Response Surface Methodology To Optimize The Ilmenite Extraction Process

This thesis is focused on the technique of the recovery of all fractions ilmenite from the tailings of magnetic separation. And a new output model (harmonic-mean model) of response surface methodology (RSM) is proposed in this thesis, which is applied to optimize the technique of recovering ilmenite by flotation. The new output model was compared with arithmetic-mean model and geometric-mean model. The RSM was also applied to demonstrate the relationship of the grade or the recovery of the ilmenite rough concentration with each factor in the processing of flotation. The research of flotation characteristic on the crude ore is traced deeply to the research on the flotation characteristic of ilmenite and gangue and the absorption of the collector of ilmenite. The result demonstrates:a) On the all-open-circle technique that is "screening- grinding- removal of magnetite- removal of sulfides- rough concentration(once)- concentration(twice)", the grade(the result of optimization) of ilmenite concentration is more than 47%, and the recovery (the result of optimization) is more than 45%. The optimum technological conditions are set as this:rough concentration:1065,1060g/t and 5.15(collector quantities, depressor quantities, pH value respectively), concentration:45.35g/t,83.16g/t and 3.86 (collector quantities, depressor quantities, pH value respectively).b) The three types of models (arithmetic-mean model, geometric-mean model and harmonic-mean model) are significant, and their predicabilities bear much resemblance. However, the abilities of the three models, in term of optimizing the process of flotation of ilmenite, lack resemblance. In particular, the effect is harmonic-mean> geometric-mean> arithmetic-mean.c) The pH value plays an important role in the technique. And a lower pH value condition is beneficial to it. The collector quantities, the depressor quantities and the pH value are all factors of importance to the grade of ilmenite concentration. The collector quantities and the pH value have great impact on the recovery of ilmenite concentration.d) The recovery of the ilmenite is higher than that of gangue when collected by SYB2#. Under the circumstances of no depressor, pH value exerts little influence on the recovery of ilmenite and gangue. Sodium carboxymethylcellulose can strongly depress ilmenite and gangue. The sulphuric acid performs as an anti-depressor to ilmentie, but it is not an obvious anti-depressor on gangue. It is manifested that there is a positive correlation between the recovery of ilmenite and the adsorption capacity of SYB2#.