30 national and interstate standards became effective since November 2021.
There are series of standards on refractories and refractory raw materials, electrotechnical periclase among them. Now we will focus on these documents in more details.
GOST 12170 – 2021 «Refractories. Stationary method of thermal conductivity determination» replaced GOST 12170-85 taking into account the application of GOST 12170-85, current rules and requirements of standardization and metrology and actualization of the Federal Information Collection of Standards on test methods of the refractories.
Interstate standard is distributed on molded refractories and describes stationary method of determination of the coefficient of thermal conductivity in the range from 0, 03 to 15 W/mK with stationary one-dimensional temperature field in the plane sample and with the temperature on the hot side of the sample varying from 300 °С to 1350 °С.
The sample is heated by an electric oven, its contact with the water-cooled calorimeter occurs from the bottom.
GOST 2642.15-2021 «Refractories and refractory raw materials. Methods for determination of general carbon» covers the refractories and refractory raw materials except for silicon-carbide ones and sets the methods of quantitative determination of total carbon.
The essence of the coulometric method of determination of total carbon ( weight content is in the range from 0,03% to 40 %) lies in burning of an analytical sample in the current of oxygen with the temperatures varying from 1150 to 1200 °С, absorption of the emitted carbon dioxide by an absorbing solution with relevant initial pH index and further measurements on the equipment for the coulometric titration necessary for the reproduction of initial pH index of the quantity of electricity which is proportionate to the weight content of carbon in an analytical sample.
Infrared-absorptive method of determination of weight content of total carbon (weight content is in the range from 2,5% to 20 %) covers burning of an analytical sample put into special combustion boat in the current of an oxygen with the temperature 1250 ± 100 °C and further measurement of the content of total carbon by this method.
One more method of determination of weight content of total carbon is an infrared-absorptive one with the weight content varying from 1 · 10–4 % to
100 %. This method lies in the determination of the weight content of total carbon by the analyzer dedicated for such kinds of measurements with an automatic weighing of an analytical sample and indication of the results of measurements.
GOST 24523.0-2021 «Electrotechnical periclase. General requirements for methods of chemical analysis» sets general requirements for the methods of chemical analysis of white powder material (magnesium oxide) filling the space between the heating unit and metal tube of the tubular electric heating element.
It is necessary to carry out chemical tests connected with the emission
of poisonous vapors or gases in fume cupboards or special boxes.
The process is conducted in parallel with two analytical samples. Control experiment on contamination of chemical agents is carried out in line with the analytical sample through all stages of the analysis.
GOST 24523.1 – 2021 «Electrotechnical periclase. Method for determination of silicon (IV) dioxide» is distributed on an electrotehnical periclase and sets photometrical method of determination of silicon dioxide with the weight content varying from 0,2 % to 3,0 %.