| Abstract [eng] |
The topic of the Master Theses is “Cleaning of Extractive Phosphorous Acid”. The phosphorous acid extracted by AB “Lifosa” was used. The extractive phosphorous acid (EPA) was cleaned by Kovdor apatite (KA) supplied to the factory from Murmansk district (Russia) in order to remove sulphates. The phosphorous acid was cleaned from many metal ions (Al3+, Fe2+, Ca2+, Mg2+, Si4-, As3-, Pb2+, Cd2+, Mn2+, K+, Na+, Ti2+, Cr3+, Cu2+, Ni2+, V2+, Zn2+) by extracting phosphorous acid using chemically clean organic solvent (methylisobutylketone – MIBK). The yellowish colour of phosphorous acid was removed using the chemically clean activated carbon. The concentration of phosphorous acid pentoxide was determined during the work. The metal analysis in the acid was performed by ICP – OES spectrometer. The amount of sulphates in extractive phosphorous acid depends on the amount of Kovdor apatite. As the stoichiometric ratio of phosphorous acid and apatite is increasing, the number of sulphates is decreasing. The smallest amount of sulphates (0,02 %) was determined at stoichiometric ratio EPA:KA=1:1,5. The effectiveness of desulfurization process is affected a lot by temperature. It is attempted to achieve the biggest effectiveness of desulfurization and extraction process with the smallest energy expenditure. The smallest amount of sulphates in phosphorous acid after the desulfurization was determined at 80°C temperature. The extraction process is carried out when the ration of desulfurizated phosphorus acid and MIBK is 1:3. In order to achieve economic benefit, the organic solvent is diluted with water up to 60, 55 and 50 %. When phosphorous acid desulfurizated at 0, 80 and 90 C temperatures was extracted, the biggest reduction of researched ions was determined in acids desulphated at 70°C and 80°C. Using activated carbon the concentration of majority of ions (Fe2+, Mg2+, Mn2+, K+, Ti2+, Cr3+, Ni2+, V2+) was reduced and clear colourless solution was received. In assessment of the received experimental results, the technological solutions of cleaning of extractive phosphorous acid were presented in the work. |
