Glass - Back to the Future!

Presenting Author:
Patrice Charvin

article posted 22 March 2016

Patrice Charvin is a process engineer at CEA (French Atomic Energy Commission). In 2004-2007 - PhD in High Temperature Processes (research on Hydrogen production from water splitting by solar energy). Since 2008 Process engineer on nuclear waste vitrification processes involving plasma torches (CEA).
Since 2010 Person in charge of process part development in the PIVIC project.

Innovative glass melting and stirring process via molten metal

Patrice Charvin*, Aldo Russello, A. Quintas & Florent Lemont
C.E.A., DEN, DTCD, BP 17171, 30207 Bagnols sur cze Cedex, FRANCE

The Innovative Process Laboratory (LPIC) of the French Atomic Energy Commission (CEA) develops vitrification processes for radioactive waste immobilization. In this objective of mixed waste treatment including metallic, organic and mineral fractions, a new process is currently under study to melt glass and metal simultaneously and directly into the final metallic canister fitted with insulating layer and an internal ceramic crucible. In this process, heating is provided through induction in the metal phase. Glass is heated and melted by conduction transfer from high temperature molten metal phase. Low frequency induction in a molten metal phase induces important stirring effect of liquid metal due to Lorenz forces. At the interface, glass is carried along by friction with molten metal. First tests achieved on a large scale prototype for a year, have proved the feasibility of the concept. A minimum of metal (depending on the bath geometry) is required at the beginning to transfer power in the canister. A correct stirring of glass is then obtained without additional equipment like bubbler or mechanic stirrer. Studies are in progress in order to quantify thermal and movement transfer from molten metal to glass. Chemical interactions between phases are examined too with post-mortem analysis of each phase.
This innovative process of glass melting via molten metal presents advantages and drawbacks compared to others well-known processes.