Petroleum sulfonates, with the general chemical formula RSO₃Na, are produced by sulfonation of petroleum refining byproducts. Recent production practices have demonstrated their promising application in the flotation of non-sulfide ores. Compared to fatty acids, petroleum sulfonates exhibit better low-temperature resistance, stronger resistance to hard water, stronger foaming ability, slightly lower collecting ability, but better selectivity.
Petroleum sulfonates are further classified into two main categories based on their solubility: water-soluble and oil-soluble. Water-soluble sulfonates have smaller hydrocarbon molecular weights, contain more branched chains, or contain mixed alkyl and aryl hydrocarbon chains. They have good water solubility, relatively weak collecting ability, and good foaming properties, and can be used as foaming agents (such as sodium dodecyl sulfonate) and also for the flotation of non-sulfide ores (such as sodium hexadecyl sulfonate). Oil-soluble sulfonates have relatively large molecular weights with alkyl groups; when the hydrocarbon group is alkyl, the hydrocarbon chain contains more than 20 carbon atoms. They are essentially insoluble in water but soluble in non-polar oils. They exhibit strong collecting properties and are mainly used as collectors for non-sulfide ores, commonly used in the flotation of oxidized iron ores and non-metallic minerals (such as fluorite and apatite).
Petroleum sulfonates have gained attention in iron ore flotation due to their good selectivity. The Groland concentrator in the United States uses petroleum sulfonates, tall oil, and fuel oil as collectors, and sulfuric acid and water glass as modifiers. The flotation process employs a primary roughing and secondary cleaning stage. When the raw ore contains 33.9% Fe, the concentrate grade is 60%, and the recovery rate reaches 85.8%. The Qidaishan iron ore concentrator in my country also uses this reagent system, achieving good results through a primary roughing and tertiary cleaning stage. When the raw ore contains 26.6% Fe, a concentrate grade of 65% and a recovery rate of 78% are obtained.