Batch coal flotation model based on water recovery concept

Abstract

The results obtained from batch flotation experiments on two coals were used to develop relationships between the recoveries of water and solids into the concentrate. When the recovery of non-ash material (R_N) for any size fraction is plotted against a parameter X, defined as

$${\rm{X}} = \left| {\matrix{{{\rm{Amount}}\;{\rm{of}}\;\left({\rm{W}} \right)\;{\rm{recovered}}} \hfill \cr {{\rm{in}}\;{\rm{the}}\;{\rm{concentrate}}\;\left({{\rm{cc}}} \right)} \hfill \cr } } \right|\; \times \;\left| {\matrix{{{\rm{Collector}}\;{\rm{dosage}}\;\left({\rm{C}} \right)} \hfill \cr {\left({{\rm{kg/t}}} \right)} \hfill \cr } } \right|$$

a single “non-ash recovery curve” is obtained. Non-ash recovery curves thus obtained from different size fractions are used to get a unique “modified non-ash recovery curve” for a given coal, using the reduced efficiency curve concept. Similar observations have been noted in the case of recovery of ash material (RA) also.

The amount of water recovered into the concentrate is plotted against a parameter “Water Recovery Factor (WRF),” defined as

$${\rm{WRF}} = {\rm{T}}{\rm{.F}}.\left({1 + {\rm{C}}} \right)$$

where T is time (in sec) and F is frother dosage (in kg/t). Plotted in this form a characteristic water recovery curve for a given coal is obtained that may be defined by the following equation:

$${\rm{W}} = {{\rm{W}}_\infty }\left({1\;{\rm{-}}\;{{\rm{e}}^{{\rm{- pWR}}{{\rm{F}}^{\rm{q}}}}}} \right)$$

The above relationships have been verified against the experimental results obtained from three more coals and are found to give satisfactory predicted values.