Ceramic particles for use in a solar power tower
Ceramic particles for use in a solar power tower and methods for making and using the ceramic particles are disclosed. The ceramic particle can include a sintered ceramic material formed from a mixture of a ceramic raw material and a darkening component comprising MnO as Mn 2+ . The ceramic particle can have a size from about 8 mesh to about 170 mesh and a density of less than 4 g/cc.
1. A ceramic particle for use in a solar power tower, comprising:
a sintered ceramic material formed from a mixture of a ceramic raw material and MnO, the ceramic particle having a size from about 8 mesh to about 170 mesh and a bulk density of less than 3 g/cc, wherein the sintered ceramic material comprises Mn 2 O 3 and Fe 2 O 3 , wherein the ceramic raw material comprises from about 0.1 wt % to about 50 wt % silica and from about 30 wt % to about 99 wt % alumina.
2. The ceramic particle of claim 1 , wherein the ceramic particle has a surface roughness of less than 5 μm.
3. The ceramic particle of claim 1 , further comprising a spherical shape.
4. The ceramic particle of claim 3 , wherein exposure of the ceramic particle to solar heat energy in the solar power tower reduces a Munsell Value of the ceramic particle by at least about 0.1.
5. A solar power tower comprising the ceramic particle of claim 1 .
6. A ceramic particle for use in a solar power tower, comprising:
a sintered ceramic material formed from a mixture of a ceramic raw material and MnO, the ceramic particle having a size from about 8 mesh to about 170 mesh and a bulk density of less than 3 g/cc, wherein the sintered ceramic material comprises Mn 2 O 3 and Fe 2 O 3 , wherein the mixture further comprises about 0.1 wt % to about 20 wt % FeO.
7. A method of manufacturing ceramic particles, comprising:
preparing a slurry comprising water, a binder, a first portion of a ceramic raw material, and manganese oxide;
atomizing the slurry into droplets;
coating seeds comprising a second portion of the ceramic raw material with the droplets to form a plurality of green pellets; and
sintering the green pellets to provide a plurality of ceramic particles, wherein the sintering oxidizes a first portion of the manganese oxide from MnO to Mn 2 O 3 .
8. The method of claim 7 , wherein the ceramic raw material comprises from about 0.1 wt % to about 50 wt % silica and from about 30 wt % to about 99 wt % alumina.
9. The method of claim 7 , wherein a second portion of the manganese oxide is oxidized from MnO to Mn 2 O 3 upon being subjected to solar heat energy in a solar power tower.
10. The method of claim 7 , wherein the slurry further comprises about 0.1 wt % to about 20 wt % iron oxide.
11. The method of claim 10 , wherein the sintering oxidizes a first portion of the iron oxide from FeO to Fe 2 O 3 .
12. The method of claim 11 , wherein a second portion of the iron oxide is oxidized from FeO to Fe 2 O 3 upon being subjected to solar heat energy in a solar power tower.
13. The method of claim 7 , wherein the plurality of ceramic particles has a Munsell value of at least 6 prior to exposure to solar heat energy in a solar power tower.
14. The method of claim 13 , wherein the plurality of ceramic particles has a Munsell value of less than 6 after exposure to the solar heat energy in the solar power tower.
15. A method of manufacturing ceramic particles, comprising:
providing a slurry of ceramic raw material, a reactant and MnO, wherein the ceramic raw material comprises from about 0.1 wt % to about 50 wt % silica and from about 30 wt% to about 99 wt % alumina;
flowing the slurry through a nozzle in a gas while vibrating the slurry to form droplets;
receiving the droplets in a vessel containing a liquid having an upper surface, the liquid containing a coagulation agent;
reacting the reactant with the coagulation agent to cause coagulation of the reactant in the droplets;
transferring the droplets from the liquid;
drying the droplets to form green pellets;
sintering the green pellets in a selected temperature range to form a plurality of ceramic particles, wherein the sintering oxidizes a first portion of the MnO to Mn 2 O 3 .
16. The method of claim 15 , wherein a second portion of the MnO is oxidized to Mn 2 O 3 upon being subjected to solar heat energy in a solar power tower.
17. A method of manufacturing ceramic particles, comprising:
providing a slurry of ceramic raw material, a reactant and MnO, wherein the slurry further comprises about 0.1 wt % to about 20 wt % iron oxide;
flowing the slurry through a nozzle in a gas while vibrating the slurry to form droplets;
receiving the droplets in a vessel containing a liquid having an upper surface, the liquid containing a coagulation agent;
reacting the reactant with the coagulation agent to cause coagulation of the reactant in the droplets;
transferring the droplets from the liquid;
drying the droplets to form green pellets;
sintering the green pellets in a selected temperature range to form a plurality of ceramic particles, wherein the sintering oxidizes a first portion of the MnO to Mn 2 O 3 .
18. The method of claim 17 , wherein the sintering oxidizes a first portion of the iron oxide from FeO to Fe 2 O 3 .
19. The method of claim 18 , wherein a second portion of the iron oxide is oxidized from FeO to Fe 2 O 3 upon being subjected to solar heat energy in a solar power tower.