NOVELTY - Solar grade silicon is produced by introducing the fluid silicon precursor at ambient temperatures through a pipe, holding steep temperature gradient in reactor, conducting reactants at great speed toward the surface of the molten silicon, and reacting formed silicon portion with the excess hydrogen in the upper portion of the reactor and falls as particulate solid silicon.    USE - For producing solar grade silicon.    ADVANTAGE - The invention provides pure silicon from reduction of silicon precursor with hydrogen in reactor.    DETAILED DESCRIPTION - Production of solar grade silicon comprises thermal decomposing of silicon precursor in the presence of excess hydrogen through separately introducing hydrogen gas and silicon precursor in vertically oriented reaction chamber (8) where lower portion holds pool of molten silicon; withdrawing the surface where reactant are directed and reacted during formation of elementary silicon and hydrogen chloride, off gases, and by-products; withdrawing the silicon formed from the lower portion of the reactor (1); introducing the fluid silicon precursor at ambient temperatures through a pipe (2, 6) arranged coaxially in a feed pipe for hydrogen gas; holding steep temperature gradient in reactor; conducting reactants at great speed toward the surface of the molten silicon; and reacting formed silicon portion with the excess hydrogen in the upper portion of the reactor and falls as particulate solid silicon.    INDEPENDENT CLAIMS are also included for:    (1) a reactor for producing solar grade silicon comprising elongated container with inert lining and injection system for silicon precursor; outlet for unconverted hydrogen, hydrochloric acid, and any by-products; and constant level outlet system for produced liquid silicon (9);    (2) a method for the removal of particles from off gas comprising placing a particle recapture tower (7) on the off gas outlet from a reactor or kiln, holding the particle recapture tower and reactor at temperature above the melting point of the particles that leads to capture and melting of the particles and their flowing back to molten material; and    (3) a particle recapture tower for removing particles from off gas comprising channel having partitions with downward sloping geometry that is designed to form opening between partition and channel wall.    The feed system comprises outer pipe for introducing hydrogen gas and pipe arranged coaxially with pipe for introducing of fluid silicon precursor. The reactor is sufficient to establish the necessary steep temperature gradient.    DESCRIPTION OF DRAWING(S) - The figures show the primary decomposition chamber with particle recapture tower and second decomposition chamber on the off gas outlet, and the injection system.    Reactor (1)    Pipe (2, 6)    Particle recapture tower (7)    Reaction chamber (8)    Liquid silicon (9)