Manufacturing methods of glass items

Abstract

This invention provides a method for manufacturing glass articles that can control and balance the raw material input rate in a cold-top melting process and is less prone to unmelted glass raw materials. The method involves using a glass raw material containing silica fume A and silica fume B, and melting the raw material using a cold-top melting process. The median diameter of silica fume A in volume is greater than the median diameter of silica fume B in volume. The content of silica fume B, relative to the total content of silica fume A and silica fume B, is adjusted within the range of 1 to 99% by mass. Silica fume A and silica fume B satisfy the following necessary conditions 1 and 2: Necessary condition 1: The median diameter of both silica fume A and silica fume B in volume is 300 μm or less; Necessary condition 2: The value obtained by subtracting the median diameter of silica fume B in volume from the median diameter of silica fume A in volume is 35 μm or more.

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