Author: Site Editor Publish Time: 2022-03-21 Origin: Site
85% of the concentrated phosphoric acid has a molar concentration of 1.874g/mL (liquid). 85% phosphoric acid is a colorless transparent or with light color, thick liquid, easy to melting temperature 42.35 ℃, boiling point 213 ℃ (1/2 h2o) lost, generate a pyrophosphate, heated to 300 ℃ into metaphosphate, easy solution in water, soluble in ethanol, the weak acid with sulfuric acid, hydrochloric acid and nitric acid, acetic acid and boric acid, concentrated phosphoric acid in China are erosion, Hygroscopicity.
Phosphoric acid or orthophosphoric acid, chemical formula H3PO4, molecular weight 97.994, is a common inorganic acid, is medium strong acid. From phosphorus pentoxide dissolved in hot water can be obtained. Apatite can be obtained by treating apatite with sulfuric acid in orthophosphate industry. Phosphoric acid deliquesces easily in air. Heating will lose water to get pyrophosphate, further loss of water to get metaphosphoric acid. Phosphoric acid is mainly used in pharmaceutical, food, fertilizer and other industries, including as rust inhibitor, food additive, dental and orthopaedic surgery, EDIC etchant, electrolyte, flux, dispersant, industrial etchant, fertilizer raw material and component of household cleaning products. Also used as a chemical reagent, phosphate is a nutrient for all life forms.
Phosphoric acid is a medium strong acid, and its crystallization point (freezing point) is 21℃. When the temperature is lower than this, hemihydrate crystals (ice) will be precipitated. Of course, usually phosphoric acid at more than 10℃ or even lower temperature does not form (ice) crystal, this is due to the characteristics of phosphoric acid supercooling, that is, the actual phosphoric acid on the market below 21℃ will deviate from its formation (ice) crystal point, will not immediately form (ice) crystal phenomenon exists. But as long as such a low temperature is maintained for a period of time, phosphoric acid can easily form crystallized (ice) in a static state
Agriculture: Phosphoric acid is the raw material for the production of important phosphate fertilizers (superphosphate, potassium dihydrogen phosphate, etc.), as well as feed nutrients (calcium dihydrogen phosphate).
Industry: phosphoric acid is an important chemical raw material, the main functions are as follows:
Treating the metal surface, forming an insoluble phosphate film on the metal surface to protect the metal from corrosion.
Mixed with nitric acid as a chemical polish to improve the finish of metal surfaces.
Production of detergent, insecticide raw material phosphate ester.
Raw materials for the production of flame retardants containing phosphorus.
Food: phosphoric acid is one of the food additives, in the food as sourness agent, yeast nutrition agent, Coca-Cola contains phosphoric acid. Phosphates are also important food additives and can be used as nutritional enhancers.
Medicine: phosphoric acid can be used to make phosphate-containing drugs, such as sodium glycerophosphate.
Phosphoric acid has no strong oxidation, no strong corrosion, is a relatively safe acid, is low toxicity, irritant.
LD50:1530mg/kg (rat oral); 2740mg/kg (rabbit transcutaneous)
Irritation: rabbit percutaneous 595mg/24 hours, severe irritation; Severe stimulation of 119mg in rabbit eyes.
Avoid contact with eyes, skin and mouth.
Flammable in case of H pore-releasing agent; When heated, toxic phosphorus oxide fumes are emitted.
Phosphoric acid vapor can cause nasal mucosa atrophy. It has a strong corrosive effect on the skin and can cause skin inflammatory diseases. Can cause systemic poisoning.
If there is phosphoric acid vapor in the eyes, should be immediately washed with a large amount of normal saline, then sent to the hospital for treatment.
The maximum allowable concentration in air is 1mg/m3. Production personnel should wear protective equipment when working, such as overalls, rubber gloves, rubber or plastic aprons, rubber boots. Pay attention to the protection of respiratory organs and skin, if accidentally splashed into the skin, should be immediately washed with plenty of water, phosphoric acid after washing, generally can be applied with red mercury solution or gentian purple solution on the affected area, in serious cases, should be immediately sent to the hospital for treatment.