Industry dynamics

The production process of Sodium Tripolyphosphate / STPP
Time:2017-09-19 Hit:78

Sodium tripolyphosphate by the phosphoric acid by soda ash and sodium positive, then by condensation. There are two types of wet phosphoric acid and heat production methods. Wet is the phosphate and inorganic acid (usually sulfuric acid, have recently been using hydrochloric acid) after the reaction, extraction, refining obtained after phosphoric acid. Calorimetry is in an electric furnace with coke and silica calcined phosphate together, phosphate was reduced to phosphorus, followed by oxidation, hydration, that was phosphoric acid.;

Preparation by the orthophosphate sodium tripolyphosphate process is relatively simple, the process is short, easy to control operations. There are two main methods.

 spray drying - converter polycondensation Sec method: spray dryer is a cylinder, the upper and horizontal burner nozzle in contact with the gas. Temperature is 400 ~ 500  of gas through the burner pass into the upper spray drying tower, while high pressure (4.2MPa) pump orthophosphate solution was injected into. Aqueous 5% or less of dried products continue to be removed from the lower portion of the dryer. Orthophosphate mixture in a rotary furnace dehydration condensation into sodium tripolyphosphate. This method is characterized by the product without the need for grinding, spray dryer drying efficiency, dry material is very uniform, stratification does not occur; drawback is dried and condensed in two stages, direct heating dehydration dust loss large.

 dried - dehydrated section of law: the slurry is sprayed into the rotary kiln, furnace or combustion nozzle into the hot oil to heat. Annular baffle furnace into flame section and heating section. In the heating section, the material is converted to the final dehydration polycondensation sodium tripolyphosphate. A cooling tube and a rotary kiln fused by the cooling tube out of the granular product in the mill grinding, from the furnace to bring out the small amount of powder recovered in the cyclone. This method will be drying, dehydration and cooling combined in one unit equipment, the flow is greatly simplified, high thermal efficiency, and can reduce capital investment and improve working conditions.