Riba equal quantities of the same kind of commodity ("like for like") — for example 100 kilograms of wheat for 100 kg of wheat — in a riba-free transaction called for by quoted ahadith. Or how "divine law" could prescribe that a jeweler — "who has spent his time and effort to convert gold into jewelry" and is taking gold as payment — not be compensated? M.A. Khan also notes that the authors of the IIIE blueprint have no objection to traders selling higher purity/quality commodity for cash and using the proceeds to buying more less purity/quality commodity, and wonders what
Industrial separation processes operations are having several different functions: A heterogeneous mixture (e. g. liquid and solid) can be separated by mechanical separation processes like filtration or centrifugation. Homogeneous mixtures can be separated by molecular separation processes; these are either equilibrium-based or rate-controlled. Equilibrium-based processes are operating by the formation of two immiscible phases with different compositions at equilibrium, an example is distillation (in distillation the vapor has another composition than the liquid). Rate-controlled processes are based on different transport rates of compounds through a medium, examples are adsorption, ion exchange or crystallization. Separation of a mixture into two phases can be done