Fatty acid refers to the molecule with a carboxyl group of aliphatic organic acids. In the mineral processing industry, the department of flotation use the hydroxide collector. The general formula is R-COOH, and the R group is a linear or branched akyl, alkenyl or cycloalkyl group. According to the length of carbon chain, properties varies, in addition to use as the collector, but also as a foaming agent, inhibitors and dispersants.
Natural animal and vegetable fats and oils are the main source of fatty acids. The fatty is decomposed into fatty acids or fatty acid soap(sodium soap or potassium soap) after hydrolysis or saponification, the soap generates fatty acids through acidification. Alkaline washing with some crude oil fraction, sodium naphthenate soap, by-product, can be obtained , and then naphthenic acid can be obtained from soap acidification. Mixed fatty acids or pure single fatty acids can be obtained from deeply oxidizing and separating refined kerosene, paraffin and other hydrocarbons.
According to the length of carbon chain, fatty acids customarily divided into two kinds: lower fatty acids and higher fatty acids. The number of carbon atoms in the molecule of less than ten is a lower fatty acid, and the number of carbon atoms of ten or more is a higher fatty acid. Fatty acids containing unsaturated bonds in the carbon chain(such as double bond) is called unsaturated fatty acids, while do not containing unsaturated bonds are called saturated fatty acids. Natural unsaturated fatty acids mainly includes oleic acid, linoleic acid, linolenic acid and ricinoleic acid. Natural saturated fatty acids mainly includes stearic acid, palmitic acid, cinnamic acid, lauric acid, capric acid, caprylic acid and caproic acid and the like. Higher fatty acids have higher foam stability than lower fatty acids. For example, the sodium salt of oleic acid, linoleic acid and stearic acid can form a stable foam. And the concentration of the medicament in the foam layer is higher than that in the pulp. When the concentration of different solutions of pharmaceutical agents achieves a certain value, the solution significantly formed micelles. When a single molecule or ion began to accumulate into the orderly arrangement of the molecular weight, the drug concentration is called the "critical micelle concentration."This concentration has a close relationship with the role of flotation, for example, the adsorption of sodium oleate by magnetite increased with the concentration of the agent increased, and the buoyancy also increased. However, when the concentration of the drug increased to near the critical micelle concentration, the floatability decreased significantly, even to zero.