Recycling of Drill Bits

 

 

Project Managers: ____ Dipl.-Ing. Claudia Kerschbaumer
Priv.-Doz. Dipl.-Ing. Dr.mont. Stefan Luidold

 

The aim of the project as a part of the `Christian Doppler Laboratory for Extractive Metallurgy of Technological Metals´ is to devise a method to recycle bits for oil and gas drilling that is both industrially applicable and economically reasonable. The PDC bit of the drill head as depicted in Figure 1 consists of a mixture of cast tungsten carbide and stoichiometric tungsten carbide that is infiltrated with a binder alloy of copper, manganese, nickel, and zinc.

Drill bit

Figure 1:  Drill bit made of a body of infiltrated tungsten carbide and polycrystalline diamond
cutter inserts (PDC drill bit) (Source: http://www.globaltungsten.com)

For efficiently recovering tungsten carbide as well as the constituents of the complex binder alloy as re-usable products, three methods will be reviewed. First, selective chemical digestion of the binder phase shall be tested using different reagents and varying operating conditions. Another method for selective digestion of the binder matrix with tungsten carbide being left intact constitutes an electrochemically assisted selective digestion. The third option represents on indirect recycling where binder and tungsten carbide are chemically transformed.