Lead-contaminated soil and battery casings are remediated using a plasma arc furnace which pyrolyzes the soil and waste battery casings so as to form a vitrified slag and a combustible gas, respectively. The combustible gas along with volatilized lead (and other heavy metals which may be present) are transferred to, and used as a primary fuel by, a conventional smelting furnace. The volatilized lead that is entrained in the combustible gas is thus transferred to the recovery and environmental protection/control equipment associated with the smelting furnace. The soil, on the other hand, is converted into a non-toxic (i.e., according to the Toxicity Characteristic Leaching Procedure) vitrified slag by the plasma arc which may be crushed and used as a commercial material (e.g., roadway aggregate, asphalt filler material and the like) or simply transferred to a landfill where it poses no environmental threat.
Used batteries and other material for reclamation and recovery or environmentally safe disposal are transferred from a feed bin by an auger into a crusher and then into a pyrolysis chamber. The feed system excludes air or oxygen from passing through the auger and crusher into the pyrolysis chamber. The material from the crusher is transferred by an auger through the pyrolysis chamber which is heated to a decomposition temperature between 350.degree. and 650.degree. F. and is decomposed. The pyrolysis chamber includes a vapor recovery system for removing the vapors and maintaining a vacuum in the pyrolysis chamber. The vapors are withdrawn through a heat exchanger and into the liquid/gas separator where the condensed liquids are removed and the gas is further processed. The residue from the pyrolysis chamber is discharged into a residue recovery system which includes a closed auger for transferring the residue from the pyrolysis chamber into a bin. A pressure sensitive switch which maintains a minimum level of solid material in the bin which acts as a seal to prevent air or oxygen from entering the pyrolysis chamber. The residue is transferred to a screening collector having an upper and a lower screen. The screens are vibrated and the finer sized metals are collected from the bottom of the screening collector, the heavier metals off the lower screen and the paper and plastic off the upper screen.
An arc furnace that utilizes a combined DC arc system and an AC joule heating system to melt the waste disposed therein and to keep the waste material in a molten condition. The DC arc system utilizes the AC joule heating electrodes as part of the DC current path, thereby eliminating the need for a counter DC electrode. Furthermore, the AC joule heating system provides for peripheral and radial AC current flow to neighboring AC joule heating electrodes, thereby creating a stirring effect in the molten waste. This design greatly simplifies the arc furnace control system while providing a more effective thermal control of the molten waste.
The present invention relates to a vitrification process for a pulverulent material and an apparatus for implementing said process. The process consists in introducing the pulverulent material into the fusion area of a furnace via injection means, where it is melted by means of at least one plasma torch to obtain a melt, and where the melt is removed from the furnace via a casting zone, the material being introduced laterally into the fusion zone in a direction comprising a horizontal component, and the melt being removed from the furnace by overflowing via the said casting zone, more or less along said horizontal component and away from the means for injecting the material into the furnace, in relation to the fusion zone.
The apparatus of the present invention is a melter housing having a pretreat chamber heated with a feed material heater that is partially isolated from a melter chamber. The method of the present invention has the steps of introducing feed material into a pretreat chamber and heating the feed material to a softening temperature of the feed material, and passing the pretreated feed material to a melter chamber.
Chemical agents, such as chemical munitions, are decomposed by bringing them into contact with a plasma arc of a DC plasma arc furnace operated at a temperature of greater than about 30,000.degree. F.
