Abstract: A method is disclosed for rapidly carbonating large cement structures, by forming and hardening cement in a mold under high carbon dioxide density, such as supercritical or near-supercritical conditions. The method is more reliable, efficient, and effective than are post-molding treatments with high-pressure CO2. Cements molded in the presence of high-pressure CO2 are significantly denser than otherwise comparable cements having no CO2 treatment, and are also significantly denser than otherwise comparable cements treated with CO2 after hardening. Bulk carbonation of cementitious materials produces several beneficial effects, including reducing permeability of the cement, increasing its compressive strength, and reducing its pH. These effects are produced rapidly, and extend throughout the bulk of the cement—they are not limited to a surface layer, as are prior methods of post-hardening CO2 treatment.

Abstract: A method is disclosed for rapidly carbonating large cement structures, by forming and hardening cement in a mold under high carbon dioxide density, such as supercritical or near-supercritical conditions. The method is more reliable, efficient, and effective than are post-molding treatments with high-pressure CO2. Cements molded in the presence of high-pressure CO2 are significantly denser than otherwise comparable cements having no CO2 treatment, and are also significantly denser than otherwise comparable cements treated with CO2 after hardening. Bulk carbonation of cementitious materials produces several beneficial effects, including reducing permeability of the cement, increasing its compressive strength, and reducing its pH. These effects are produced rapidly, and extend throughout the bulk of the cement—they are not limited to a surface layer, as are prior methods of post-hardening CO2 treatment.

Abstract: A method is disclosed for rapidly carbonating large cement structures, by forming and hardening cement in a mold under high carbon dioxide density, such as supercritical or near-supercritical conditions. The method is more reliable, efficient, and effective than are post-molding treatments with high-pressure CO2. Cements molded in the presence of high-pressure CO2 are significantly denser than otherwise comparable cements having no CO2 treatment, and are also significantly denser than otherwise comparable cements treated with CO2 after hardening. Bulk carbonation of cementitious materials produces several beneficial effects, including reducing permeability of the cement, increasing its compressive strength, and reducing its pH. These effects are produced rapidly, and extend throughout the bulk of the cement—they are not limited to a surface layer, as are prior methods of post-hardening CO2 treatment.

Abstract: In a gas-generating chemical reaction carried out in a borehole that is largely filled with water, substantial pressure increases can be generated. This pressure can be used to fracture rocks around the borehole and, hence, stimulate water, oil or gas wells in tight rock formations. This pressure increase can also be used to fracture coal seams for enhanced in-situ gasification or methane recovery. This invention discloses the use of a new, novel system, based on the homogeneous reaction of aluminum alkyls with water, to create a controlled pressure increase. The most appropriate reaction mixture, as characterized by the rise of time of the generated pressure pulse and the energy content per unit length of borehole charge, is disclosed in this new invention.