초록 ▼

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

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.

대표청구항 ▼

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; andmixing the glass raw material powder together with the alkaline solution after the addition of boric acid to

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; andmixing the glass raw material powder together with the alkaline solution after the addition of boric acid to obtain a glass raw material powder mixture; andgranulating 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 oxidesSiO2: from 40 to 85 mass %,Al2O3: from 1 to 22 mass %,B2O3: 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 R2O: 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 R2O 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 granulationwherein the glass raw material powder is a borosilicate glass, comprising as represented by mass percentage based on oxidesSiO2: from 40 to 85 mass %,Al2O3: from 1 to 22 mass %,B2O3: 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 R2O: 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.