Common Enamel Frit Melting Process
The melting equipment of enamel frit includes crucible furnace, pool furnace, converter, electric melting furnace and so on. Among them, the process parameters of pool furnace melting are mainly temperature, feeding amount, liquid layer depth and discharge flow rate. Melting temperature is one of the most important parameters for melting enamel frit. Only when the temperature is appropriate can the melting quality of enamel be guaranteed. The melting temperature is the basis for determining several other parameters.
The size of the discharge flow is determined by the amount of feed. The output flow rate of the pool furnace for intermittent feeding is:
Output flow rate (kg/min) = feeding amount at one time X yield rate/feeding interval time
For enamel varieties with high melting temperature that need to exclude all or most of the gas, the depth of the liquid layer is required to be larger. The liquid layer depth of industrial acid-resistant cover coat is required to be 10~11min, the liquid layer depth of other varieties is preferably 6~8cm, and the antimony frit and colored frit with low melting temperature can be 4~5cm.
The process parameters of commonly used enamel for batch feeding pool furnace are as follows:
Nickel ground coat: feeding time is 30min once, temperature is 1230~1250℃, liquid layer is 6.5~7.5cm.
If the melting temperature of the nickel ground coat is too high, it will cause excessive melting, and the adhesion strength of the enamel products after enamel is poor; Cold blast.
Antimony white frit: feed every 30 minutes, temperature 1220~1240℃, liquid layer 6.5~7.5cm.
The melting temperature of antimony white frit is too high, resulting in excessive melting, the color of the frit is blue, and the whiteness of the enamel product is poor; Pitting, poor gloss.
Titanium white frit: feed every 30 minutes, temperature 1220~1240℃, liquid layer 8~9cm.
If the melting temperature of titanium white frit is too high, it will cause excessive melting, and the color of the frit will be dark brown. After firing, the porcelain surface of the product is blue gray, with poor whiteness and gloss, and the porcelain surface is rough and has pores.