The Factors That Affect The Melting of Enamel Frit

The main factors affecting the melting of enamel frit are as follows:

The properties of enamel frit formulation
The chemical composition of the formula is diverse, and the requirements for the melting conditions are also different. The ratio of refractory raw materials to fluxing raw materials in the batch is small, and the melting temperature is relatively low; when the ratio is large, the melting temperature of the batch is higher.

Granularity, performance and shape of enamel frit
Including the thermal characteristics of the batch, the nature and quantity of gas components, the nature and quantity of impurities, particle size and shape, etc. There are many raw materials that can form an exothermic reaction, can release gas, have small particles, flakes or have angular shapes in the batch, and their melting speed is faster.

Uniformity of batch mixing
Refractory raw materials and fluxing raw materials are evenly mixed, and they are easy to melt if they are in close contact with each other.

Furnace atmosphere
Enamel frit melting usually requires an oxidizing atmosphere in the furnace.

Melting temperature and time
The melting temperature is one of the most important technical parameters for enamel frit melting. The melting temperature is low, the batch material lacks the necessary conditions for the reaction, and the melting quality is poor; the melting time is also a necessary condition to ensure the complete progress of the melting reaction. Without enough melting time, a good enough enamel cannot be obtained. However, if the melting temperature and time range exceed a certain range, the enamel frit will be over-melted and the quality of the enamel will also deteriorate.
The raw materials used in enamel frit and glass are similar, and the factors affecting physical and chemical properties are similar. However, there is a big difference in the melting process between enamel and glass.
1. Melting of enamel frit. Except for the industrial acid-resistant top frit, it is semi-clear or not clarified, that is, the enamel should not completely exclude the gas in the melt, and a certain amount of semi-melt is allowed. The glass must be completely eliminated from the gas in the melt, and the melting must be complete to obtain a transparent and uniform glass body. In this way, it must go through a long period of high temperature clarification and homogenization stage. Therefore, the melting temperature of glass is high and the melting time is long.
2. When the enamel frit is melted, in order to integrate the opacifier and colorant into the enamel, and also to facilitate the escape of some gases, the high-temperature viscosity of the enamel is required to be small. For glass to be easily shaped, it must have a relatively large high temperature viscosity. Therefore, the glass has a heat preservation and cooling process in the later stage of melting.