Abstract: Apparatus and method for the cryothermal recovery of sulfuric acid as predicated on the capture and conversion of sulfur dioxide contained in industrial waste gases. The apparatus includes a waste gas purifier comprising a chamber through which waste combustion gases are passed so as to traverse an ice bed filter means containing ice produced so as to contain entrained oxygen by an independent ice-making machine and chilled by the use of a cryogenic material, preferably liquid nitrogen. The incoming gases may be chilled by recirculating the gases that have passed through the ice filter bed so as to chill the portion of the chamber that is contacted by the incoming gases prior to their passage through the ice filter bed. Oxygen entrainment may be enhanced by the employment of a source of oxygen and the entrained oxygen at the low temperature provided by the ice bed reacts with sulfur dioxide contained in the waste combustion gases by transition through sulfur trioxide to sulfuric acid.

Abstract: Apparatus and method for cryogenic flash freezing of confined water in a rock formation with concomitant fracturing of the rock formation utilizes an anchoring device comprising gripping means actuatable responsive to release of pressurized gas effected by opening a valve responsive to the firing of an explosive charge in combination with an elongated container for a cryogenic liquid so that the anchoring device may be positioned with said container depending therefrom in a hole in the rock formation and so that cryogenic liquid so held in position may be forcefully discharged from the container upon opening a valve responsive to the firing of an explosive charge for injection into water confined in the hole or in a cavity or crevice in the surrounding rock formation, the location of water to be flash frozen, if desired, being accomplished by a plug adapted to be fixed in place at different positions and to retain water thereon when fixed in place.