Electricite De France - Service National

Aerospatiale Societe Nationale Industrielle

Service National Ealectricite De France

Pierre Pasquini

Jacques Nuns

Maxime Labrot

Didier M Pineau

Olivier Leclerc

Jean-Pierre Serrano

Roger Meunier

Fabrice Lebrun

This process comprises; mixing (1) the solid residues with a solid reducing agent; treating (2) the mixture in a furnace at a temperature above 1000.degree. C. to obtain (3) a vitrified product rendered poor in metals and an emission of gas enriched in metallic elements in a vapour phase; air quenching (4) the gases rich in metals; filtering (5) the products resulting from the air quenching to obtain secondary ashes rich in metallic salts; at the end of the filtering operation, washing the smoke (6) for discharging it to the atmosphere; and subjecting the secondary ashes rich in metallic salts to a treatment for producing a product rich in valuable metals (7 to 10).

Process for the treatment of solid residues containing metals, in

The plasma torch (10; 11, 12, 14) comprises an electrical power supply (20) with an arc circuit (21) and a coil circuit (22) which are mounted in series and with means (30) for controlling the level of the current flowing in the coil (22) consisting, inter alia, mounted in parallel with this coil (14), of a chopper consisting of a battery of capacitors (31) and of at least one electronic power switch (32) which may be placed distant from the coil. The electronic switch is preferably of the thyristor diode (321, 322) type, with a resonant turn-off circuit (31, 323). A variant of this chopper uses at least one electronic switch of the GTO thyristor type, controllable in triggering and in switching off, or at least one conventional thyristor equipped with an auxiliary extinction circuit. Application to high-power torches, for industrial, for example metallurgical, use.

Plasma torch with power supply for equalizing wear to prolong the

Method for equalizing wear to prolong the lifespan of a plasma torch

The invention concerns plasma torches comprising an upstream electrode (12), a downstream electrode (11), a chamber (15) for the injection of plasma producing gas, a priming electrode (13) and optionally a magnetic field coil (14), in which the upstream root of the arc is displaced on the upstream electrode. According to the invention, in order to control a continuous or reciprocating and/or an oscillatory translation, the field coil is supplied with a variable direct current, if need be a pulsatory undulatory current, and/or a diffuser is placed at the inner end of the upstream electrode which is supplied with a modulated flow of gas which it causes to whirl. Application in high power plasma torches for regularizing and rendering uniform the wear of the electrodes so as to prolong the life thereof.

Plasma torch having a longitudinally mobile arc root, and process for

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Fontainebleau, France

Pierre Pasquini