A system and method of desalinating a brine stream are provided. The multistage desalination process with carbon dioxide capture recovers valuable products where the reject brine is passed through seven stages. In each stage, a specific metal ion is recovered. In stage 1, a ˜100% recovery of magnesium ions as magnesium hydroxide solid was obtained by chemical reaction with ammonia solution. In stage 2, Na.sup.+ reduction, as sodium bicarbonate, and CO.sub.2 uptake was achieved. In stage 3, electrocoagulation (EC) was used to recover sulfate ions as pure calcium sulfate solid and to regenerate NH.sub.3 as ammonium hydroxide. In stage 4, CaO was added to the treated brine. In stage 5, more recovery of NaHCO.sub.3 was attained by adding ammonium bicarbonate, while in stage 6, the treated brine mixture was passed through another modified Solvay process. In stage 7, EC was again used to recover CaCl.sub.2 solution and NH.sub.3 compounds.

A system and method of desalinating a brine stream are provided. The multistage desalination process with carbon dioxide capture recovers valuable products where the reject brine is passed through seven stages. In each stage, a specific metal ion is recovered. In stage 1, a ˜100% recovery of magnesium ions as magnesium hydroxide solid was obtained by chemical reaction with ammonia solution. In stage 2, Na.sup.+ reduction, as sodium bicarbonate, and CO.sub.2 uptake was achieved. In stage 3, electrocoagulation (EC) was used to recover sulfate ions as pure calcium sulfate solid and to regenerate NH.sub.3 as ammonium hydroxide. In stage 4, CaO was added to the treated brine. In stage 5, more recovery of NaHCO.sub.3 was attained by adding ammonium bicarbonate, while in stage 6, the treated brine mixture was passed through another modified Solvay process. In stage 7, EC was again used to recover CaCl.sub.2 solution and NH.sub.3 compounds.

A sodium carbonate production system for recapturing thermal energy lost during sodium carbonate manufacturing includes a triple effect evaporator apparatus, a thermal energy waste recovery apparatus, and a barometric surface condenser. The thermal energy waste recovery apparatus comprises an ammonia heat exchanger in operational communication with the triple effect evaporator apparatus. An ammonia turbine is in operational communication with the ammonia heat exchanger. An electric generator is in operational communication with the ammonia turbine to produce electricity. An ammonia compressor is in operational communication with the ammonia turbine and the ammonia heat exchanger. The ammonia heat exchanger is in operational communication with the barometric surface condenser.

Process wherein a low CO.sub.2 content process gas generated by an ammonia-soda process unit or a refined sodium bicarbonate unit is enriched by using a Temperature Swing Adsorption CO.sub.2 concentration module into a CO.sub.2 enriched gas whose CO.sub.2 content is increased by at least +10% by volume on dry gas basis relative to the process gas, and which is subsequently recycled to the ammonia-soda process unit or optionally to the refined sodium bicarbonate unit, in order: to produce sodium carbonate, or sodium bicarbonate, or to carbonate at least part of effluent from the unit for producing sodium carbonate or bicarbonate. The TSA CO.sub.2 concentration module comprises a stator and a rotor connected to the stator and rotatable relatively to the stator about a rotational axis, the rotor comprising a plurality of sectors, each sector containing a separation device to separate at least part of the CO.sub.2 from the process gas which is led into the separation device, and each sector being fluidically connected with at least one rotary active valve.

Process wherein a low CO.sub.2 content process gas generated by an ammonia-soda process unit or a refined sodium bicarbonate unit is enriched by using a Temperature Swing Adsorption CO.sub.2 concentration module into a CO.sub.2 enriched gas whose CO.sub.2 content is increased by at least +10% by volume on dry gas basis relative to the process gas, and which is subsequently recycled to the ammonia-soda process unit or optionally to the refined sodium bicarbonate unit, in order: to produce sodium carbonate, or sodium bicarbonate, or to carbonate at least part of effluent from the unit for producing sodium carbonate or bicarbonate. The TSA CO.sub.2 concentration module comprises a stator and a rotor connected to the stator and rotatable relatively to the stator about a rotational axis, the rotor comprising a plurality of sectors, each sector containing a separation device to separate at least part of the CO.sub.2 from the process gas which is led into the separation device, and each sector being fluidically connected with at least one rotary active valve.

