Adjustment of Milling Additives Formulation

Release time:

2026-07-24 16:03

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The grinding media formulation is also a crucial factor affecting the production operating conditions of enamel processing, especially its impact on enamel adhesion. Because different forms of enamel have different adhesion characteristics, the grinding media formulation usually needs to be adjusted when grinding different enamels. Clay in the grinding media is generally considered a suspending agent, preventing enamel particle sedimentation, enhancing the strength of the dried film, and contributing to adhesion characteristics. The requirements for the clay used are low iron and mica content, and stable viscosity. Generally, to increase enamel adhesion, a high-adhesion clay can be used in the grinding formulation, the amount of clay added can be increased, or bentonite can be partially substituted for the clay.

To control the bubble structure and adhesion of the ground coat, high-adhesion clay and low-adhesion clay can be mixed in the grinding formula. Electrolytes, also known as "retention agents," are salts. They can ionize and react with clay and fine porcelain enamel particles to alter the adhesion.

Table 2 shows that most electrolytes increase the adhesion of enamel slurry; the most commonly used are as follows:

Name	Chemical formula	Appearance	Water-soluble	Functions	Maximum usage	Remark
Sodium nitrite	NaNO₂	White or yellow hygroscopic powder	80℃	ground coat, cover coat anti-sagging agent	0.5%	The ground coat can prevent rust, and the cover coat can prevent enamel cracking.
Sodium aluminate	NaAlO₂	White powder is hygroscopic.	soluble	Acid-resistant titanium-based anti-sagging agent	0.5	Titanium-based enamels have a slightly bluish tint.
Potassium chloride	KCl	Colorless crystalline powder	34℃	Titanium-based anti-sagging agent	0.5	Titanium-based materials can reduce watermarks; one-time application is not recommended.
Potassium carbonate	K2CO3	White powder	110	ground coat, acid-resistant enamel anti-sagging agent	0.5	Zirconium silicate enamel is not suitable (it becomes ineffective after exposure to moisture).
lithium carbonate	Li₂CO₃	Colorless or white powder	Slightly soluble	Flux	0.5	Improve surface gloss and smoothness
Magnesium carbonate	MgCO₃	White powder	0.01	ground coat, cover coat anti-sagging agent	0.5	Titanium-based enamel does not yellow
Urea	CO(NH₂)₂	White powder	100	Prevent enamel cracking	0.75	Does not affect the sagging
Magnesium sulfate	MgSO₄‧7H₂O	Colorless crystals	29	Specific color enamel anti-sagging agent	1.0	The ground coat is prone to rusting, and the cover coat is prone to scum formation.
Borax	Na₂B₄·10H₂O	Colorless crystals	2	ground coat Anti-Sagging Agent	0.5	Prevents copper spots from forming on the ground coat; prevents enamel cracking with transparent enamel.
soda ash	Na₂CO₃	White powder	30	Pretreatment neutralizer	0.5	To prevent rust and lower the firing temperature
clay	Al₂O₃-6SiO₂-2H₂O	Grayish-brown (white)	Insoluble	Suspension	10	It will improve heat resistance
Bentonite	Al₂O₃-4SiO₂-2H₂O	gray powder	Insoluble	Suspension	1.0	It has more than 5 times the efficacy of clay.
quartz	SiO₂	White powder	Insoluble	Refractory reinforcement in ground coat	30	The ground coat prevents enamel cracking and the formation of fish scale patterns.
Antimony oxide	Sb₂O₃	White powder	Insoluble	Enhanced adhesion of ground coat	0.5	To prevent fish scales from forming and increase adhesion
Barium molybdate	BaMoO₄	White powder	Insoluble	Enhanced adhesion of ground coat	0.5	To prevent fish scales from forming and increase adhesion
Lithium nickel oxide	Li₂Ni₈O₁₀	black powder	Insoluble	Enhanced adhesion of ground coat	0.4~1.0	To prevent fish scales from forming and increase adhesion
Nickel oxide	NiO	Green powder	Insoluble	Enhanced adhesion of ground coat	0.5	To prevent fish scales from forming and increase adhesion
Sodium pyrophosphate	Na₄P₂O₇	White powder	20	Used for ground coat and cover coat	0.02~0.05	Increasing the adhesion of enamel slurry without changing the specific gravity