Process for producing glass material granules and process for producing glass product
View Patent ↗To provide a process for producing glass raw material granules which are less likely to be formed into fine powders which cause a change of the glass composition at a time of forming a glass melt or defects of glass, and which can be preferably used for producing glass. A process for producing glass raw material granules, which comprises a granulation step of adding boric acid to either one of or both of a glass raw material powder and an alkaline solution having a pH of at least 9 and mixing the glass raw material powder together with the alkaline solution. The glass raw material powder preferably contains at least 10 mass % of boric acid.
1. A process for producing glass raw material granules, comprising:
adding boric acid to at least one of or a glass raw material powder and an alkaline solution having a pH of at least 9; and
mixing the glass raw material powder together with the alkaline solution after the addition of boric acid to obtain a glass raw material powder mixture; and
granulating the glass raw material powder mixture to form the glass raw material granules;
wherein the mixing and granulating are conducted by tumbling granulation;
wherein the glass raw material powder is a borosilicate glass, comprising as represented by mass percentage based on oxides
SiO 2 : from 40 to 85 mass %,
Al 2 O 3 : from 1 to 22 mass %,
B 2 O 3 : from 2 to 20 mass %,
MgO: from 0 to 8 mass %,
CaO: from 0 to 14.5 mass %,
SrO: from 0 to 24 mass %,
BaO: from 0 to 30 mass %,
and R 2 O: from 0 to 10 mass % wherein R is an alkali metal.
2. The process according to claim 1 , wherein a content of boric acid in the at least one of the glass raw material powder and the alkaline solution having a pH of at least 9 is at least 10 mass % based on a total amount of the glass raw material powder and/or the alkali solution to which the boric acid is added.
3. The process according to claim 1 , wherein the boric acid is added to the glass raw material powder, and a content of the boric acid is at least 10 mass % of based on the glass raw material powder.
4. The process according to claim 1 , wherein the alkaline solution is sprayed to the glass raw material powder during the mixing.
5. The process according to claim 1 , further comprising: of drying the formed glass raw material granules.
6. The process according to claim 1 , wherein an average particle size of the glass raw material granules is from 50 to 1,000 μm.
7. The process according to claim 1 , wherein the content of the R 2 O is 0.1% or less.
8. A process for producing glass raw material granules, comprising:
mixing and granulating a glass raw material powder containing comprising boric acid together with an alkaline solution having a pH of at least 9;
wherein the mixing and granulating are conducted by tumbling granulation
wherein the glass raw material powder is a borosilicate glass, comprising as represented by mass percentage based on oxides
SiO 2 : from 40 to 85 mass %,
Al 2 O 3 : from 1 to 22 mass %,
B 2 O 3 : from 2 to 20 mass %,
MgO: from 0 to 8 mass %,
CaO: from 0 to 14.5 mass %,
SrO: from 0 to 24 mass %,
BaO: from 0 to 30 mass %,
and R 2 O: from 0 to 10 mass % wherein R is an alkali metal.
9. A process for producing a glass product, comprising:
heating the glass raw material granules produced by the process as defined in claim 1 to form a glass melt;
forming and solidifying the glass melt.
10. The process for producing a glass product according to claim 9 , wherein heating the glass raw material granules to form a glass melt, comprises melting the glass raw material granules in a gas phase atmosphere to form molten glass particles, and collecting the molten glass particles to form a glass melt.
11. The process for producing a glass product according to claim 10 , wherein the glass raw material granules are pneumatically conveyed and introduced to the gas phase atmosphere.