A process for manufacturing an aqueous sodium chloride solution and the use of such solution for the manufacturing of crude sodium bicarbonate from SOLVAY ammonia process or for the manufacturing of soda ash, comprising the steps of: a) dispersing a first solid material comprising sodium chloride, sodium carbonate, and sodium sulfate, and a second solid material comprising calcium chloride in an aqueous liquid to produce an aqueous medium; b) subjecting the aqueous medium to clarification to produce a clarified aqueous medium; and c) recovering the clarified aqueous medium as aqueous sodium chloride solution; wherein a weight L/S ratio between the weight of the aqueous liquid used to produce the aqueous medium and the total weight of the first solid material and the second solid material is in the range of from 0.7 to 3.5.

A process for manufacturing an aqueous sodium chloride solution and the use of such solution for the manufacturing of crude sodium bicarbonate from SOLVAY ammonia process or for the manufacturing of soda ash, comprising the steps of: a) dispersing a first solid material comprising sodium chloride, sodium carbonate, and sodium sulfate, and a second solid material comprising calcium chloride in an aqueous liquid to produce an aqueous medium; b) subjecting the aqueous medium to clarification to produce a clarified aqueous medium; and c) recovering the clarified aqueous medium as aqueous sodium chloride solution; wherein a weight L/S ratio between the weight of the aqueous liquid used to produce the aqueous medium and the total weight of the first solid material and the second solid material is in the range of from 0.7 to 3.5.

Process for producing sodium carbonate with ammonia and/or for producing refined sodium bicarbonate, wherein: a low CO.sub.2 content gas generated by a unit for producing sodium carbonate with ammonia and/or generated by a unit for producing refined sodium bicarbonate is enriched into a CO.sub.2-enriched gas by using a CO.sub.2 concentration module, such as an amine-type or ammonia or PSA or TSA or cryogenic distillation or membrane-type CO.sub.2 concentration module, and said CO.sub.2-enriched gas has an increased CO.sub.2 content of: +10% (at least) to +90% (at most), by volume on a dry gas basis relative to the CO.sub.2 concentration of the low content gas, and the CO.sub.2-enriched gas is subsequently recycled to the unit for producing sodium carbonate with ammonia and/or to the unit for producing refined sodium bicarbonate, to produce sodium carbonate, or sodium bicarbonate, or to carbonate at least one part of effluent from the unit for producing sodium carbonate and/or from the unit for producing sodium bicarbonate.

Process for producing sodium carbonate with ammonia and/or for producing refined sodium bicarbonate, wherein: a low CO.sub.2 content gas generated by a unit for producing sodium carbonate with ammonia and/or generated by a unit for producing refined sodium bicarbonate is enriched into a CO.sub.2-enriched gas by using a CO.sub.2 concentration module, such as an amine-type or ammonia or PSA or TSA or cryogenic distillation or membrane-type CO.sub.2 concentration module, and said CO.sub.2-enriched gas has an increased CO.sub.2 content of: +10% (at least) to +90% (at most), by volume on a dry gas basis relative to the CO.sub.2 concentration of the low content gas, and the CO.sub.2-enriched gas is subsequently recycled to the unit for producing sodium carbonate with ammonia and/or to the unit for producing refined sodium bicarbonate, to produce sodium carbonate, or sodium bicarbonate, or to carbonate at least one part of effluent from the unit for producing sodium carbonate and/or from the unit for producing sodium bicarbonate.

A process is developed wherein sodium carbonate is reclaimed from Trona-treated fly ash waste stream, and the fly ash rendered suitable for use as a Pozzolan. The process is a closed system wherein all separated aspects of the waste stream are reused by the generating power plant or offered as a commercial product.