Recycling of drilling tools for oil and gas exploration

Leaching experiments served to uncover the conditions required for the accomplishment of selective drill bit digestion. Here, one focus point lay on the time needed for complete disintegration and another on finding the acceptable solid-to-liquid ratio. The mass balances for different kinds of infiltrated material illustrated the varying behaviors of the respective parts of the drill bit. All in- and outgoing mass flows have been analyzed in detail by ICP-MS, XRF, and carbon analysis. Reduction of the gained solid residue with hydrogen gas has helped to determine the degree of oxidation. Furthermore it was possible to prove the special influence of steel on the dissolution behavior of tungsten.