Abstract: In a reactor apparatus including a reactor having a straight body, an agitation shaft, and an agitating blade, dimensions of the straight body, dimensions of the agitating blade, and a set value of a number of rotations of the agitation shaft satisfy a relationship represented by N(b/d)(L/D)/n?6.0. N represents a number of agitating blades, b represents a maximum value [m] of blade widths of the agitating blades, d represents a maximum value [m] of blade diameters of the agitating blades, L represents a length [m] of the straight body in an extending direction, D represents a maximum value [m] of diameters of inscribed circles substantially inscribed in the straight body, and n represents the set value of the number of rotations [rps] of the agitation shaft.

Abstract: A reactor apparatus includes a reactor having a tubular shape, and a plurality of first cooling pipes arranged inside the reactor, for circulating a coolant. Each of the plurality of first cooling pipes has a serpentine portion that extends while repeatedly bending. The serpentine portion includes a plurality of extending portions that extend linearly or extend while curving, and a plurality of bending portions which couple ends of two adjacent extending portions, among the plurality of extending portions. At least two of the plurality of first cooling pipes have different distances from an inner wall surface of the reactor.

Abstract: Disclosed herein is a method for treatment of arsenic-contaminated soil, said method being capable of insolubilizing arsenic compounds (in organic form or tri- or pentavalent inorganic form), thereby reducing their leaching level below the environmental standard value for soil. The method consists of heating arsenic-contaminated soil at 200 to 700° C. and mixing the heated soil with a calcium compound and water. The method also consists of mixing arsenic-contaminated soil with a calcium compound, heating the mixed soil at 200 to 700° C., and mixing the heated soil with water.

Abstract: Disclosed herein is a method for treatment of arsenic-contaminated soil, said method being capable of insolubilizing arsenic compounds (in organic form or tri- or pentavalent inorganic form), thereby reducing their leaching level below the environmental standard value for soil. The method consists of heating arsenic-contaminated soil at 200 to 700° C. and mixing the heated soil with a calcium compound and water. The method also consists of mixing arsenic-contaminated soil with a calcium compound, heating the mixed soil at 200 to 700° C., and mixing the heated soil with water.