Light weight ceramic aggregates made by agglomerating ceramic fibers
A method of agglomerating bulk ceramic fibers includes mixing the bulk ceramic fibers with water to form wet fibers; mixing the wet fibers with a binder including an organic binder and/or an inorganic binder to form agglomerates; and drying the agglomerates. The agglomerates may be mixed with additional binders and fillers to form an insulating mix that may be used to insulate a furnace or other heat source. A foaming nozzle may be used for the application of agglomerates. A foaming agent and water are air atomized within the foaming nozzle and the resulting foam is mixed into pneumatically conveyed agglomerates, which result results in a lightweight refractory material layer on a target substrate.
1 . A method, comprising:
mixing bulk ceramic fibers with a binder comprising an organic binder and/or an inorganic binder to form agglomerates;
supplying the agglomerates to a spray nozzle via a first supply hose;
supplying a foam to the spray nozzle via a second supply hose that is different from the first supply hose;
mixing the foam with the agglomerates within the spray nozzle to form a foam and agglomerates mixture; and
using the spray nozzle, spraying the foam and agglomerates mixture onto an object.
2 . The method of claim 1 , further comprising sizing the agglomerates by transferring the agglomerates into a disk pelletizer to create spherical shaped granules.
3 . The method of claim 1 , wherein the bulk ceramic fibers comprise refractory ceramic fibers, low bio-persistent fibers, polycrystalline ceramic fibers, and/or glass fibers; and
wherein the agglomerates comprise 0.5 to 3 wt % of cellulose fibers, based on a total weight of the agglomerates.
4 . The method of claim 1 , wherein the binder comprises polyvinyl alcohol, carboxy methyl cellulose, plant-based starches, surfactants, colloidal silica, colloidal alumina, or combinations thereof.
5 . The method of claim 1 , wherein the mixing the bulk ceramic fibers utilizes a horizontal shaft mixer or a vertical shaft mixer.
6 . The method of claim 1 , wherein the agglomerates have particle sizes of less than 15 mm;
wherein the agglomerates have a median particle size of 1 to 5 mm, 2 to 4 mm, or about 3 mm; and
wherein the agglomerates do not include any particles having a size of less than 0.1 mm.
7 . The method of claim 1 , further comprising applying the agglomerates to an object by casting, ramming, hand packing, pumping, and/or pneumatic gunning.
8 . The method of claim 1 , further comprising forming a pressed shaped by axial pressing, isostatic pressing, semi-isostatic pressing and/or extrusion of the agglomerates.
9 . The method of claim 1 , further comprising:
mixing a foaming agent and water to form a foaming mixture;
foaming the foaming mixture in a foaming nozzle fluidically coupled to the spray nozzle and the second supply hose to form the foam; and
supplying the foam to the spray nozzle via the foaming nozzle.
10 . The method of claim 9 , wherein the foaming nozzle comprises a foaming tube that facilitates foaming of the foaming mixture.
11 . The method of claim 10 , wherein the foaming tube contains a metal wool.
12 . The method of claim 11 , further comprising:
supplying atomizing air to the foaming tube to facilitate the foaming of the foaming mixture at pressure between 0.5 and 2 bar.
13 . The method of claim 12 , wherein supplying the foam to the spray nozzle via the foaming nozzle further comprises:
supplying, via a foam outlet hose of the foaming nozzle that is different from the first supply hose, the foam from the foaming tube to a water distribution body fluidically coupled to the spray nozzle; and
supplying the foam from the foaming nozzle to the spray nozzle via the water distribution body.
14 . The method of claim 13 , further comprising:
splitting the supply of foam from the foam outlet hose to the water distribution body into first and second foam hoses to facilitate distribution of the foam to the spray nozzle via the water distribution body.
15 . The method of claim 9 , wherein the foaming agent comprises polyvinyl alcohol, ammonium lauryl sulfate, or a protein based foaming additive.
16 . The method of claim 9 , further comprising:
supplying aggregates, comprising perlite, vermiculite, expanded clay, diatomaceous earth, or combinations thereof, with the agglomerates to the spray nozzle via the first supply hose.
17 . The method of claim 1 , further comprising:
adjusting, using a valve fluidically coupled with the second supply hose, a flow of the foam supplied to the spray nozzle.
18 . The method of claim 1 ,
wherein the agglomerates are supplied to the spray nozzle via the first supply hose at a first flow rate; and
wherein the foam is supplied to the spray nozzle via the second supply hose at a second flow rate that is less than the first flow rate.
19 . The method of claim 1 , wherein mixing the bulk ceramic fibers with the binder further comprises:
mixing the bulk ceramic fibers with water to form wet fibers.
20 . The method of claim 19 ,
wherein the ceramic fibers are mixed with water at a first mixing intensity;
wherein the wet fibers are mixed with the binder at a second mixing intensity that is greater than the first mixing intensity; and
wherein the method further comprises sizing the agglomerates via additional mixing at a third mixing intensity that is greater than the second mixing intensity.
21 . The method of claim 19 ,
wherein the steps of mixing the bulk ceramic fibers with water and mixing the bulk ceramic fibers with the binder are combined such that the water and the binder are added to the bulk ceramic fibers together.
22 . The method of claim 1 ,
wherein the agglomerates have a bulk density of greater than 0.25 g/cm 3 .
23 . A method for installing a foam and agglomerates mixture, comprising:
mixing bulk ceramic fibers with a binder comprising an organic binder and/or an inorganic binder to form agglomerates;
supplying the agglomerates to a spray nozzle via a first supply hose;
mixing a foaming agent and water to form a foaming mixture;
supplying the foaming mixture to a foaming nozzle via a second supply hose that is different from the first supply hose;
supplying atomizing air to the foaming nozzle at a pressure between 0.5 and 2 bar;
foaming the foaming mixture in a foaming tube of the foaming nozzle to create a foam, wherein the supply of atomizing air facilitates the foaming of the foaming mixture, and wherein the foaming tube contains a metal wool that facilitates the foaming of the foaming mixture;
supplying the foam from the foaming nozzle to the spray nozzle via a foam outlet hose of the foaming nozzle that is different from the first supply hose;
splitting the supply of foam from the foam outlet hose to the spray nozzle into first and second foam hoses to facilitate distribution of the foam to the spray nozzle;
mixing the foam with the agglomerates within the spray nozzle to form a foam and agglomerates mixture; and
using the spray nozzle, spraying the foam and agglomerates mixture onto an object.