GB/T 5505-2008Inspection of grain and oils -- Determination of the ash content by incineration (English PDF)

3.1 Principle

The sample was 550 °C ± 10 °C ashing temperature to completely burning the volatile organic compounds after weighing the residues.

3.2 Reagents

3.2.1 Ferric chloride. AR.

3.2.2 ferric chloride solution (5g/L). Weigh 0.5g of ferric chloride dissolved in 100mL blue-black ink.

3.3 Instrument

3.3.1 muffle furnace. also known as Mao Fu furnace, Muffle furnace, high temperature furnace, capable of producing more than 550 °C high temperature, and temperature control.

3.3.2 Analytical Balance. a sense of the amount of 0.0001g.

3.3.3 porcelain crucible. a capacity of 18mL ~ 20mL.

3.3.4 dryers. built-effective color gel.

3.3.5 crucible tongs. long handle and short handle.

3.4 Analysis Steps

3.4.1 Moisture

According to GB/T 5497 Determination of sample water (W).

3.4.2 Sample Preparation

Samples were prepared according to GB/T in 5497 requirements.

3.4.3 Crucible process

Take a clean, dry porcelain crucible with a brush dipped in a solution of ferric chloride blue or black ink in the crucible ID number and then placed in a crucible 550 °C ± 10 °C muffle furnace burning 30min ~ 60min, to move the crucible furnace door, until red hot crucible disappear, transferred to a dryer the cooling to room temperature, taken out and weighed crucible mass, repeated burning, cooling, weighing, until the mass difference before and after no more than two 0.0002g, record crucible mass (m1 0).

3.4.4 Sample Determination

Weigh and mix the sample (m1) 2g ~ 3g, accurate to 0.0002g, to deal with a good crucible, the crucible on the furnace, staggered crucible Cover, heating the sample until completely carbonized. Then, the crucible in a muffle furnace 550 °C ± 10 °C, the first on the mouth for a moment, then moved Furnace, staggered crucible lid, close the door, at 550 °C ± 10 °C burning 2h ~ 3h. In the burning process, the crucible should swap positions 1 to 2 times, burning sample to black soot disappeared into a gray so far. Moving to the crucible furnace door, to be red hot crucible disappear After transfer to cool to room temperature in a desiccator, and weigh. Then burn 30min, cooling, weighing, until constant mass (m1). Last burning quality