum, which is characterized by comprising the following steps: S1, phosphogypsum pretreatment, namely mixing phosphogypsum with a purifying agent, uniformly stirring, filtering the obtained suspension, wherein the purifying agent is one or more of methylamine, ethylamine, ethylenediamine, triethanolamine, ethylenediamine tetraacetic acid, propylene diamine diacetic acid, ethylenediamine diacetic acid, ethylene glycol diethyl ether diamine tetraacetic acid, triethylenetetramine hexaacetic acid, cyclohexanediamine tetraacetic acid and sulfosalicylic acid; S2, dropwise adding the filtrate in the step S1 into the phosphorus source solution under the stirring condition, slowly dropwise adding an ammonia water solution into the solution, adjusting the pH value of the mixed solution to be alkaline, and continuously stirring to obtain the mixed solution; S3, adding a morphology control agent into the mixed solution obtained in the step S2, uniformly stirring, and performing hydrothermal reaction, wherein the morphology control agent is one or more of glucose, polyethylene glycol, hexadecyl ammonium bromide, ammonium citrate, sodium citrate, potassium citrate, calcium citrate, sodium salicylate, ethylenediamine tetraacetic acid and oleyl alcohol polyoxyethylene ether; and S4, filtering out filtrate after the hydrothermal reaction is finished, and obtaining filter residues which are the fibrous hydroxyapatite.
2. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 1, wherein the concentration of the purifying agent is 0.1 to 1mol/L.
3. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 1, wherein the phosphorus source solution in step S2 comprises one or more of sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, calcium hydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate.
4. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 3, wherein the concentration of the phosphorus source solution is 0.001-1 mol/L.
5. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 1, wherein in step S2, the pH of the mixed solution is between 11 and 13.
6. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 1, wherein the concentration of the morphology control agent is 0.01-20 g/L.
7. The method for preparing fibrous hydroxyapatite from phosphogypsum according to claim 1, wherein the hydrothermal reaction temperature in the step (3) is 100-200 ℃ and the reaction time is 2-24 hours.

Description

Method for preparing fibrous hydroxyapatite from phosphogypsum Technical Field The invention relates to the field of separation science and technology, relates to industrial solid waste treatment, and in particular relates to phosphogypsum treatment and resource utilization. Background Phosphogypsum is an unavoidable solid byproduct in the wet-process phosphoric acid process and the phosphate fertilizer industry, and the main component is calcium sulfate dihydrate. More than 90% of the currently available phosphoric acid is prepared using wet processes. About 5 tons of phosphogypsum are produced per 1 ton of phosphoric acid produced. The actual comprehensive utilization rate of phosphogypsum in China is about 30%, and the phosphogypsum mainly comprises the preparation of industrial gypsum and gypsum building materials, and the preparation of cement retarder, two-stage calcination and co-production of cement and sulfuric acid. But because phosphogypsum also retains phosphorus, fluorine, aluminum, iron, potassium, sodium, silicon and a very small amount of radioactive elements in the phosphate ore, and impurities such as flotation reagents introduced in the wet phosphoric acid process. These impurities cannot be completely removed, which affects and limits the application of phosphogypsum as industrial gypsum, and the industrial value of the phosphogypsum itself is low, and the cost of treating and recycling the phosphogypsum is far higher than the value of the industrial gypsum itself. In particular, soluble phosphorus, fluorine and other impurities limit the use of phosphogypsum in the field of building materials. Therefore, most of phosphogypsum treatment worldwide is mainly piled up. The simple, efficient and low-cost phosphogypsum treatment and purification technical means is a core step for recycling phosphogypsum. Disclosure of Invention At present, calcium-containing compounds in phosphogypsum are converted into soluble substances by mixing a composite solvent with phosphogypsum, and solid-liquid reaction in the conventional preparation process of hydroxyapatite is converted into liquid-phase reaction with larger reaction degree. Calcium sulfate in phosphogypsum is converted into high-value hydroxyapatite by hydrothermal reaction in a liquid phase with a composite phosphorus source in a high-temperature environment. The invention provides a method for preparing fibrous hydroxyapatite by phosphogypsum. The method has the advantages of simple process, high purity of the prepared hydroxyapatite, high crystallinity and regular fibrous appearance. In order to achieve the aim, the technical scheme adopted by the invention is that the method for preparing fibrous hydroxyapatite by using phosphogypsum is characterized by comprising the following steps: s1, phosphogypsum pretreatment, namely mixing phosphogypsum with a composite solvent, uniformly stirring, and filtering the obtained suspension; S2, dropwise adding the filtrate in the step S1 into the phosphorus source solution under the stirring condition, slowly dropwise adding an ammonia water solution into the solution, adjusting the pH value of the mixed solution to be alkaline, and continuously stirring to obtain the mixed solution; s3, adding the morphology control agent into the mixed solution obtained in the step S2, and carrying out hydrothermal reaction after uniformly stirring; and S4, filtering out filtrate after the hydrothermal reaction is finished, and obtaining filter residues which are the fibrous hydroxyapatite. The purifying agent in the step S1 comprises one or more of methylamine, ethylamine, ethylenediamine, triethanolamine, ethylenediamine tetraacetic acid, propylenediamine diacetic acid, ethylenediamine diacetic acid, ethylene glycol diethylether diamine tetraacetic acid, triethylenetetramine hexaacetic acid, cyclohexanediamine tetraacetic acid and sulfosalicylic acid. The concentration of the purifying agent is 0.5-1 mol/L. In this case the purifying agent is used to convert calcium sulphate in phosphogypsum from a poorly soluble solid to a liquid. Mixing and stirring phosphogypsum and a purifying agent, dissolving calcium sulfate in the phosphogypsum into the purifying agent, filtering, transferring the calcium sulfate into filtrate, and adding the purifying agent enables the calcium sulfate to react more thoroughly, thereby being beneficial to reducing the calcium-phosphorus ratio of the prepared hydroxyapatite and reducing the impurity content in the product. The phosphorus source solution in the step S2 comprises one or more of sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, calcium hydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate. The concentration of the phosphorus source solution is 0.5-1 mol/L. In the application, phosphate radical in a phosphorus source solution, calcium sulfate in a purifying agent in solu