A method for continuously forming gypsum-based panels of high fixing strength comprises the steps of: •forming a mixture comprising stucco, non-pregelatinized migratory starch, glass fibre, fluidizer and water; •casting the mixture in a continuous band; •maintaining the band under conditions sufficient for the stucco to form an interlocking matrix of set gypsum; •cutting the band to form one or more wet panel precursors; and •drying the wet panel precursor to form one or more gypsum-based panels. •The weight ratio of water to stucco in the mixture is less than 0.7; •the stucco is present in the mixture in an amount of over 60 wt % relative to the total solids content of the mixture; •the starch is present in the mixture in an amount of over 3 wt % relative to the stucco; •the glass fibre is present in the mixture in an amount of over 1 wt % relative to the stucco; •the fluidizer is present in the mixture in an amount of at least 0.1 wt % relative to the stucco; and the density of the gypsum-based panel is greater than 700 kg/m.

In general, the present invention is directed to a building panel, such as a gypsum board, comprising a core having a first side and a second side opposing the first side and at least one facing material having a coating comprising at least one fungicide, at least one polymeric binder, and at least one pigment. The panel satisfies at least one of the following: the board exhibits a rating of 2 or less when tested in accordance to ASTM G21-15 or the board exhibits a rating of at least 8 when tested in accordance to ASTM D3273-16. The panel may also exhibit at least a Level 3 finish.

Beads of materials such as activated alumina, zeolite and silica gel, are used as chloride salt absorbers. The beads are mixed with high-salt gypsum. After mixing for a short time, the mixtures are dried, and the beads and the powder are separated by using a sieve or other physical separation device resulting in a low-salt gypsum which can be used as a gypsum source to make gypsum wallboard.

A reduced weight, reduced density gypsum panel that includes high expansion vermiculite with fire resistance capabilities that are at least comparable to (if not better than) commercial fire rated gypsum panels with a much greater gypsum content, weight and density.

Disclosed is an acid-modified flour and a method of making the acid-modified flour. The acid-modified flour is desirably prepared using a dry milling process. A starting flour is combined with a strong acid to form a mixture. The mixture is heated. A neutralizer is added to increase the pH of the mixture. If desired, the mixture can be dried and any agglomerates can be removed. The acid-modified flour can be used as a binder in a slurry for preparing one or more gypsum layers in a gypsum board.

A method of recovering desalinated activated alumina (AA) beads from a composition including salt laden (high salt absorbed) activated alumna (AA) beads and free anions and free cations, comprising the step of electrodialysis of the composition to reduce salt content of the activated alumina (AA) beads to produce a stream comprising the desalinated activated alumina (AA) beads.

Gypsum board having improved performance is obtained by controlling the distribution of starch in the gypsum core of the board and the gelling temperature of the starch. Starch migration in the board is controlled by the degree of acid-modification, to adjust the starch viscosity profile. The starch gelling temperature is controlled by chemical modification of the starch —OH groups.

Disclosed are product (e.g., board), slurry, and methods relating to an uncooked starch that can be used to enhance strength in one or more gypsum layers in the board. The uncooked starch has a hot water viscosity of from about 20 BU to about 300 BU according to the HWVA method, and/or a mid-range peak viscosity of from about 120 Brabender Units to about 1000 Brabender Units.

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.

The present disclosure relates to plaster boards and methods for making them. For example, one aspect of the disclosure is a plaster board comprising one or more continuous layers of material disposed within a body of hardened plaster material, the first side and second side of each continuous layer of material being substantially covered by the hardened plaster material. In certain such embodiments, each continuous layer of material includes a polymer (e.g., a damping polymer) disposed on a carrier sheet. Another aspect of the disclosure relates to a method for making a plaster board that involves drying a wet body of plaster material while a continuous layer of material or precursor therefor is disposed within it.