Abstract: A method for increasing the evaporation rate of an evaporative pond containing pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., the method comprising the following steps: feeding part of the pond liquor to a heat exchanger; heating the pond liquor in the heat exchanger with heat and producing a heated pond liquor; feeding the heated pond liquor into a spraying device at an operating temperature of at least 10° C. above the ambient air temperature; and spraying the heated pond liquor into an open area of the evaporative pond with the spraying device, so as to evaporate at least part of the water of the pond liquor when sprayed.

Abstract: A method for increasing the evaporation rate of an evaporative pond comprising a pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., the method comprising the following steps: feeding part of the pond liquor to a heat exchanger; heating the pond liquor in the heat exchanger with heat and producing a heated pond liquor; feeding the heated pond liquor into a spraying device at a temperature called hereafter ‘operating temperature’ of at least 10° C. above the ambient air temperature; and spraying the heated pond liquor into an open area of the evaporative pond with the spraying device, so as to evaporate at least part of the water of the pond liquor when sprayed.

Abstract: A particulate sodium bicarbonate product with an excellent flowability characterized by an angle of repose less than 30 degrees. An angle of repose of less than 27.5 is particularly good. The product is preferably in the form of ovoid or spherical particles, in that the particles have a mean axial ratio of at least 0.5. In some embodiments, the sodium bicarbonate product has a smooth particle surface in which less than 75% of the particle surface is covered with spikes. The particles may have a mean diameter D50 of at least 75 microns but less than 300 microns. The particulate sodium bicarbonate product comprises inorganic and organic impurities embedded in its polycrystalline structure, for example at least 75 ppm TOC; or at least 30 ppm Ca; or from 1 to 18 ppm Mg; or more than 0.6 g/kg NaCl; and/or from 100 to less than 500 ppm Si. A process for manufacturing such product, and its use for the treatment of pollutants in gases such as removal of acid gas.

Abstract: A method for removing impurities from a waste solid to provide at least a portion of a suitable crystallizer feed to a process for making crystalline sodium carbonate, bicarbonate, and/or other derivatives. The method comprises: contacting the waste solid with a leach solution to dissolve at least one impurity and dissolving the resulting leached residue. Leaching may include heap percolation. The leach solution may comprise a crystallizer purge liquor, a process waste effluent, a mine water, or mixtures thereof. The method may further comprise adding a magnesium compound to the resulting leached residue during or after its dissolution to remove another impurity. The waste solid preferably comprises a pond solid containing such impurities. The pond solid may be recovered from a pond receiving crystallizer purge liquor(s) and/or other process waste effluent(s). The pond solid may contain sodium carbonate, any hydrate thereof, sodium bicarbonate, and/or sodium sesquicarbonate.

Abstract: A method for increasing the evaporation rate of an evaporative pond comprising a pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., the method comprising the following steps: feeding part of the pond liquor to a heat exchanger; heating the pond liquor in the heat exchanger with heat and producing a heated pond liquor; feeding the heated pond liquor into a spraying device at a temperature called hereafter ‘operating temperature’ of at least 10° C. above the ambient air temperature; and spraying the heated pond liquor into an open area of the evaporative pond with the spraying device, so as to evaporate at least part of the water of the pond liquor when sprayed.

Abstract: A method for increasing the evaporation rate of an evaporative pond containing pond liquor comprising water and at least 1% by weight of sodium carbonate, said evaporative pond being in contact with an ambient air at an ambient air temperature of more than 0° C., the method comprising the following steps: feeding part of the pond liquor to a heat exchanger; heating the pond liquor in the heat exchanger with heat and producing a heated pond liquor; feeding the heated pond liquor into a spraying device at an operating temperature of at least 10° C. above the ambient air temperature; and spraying the heated pond liquor into an open area of the evaporative pond with the spraying device, so as to evaporate at least part of the water of the pond liquor when sprayed.

Abstract: A particulate sodium bicarbonate product with an excellent flowability characterized by an angle of repose less than 30 degrees. An angle of repose of less than 27.5 is particularly good. The product is preferably in the form of ovoid or spherical particles, in that the particles have a mean axial ratio of at least 0.5. In some embodiments, the sodium bicarbonate product has a smooth particle surface in which less than 75% of the particle surface is covered with spikes. The particles may have a mean diameter D50 of at least 75 microns but less than 300 microns. The particulate sodium bicarbonate product comprises inorganic and organic impurities embedded in its polycrystalline structure, for example at least 75 ppm TOC; or at least 30 ppm Ca; or from 1 to 18 ppm Mg; or more than 0.6 g/kg NaCl; and/or from 100 to less than 500 ppm Si. A process for manufacturing such product, and its use for the treatment of pollutants in gases such as removal of acid gas.

Abstract: A magnesium treatment for removing water-soluble impurities in a process for making crystalline sodium carbonate, bicarbonate, or sulfite. A waste comprising such impurities is treated with a magnesium compound to form water-insoluble matter which is removed to form a purified solution. The treatment may be performed on a solution which contains the waste and optionally dissolved calcined trona. The purified solution may be used as a feedstock to form crystalline soda ash, and/or used as a reactant to produce crystalline sodium sulfite or bicarbonate via reaction with SO2 or CO2. In preferred embodiments, the waste may comprise a purge or weak liquor, a reclaimed solid, or combinations thereof. The water-soluble impurities may be silicates and/or foam-causing impurities, and the waste may contain sodium bicarbonate, sodium sesquicarbonate, and/or one or more sodium carbonate hydrates, such as decahydrate.

Abstract: A method for removing impurities from a waste solid to provide at least a portion of a suitable crystallizer feed to a process for making crystalline sodium carbonate, bicarbonate, and/or other derivatives. The method comprises: contacting the waste solid with a leach solution to dissolve at least one impurity and dissolving the resulting leached residue. Leaching may include heap percolation. The leach solution may comprise a crystallizer purge liquor, a process waste effluent, a mine water, or mixtures thereof. The method may further comprise adding a magnesium compound to the resulting leached residue during or after its dissolution to remove another impurity. The waste solid preferably comprises a pond solid containing such impurities. The pond solid may be recovered from a pond receiving crystallizer purge liquor(s) and/or other process waste effluent(s). The pond solid may contain sodium carbonate, any hydrate thereof, sodium bicarbonate, and/or sodium sesquicarbonate.

Abstract: A magnesium treatment for removing water-soluble impurities in a process for making crystalline sodium carbonate, bicarbonate, or sulfite. A waste comprising such impurities is treated with a magnesium compound to form water-insoluble matter which is removed to form a purified solution. The treatment may be performed on a solution which contains the waste and optionally dissolved calcined trona. The purified solution may be used as a feedstock to form crystalline soda ash, and/or used as a reactant to produce crystalline sodium sulfite or bicarbonate via reaction with SO2 or CO2. In preferred embodiments, the waste may comprise a purge or weak liquor, a reclaimed solid, or combinations thereof. The water-soluble impurities may be silicates and/or foam-causing impurities, and the waste may contain sodium bicarbonate, sodium sesquicarbonate, and/or one or more sodium carbonate hydrates, such as decahydrate.