摘要:
A panel is provided that includes stucco, water and a dispersant component having dispersing properties and comprising a comb-branched polymer with polyether side chains, naphthalene sulfonate-formaldehyde condensate or melamine sulfonate-formaldehyde condensate. A polycondensation component is also included in the slurry that includes three repeating units. A method of making the gypsum panel includes combining stucco, water and a first dosage of a first dispersant to form a slurry, the first. A second dosage of a second dispersant is added to the slurry. Properties of the gypsum slurry are tested and it is formed into a product. The product sets and properties of the product are identified. The first dosage or the second dosage is changed based on the properties of the slurry or product.
摘要:
Polymerization of siloxane is improved using a gypsum-based slurry that includes stucco, Class C fly ash, magnesium oxide and an emulsion of siloxane and water. This slurry is used in a method of making water-resistant gypsum articles that includes making an emulsion of siloxane and water, then combining the slurry with a dry mixture of stucco, magnesium oxide and Class C fly ash. The slurry is then shaped as desired and the stucco is allowed to set and the siloxane polymerizes. The resulting product is useful for making a water-resistant gypsum panel having a core that includes interwoven matrices of calcium sulfate dihydrate crystals and a silicone resin, where the interwoven matrices have dispersed throughout them a catalyst comprising magnesium oxide and components from a Class C fly ash.
摘要:
Provided are methods and systems for introducing a wet gypsum accelerator or other high viscosity production additive to an aqueous dispersion of calcined gypsum in a discharge apparatus downstream of a stucco mixer in which the dispersion was prepared. These methods and systems are useful in the production of various gypsum products such as board including wallboard and ceiling tiles.
摘要:
A multi-leg discharge boot can include an inlet conduit and first and second outlet conduits separated by a junction portion. The inlet conduit includes an entry segment, a transition segment and a heel portion disposed therebetween. The inlet conduit can include an inlet end and a junction end. A junction portion is disposed at the junction end of the inlet conduit between first and second junction openings. The junction portion includes a substantially planar wall region that is substantially perpendicular to a main flow discharge axis.
摘要:
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.
摘要:
The present invention provides a wet starch preparation system for gypsum wallboard comprising a loss-in-weight starch feeder, a venturi mixer, a vacuum pick-up unit for supplying the dry starch from the feeder at an adjustable rate to the venturi mixer, a first water pump for supplying water at an adjustable rate to the venturi mixer to form a starch pre-dispersion of from about 2% to about 10% by weight starch and a second water pump for supplying gauging water to the starch pre-dispersion, the system equipped with appropriate system controls. The present system provides more efficient use of starch such that the amount of pregelatinized starch is at least about 10% less than a system in which the starch is not pre-dispersed in water prior to the board mixer. The system can be used to make gypsum-containing products including gypsum wallboard having increased board strength and reduced board weight.
摘要:
Cementitious compositions and methods for making same, in which the cementitious compositions include 35-60 wt. % cementitious reactive powder (also termed Portland cement-based binder), 2-10 wt. % expanded and chemically coated perlite filler, 20-40 wt. % water, entrained air, and optional additives such as water reducing agents, chemical set-accelerators, and chemical set-retarders. In addition, the lightweight cementitious compositions may contain 0-25 wt. % on a wet basis secondary fillers such as expanded clay, shale aggregate, and pumice.
摘要:
The invention provides in one embodiment a gypsum-containing slurry including stucco and an aqueous pre-dispersion of a pregelatinized starch. Also provided is a method of making gypsum wallboard by providing a pre-dispersion of the pregelatinized starch in water, and adding the pregelatinized starch pre-dispersion to the gypsum-containing slurry. The pregelatinized starch can have a particle size distribution within the following range: d (0.1)=about 20μ-35μ, d (0.5)=about 60μ-110μ, d (0.9)=about 100μ-220μ.
摘要:
In a first embodiment of the invention, aged brushite is combined with calcium sulfate hemihydrate and water to make a gypsum slurry. Aged brushite slurry behaves similarly to calcium sulfate dihydrate to act as a seed crystal and rapidly initiate crystallization. The brushite slurry does not require the addition of a coating to maintain its activity over time compared to calcium sulfate dihydrate set accelerators. A gypsum-based product made using brushite slurry as the set accelerator is a second embodiment. The product has the brushite molecules integrated as part of the calcium sulfate dihydrate matrix and is distributed throughout the matrix.
摘要:
A method of making a lightweight cementitious binder composition with improved compressive strength for products such as cementitious panels is disclosed. The method mixes fly ash, alkali metal salt of citric acid, alkali metal silicate, foaming agent for entraining air, water and in the preferred embodiment a foam stabilizing agent. Compositions which include fly ash selected from the group consisting of class C fly ash, class F fly ash and mixtures thereof, alkali metal salts of citric acid, alkali metal silicates, foaming agents, and preferably a foam stabilizer, such as polyvinyl alcohol, and do not require use of set retarders. Compositions containing class F fly ash can optionally contain Type III Portland cement.