High-purity quartz glass and method for the preparation thereof
US5968259A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1997 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Aug 27, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/40
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided are high-purity quartz glass having a high purity, in particular, with little zirconium (Zr) and manufactured at low costs from natural quartz as the starting material and a method for the preparation thereof. High-purity quartz glass is manufactured, in a method for the preparation of natural quartz glass which is prepared by subjecting crystalline natural quartz to fusion by heating, in conducting refining of the starting material of the crystalline natural quartz by successively practicing a combination of at least one unit refining procedure, in a procedure in which a portion of the starting quartz after practicing the specified unit refining procedure is taken by sampling for analysis, the same is decomposed with hydrofluoric acid or an acid mixture of hydrofluoric acid and another inorganic acid, the decomposition solution is subjected to evaporation to dryness either as such or after addition of another inorganic acid, the residue is melted by heating with admixture of a salt or hydroxide of an alkali metal, the salt or hydroxide of the alkali metal is then dissolved in an aqueous solution of an inorganic acid or in pure water, the solution is subjected to quantitat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.