A p-type oxide which is amorphous and is represented by the following compositional formula: xAO.yCu.sub.2O where x denotes a proportion by mole of AO and y denotes a proportion by mole of Cu.sub.2O and x and y satisfy the following expressions: 0x<100 and x+y=100, and A is any one of Mg, Ca, Sr and Ba, or a mixture containing at least one selected from the group consisting of Mg, Ca, Sr and Ba.

A p-type oxide which is amorphous and is represented by the following compositional formula: xAO.yCu.sub.2O where x denotes a proportion by mole of AO and y denotes a proportion by mole of Cu.sub.2O and x and y satisfy the following expressions: 0x<100 and x+y=100, and A is any one of Mg, Ca, Sr and Ba, or a mixture containing at least one selected from the group consisting of Mg, Ca, Sr and Ba.

Recovering bromine from solid waste containing bromine compounds, and applications thereof, such as for recovering bromine in a form suitable for reuse, or for manufacturing bromine salt (for example, calcium bromide). Bromine recovery method and system include: providing and mixing (i) solid waste containing bromine compounds and (ii) solid calcium hydroxide; heating the mixture in a chemical reducing (non-oxidizing) environment, thereby forming heated product consisting essentially of only solid calcium bromide (salt); and processing the heated product, to form bromine. Calcium bromide manufacturing method and system include: providing and mixing (i) solid waste containing bromine compounds and (ii) solid calcium hydroxide; heating the mixture in a chemical reducing (non-oxidizing) environment, thereby forming solid calcium bromide (salt). Applicable to processes of, or involving, manufacturing bromine-based flame (fire) retardant materials.

Recovering bromine from solid waste containing bromine compounds, and applications thereof, such as for recovering bromine in a form suitable for reuse, or for manufacturing bromine salt (for example, calcium bromide). Bromine recovery method and system include: providing and mixing (i) solid waste containing bromine compounds and (ii) solid calcium hydroxide; heating the mixture in a chemical reducing (non-oxidizing) environment, thereby forming heated product consisting essentially of only solid calcium bromide (salt); and processing the heated product, to form bromine. Calcium bromide manufacturing method and system include: providing and mixing (i) solid waste containing bromine compounds and (ii) solid calcium hydroxide; heating the mixture in a chemical reducing (non-oxidizing) environment, thereby forming solid calcium bromide (salt). Applicable to processes of, or involving, manufacturing bromine-based flame (fire) retardant materials.

Carbon-neutral fuels are produced from aragonite in a solar thermal decomposition process in which the carbon dioxide generated from the aragonite is catalytically converted to methane, ethanol, or Fischer-Tropsch liquids. Advantageously, heat from the aragonite production can be recovered and used in downstream processes to thereby minimize the carbon footprint of the fuel production.

Carbon-neutral fuels are produced from aragonite in a solar thermal decomposition process in which the carbon dioxide generated from the aragonite is catalytically converted to methane, ethanol, or Fischer-Tropsch liquids. Advantageously, heat from the aragonite production can be recovered and used in downstream processes to thereby minimize the carbon footprint of the fuel production.

The present application pertains to methods for making metal oxides and/or citric acid. In one embodiment, the application pertains to a process for producing calcium oxide, magnesium oxide, or both from a material comprising calcium and magnesium. The process may include reacting a material comprising calcium carbonate and magnesium carbonate. Separating, concentrating, and calcining may lead to the production of oxides such as calcium oxide or magnesium oxide. In other embodiments the application pertains to methods for producing an alkaline-earth oxide and a carboxylic acid from an alkaline earth cation-carboxylic acid anion salt. Such processes may include, for example, reacting an alkaline-earth cation-carboxylic acid anion salt with aqueous sulfur dioxide to produce aqueous alkaline-earth-bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

The present application pertains to methods for making metal oxides and/or citric acid. In one embodiment, the application pertains to a process for producing calcium oxide, magnesium oxide, or both from a material comprising calcium and magnesium. The process may include reacting a material comprising calcium carbonate and magnesium carbonate. Separating, concentrating, and calcining may lead to the production of oxides such as calcium oxide or magnesium oxide. In other embodiments the application pertains to methods for producing an alkaline-earth oxide and a carboxylic acid from an alkaline earth cation-carboxylic acid anion salt. Such processes may include, for example, reacting an alkaline-earth cation-carboxylic acid anion salt with aqueous sulfur dioxide to produce aqueous alkaline-earth-bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

A process for producing a metal oxide powder by flame spray pyrolysis where a) a stream of a solution containing at least one oxidizable or hydrolysable metal compound is atomized to afford an aerosol by means of an atomizer gas, b) this aerosol is brought to reaction in the reaction space of the reactor with a flame obtained by ignition of a mixture of fuel gas and air, c) the reaction stream is cooled and d) the solid product is subsequently removed from the reaction stream, wherein e) the reaction space comprises one or more successive double-walled internals, wherein the wall of the double-walled internal facing the flame-conducting region of the reaction space comprises at least one slot through which a gas or vapour is introduced into the reaction space in which the flame is burning and f) the slot is arranged such that this gas or vapour brings about a rotation of the flame.

A process for producing a metal oxide powder by flame spray pyrolysis where a) a stream of a solution containing at least one oxidizable or hydrolysable metal compound is atomized to afford an aerosol by means of an atomizer gas, b) this aerosol is brought to reaction in the reaction space of the reactor with a flame obtained by ignition of a mixture of fuel gas and air, c) the reaction stream is cooled and d) the solid product is subsequently removed from the reaction stream, wherein e) the reaction space comprises one or more successive double-walled internals, wherein the wall of the double-walled internal facing the flame-conducting region of the reaction space comprises at least one slot through which a gas or vapour is introduced into the reaction space in which the flame is burning and f) the slot is arranged such that this gas or vapour brings about a rotation of the flame.