Phosphate Acid Plant in Petrokimia Gresik

Flow diagram of the process to making phosphate acid

1.  Phosphate Rock Grinding

     Ball Mill is the main tool that serves to smooth rock phosphate oversized includes granular                  agglomerate due to moisture and reducing the water content with the help of hot air. Phosphate            rock that passes screening (size required) is fed to the reaction section and filtration hemihidrate.

2.  Reaction and hemihydrate filration

     Equipment primarily Premixer which serves as a stirring beginning between phosphate rock with       the return acid, causing a bit of a reaction (the product in the form of slurry) and Digester whose        function reacting the slurry with sulfuric acid 60% to form a crystalline hemihydrate, while the            filter serves to separate the crystals hemihydrate with phosphoric acid , Enter premixer fine                  phosphate rock mixed with return and recycle acid hemihydrate while stirring well controlled rate      of return acid to obtain a product slurry with 45-46% P2O5 content of the next entry into the               digester to enhance the reaction and so as not to precipitate hemihydrate crystal equipped agitator.       Hemihydrate filter to separate the slurry entered hemihydrate cake and liquid results (first filtrate) is   further accommodated in storate acid tank.

3.  Hydration and dihydrate filtration

    Function at this stage is reacting hemihydrate with dilute sulfuric acid so that it becomes dihydrate with the hydration process and to take P2O5 remaining in the cake dihydrate. Hemihydrate gypsum slurry from the first sign of hydration filtration tank mixed with 98.5% H2SO4 and the result is a gypsum slurry (CaSO4.2H2O) flowed while the other gets a second filtration unit is recirculated to the first reaction and filtration, to accelerate the hydration reaction is added to silica. The second filtration results in the form of further filtrate collected to be used as a liquid medium prewashing gypsumnya cake after washing with hot water delivered to the mill ZA and CR for further processing.

4. Flourine recovery

At this stage consists of the exhaust gas treatment unit (gas purification) and fluorine gas absorption unit (fluorine recovery) which serves to liberate the exhaust gases of fluorine content before it is emitted into the atmosphere. Gas output digester, hydration tank and filter containing fluorine is absorbed in a fume scrubber was subsequently circulated to the fluorine recovery unit. Fluosilicic acid formed and the concentration of fluorine scrubber unit contains little silica and after being separated from silicanya, fluosilicic acid which has been sent to H2SiF6 clean the storage tank as a product. Silica produced from filter diluted with wash water to form a slurry which is then sent to the hydration tank to get in shape and good crystal growth.

5. Concentration

Function at this stage concentrating the phosphoric acid from the first filtration unit to produce phosphoric acid at levels of 52-56% with the main tool Vaporizer. Phosphoric acid which has been heated in the heater vaporizer subsequently flowed into a vacuum, so it will form a concentrated phosphoric acid partial results were mixed with phosphoric acid feedstock in the first filtration unit and partly flowed into the holding tank. Before being sent to the unit plant phosphate fertilizers, phosphoric acid is cooled in the cooler until the resulting phosphoric acid temperature of + 60 ° C, while the steam from the vaporizer after being separated in the separation tank obtained solution containing acid which is then returned into the vaporizer and gas fluorine is subsequently absorbed by the water to form fluosilikat acid solution.