Chemical fertilizer industry
Phosphates are generally used in detergents as water softeners, but because the prosperity and decline cycle of algae affects the discharge of phosphates in watersheds, phosphate detergents are regulated in some areas.
In agriculture, phosphate is one of the three main nutrients of plants and the main ingredient of fertilizers. Phosphate rock powder is mined from the phosphorus layer of sedimentary rock. In the past, it can be used without processing after mining, but now the unprocessed phosphate is only used for organic farming. Generally, it will be chemically processed into lime superphosphate, superphosphate or ammonium dihydrogen phosphate. Their concentration is higher than that of phosphate, and they are more soluble in water, so plants can absorb it faster.
Fertilizer grades generally have three numbers: the first refers to the amount of nitrogen, the second refers to the amount of phosphate, and the third refers to alkaline water. So a 10-10-10 fertilizer has 10% of each ingredient, and the others are fillers.
Phosphate flowing from over-fertilized farmland can be the cause of eutrophication, red tide and subsequent hypoxia. This, like phosphate cleaners, can cause hypoxia in fish and other aquatic life. 
Phosphate is used as a binder in refractory materials. Phosphate binder is a refractory binder with acidic orthophosphate or polycondensed phosphate as the main compound and has gelling properties. The combination of phosphate binder is chemical reaction combination or polymerization combination. Most of the binders made by the reaction of phosphoric acid with alkali metal or alkaline earth metal oxides and their hydroxides are air-hardening binders, that is, condensation and hardening can occur at room temperature without heating. Most of the binders made by the reaction of phosphoric acid with amphoteric oxides and hydroxides or acidic oxides are thermosetting binders, that is, they must be heated to a certain temperature to react before they can condense and harden. Phosphate is used as a bonding agent for refractory materials and has a strong bonding strength in the middle and low temperature range before ceramic bonding, so it is widely used as a bonding agent for unshaped refractories and unburned refractories. 
Phosphorus is an important mineral element necessary for the human body. The main source of phosphorus intake by the human body is natural food or food phosphate additives. Phosphate is one of the natural components of almost all foods. Because phosphate can improve or impart a series of excellent properties to food, it has been used in food processing as early as a hundred years ago, and it has been used in large quantities after the 1970s. Phosphate is one of the most widely used food additives with a large amount. As an important food ingredient and functional additive, it is widely used in meat products, poultry products, seafood, fruits, vegetables, dairy products, bakery products, beverages, etc. During the processing of potato products, seasonings, convenience foods, etc. The phosphates used in food processing are usually sodium, calcium, potassium, and iron and zinc salts as nutrient fortifiers. There are more than 30 varieties of commonly used food-grade phosphates. Sodium phosphate is a Chinese food. The main consumption types of phosphate, with the development of food processing technology, the consumption of potassium phosphate is also increasing year by year.
In order to give full play to the synergistic effect of various phosphates and phosphates and other additives, and to meet the development needs of food processing technology, various compound phosphates are often used as food ingredients and functional additives in practical applications. The research and development of formulated phosphate has increasingly become the development direction of the development and application of phosphate food additives.  
According to the US Food Chemical Pharmacopoeia (FCC), the functions of phosphates in the food industry can be divided into 15 categories:
1. Sour agent: phosphoric acid
2. Anti-caking agent: calcium phosphate
3. Antioxidant: calcium hypophosphite
4. Buffer: diammonium phosphate, ammonium dihydrogen phosphate, calcium hydrogen phosphate, calcium phosphate, calcium pyrophosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, sodium acid pyrophosphate, sodium dihydrogen phosphate, dihydrogen phosphate Sodium, sodium phosphate, sodium pyrophosphate
5. Dough improver: diammonium phosphate, ammonium dihydrogen phosphate, calcium dihydrogen phosphate, calcium hydrogen phosphate
6. Emulsifier: potassium phosphate, potassium polymetaphosphate, potassium pyrophosphate, sodium aluminum phosphate (alkaline), sodium metaphosphate (insoluble), sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium polyphosphate (glass), Sodium Pyrophosphate
7. Hardener: calcium dihydrogen phosphate
8. Moisturizer: potassium polymetaphosphate
9. Leavening agent: diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium acid pyrophosphate, sodium aluminum phosphate (acidic)
10. Nutrients: calcium dihydrogen phosphate, calcium hydrogen phosphate, calcium phosphate, calcium pyrophosphate, iron phosphate, iron pyrophosphate, magnesium hydrogen phosphate, magnesium phosphate, manganese hypophosphite, sodium iron pyrophosphate, sodium dihydrogen phosphate, phosphoric acid Disodium hydrogen, sodium phosphate, sodium pyrophosphate
11. Preservative: sodium hypophosphite
12. Chelating agent: calcium dihydrogen phosphate, phosphoric acid, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, sodium acid pyrophosphate, sodium metaphosphate (insoluble), sodium polyphosphate (glassy)
13. Improved starch additives: trimeta pyrophosphate, potassium dihydrogen phosphate
14. Tissue modifier: potassium pyrophosphate, potassium tripolyphosphate, sodium metaphosphate (insoluble), disodium hydrogen phosphate (glassy), sodium tripolyphosphate
15. Fermented food: ammonium dihydrogen phosphate, diammonium hydrogen phosphate, calcium dihydrogen phosphate, calcium dihydrogen phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate.
It can be seen from the above that the functions of phosphate in food processing mainly have two points, one is a quality improver, and the other is a nutritional fortifier.