Commonly used carboxylic acid collectors include oleic acid, oxidized paraffin soaps, and tall oil. Because they all contain chemically highly reactive carboxyl groups, they can collect many minerals, mainly oxidized minerals and some other non-sulfide minerals. These minerals include alkaline earth metal salts (such as scheelite, fluorite, apatite, barite, etc.), ferrous and rare metal oxides (such as hematite, pyrolusite, cassiterite, wolframite, ilmenite, etc.), silicate minerals of calcium, iron, beryllium, lithium, zircon, etc. (such as beryl, spodumene, zircon, hedonicite, tourmaline, etc.), and copper, iron, and zinc oxides (such as malachite, azurite, cerussite, smithsonite, etc.).

Oleic acid is not easily soluble and dispersed, and in practice, it often requires emulsification with solvents or heating treatment. The temperature used in its application is generally above 18°C. Its disadvantages include poor selectivity and insensitivity to hard water. Dosage should be strictly controlled, often added in stages, and used in conjunction with modifiers such as sodium carbonate and water glass.

Compared to oleic acid, oxidized paraffin soap is cheaper and is currently a widely used reagent in industry. Its main drawback is poor flotation performance at low temperatures. It requires emulsification for use at room temperature. In the flotation of iron oxide ore, oxidized paraffin soap is often mixed with crude tall oil, which has strong foaming power, to compensate for its shortcomings and achieve better results.

Tall oil comes in crude and refined forms. Refined tall oil has good collecting properties and is resistant to low temperatures, making it a good carboxylic acid collector. In crude tall oil, the active ingredient responsible for collecting is stable, resulting in better flotation performance and strong foaming power. However, large dosages can lead to excessive foaming, making flotation difficult and lowering performance indicators. In production practice, it is often mixed with oxidized paraffin soap.

In summary, carboxylic acid collectors have strong collecting power but poor selectivity, and are often used in conjunction with modifiers.