CN-122012110-A - Modified phosphogypsum product for treating farmland soil acidification, and preparation method and application thereof

Abstract

The invention relates to the technical field of soil remediation, in particular to a modified phosphogypsum product for treating farmland soil acidification, and a preparation method and application thereof. The invention discloses a modified phosphogypsum product for treating farmland soil acidification, which consists of purified phosphogypsum powder, a pH regulator, an alkaline slow-release material, an organic bonding carrier and a composite microbial agent, and is prepared into particles with a core-shell structure. The preparation method comprises calcining and washing phosphogypsum to obtain purified powder, pressing into inner core, coating functional layer, and loading microbial agent. The product integrates rapid acid regulation, long-acting slow release, structure improvement and biological activation, and can synchronously promote the pH of soil, deactivate aluminum toxicity, improve the agglomeration structure and promote the growth of crops. The invention realizes the safe recycling of phosphogypsum and provides an economic, efficient and functional synergistic solution for farmland acidification treatment.

Inventors

• TAN XIANGQIAN
• LIN TAO
• FANG JIANCONG
• WEN MINGHUI
• KOU LEI
• HUANG LIYUE
• Dai Xuke
• JIANG DAYUAN
• HAN DING
• LIU TIANQI
• WANG SHIQING
• CHEN GUANYU

Assignees

• 湖北省地质局第七地质大队

Dates

Publication Date

20260512

Application Date

20260204

Claims (10)

1. 1. The modified phosphogypsum product for treating the acidification of the cultivated land soil is characterized by being prepared from the following raw materials, by weight, 75-90 parts of purified phosphogypsum powder, 3-10 parts of a pH regulator, 51-2 parts of an alkaline slow-release material, 3-8 parts of an organic bonding carrier and 0.5-2 parts of a composite microbial agent.
2. 2. The modified phosphogypsum product of claim 1, wherein the product is a core-shell structure particle, the core-shell structure comprises an inner core formed by the purified phosphogypsum powder and a pH regulator, an intermediate layer coated on the inner core, the intermediate layer is formed by compositing an organic bonding carrier and an alkaline slow-release material, and an outer layer structure loaded with a composite microbial agent.
3. 3. The modified phosphogypsum product of claim 1, wherein the pH regulator comprises one or more of quicklime, slaked lime, calcium carbonate, magnesium carbonate, basic calcium carbonate.
4. 4. The modified phosphogypsum product of claim 1, wherein the alkaline slow release material comprises one or more of dolomite powder, siegesbeckia-magnesium fertilizer, calcined shell powder, and calcium magnesium phosphate fertilizer.
5. 5. The modified phosphogypsum product of claim 1, wherein the organic binder carrier comprises one or more of humic acid, seaweed extract, lignosulfonate, soluble starch.
6. 6. The modified phosphogypsum product of claim 1, wherein the composite microbial agent contains microorganisms with functions of phosphate dissolution, potassium dissolution, nitrogen fixation or growth promotion, and the total viable count of the composite microbial agent is not less than 1.0x10 9 CFU/g.
7. 7. A method of making the modified phosphogypsum product of claim 1, comprising the steps of: S1, calcining phosphogypsum raw powder at a first temperature for a first time, then washing with an organic acid solution or an organic acid ammonium salt solution, and carrying out solid-liquid separation, drying and crushing to obtain purified phosphogypsum powder; s2, fully mixing the purified phosphogypsum powder and the pH regulator under a first pressure, and performing compression molding to obtain an inner core blank; s3, preparing the organic bonding carrier and the alkaline slow-release material into coating slurry, coating the coating slurry on the surface of the inner core blank, and drying to form particles with an intermediate layer; s4, loading the composite microbial agent on the surface of the particles with the middle layer, and curing and drying to obtain the modified phosphogypsum product.
8. 8. The method of claim 7, wherein the first temperature comprises 160-220 ℃, the first time comprises 30-90 min, and the first pressure comprises 10-20 mpa.
9. 9. The method according to claim 7, wherein the organic acid solution or organic acid ammonium salt solution comprises a citric acid solution, an oxalic acid solution, an ammonium citrate solution, and an oxalic acid solution.
10. 10. Use of a modified phosphogypsum product according to any one of claims 1 to 6 or a modified phosphogypsum product obtainable by a process according to any one of claims 7 to 9 for improving acidic soil.

