What are the main production processes for phosphoric acid?
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May I ask: What are the main production processes for phosphoric acid?
The simplest method is the extraction of phosphate ore with sulfuric acid, resulting in the precipitation of phosphogypsum and phosphoric acid.
Currently, the main types are wet-process phosphoric acid and hot-process phosphoric acid. However, in recent years a process called pit-process phosphoric acid has emerged; there are discussions on this topic in various forums, so you can search for them.
Phosphoric acid production processes can be classified into three types according to their method: thermal phosphoric acid process, wet phosphoric acid process, and kiln phosphoric acid process. Among them, the thermal phosphoric acid production process is divided into: one-step process and two-step process ； The wet phosphoric acid production processes that are currently used on an industrial scale include those produced by the sulfuric acid method: the dihydrate process, the hemihydrate process, and the dihydrate-hemihydrate process ； Kiln-process phosphoric acid includes tunnel kiln processes and tall tower furnace processes. As a new process, kiln-process phosphoric acid is not yet widely adopted and remains mostly at the pilot plant stage.
In production, the dihydrate method in the wet process is commonly used, while the thermal method is less frequent
It is understood that the thermal method achieves a high phosphoric acid recovery rate of over 99%, with good product quality and low levels of impurities, but it is more costly； The quality of wet-process phosphoric acid is a bit lower, right?
If the wet method involves dihydrate, hemihydrate, anhydrous, hemihydrate-dihydrate forms, etc
Also, different acids are used, such as sulfuric acid, hydrochloric acid, nitric acid, and fluorosilicic acid; the latter has limited availability and has not been put into industrial use
The process used in our factory is the wet-process diprotonic phosphate method, an industry imported from France years ago... It’s really poor quality now...