Interactive Optimization of Impressive Parameters Middling in Biological Leaching

In this study, single and interactive effect of three parameters, pH, ferrous and pulp concentration has been investigated by a 2^3 full factorial CCRD （central composite rotatable design） composed of eight factorial points, six central and six axial points. Initially, ＂none＂ mode from transformation subsection was chosen as the default choice for both responses, i.e. %recovery and gram of recovered zinc. Box-Cox plots give the best Lambda for each response （y^Lambda= f （A, B, C ...）） which occur at 1.91 and 2.16 for %recovey and gram of recovered zinc, respectively. A linear （y^1.91 = f （linear）） and a quadratic （y^2. 16= f （quadratic）） equation were suggested by software as the model for %recovery and gram of recovered zinc, respectively. Analysis of variance （ANOVA） for both models shows a high coefficient of determination （R^2）. In order to optimize and find the best conditions under which three parameters occur appropriately, optimization was done numerically. Desirability plots indicate properly that the best conditions occur at pH = 1.46, ferrous = 6.67 g/L, %pulp = 7.1 （%w/v）, %recovery = 86.5, gram of recovered zinc = 0.63 g and desirability = 0.777. Finally, PRP （progressive route of the process） analysis donates us a proper insight of what is happening during these 30 days. PRP analysis categorizes flasks in two parts, 1- flasks worth economically, 2- flasks with one-time-usable feed materials.