Abstract: A method and apparatus for reducing matter, particularly chemical compounds, to constituent elements in a high temperature environment (a plasma) and separating one of the elements from the other elements. Reduction is effected by raising the input compound to a high temperature -- thermally disassociating it. Separation is effected by partly ionizing one of the species (elements) to be separated and moving the resultant mixture of gas and plasma at a velocity (v) through a magnetic field (B) having a vector component (B.sub..vertline.) perpendicular to the plasma velocity vector. The interaction of the perpendicular and 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 separating force acts on the entire specie which is significantly ionized even though it is only partially ionized.