Abstract Process for preparing a molten glass containing selenium as an additive material and an alkali metal oxide as one of the essential ingredients comprising the steps of mixing the source of selenium with a portion of a raw glass batch of which the content of the alkali metal oxide in percentage by weight is 1.510 times as large as that of the intended molten glass, sintering the resulting mixture at a temperature between 500* and 1,000* C., then mixing the sintered product and remaining portion of the raw glass batch, wherein the content of the alkali in the remaining portion of raw glass is reduced lower than that of the intended molten glass so as to balance the mean content of the alkali metal oxide in the above sintered product and the above remaining raw glass batch to that of the intended molten glass, and melting the latter mixture in a glass melting furnace.
The improvement according to claim 1, wherein the portion of the raw glass batch with which the source of selenium is to be mixed is approximately one-fiftieth to one-half by weight of the total raw glass batch.
Claim 2
Dependent Claim
47 words
The improvement according to claim 1, wherein the content of the network former of the portion of the raw glass batch with which the source of selenium is to be mixed is less than that of the finally produced molten glass and more than half of it.
Claim 3
Dependent Claim
14 words
The improvement according to claim 1, wherein the source of selenium is metal selenium.
Claim 4
Dependent Claim
156 words
In method of preparing a molten glass containing selenium as an additive material and an alkali metal oxide as one of the essential ingredients, the improvement which comprises mixing a source of selenium selected from the group consisting of selenium and selenium compounds with a raw glass batch of which the content of the alkali metal oxide in percentage by weight is 1.5-10 times as large as that of the finally desired molten glass product, melting the resulting mixture at a temperature higher than 1,000* C., then mixing the melted product with another raw glass batch, wherein the content of the alkali metal oxide is lower than that of the finally desired molten glass product so as to balance the mean content of the alkali metal oxide of the above sintered product and the other raw glass batch to that of the finally produced molten glass, and melting the latter mixture in a glass melting furnace.