A method for producing a carbonate-containing species-rich, nitrogen-containing species-free solution from a urea-rich solution is proposed. The method comprising the steps of: providing a first reservoir comprising a first mixture including urea and a catalyser comprising an enzymatic catalyser and/or a microorganism; allowing an enzymatic reaction catalysed by the catalyser to decompose urea, thereby obtaining a second mixture comprising nitrogen-containing species and carbonate-containing species; converting at least some of the nitrogen-containing species into gaseous nitrogen-containing species to obtain a third mixture comprising the gaseous nitrogen-containing species and the carbonate-containing species; filtering the third mixture by a gas- permeable filter, thereby separating at least some of the gaseous nitrogen-containing species from the carbonate-containing species while keeping the catalyser away from the gas-permeable filter; and collecting the so-obtained carbonate-containing species-rich, nitrogen-containing species-free solution.

The invention is directed towards a process for complete conversion of multiple industrial wastes to sustainable alternatives and usable products resulting in water in-soluble product alike chemical gypsum useful for cement manufacturing used in construction industry. The inventor has utilized industrial wastes from multiple industries together taking into consideration their chemical and physical properties without using any form of energy. The whole process is carried out at ambient temperature under open sky. In described two exemplary processes, the inventor has disclosed process comprising the steps of mechanically mixing metallurgical inert waste of aged dry Jarofix containing crystallized Gypsum with freshly generated Jarosite or dry/wet Red Mud followed by addition of adequate acidic concentration waste water, calcitic wastes, pozzolanic property enhancers & lime treatment. The multiple wastes mix crystallized chemical gypsum mass on drying is used as a whole without any leftover.

The invention is directed towards a process for complete conversion of multiple industrial wastes to sustainable alternatives and usable products resulting in water in-soluble product alike chemical gypsum useful for cement manufacturing used in construction industry. The inventor has utilized industrial wastes from multiple industries together taking into consideration their chemical and physical properties without using any form of energy. The whole process is carried out at ambient temperature under open sky. In described two exemplary processes, the inventor has disclosed process comprising the steps of mechanically mixing metallurgical inert waste of aged dry Jarofix containing crystallized Gypsum with freshly generated Jarosite or dry/wet Red Mud followed by addition of adequate acidic concentration waste water, calcitic wastes, pozzolanic property enhancers & lime treatment. The multiple wastes mix crystallized chemical gypsum mass on drying is used as a whole without any leftover.

The invention is directed towards a process for complete conversion of multiple industrial wastes to sustainable alternatives and usable products resulting in water in-soluble product alike chemical gypsum useful for cement manufacturing used in construction industry. The inventor has utilized industrial wastes from multiple industries together taking into consideration their chemical and physical properties without using any form of energy. The whole process is carried out at ambient temperature under open sky. In described two exemplary processes, the inventor has disclosed process comprising the steps of mechanically mixing metallurgical inert waste of aged dry Jarofix containing crystallized Gypsum with freshly generated Jarosite or dry/wet Red Mud followed by addition of adequate acidic concentration waste water, calcitic wastes, pozzolanic property enhancers & lime treatment. The multiple wastes mix crystallized chemical gypsum mass on drying is used as a whole without any leftover.

A lime-based cement extender composition, and associated systems and methods are disclosed herein. In some embodiments, the lime-based cement extender composition includes 5-20% by weight lime particles, 40-50% by weight limestone particles, and 40-50% by weight pozzolan particles. Additionally or alternatively, the lime-based cement extender composition can comprise a calcium oxide concentration of 45-65%, a magnesium oxide concentration of 0.5-2%, an iron oxide concentration of 0.5-2.0%, an aluminum oxide concentration of 2-8%, a silicon dioxide concentration of 20-40%, a potassium oxide concentration of 20,000-30,000 ppm, and a sodium oxide concentration of 10,000-20,000 ppm. In some embodiments, the lime-based cement extender composition, or product, is combined with cement to produce a cement blend for use in the mining industry as mine backfill.

A lime-based cement extender composition, and associated systems and methods are disclosed herein. In some embodiments, the lime-based cement extender composition includes 5-20% by weight lime particles, 40-50% by weight limestone particles, and 40-50% by weight pozzolan particles. Additionally or alternatively, the lime-based cement extender composition can comprise a calcium oxide concentration of 45-65%, a magnesium oxide concentration of 0.5-2%, an iron oxide concentration of 0.5-2.0%, an aluminum oxide concentration of 2-8%, a silicon dioxide concentration of 20-40%, a potassium oxide concentration of 20,000-30,000 ppm, and a sodium oxide concentration of 10,000-20,000 ppm. In some embodiments, the lime-based cement extender composition, or product, is combined with cement to produce a cement blend for use in the mining industry as mine backfill.

Provided herein are compositions and methods of carbonation processing for the fabrication of cementitious materials and concrete products. Embodiments include manufacturing processes of a low-carbon concrete product comprising: forming a cementitious slurry including portlandite; shaping the cementitious slurry into a structural component; and exposing the structural component to a CO.sub.2 waste stream, thereby enabling manufacture of the low-carbon concrete product.

The effectiveness of expansive cement systems may be diluted when, during a well cementing operation, commingling takes place between the cement slurry and a spacer fluid, a drilling fluid, or both. Incorporating expansive agents in the spacer fluid or drilling fluid may reduce or negate the loss of expansion at the cement slurry/spacer interface or the cement slurry/drilling fluid interface, thereby promoting zonal isolation throughout the cemented interval.

The effectiveness of expansive cement systems may be diluted when, during a well cementing operation, commingling takes place between the cement slurry and a spacer fluid, a drilling fluid, or both. Incorporating expansive agents in the spacer fluid or drilling fluid may reduce or negate the loss of expansion at the cement slurry/spacer interface or the cement slurry/drilling fluid interface, thereby promoting zonal isolation throughout the cemented interval.

Methods for repair of cracks and niches in concrete using carbonic anhydrase embedded in a gelatin, hydrogel, or other aqueous matrix are provided. A durable corrosion resistant concrete mix containing carbonic anhydrase is provided, as are methods of making and using the durable corrosion resistant concrete. Corrosion resistance and durability derive from decreased porosity compared to concrete without the enzyme, conferring decreased access of deleterious materials such as chloride ions to interior portions of the concrete.