GLASSES CONTAINING IRON OXIDE. IX-a

Abstract

The present study relates to a case where metallic powder is used as a reducing agent in glass melting.In case FeO and other reducing substances are coexisting in glass it is imposible to analyse amounts of respective substances through the present day processes of analysis. The author has therefore chosen for temporary convenience the following method in this study.A glass containing a little amount of iron oxide has been melted by adding therete metallic powder as a reducing agent. The glass obtained has then been treated by a method similar to that ordinary employed in quantitative analysis with FeO. Next, by titrating the amount of the total reducing substance with the N/100KMnO4 solution the required number of c.c. has been found. On the other hand a total iron oxide in the glass has been measured as Fe2O3 and this has then been converted into an amount formed to FeO. The number of cc of said N/100KMnO4 solution correponding to the amount of said FeO thus obtained.By deducing the number of c.c. of the said N/100KMnO4 solution used for the latter case FeO from the number of cc of the like solution used for the total reducing substance, the difference has been obtained and the said difference being an amount of the standard solution consumed by the reducing substances beside FeO in the Glass.This method is not applicable to cases entirely disregarding the amount of iron oxide contained in the glasses but the same is applied to such glasses in which a difference in the iron oxide contents is in a narrow extent and to find out the relative value.(1) A glass having metallic zinc added as a reducing agent(a) Glasses have been obtained by adding to FA-1 glass batch the metallic zinc powder in such amounts corresponding to 0, 1, 2, 4 and 8% in weight of the glass.(b) Glasses have been obtained by adding to FA-4 glass batch the metallic zinc powder in such amounts corresponding to 0, 1, 2, 4, 6 and 8% in weight of the glass.(2) A glass having metallic magnesium added as a reducing agent.(a) Glasses have been obtained by adding to FA-1 glass batch the magneum powder in such amounts corresponding to 1, 2, 4% in weight of the glass.(b) Glasses have been obtained by adding to FA-4 glass batch the metallic magnesium powder in such amounts corresponding to 0, 0.1, 0.5, 1.0, 2.0 and 4.0% in weight of the glass.The transmission curves of glasses of FA-4-Zn series and FA-4-Mg series have been sought.In glasses of FA-4-Zn and FA-4-Mg series they have turned to yellowish instead of becoming bluish in spite of the fact that the amount of FeO in the glass has been increasing as the amount of the metallic powder added as a reducing agent has been increased.It has been found difficult to ascertain the cause there of.