Provided herein are zero carbon dioxide (CO.sub.2) emission processes and systems to carry out the processes, comprising a) calcining limestone in a cement plant in an electric kiln to form a mixture comprising calcium oxide and a first gaseous stream comprising clean carbon dioxide, wherein the clean carbon dioxide comprises no gaseous or non-gaseous components from combustion of fuel; b) treating the mixture comprising calcium oxide with a N-containing salt solution under one or more dissolution conditions to produce a first aqueous solution comprising calcium salt; and c) contacting the first aqueous solution with the first gaseous stream comprising clean carbon dioxide under one or more precipitation conditions to produce a precipitation material comprising vaterite, aragonite, calcite, or combinations thereof.

A method of treating a metal carbonate salt includes hydrolyzing a metal halide salt to form a hydrohalic acid and a hydroxide salt of the metal in the metal halide salt. The metal includes an alkaline earth metal or an alkali metal. The method includes reacting the hydrohalic acid with the metal carbonate salt, wherein the metal carbonate salt is a carbonate salt of the alkaline earth metal or alkali metal, to form CO.sub.2 and the metal halide salt. At least some of the metal halide salt formed from the reacting of the hydrohalic acid with the metal carbonate salt is recycled as at least some of the metal halide salt in the hydrolyzing of the metal halide salt to form the hydrohalic acid and the hydroxide salt.

A method of treating a metal carbonate salt includes hydrolyzing a metal halide salt to form a hydrohalic acid and a hydroxide salt of the metal in the metal halide salt. The metal includes an alkaline earth metal or an alkali metal. The method includes reacting the hydrohalic acid with the metal carbonate salt, wherein the metal carbonate salt is a carbonate salt of the alkaline earth metal or alkali metal, to form CO.sub.2 and the metal halide salt. At least some of the metal halide salt formed from the reacting of the hydrohalic acid with the metal carbonate salt is recycled as at least some of the metal halide salt in the hydrolyzing of the metal halide salt to form the hydrohalic acid and the hydroxide salt.

A process for the production of lithium carbonate from an aqueous salt solution at least containing lithium ions, chloride ions and calcium ions; the aqueous salt solution with a lithium content of at least 0.005% by weight and a maximum 0.2% by weight is condensed in a first evaporation step at a temperature between 40° C. and 160° C. until a concentrate I with a water content of ≤70% by weight and >60% by weight is formed. In a second evaporation step, the concentrate I is evaporated at a temperature between 60° C. and 180° C. until a concentrate II with a water content of ≤60% by weight is formed. In a Li concentration step, the lithium content is raised to at least 0.14% by heating the concentrate II to a temperature of at least 60° C. and thus a lithium-rich concentrate III and a residue III are formed.

The present disclosure relates to a preparation method of a methionine-metal chelate, and the methionine-metal chelate, which is prepared by first reacting Ca(OH).sub.2 and methionine and adding metal chloride salts, can be used as feeds and feed additives.

The present disclosure relates to a preparation method of a methionine-metal chelate, and the methionine-metal chelate, which is prepared by first reacting Ca(OH).sub.2 and methionine and adding metal chloride salts, can be used as feeds and feed additives.

A process for producing olefins may include dehydrogenating a first alkane in a first reactor to produce a first effluent comprising at least one of a first n-olefin or a first diolefin; removing the first effluent from the first reactor; and regenerating the first reactor. The first reactor may include a first dehydrogenation catalyst and a first phase change material.

A process for producing olefins may include dehydrogenating a first alkane in a first reactor to produce a first effluent comprising at least one of a first n-olefin or a first diolefin; removing the first effluent from the first reactor; and regenerating the first reactor. The first reactor may include a first dehydrogenation catalyst and a first phase change material.

Provided are a method of preparing a metal oxide-silica composite aerogel which includes preparing a silicate solution by dissolving water glass at a concentration of 0.125 M to 3.0 M, after adding and mixing a metal salt solution having a metal ion concentration of 0.125 M to 3.0 M to the silicate solution, precipitating metal oxide-silica composite precipitates by adjusting a pH of a resulting mixture to be in a range of 3 to 9, and separating and drying the metal oxide-silica composite precipitates, wherein the metal salt solution includes a magnesium (Mg)-containing metal salt in an amount such that an amount of magnesium ions is greater than 50 mol % based on a total mole of metal ions in the metal salt solution, and a metal oxide-silica composite aerogel having low tap density and high specific surface area prepared by the method.

Methods of melting ice using ice-melt compositions including calcium chloride coated with a lignosulfonate material are disclosed. The ice-melt compositions can be useful as ice-melt products with improved safety. A method can include applying an ice-melt composition to ice, the ice-melt composition comprising coated particles. Each coated particle can include a core comprising calcium chloride and a coating at least partially surrounding the core, the coating comprising a lignosulfonate material.