Purification Of Wet Phosphoric Acid Research Articles

Continuous purification of phosphoric acid in a microchannel

Solvent extraction is an economically efficient method widely used in the purification of wet phosphoric acid. In this study, microchannel was applied to promote mixing and purification of phosphoric acid during continuous production. For this aim, liquid-liquid extraction was conducted to purify phosphoric acid via methyl isobutyl ketone/tri-butyl phosphate mixtures. Additionally, the Box-Behnken experimental design method was used to survey the liquid-liquid extraction process. The effect of various operational parameters such as solvent concentration (45–65 %wt.), temperature (18-28˚C) and organic/aqueous phase ratio (2:1–6:1) at a constant flow rate of 70 ml/l was examined. Experimental results indicated that the microchannel at the residence time of 6.85 min could promote the extraction percentage of and sulfate removal more than 98% and 60%, respectively, compared to the batch extractor.

Comparative Simulation of the Purification of Wet Phosphoric Acid by Tbp, Mibk and a Mixture (MIBK+TBP)

Liquid-liquid solvent extraction technology is used in several industrial processes such as petrochemical processing, pharmaceutical production, food and hydrometallurgy. It is successfully applied for the purification of Wet Phosphoric Acid (WPA) with fairly good purification performances. The purification process is basically carried out in three steps: extraction, washing and recovery, each of these steps is a liquid-liquid extraction operation. The aim was to develop a computer code that helps predicting the overall performance of the purification process for a given set of operating conditions. The adopted approach is based on determining the necessary theoretical stages for each step in the purification process using a numerical technique. Some simulation results for the WPA purification process with Tri-Butyl Phosphate (TBP) at 45°C, Methyl Isobutyl Ketone (MIBK) at 25°C and a mixture (MIBK+TBP) at 30°C are presented.

Purification of wet phosphoric acid from ferric ions using modified rice husk

A new method has been developed to reduce the concentration of Ferric ions present as inorganic impurities in crude Egyptian phosphoric acid. This method is based on the silica extracted by alkaline treatment of rice husk to carry out the exchange of ions. Several parameters (contact time, temperature, sorbent type, sorbent mass, and batch factor) were examined. Simultaneous determination of Fe 3+ ions in presence of uranium ions before and after treatment revealed that the concentration of uranium was reduced by ∼18% during the removal of Fe 3+. Adsorption isotherm indicates that the monolayer coverage is 0.386 g Fe 3+ ions per g sorbent. In dynamic mode, the adsorption capacity at ( C e/ C o=50% or Q 0.5) was=22.5 mg/g and the column recycled at least three times and only needs 150 ml of 0.1 M HNO 3 for each regeneration and no weight loss in sorbent per cycle should be considered. Therefore, the developed rice husk adsorbent is considered as a better replacement technology for removal of Fe 3+ ions due to its low cost and good efficiency in this application. The cost of 1 kg of the modified rice husk (MRH) is estimated and the sorption mechanism is discussed.

Purification of wet phosphoric acid using modified activated carbon

Phosphoric acid is very important to the Tunisian economy. A new method has been developed to reduce the concentration of inorganic impurities present in commercial Tunisian phosphoric acid. This method is based on the modification of activated carbon with sodium dodecyl sulphonate to carry out the exchange of ions. The preliminary results with the column used for this purpose was shown to be effective; the concentration of Cd in the acid was reduced to approximately zero, V was reduced with 86% and Zn, B & Cr were reduced with 50%. Another system (activated carbon–sodium diethyldithiocarbamate) was tested for the purification of phosphoric acid, and it shows effective results for the elimination of Ni and V specially at lower acid concentrations. At high acid concentration, these columns remain effective mainly for the elimination of B by carbon-SDS column and the elimination of Ni by SDDC-carbon column.

PURIFICATION OF WET PROCESS PHOSPHORIC ACID BY SOLVENT EXTRACTION WITH PROPYL ETHERS.

ABSTRACT The distribution data for the impurities (SO= 4, F−, Fe, Al and Mg) during purification of wet phosphoric acid (WPA) with di-n-propy1 ether (DPE), di-n-propy1 ether containing 6. 5% of the isomer n-propylriso-propyl ether (DPE(M)) and di-iso-propyl ether (DIPE) at 25°C are reported. The distribution of phosphoric acid (PA)(SO= 4, F−, Fe, Al and Mg between the conjugated phases has been investigated. The system W-WPA-DIPE shows a three-liquid-phases-at-equilibrium zone with 65.7% of phosphoric acid in the aqueous phase, 43.9% in the heavy organic phase and 4.3% in the light organic phase. The degree of purification increases, for the three solvents studied, when decreasing the PA concentration in the organic phase (except for F−when using DPE}. Purification data for iso-arayl alcohol (1) and these three solvents are compared, showing that di-n-propyl ether with 6.5% of the isomer propyl-iso-propyl ether is the best solvent (from all solvents investigated in these series) for the purification of th...