Feed material comprising uniform solution precursor droplets is processed in a uniform melt state using microwave generated plasma. The plasma torch employed is capable of generating laminar gas flows and providing a uniform temperature profile within the plasma. Plasma exhaust products are quenched at high rates to yield amorphous products. Products of this process include spherical, highly porous and amorphous oxide ceramic particles such as magnesia-yttria (MgOY.sub.2O.sub.3). The present invention can also be used to produce amorphous non oxide ceramic particles comprised of Boron, Carbon, and Nitrogen which can be subsequently consolidated into super hard materials.

Feed material comprising uniform solution precursor droplets is processed in a uniform melt state using microwave generated plasma. The plasma torch employed is capable of generating laminar gas flows and providing a uniform temperature profile within the plasma. Plasma exhaust products are quenched at high rates to yield amorphous products. Products of this process include spherical, highly porous and amorphous oxide ceramic particles such as magnesia-yttria (MgOY.sub.2O.sub.3). The present invention can also be used to produce amorphous non oxide ceramic particles comprised of Boron, Carbon, and Nitrogen which can be subsequently consolidated into super hard materials.

A process for the treatment of a silicate mineral, includes: preparing a first composition including an alkali metal magnesium orthosilicate and optionally either (i) magnesium oxide or (ii) an alkali metal silicate, by reaction, at a temperature from 500 to 1200 C., of an alkali metal carbonate compound, which compound is an alkali metal carbonate, an alkali metal bicarbonate or a mixture thereof, with a magnesium silicate, the molar ratio of alkali metal carbonate compound, expressed as alkali metal oxide of the formula R.sub.2O, in which R represents an alkali metal, to magnesium silicate, expressed as silicon dioxide, of the formula SiO.sub.2, being from 4:1 to 1:4, and contacting the first composition with water to produce a second composition comprising an amorphous magnesium silicate hydrate (M-SH).

A process for the treatment of a silicate mineral, includes: preparing a first composition including an alkali metal magnesium orthosilicate and optionally either (i) magnesium oxide or (ii) an alkali metal silicate, by reaction, at a temperature from 500 to 1200 C., of an alkali metal carbonate compound, which compound is an alkali metal carbonate, an alkali metal bicarbonate or a mixture thereof, with a magnesium silicate, the molar ratio of alkali metal carbonate compound, expressed as alkali metal oxide of the formula R.sub.2O, in which R represents an alkali metal, to magnesium silicate, expressed as silicon dioxide, of the formula SiO.sub.2, being from 4:1 to 1:4, and contacting the first composition with water to produce a second composition comprising an amorphous magnesium silicate hydrate (M-SH).

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20 C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl.sub.2); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl.sub.2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl.sub.2, thereby obtaining a carboxylic acid precipitate and a MgCl.sub.2 solution.

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20 C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl.sub.2); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl.sub.2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl.sub.2, thereby obtaining a carboxylic acid precipitate and a MgCl.sub.2 solution.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20 C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl2); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl2, thereby obtaining a carboxylic acid precipitate and a MgCl2 solution.

The present invention provides a process for producing high purity hydromagnesite from a source of magnesium chloride. The process involves preparation of a magnesium chloride brine of a specific concentration and reacting with sodium carbonate, while maintaining the reaction at a specific temperature range to form a hydromagnesite precipitate. The product can be calcined to generate high purity magnesium oxide compounds.