Determination of graphite electrode oxidisability

The number of milligrams of oxidation loss per gram per hour of graphite electrode specimen in 650℃ dry air was determined.
Graphite electrode can be oxidized by oxygen, water vapor and carbon dioxide in the air at high temperature. The initial oxidation temperature and degree of oxidation are different due to the graphitization degree, structure, volume density and ash composition and content of the electrode. The most influential factors are the oxygenation velocity and oxidation temperature.
Method: sample processing into a square or cylindrical (10 mm x 10 mm x 10 mm or phi 10 mm x 10 mm), surface to scrub clean with alcohol, in 115 ℃ + 5 ℃ oven drying, in the said of the thermobalance plate, control temperature, thermocouple temperature measurement, temperature reached 400 ℃, bubbled into 0.5 L/min nitrogen, continuous heating to 650 ℃, access to 2 L/min air (2 min), record the time of initial weights and sample immediately. Enter the air, record the weight every half an hour, and calculate the oxidation rate according to the following formula:
O = W/Gt
Where O is the oxidation rate mg/g·h; W is oxidation weight loss mg; G is the sample weight, G; T is the oxidation time, h.