Purification of Wet Process Phosphoric Acid by Solvent Extraction using Cyclohexanol

Abstract

Solvent extraction using organic solvents is an important technology for the purification of wet process phosphoric acid (WPA). In this study, the purification process of WPA, using a new type of solvent extraction system, cyclohexanol diluted in kerosene, was investigated. The equilibrium phase diagram of the system H 3 PO 4 H 2 O solvent mixtures at 313.2K was obtained. The effects of extraction time, phosphoric acid concentration, cyclohexanol concentration, temperature, phase ratio on extraction efficiency were studied. The extracted species was shown to be 2H 3 PO 4 · 2C 6 H 12 O. The extraction process of H 3 PO 4 is exothermic and the enthalpy change, H, was obtained. Via a cross-current three-stage extraction, the solvent mixtures have a high efficiency for phosphoric acid purification from the actual industrial WPA with an H 3 PO 4 extraction yield of 90.2% at room temperature. The study is capable of enriching theoretical foundation and technical guidance for the phosphoric acid purification process.

Overview on the removal of iron from phosphoric acid: A Comparative study

“…The concentration of iron should be <1.5% Fe 2 O 3 as standard for fertilizer grade phosphoric acid of 50% P 2 O 5 [16][17][18][19]. Many trials were performed by various techniques in order to purify the WPA via precipitation [4], adsorption, , ion exchange [20][21][22], reverse osmosis, ultrafiltration [23][24][25][26][27][28], electrodeposition [29], solvent extraction [30][31][32] and magnetic separation [33] The concentration of iron in phosphate rocks varies from 0.1% -4.0 % as Fe 2 O 3 depend on their origin [34,35].The present overview discusses some of the techniques used for iron removal from WPA mainly, precipitation, adsorption and solvent extraction, magnetic separation, crystallization, reverse osmosis, nanofilteration as well as electrodialysis.…”

Chelation of metal ions with citric acid in the ammoniation process of wet‐process phosphoric acid

“…Generally, it can be divided into fertilizer grade and industrial grade, and most of it is used as fertilizer . WPA usually contains a large amount of impurity ions, such as Fe 3+ , Al 3+ , Mg 2+ , Ca 2+ , Mn 2+ , and F − . The presence of impurities has a significant influence on the crystallization of gypsum and the quality of phosphoric acid in the production of WPA .…”

The use of Alizarin modified bentonite for removal of some heavy metals ions from the wet process phosphoric acid

“…The choice of an economically suitable technique depends upon many parameters such as the concentration of wet process phosphoric acid, the amount and the concentration of the co-dissolved impurities. These techniques are precipitation (Abdennebi et al, 2017), floatation (Haraldsen, 1991), membrane extraction (Al-Harahsheh et al, 2017;Machorro et al, 2013), crystallization ((Aaltonen et al, 2004;Chen et al, 2012), ion exchange (Marcus et al, 2004;Cheira, 2015), liquid-liquid extraction (Singh et al, 2009;Chen et al, 2016;Assuncao et al, 2017;Li et al, 2017), and solid phase extraction (Awwad et al, 2013 ).…”