Raffinage

Raffinage, or refining, is the industrial purification of a substance by removing impurities to obtain materials of higher purity and quality. The term encompasses a range of processes across sectors, including petroleum, sugar, metals, and chemicals. Common principles include separation, chemical treatment, and sometimes electrochemical methods to transform crude or impure inputs into marketable products.

Petroleum refining begins with distillation of crude oil to separate fractions by boiling range. Subsequent conversion processes—such as cracking, reforming, hydrocracking, and alkylation—generate products like gasoline, diesel, jet fuel, and feedstocks for petrochemicals. Hydrotreating and desulfurization remove sulfur and other contaminants, while blending adjusts final product specifications.

Sugar refining converts raw cane or beet sugar into white refined sugar. Impurities are removed through purification and decolorization, and the purified sugar is crystallized and separated by centrifugation to yield granulated sugar, with molasses recovered as a byproduct.

Metal refining uses chemical or electrochemical methods to remove impurities. Electrorefining deposits pure metal at a cathode from an impure anode, as in copper refining. Pyrometallurgical smelting and other refining techniques are used for aluminum, nickel, zinc, and precious metals to achieve high purity and meet industry standards.

Environmental and economic factors influence refining choices, including energy use, waste handling, emissions, and regulatory compliance. Quality control and feedstock variability are important considerations in refining operations.