Desalination of high chloride salt absorbed porous beads

A method of recovering desalinated activated alumina (AA) beads from a composition comprising salt laden activated alumna (AA) beads and free anions and free cations, wherein the salt of the salt laden activated alumna (AA) beads comprises a chloride salt, comprising:

• electrodialysis of the composition to reduce chloride salt content of the activated alumina (AA) beads to produce a stream comprising the desalinated activated alumina (AA) beads,
• wherein the activated alumina (AA) beads have a D50 median particle size of 0.5 mm to 5 mm,
• wherein the composition comprises a mixture of the salt laden activated alumina (AA) beads, liquid water and electrolyte, wherein the chloride salt forms the free anions and free cations in the water, wherein the cations comprise alkali metal ions and the anions comprise chloride ions and optionally potassium ions;
• subjecting the mixture of activated alumina, liquid water, and electrolyte to the electrodialysis in an electrodialysis device by running an electric current through the mixture of activated alumina, liquid water, and electrolyte to remove the anions and the cations from the mixture to produce the desalinated activated alumina having reduced concentration of chloride salt absorbed on the activated alumina relative to concentration of chloride salt absorbed on the salt laden activated alumina prior to the electrodialysis, wherein the electrodialysis device comprises an anode and a cathode;
• wherein anolyte comprising the salt laden activated alumina beads and water is added into the electrodialysis device;
• wherein catholyte comprising the water is added into the electrodialysis device;
• wherein the electrolyte comprises tetraethylammonium tetrafluoroborate, and wherein the electrolyte is added to the salt laden activated alumina beads and the water in the electrodialysis device, and
• separating the desalinated activated alumina beads from liquid of the mixture;
• optionally repeating the process to reuse the liquid to extract chloride from an additional batch of salt laden activated alumina (AA) beads.

A method for making a gypsum board comprising:

• recovering desalinated activated alumina (AA) beads from a composition comprising the salt laden activated alumna (AA) beads and free anions and free cations by the method of recovering desalinated activated alumina (AA) beads from a composition comprising salt laden activated alumna (AA) beads and free anions and free cations, wherein the salt of the salt laden activated alumna (AA) beads comprises a chloride salt, comprising:
• electrodialysis of the composition to reduce chloride salt content of the activated alumina (AA) beads to produce a stream comprising the desalinated activated alumina (AA) beads,
• wherein the activated alumina (AA) beads have a D50 median particle size of 0.5 mm to 5 mm;
• and
• treating a salt-containing gypsum source comprising salt-containing gypsum powder particles with the activated alumina (AA) beads, wherein the activated alumina (AA) beads comprise one or more of the group consisting of desalinated activated alumina (AA) beads and salt absorbing activated alumina (AA) beads, said treating comprising:
• mixing the activated alumina (AA) beads, which have an absence of moisture or up to 30% free moisture, with the salt-containing gypsum powder particles, which contain 5-30 wt. % of free moisture, for a time in a range of 5 minutes to 5 hours,
• at a mix ratio of the chloride salt absorbing beads to the salt-containing gypsum powder particles in a range 5 to 50 parts by weight beads to 100 parts by weight salt-containing gypsum powder particles on a moisture inclusive basis, to transfer chloride salt from the salt-containing gypsum powder particles to the activated alumina (AA) beads to produce a mixture of salt laden activated alumina (AA) beads and treated gypsum powder particles, wherein the salt laden activated alumina (AA) beads are all larger in particle size than the treated gypsum powder particles;
• wherein the salt-containing gypsum powder particles comprise at least 80 wt. % calcium sulfate dihydrate on a dry basis,
• wherein the salt-containing gypsum powder particles comprise greater than 300 parts by weight chloride anion per 1,000,000 parts by weight said salt-containing gypsum powder particles on a dry basis,
• wherein the salt-containing gypsum powder particles have a D50 median particle size of 10 to 100 microns,
• wherein the activated alumina (AA) beads have a D50 median particle size of 0.5 mm to 5 mm, and
• after said mixing of the activated alumina (AA) beads with the salt-containing gypsum powder particles, drying the mixture of the salt laden activated alumina (AA) beads and the treated gypsum powder particles and separating the treated gypsum powder particles from the salt laden activated alumina (AA) beads to recover the treated gypsum powder particles and recover the salt laden activated alumina (AA) beads;
• calcining the recovered treated gypsum powder particles to make stucco comprising calcium sulfate hemihydrate;
• mixing the stucco with water to form an aqueous gypsum slurry comprising the calcium sulfate hemihydrate;
• depositing the aqueous gypsum slurry on a surface to form a layer of the aqueous gypsum slurry;
• allowing the deposited layer of the aqueous gypsum slurry to set to form a layer comprising set gypsum;
• cutting and drying the layer comprising set gypsum to make the gypsum board comprising the set gypsum as a core layer.