Fire resistant gypsum panels are provided herein, with assemblies including the same, and methods for making the same. A gypsum panel includes a set gypsum core and a mat facing material. The set gypsum core includes a fire resistant additive. The fire resistant additive consists essentially of clay, or a non-intumescent fire resistant additive. The panel displays an acceptable fire rating without requiring the use of vermiculite or intumescent materials.

A process for the selective recovery of lithium values from feedstock is provided. The process includes concentration by one or more of air classification and flotation; selective leaching to remove Mg, Ca or Na formations; and leaching/sonication with an acid. Further, a method of beneficiating a lithium-containing ore is provided treating an aqueous pulp of the lithium-containing ore with a conditioning reagent; and floating, lithium values fraction of the lithium-containing ore from gangue slimes, wherein the treating improves the selectivity of an anionic collector to one or more of spodumene and said lithium values. Further, a process for the selective recovery of lithium from lithium ion batteries is provided.

The present disclosure provides a method for preparing an alkali and co-producing gypsum, and belongs to the technical field of chemical production. The method comprises the steps of placing a cation exchange membrane into an electrolytic cell, adding a solution of sodium salt of a weak acid and a compound MH to an anode region as an anode electrocatalyst, adding sodium carbonate or sodium hydroxide to a cathode region, adding a compound M as a cathode electrocatalyst, and applying a DC power supply between a cathode electrode and an anode electrode. The electrolysis oxidizes the MH into the M and releases H.sup.+, Na.sup.+ in the anolyte penetrates through the cation exchange membrane to reach a cathode region to be combined with OH.sup. in the catholyte to generate NaOH, or further absorbs CO.sub.2 and converts into Na.sub.2CO.sub.3; the anolyte containing a large amount of H.sup.+ is generated by the electrolysis for dissolution reaction with limestone, and the H.sup.+ is consumed to generate Ca.sup.2+, and SO.sub.4.sup.2 and Ca.sup.2+ are combined to generate high-purity CaSO.sub.4 precipitate. According to the present disclosure, a compound capable of generating PCET reaction is used as an electrocatalyst, while M is its oxidation state and MH is its reduction state, and mirabilite and limestone are used as raw materials to realize the preparation of soda ash, caustic soda and gypsum.

A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO.sub.3 equal to or less than 1.5% and a content of free P.sub.2O.sub.5, a conversion of at least part of said first slurry by heating to a temperature greater than 80 C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of -calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO.sub.3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure -calcium sulphate hemihydrate.

A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO.sub.3 equal to or less than 1.5% and a content of free P.sub.2O.sub.5, a conversion of at least part of said first slurry by heating to a temperature greater than 80 C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of -calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO.sub.3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure -calcium sulphate hemihydrate.

A gypsum wallboard having a core with a central core layer and one or more densified layers is disclosed. At least one densified layer contains salt absorbent particles of zeolite and/or hydrotalcite to improve adhesion of the gypsum core to a cover sheet. Also, methods of making the gypsum wallboard and a wall system for employing the gypsum wallboard are disclosed.

A material composition for use in construction includes calcium sulfate hemihydrate (CSH), calcium carbonate (CC) powder, hydrophobic dispersible polymer, and a retarder comprising modified amino acid. Further, a method of using material composition in one or more construction activities includes adding the material composition to water in a mixer, the material composition comprises calcium sulfate hemihydrate (CSH), calcium carbonate (CC) powder, hydrophobic dispersible polymer, and a retarder comprising modified amino acid. The method further includes blending the material composition with water in the mixer for a predetermined amount of time to produce a jointing compound having a predetermined consistency and workability.