A method and apparatus for reducing matter, particularly chemical compounds, to constituent species in a high temperature environment (plasma) and separating one of the species from the other species. Reduction is effected by raising the input compound to a high temperature so that it is thermally dissociated. Reduction can also be effected by chemically reducing the compound to a gas consisting of a specie which can be more readily ionized and another product of the chemical reduction reaction. Separation is effected by partly ionizing one of the species to be separated and moving the resultant mixture of gas and plasma through a magnetic field (B). The magnetic field B is shaped so as to increase in intensity in the direction of flow of the gas and plasma. The plasma is squeezed by the magnetic field. Although the plasma tends to follow the magnetic field lines, there is some slippage across them. The net result is that the plasma is moving at a velocity (v) through a magnetic field B having vector components B.sub..vertline. perpendicular and parallel B.sub..parallel. to the plasma velocity vector. The interaction of the perpendicular (B.sub..vertline.) and parallel (B.sub..parallel.) components of the magnetic field with the ions and electrons in the plasma produces a separating force perpendicular to the direction of plasma flow -- the force tending to squeeze the plasma. The separating force acts upon the entire specie which is significantly ionized even though it is only partly ionized because of resonant charge exchange. The neutral or un-ionized specie is not directly affected by the magnetic field.
PRIOR PATENT APPLICATIONS
This application is a continuation-in-part of patent application Ser. No. 269,634 filed July 7, 1972 in the names James E. Drummond, David B. Chang and Derek W. Mahaffey; said application Ser. No. 269,634 being a continuation-in-part of patent application Ser. No. 172,674 filed Aug. 18, 1971 in the name of James E. Drummond, David B. Chang and Derek W. Mahaffey (now abandoned).
A metal processing furnace of the indirect arc type employing opposed electrodes projected into an ionizable atmosphere is provided with novel filter-like, vapor nucleation means which enables the furnace to be utilized for numerous different metal melting/smelting operations in a manner which precludes the presence of metals and metal oxides in their vapor or particle forms in process effluent gases delivered from the furnace. The furnace achieves substantial operating advantages in the manufacture of ferroalloys, silicon and beryllium-copper metals, and comparable products including carbides such as silicon carbide.
A process for reducing a metal from a metal halide characterized by the steps of feeding into the arc heated stream of an arc heater a quantity of a reactant metal such as an alkali or alkaline-earth metal, feeding into the arc stream a quantity of a metal halide, which metal has a melting point higher than the boiling point of the co-product salt formed by reduction of the metal, the co-products being a liquid elemental metal and a gaseous salt, projecting the co-products into a reaction chamber tangentially to cause the liquid metal to separate centrifugally from the lighter, gaseous salt, and depositing the liquid metal in an associated receptacle.
This invention provides methods and apparatus for ionizing all the elements in a complex substance such as radioactive waste and for separation of some of the elements from the other elements. One principal methods utilizes plasma confinement by toroidal magnetic fields as a gate to regulate when and where specific elements are collected. While the plasma is confined, some of the species are removed by repeatedly cycling all of the species between the plasma and the deposition stages lining the walls, whereby some species preferentially accumulate on the deposition stages. The other species are then diverted into an additional containment vessel for collection or additional separations. The apparatus is a large volume plasma processor with multiple containment vessels. The invention provides for the characterization of waste material, and for its separation all within one serf contained vacuum environment. Other applications include remediation of chemical toxic wastes and chemical and germ warfare weapons.
A plasma reactor, in which particulate matter is caused to interact with low temperature plasma (i.e. below 100,000 K.) comprises spaced stationary electrode structures 2, 11 of which at least one is annular, between which an arc or arcs 7 is established by a power supply which may include a thyristor (SCR) 9. The arc is pulsated and caused to orbit or circulate round the or each annular electrode structure to form a conical plasma zone between the electrodes, while particulate solids are introduced through inlets 5 to enter the plasma zone and interact with the plasma therein. Extended dwell periods and highly effective interaction are brought about by circulation and pulsation of the arc and a high particle population density. The arc can be circulated at high speed by electrical means, for example by sequential energization of plasma torches 1 in an annular array or of the segments 8 of a segmental anode, or by electromagnetic circulation of the arc attachment round an annular cathode or round a segmental anode with the help of coils 10 fitted between the segments. Examples of reactions that can be efficiently conducted by this method include the reduction of metal ores, beneficiation of low grade chromite ores, recovery of energy values from low grade carbonaceous matter such as colliery wastes and the formation of pozzolanic material and cements from siliceous minerals.
A specimen of molecules containing the desired element is contained in a low-pressure environment and is exposed to a beam of electrons of predetermined energy, causing the electrons to be captured by the molecules. The reaction is chosen so that there is a natural dissociation into an ion containing the desired element. The reaction region is subjected to an electrical field that accelerates the ions and removes them from the reaction region, at which time the ions are exposed to a laser beam of a wavelength sufficient to photodetach a substantial number of electrons from the ions, producing neutral atoms of the desired element. The entire particle stream exiting the interaction region is subjected to a magnetic field that bends the charged ions away from the neutral atoms so that the neutral atoms can then be directed to a test specimen or collection device, as the case may be. The apparatus for carrying out the method includes a pressure vessel for maintaining the environment in which the reactions take place at a pressure in the neighborhood of 10.sup.-4 Torr and, typically, the same magnetic field that is used to separate the ions from the neutral atoms is also used to collimate the electron beam for better localization, to interact with the molecules.
