The present invention relates to a process for reducing in a gas stream the concentration of carbon dioxide and for reducing in an aqueous stream the concentration of sodium chloride, which process comprises contacting a feed gas comprising greater than or equal to 0.1% by volume carbon dioxide with an aqueous feed comprising: (a) sodium chloride; and (b) calcium oxide and/or calcium hydroxide at a total concentration of greater than or equal to 0.5% by weight,
wherein the pH of the aqueous feed is greater than or equal to 10.0. A product aqueous stream obtained from the process of the invention is also described.

A method is disclosed for extracting metals from concentrated sulphurated minerals containing metals by direct reduction with regeneration and recycling of the reducing agent, iron, and of the flux, sodium carbonate. It is a combination of pyrometallurgical and hydrometallurgical processes which differ from the conventional processes. They do not require previous toasting of the concentrated sulphurated minerals and are technically and economically more advantageous than the presently used processes, since they directly reduce to zero the positive oxidation state of the metal, using a single reactor for extracting the metal, regenerating and recycling the metallurgical feed materials in complementary processes, the kinetics of the chemical reactions being characterised by high speed, without generating any slags or pollutant gases. The metals can be extracted at a reduced cost and in an environmentally sustainable manner

A method of transporting CO.sub.2 includes combining gaseous CO.sub.2 produced at a point of origin with a solid metal oxide salt and/or a solid metal hydroxide salt at the point of origin to form a solid metal carbonate salt that includes the CO.sub.2 from the point of origin and the metal from the metal oxide salt or the metal from the metal hydroxide salt. The method includes transporting the solid metal carbonate salt from the point of origin to a destination. The method also includes calcining the solid metal carbonate salt at the destination to generate gascous CO.sub.2 and to re-generate the solid metal oxide salt and/or the solid metal hydroxide salt.

Process for the joint production of sodium carbonate and sodium bicarbonate crystals, according to which: a solid powder derived from sodium sesquicarbonate, having a mean particle diameter comprised between 0.1 and 10 mm is dissolved in water; the resulting water solution is introduced into a crystallizer, wherein a first water suspension comprising sodium carbonate crystals is produced; the first water suspension is subjected to a separation, in order to produce crystals comprising sodium carbonate on the one hand, which are valorized, and a mother liquor on the other hand; and a part of the mother liquor is taken out of the crystallizer and put into contact in, a gas liquid contactor, with a gas comprising carbon dioxide, in order to produce a second water suspension comprising sodium bicarbonate crystals, which are separated and valorized. A reagent powder comprising sodium bicarbonate crystals made by such process.

Process for the joint production of sodium carbonate and sodium bicarbonate crystals, according to which: a solid powder derived from sodium sesquicarbonate, having a mean particle diameter comprised between 0.1 and 10 mm is dissolved in water; the resulting water solution is introduced into a crystallizer, wherein a first water suspension comprising sodium carbonate crystals is produced; the first water suspension is subjected to a separation, in order to produce crystals comprising sodium carbonate on the one hand, which are valorized, and a mother liquor on the other hand; and a part of the mother liquor is taken out of the crystallizer and put into contact in, a gas liquid contactor, with a gas comprising carbon dioxide, in order to produce a second water suspension comprising sodium bicarbonate crystals, which are separated and valorized. A reagent powder comprising sodium bicarbonate crystals made by such process.

Process for the joint production of sodium carbonate and sodium bicarbonate crystals, according to which: a solid powder derived from sodium sesquicarbonate, having a mean particle diameter comprised between 0.1 and 10 mm is dissolved in water; the resulting water solution is introduced into a crystallizer, wherein a first water suspension comprising sodium carbonate crystals is produced; the first water suspension is subjected to a separation, in order to produce crystals comprising sodium carbonate on the one hand, which are valorized, and a mother liquor on the other hand; and a part of the mother liquor is taken out of the crystallizer and put into contact in, a gas liquid contactor, with a gas comprising carbon dioxide, in order to produce a second water suspension comprising sodium bicarbonate crystals, which are separated and valorized. A reagent powder comprising sodium bicarbonate crystals made by such process.

Process for the joint production of sodium carbonate and sodium bicarbonate crystals, according to which: a solid powder derived from sodium sesquicarbonate, having a mean particle diameter comprised between 0.1 and 10 mm is dissolved in water; the resulting water solution is introduced into a crystallizer, wherein a first water suspension comprising sodium carbonate crystals is produced; the first water suspension is subjected to a separation, in order to produce crystals comprising sodium carbonate on the one hand, which are valorized, and a mother liquor on the other hand; and a part of the mother liquor is taken out of the crystallizer and put into contact in, a gas liquid contactor, with a gas comprising carbon dioxide, in order to produce a second water suspension comprising sodium bicarbonate crystals, which are separated and valorized. A reagent powder comprising sodium bicarbonate crystals made by such process.

A method for the preparation of a poly(ether ether ketone) (PEEK) includes: preparing the PEEK by aromatic nucleophilic substitution in the presence of: a) particulate sodium carbonate (Na.sub.2CO.sub.3), wherein said particulate sodium carbonate has a particle size distribution as follows: D.sub.9045 m and D.sub.90250 m and D.sub.99.5710 m, wherein said particle size distribution is measured by mechanical sieving in accordance with ASTM E 359-00 (reapproved 2005), wherein said measurement is based on the mechanical separation of various fractions on a series of superimposed sieves which are superimposed by descending order of opening mesh of 1000 m, 500 m, 250 m, 180 m, 125 m, 90 m, 63 m, and 45 m; and b) potassium carbonate (K.sub.2CO.sub.3) in an amount ranging from 0.001 to about 0.05 mol K/mol Na.

A method for the preparation of a poly(ether ether ketone) (PEEK) includes: preparing the PEEK by aromatic nucleophilic substitution in the presence of: a) particulate sodium carbonate (Na.sub.2CO.sub.3), wherein said particulate sodium carbonate has a particle size distribution as follows: D.sub.9045 m and D.sub.90250 m and D.sub.99.5710 m, wherein said particle size distribution is measured by mechanical sieving in accordance with ASTM E 359-00 (reapproved 2005), wherein said measurement is based on the mechanical separation of various fractions on a series of superimposed sieves which are superimposed by descending order of opening mesh of 1000 m, 500 m, 250 m, 180 m, 125 m, 90 m, 63 m, and 45 m; and b) potassium carbonate (K.sub.2CO.sub.3) in an amount ranging from 0.001 to about 0.05 mol K/mol Na.

Disclosed are an additive raw material composition and an additive for superhard material product, a method for preparing the additive, a composite binding agent, a superhard material product, a self-sharpening diamond grinding wheel and a method for manufacturing the same. The raw material composition consisting of components in following mass percentage: Bi2O3 25%40%, B2O3 25%40%, ZnO 5%25%, SiO2 2%10%, Al2O3 2%10%, Na2CO3 1%5%, Li2CO3 1%5%, MgCO3 0%5%, and CaF2 1%5%. The composite binding agent is prepared from the additive and a metal composite binding agent. The self-sharpening diamond grinding wheel prepared from the composite binding agent has high self-sharpness, high strength, and fine texture, is uniformly consumed during the grinding process, does not need to be trimmed during the process of being used, and maintains good grinding force all the time, fundamentally solving the problems of long trimming time and high trimming cost of the diamond grinding wheel.