Typical Physical Property Comparison of Alumina Trihydrate (ATH) and Magnesium Hydroxide (MDH)

Property ATH MDH
Physical Form Powder Powder
Particle morphology Hexagonal platelet Hexagonal platelet
Color White White
Specific gravity g/cm3 2.42 2.36
pH value 9 - 10 10 - 11
Mohs hardness 2.5 - 3.5 2.0 - 3.0
Refractive index 1.57 1.58
Decomposition temperature 220oC / 428oF 330oC / 626oF
Heat of decomposition, cal/g 280 328
Theoretical loss of ignition 34.6% 31.0%


Typical Kemgard® Physical Properties

Kemgard® Grade: 911A 911B 911C 981 425 501 MZM HPSS
Composition Calcium Molybdate Zinc Complex Zinc Molybdate Compound Zinc Molybdate / Magnesium Silicate Complex Basic Zinc Phosphate Complex Calcium Molydbate Zinc Complex Calcium Molybdate Complex Zinc Molybdate / Magnesium Hydroxide Complex Basic Zinc Molybdate / Magnesium Hydroxide Complex
Appearance White Powder White Powder White Powder White Powder White Powder White Powder White Powder White Powder
Specific Gravity 3 5.1 2.8 4.2 3 2.9 2.63 3.46
Oil Absorption (g/100g) 18.8 11.1 40.5 12.9 16.7

15.1

32.3 28.5
Median Particle Size (um) 2.7 2.3 3.3 4.4 2.6 3.7 1.2 1.5
pH Solubility (g/100mL) 8.4 6.5 6.5 6.5 8.4 8.9 9.4 8.9
Moisture (%) 0.25 0.1 0.4 0.2 0.2 0.15 0.8 0.87
Residue on 325 Mesh Screen, % max. <0.1% <0.1% <0.2% <0.1% <0.1% <0.1% <0.1% <0.1%
Specific Resistance 5500       6700 8600   800

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