Bis(2,4,4-trimethylpentyl)phosphinic acid is primarily used as an extractant in hydrometallurgical processes for the separation and purification of metal ions. It is particularly effective in solvent extraction techniques for recovering valuable metals like cobalt, nickel, and rare earth elements from ores and industrial waste. Its selective extraction properties make it a key component in the production of high-purity metals for use in electronics, batteries, and advanced materials. Additionally, it is employed in the nuclear industry for the extraction and separation of uranium and plutonium from spent nuclear fuel. Its stability and efficiency in acidic environments contribute to its widespread use in these applications.