Phosphate Phosphate Compound Fertilizer

Wet process phosphoric acid:the core link and development trend of phosphorus chemical industry

 　Wet process phosphoric acid(WPA)is a key intermediate product in the phosphate chemical industry,widely used in fields such as phosphate fertilizers,food additives,and electronic chemicals.As the mainstream process for global phosphoric acid production,the development of the wet process phosphoric acid industry directly affects the supply chain stability of agriculture,new energy,and high-end manufacturing industries.This article will provide an in-depth analysis of the production process,market landscape,technical challenges,and future trends of wet process phosphoric acid.

 1.Overview of Wet Process Phosphoric Acid

 (1)Definition and Characteristics

 Wet process phosphoric acid is an industrial phosphoric acid produced by decomposing phosphate rock(fluorapatite)with sulfuric acid(usually at a concentration of 20%-54%P₂O₅),which is different from high-purity thermal phosphoric acid(used for electronic and food grade products).

 (2)Core purpose

 　2.Wet process phosphoric acid production process

 (1)Traditional dihydrate method(mainstream technology)

 Reaction principle:

 Ca5(PO4)3F+5H2SO4+10H2O→3H3PO4+5CaSO4⋅2H2O+HFCa5​(PO4​)3​F+5H2​SO4​+10H2​O→3H3​PO4​+5CaSO4​⋅2H2​O+HF

 Process characteristics:

 The reaction temperature is 70-80℃,and the by-product is dihydrate gypsum(phosphogypsum).

 The concentration of phosphoric acid is about 28%-32%P₂O₅,which needs to be concentrated to 40%-54%for downstream use.

 Disadvantage:Difficulty in storing phosphogypsum(4-5 tons of phosphogypsum are produced per ton of phosphoric acid).

 (2)Half water dihydrate method(energy-saving improvement process)

 First,react under semi aqueous conditions to generate high concentration phosphoric acid(40%-50%P₂O₅),which is then converted into dihydrate gypsum.

 Advantages:Reduce concentration energy consumption and improve the quality of phosphogypsum crystallization.

 (3)Hydrochloric acid method(niche process)

 Decompose phosphate rock with hydrochloric acid and obtain phosphoric acid through solvent extraction.

 Applicable scenarios:Low grade phosphate ore or areas where sulfur introduction needs to be avoided(such as lithium battery materials).

 3.Global wet process phosphoric acid industry pattern

 (1)Capacity distribution

 Asia Pacific region:China is the world's largest producer of wet process phosphoric acid(accounting for over 40%),with major enterprises including Guizhou Phosphating,Yuntianhua,Guizhou Wengfu,and others.In addition,India,Japan,and South Korea are also important markets for phosphorus chemical consumption.

 North America:The United States is the main producer of phosphate chemicals in North America,with advanced wet process phosphoric acid production technology and applications.Secondly,Canada also has a certain scale in phosphate fertilizer production.

 Europe:Morocco's phosphate reserves account for over 67%of the world's total reserves,making it the second largest phosphate producing country in the world.

 Countries such as Germany,France,and the UK have mature technologies and high product quality in the high-end application fields of wet process phosphoric acid,such as food additives and electronic grade phosphoric acid.

 (2)Technological competition points

 Comprehensive utilization of phosphogypsum:China requires the comprehensive utilization rate of phosphogypsum in new projects to be≥30%(2025 target).

 Energy consumption and environmental protection:New processes such as semi water method and kiln method phosphoric acid reduce carbon emissions.

 4.Core challenges in the industry

 (1)Difficulties in the treatment of phosphogypsum

 The global stockpile of phosphogypsum exceeds 6 billion tons,with China adding approximately 80 million tons annually.

 Solution:

 Building material utilization(gypsum board,cement retarder).

 Soil amendment(required to remove heavy metals and radioactive substances).

 (2)The grade of phosphate ore has decreased

 The average grade of phosphate ore in China has decreased from 30%to 20%,increasing acid consumption and waste residue.

 Response measures:flotation enrichment technology,efficient acid hydrolysis process for low-grade ore.

 5.Future Development Trends

 (1)Green process upgrade

 Phosphate free gypsum technology:such as the byproduct of the Prayon process in Israel,alpha hemihydrate gypsum(which can be directly commercialized).

 Low carbon path:Green electricity supply,waste heat recovery to reduce energy consumption per ton of acid(currently about 1.2 tons of standard coal per ton of acid).

 (2)Extension of industrial chain

 High end development:

 Production of food/electronic grade phosphoric acid(purity≥85%)using solvent extraction method.

 Wet process phosphoric acid is used to directly prepare battery grade iron phosphate(such as the Guizhou Phosphate"Phosphate Acid Iron"Integrated Project).

 The wet process phosphoric acid industry is undergoing a triple transformation of"resource constraints,environmental pressure,and new energy demand".In the next decade,technological breakthroughs will revolve around the consumption of phosphogypsum,low-carbon production,and high-end transformation.We need to seize the opportunity of the new energy track and solve the traditional pollution problem through the circular economy model,reshaping the competitiveness of the global phosphoric acid supply chain.