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Phosphoric Acid Processes

Phosphoric acid produced by the wet process route, also known as merchant grade or green phosphoric acid, contains a certain level of impurities and can be used for fertilizer production without further purification. Most other applications require higher purity phosphoric acid. Phosphoric acid purified to technical grade can be used for the production of STTP (Sodium Tripolyphosphate), drip irrigation fertilizers, various crop nutrients, detergents, and animal feed products.

“Acid further purified to food grade can be used for a variety of applications in the food industry.”

Technologies offered include:

  • Ecoplanning concentration and purification of Merchant Grade Phosphoric acid
  • Ecoplanning solvent-extraction processes for Phosphoric acid
  • Ecoplanning processes for production of MAP/DAP using Phosphoric acid, Ammonia and Sulfuric acid
  • Various laboratory and pilot test for different applications

Ecoplanning Oy has the expertise to design and build tailored solutions to meet the even the most demanding requirements. Our team can design the entire complex process chain and build phosphoric acid purification for any capacity - anywhere in the world.

Delivering Results from Concept to Operation

Our methodology begins with pilot tests in our laboratories, followed by a proposed design configuration and pre-investment estimate of overall project costs. We then work with your preferred EPC partner to design and deliver the project on-time, on-budget, and to specification, including training to operate the facility and troubleshoot both normal and intermittent challenges.​



Depending upon the types of impurities in the green phosphoric acid and the desired final product specifications, a range of unit operations can be utilized in the pretreatment section. Typically, pretreatment units remove excess sulfate, toxic metals such as lead, arsenic and cadmium, and fluoride via precipitation and filtration. Organic matter and color are removed by activated carbon filtration.


The primary purification section utilizes liquid-liquid extraction. Ecoplanning’s extraction process applies well-proven and robust mixer-settler technology that ensures flexible and stable operation. The extraction process consists of three stages: extraction, scrubbing and stripping.


Phosphoric acid concentration is usually required for transportation or to meet specific end-user requirements. This task can be accomplished with a single-stage evaporator. Evaporation is carried out at relatively low temperature and high vacuum to prevent polymerization of phosphate. Any chlorides or fluorides remaining in the product are captured in the hot vapor in the evaporator.


The concentrated acid is cooled and filtered with a polishing filter to remove any remaining impurities. Remaining organic matter and color are removed with activated carbon filtration. Low-fluorine specifications can be obtained through additional fluorine stripping.

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Phosphoric Acid Processes Opportunities

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