Experimental study for finding the Al~(3+)-content rate of the basic aluminum-sulfate absorbent based on the flue gas desulfurization

In this paper,we would like to focus our attention on studying the aluminum content rate of the basic aluminum sulfate absorbent based on the flue gas desulfurization. So far as we know,in order to measure Al3 +concentration of the basic aluminum sulfate solution accurately,it is necessary to titrate EDTA by using the Cu SO4 standard solution with PAN as the indicator so as to optimize the measurement conditions of the four interference factors. Since alkalinity and aluminum content are the chief influential factors for defining the desulfurization characteristics of the basic aluminum sulfate-desorption desulphurization,such factors are the key parameters needed to be adjusted and controlled in the study of desulfurization method,the Al3 +concentration in the solution should be the key influential factor for calculating the alkalinity and aluminum content rate. What is more,it is necessary to analyze the calculation errors in the process of the experiment and determine the feasibility of the measuring method by taking into full account the different scopes of interference factors that may affect the measurement accuracy and compare the measuring results and the standard sample Al3 +concentrations. The results of our experimental study show that Ca2 +in the basic aluminum sulfate solution does not interfere the measurement of Al3 +content,whereas the diluted Al3 +concentration rate should be 0. 141-0. 423 g / L,which can be regarded as the target determining the optimal dilution ratio. In addition,the optimal excessive rate of EDTA is between 50%-150%,with the optimal coordination of Al3 +and EDTA being controlled in p H = 3. 42-3. 91 and boiled for 3-5 mins. The error analysis can help us to find that the average method recovery rate is 98. 86%,whereas the relative error range is between- 0. 47% to- 0. 33%,when the measured value of Al3 +concentration can be compared with the theoretical value,with the standard deviation being 0. 002 g / L and the relative standard deviation( RSD) being less than 1%. Repeated examination and analysis of the experimental results prove that the data we have gained from the experiments are faithful and stable.Taking XO as the indicator and zinc salt as a standard solution to the titration experiment,the contrast experiment results demonstrate that it is difficult to determine the titration end point due the sealing effect from Al3 +on the indicator,The relative error range has been found to be- 3. 42%-- 2. 62% as the measured values in comparison with the theoretical value. And,finally,we have confirmed that the average accuracy of the measurement results should be reduced by a factor of 2. 156%.