Gypsum product and method therefor
View Patent ↗A method comprising adding a suspension of a hydrophobic substance to a gypsum slurry. The hydrophobic substance may impart water repellent characteristics to the gypsum, may be used as a foaming aid, density reducer, dimension stabilizer, and others, and may increase the mechanical strength and durability of the gypsum product. In another embodiment of the present invention, suspensions of other substances may be used in addition to or in place of the hydrophobic substance to impart these characteristics.
1. A method comprising:
adding a wax suspension to a gypsum slurry.
2. The method according to claim 1 , wherein said wax suspension is added to said gypsum slurry on-line during the preparation of said slurry.
3. The method according to claim 1 , wherein said wax suspension is added to said gypsum slurry on-line at a production line where a gypsum product is produced.
4. The method according to claim 1 , wherein said wax suspension is manufactured at a site where the gypsum product is produced.
5. The method according to claim 4 , wherein excess heat of producing the gypsum product is used as part of manufacturing said wax suspension.
6. The method according to claim 1 , further comprising storing wax in a first storage container, storing a liquid in a second storage container, and forming said wax suspension by dispersing said wax in said liquid in a mixing device.
7. The method according to claim 1 , wherein said wax suspension is added directly from said mixing device to said gypsum slurry.
8. The method according to claim 1 , wherein said wax suspension is fed from said mixing device to an auxiliary mixing device, and said wax suspension is added from said auxiliary mixing device to said gypsum slurry.
9. The method according to claim 7 , further comprising controlling flow of said wax suspension to said gypsum slurry with a control feeder valve.
10. The method according to claim 8 , further comprising controlling flow of said wax suspension to said gypsum slurry with a control feeder valve.
11. The method according to claim 9 , comprising producing and adding said wax suspension to said gypsum slurry in a production line, wherein said production line and said control feeder valve operate in a closed control loop.
12. The method according to claim 10 , comprising producing and adding said wax suspension to said gypsum slurry in a production line, wherein said production line and said control feeder valve operate in a closed control loop.
13. The method according to claim 7 , further comprising controlling production of said wax suspension to said gypsum slurry with a control feeder valve.
14. The method according to claim 8 , further comprising controlling production of said wax suspension to said gypsum slurry with a control feeder valve.
15. The method according to claim 1 , further comprising forming a product from said gypsum slurry.
16. The method according to claim 15 , wherein adding said wax suspension to the gypsum slurry imparts at least one of the following characteristics to said product: water resistance, foaming, density reduction, dimension stabilization, and increase of mechanical strength and durability.
17. The method according to claim 15 , further comprising adding an additional substance to said wax suspension, wherein said additional substance imparts at least one of the following characteristics to said product: water resistance, foaming, density reduction, dimension stabilization, and increase of mechanical strength and durability.
18. The method according to claim 1 , wherein said wax suspension comprises a host particle, comprising a macroscopic particle of a substance other than gypsum.
19. The method according to claim 18 , wherein said host particle has at least higher tensile and flexural strength than gypsum.
20. The method according to claim 18 , wherein said host particle is generally insoluble in said gypsum slurry.
21. The method according to claim 18 , wherein said host particle has accessible voids therein, which are penetrable by said gypsum slurry and within which calcium sulfate crystals are formable.
22. The method according to claim 18 , wherein said host particle comprises a ligno-cellulosic fiber.
23. The method according to claim 1 , wherein said wax suspension comprises a surface active material.
24. The method according to claim 23 , wherein said surface active material comprises at least one of a foaming aid, a density reducer, and a dimension stabilizer.
25. The method according to claim 23 , wherein said surface active material comprises a nonionic surfactant and an anionic dispersing agent which is a sulfated compound.