Description

Modified phosphogypsum product for treating farmland soil acidification, and preparation method and application thereof Technical Field The invention relates to the technical field of soil remediation, in particular to a modified phosphogypsum product for treating farmland soil acidification, and a preparation method and application thereof. Background The acidification of cultivated land soil is a serious obstacle for agricultural production in China, especially for southern red and yellow soil areas and intensive agricultural areas. Soil acidification activates toxic ions such as aluminum, manganese and the like, so that beneficial salt ions such as calcium, magnesium, potassium and the like are lost, soil hardening is caused, the balance of a microorganism zone system is destroyed, root development and nutrient absorption of crops are severely restricted, and finally, crop yield reduction and quality reduction are caused. Currently, the management of the soil acidification problem of cultivated lands mainly depends on the application of alkaline materials such as quicklime or limestone powder. Although the method can effectively raise the pH value of soil and neutralize partial active acid in a short period, the method has various limitations in practical application, namely, firstly, the method has poor economical efficiency, particularly, under the condition of large-area continuous application, the material and transportation cost are obviously increased, and a larger burden is brought to agricultural production. Secondly, because lime materials have higher solubility and rapid neutralization reaction, if the dosage is controlled improperly or applied unevenly, local soil is easy to be too strong in alkalinity, secondary salinization and hardening are initiated, and the soil permeability is destroyed instead. Thirdly, lime can accelerate the conversion of certain trace elements (such as iron, zinc, manganese and the like) in soil to insoluble forms while regulating the pH value, reduce the bioavailability of the trace elements, and possibly induce or aggravate trace element deficiency of crops. Fourth, the main component of the material is calcium compound, the function is relatively single, and the material has weak effects on improving soil aggregate structure, improving organic matters, promoting microbial activity and the like. In addition, the traditional lime modification method cannot supplement commonly lacking sulfur elements to soil, and is difficult to realize the cooperative regulation and control of acid-base balance and nutrient supply. Phosphogypsum is a large amount of industrial solid waste generated in the wet-process phosphoric acid production process, and the main component is calcium sulfate dihydrate, and is rich in calcium and sulfur elements. In theory, the calcium ions can replace the acidogenic ions on the soil colloid, and the sulfate radical can form a precipitate with the exchanged aluminum ions, so that the acidity of the soil is neutralized and the aluminum toxicity is relieved, and the acid soil improvement material is a potential acid soil improvement material. However, the original phosphogypsum has a serious bottleneck in agriculture directly, namely, the first one, and the environmental safety risk is high. Phosphogypsum is usually acidic and contains soluble phosphorus, fluorine, heavy metals and other impurities which are easy to pollute the surrounding environment when leached by rainwater. Secondly, the improvement effect is poor and unstable. Impurities interfere with their improving function, their own acidity may exacerbate soil acidification, and unactivated phosphogypsum reacts slowly in the soil, with uncontrollable effects. Thirdly, the function is single. The original phosphogypsum mainly provides calcium and sulfur, and lacks the ecological restoration functions of improving soil aggregate structure, activating microorganisms and the like. Therefore, a modification technology capable of removing impurities in phosphogypsum and endowing the phosphogypsum with multiple improvement functions is developed, so that the phosphogypsum is safely and highly utilized, and the phosphogypsum stacking and soil acidification problems are synchronously solved. Disclosure of Invention The invention aims to overcome the defects of high environmental risk, single function, unstable effect, high cost, easy hardening, no sulfur supplementing effect and the like existing in the prior art of directly agriculture of the original phosphogypsum, and provides a safe, efficient, multifunctional and sustainable modified phosphogypsum soil conditioner product, a preparation method and application thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: In a first aspect, the present invention provides a modified phosphogypsum product for use in the remediation of acidification of arable soil. The modified phosphogypsum product is