The disclosure relates to a method and apparatus for recycling, smelting, and refining waste metal material and low grade metal material. A magneto-plasma provides a high temperature for extracting metals. The magneto-plasma is comprised of an alternating current plasma superimposed upon a direct current plasma with the plasmas being confined by an externally applied axial magnetic field. The magneto-plasma is sustained with reduced voltage fluctuations across the plasma even when the background gas of the plasma is contaminated by the products from the smelting operation. The metal material being smelted is caused to melt by the high temperatures within the magneto-plasma which can be in the range of 10,000.degree. K. The metal material upon being melted into droplets is exposed to the high temperature of the magneto-plasma for a predetermined period of time as the droplets descend through the plasma. The length of the magneto-plasma is adjusted to obtain refining of the droplets of molten metal within th plasma. In addition, the lateral cross section of the length of the magneto-plasma is adjusted to enhance refining of the molten droplets.
To heat articles in the vacuum container as uniformly as possible by bombarding them with electrons from a low voltage arc discharge, the plasma flame is not directed at the articles as hitherto usual, but caused to extend past the articles to be heated, by providing a magnetic field in which the lines of magnetic force favoring the propagation of the plasma extend in a direction skirting the surfaces of the articles. Preferably, a magnetic field is provided which is parallel to the axis of the plasma flame, and the articles to be heated are arranged cylindrically around the flame.
There is disclosed an arc reactor for treating a material in powder form conductive at very high temperatures, the reactor comprising a vertical electrically insulated sleeve cylindrical in shape, an upper electrode coaxially mounted with the sleeve at its upper end, a bottom electrode cooperating with the upper electrode, injectors for injecting a gas tangentially into the sleeve in order to create a vortex inside the same, a feed mechanism for introducing the powder material inside the sleeve near its upper end, so as to form a uniform cylindrical curtain of particles falling down into the sleeve, the particles being centrifugally projected against the internal wall of the sleeve by the vortex and entirely covering the internal wall while they are being simultaneously treated by the arc column, a crucible positioned under the sleeve to collect the treated particles in molten form that drip down from the sleeve, the molten material in use being in conductive contact with the bottom electrode, and a drive system to adjust a vertical position of the upper electrode, the upper electrode being slideable through the upper end and being made of a consumable electrode material. The upper electrode does not require water cooling and lasts for longer operation.
A method and apparatus for the destruction of PCBs and other hazardous material utilizes a gas-tight chamber (18) which includes a high current DC arc (72). The chamber (18) is adapted to receive the PCBs or other hazardous material and includes a sump (20) which contains a molten bath (22). Inlet means (24, 26, 28) are provided for introducing the hazardous material into the chamber (18) and into contact with the molten bath (22) for initial decomposition into a molten product and a gaseous product. Electrode means (66, 68) are provided for maintaining the DC arc (72) at a current level sufficient to promote decomposition of the PCBs or other hazardous material. The gaseous product is passed in the proximity of the arc (72) for producing a decomposed gaseous product which is relatively harmless. The system is capable of decomposition of solid, liquid and gaseous PCBs, as well as other hazardous material.
