Plasma magmavication of soils by nontransferred arc

Electrical plasma arcs create very high temperatures (T > 4,000 degrees C) that can be specifically directed for the in-place melting of soils. This o verview presents a summary of the basic features and capabilities of plasma torches having a nontransferred type of arc for the in situ vitrification of soils. Laboratory chamber experiments using 100 kW and 240 kW plasma sys tems and full-scale held trials using a 1 MW portable system have successfu lly melted a variety of soil types, including sands, silts, and clays. With in five minutes' exposure to the are, a core region of magma forms within t he soil matrix that expands radially outward and upward as the torch is pul led out vertically. Several days afterwards, the molten zone cools to form an artificial igneous rock similar to obsidian, basalt, or granite. The siz e of the vitrified mass is proportional to the electrical power demand. The plasma torch has a configuration similar to a flamethrower and will theref ore be amenable to placement down boreholes for purposes of in situ ground modification and subsurface remediation.