RU1824561C - Method of determination of micas heat resistance - Google Patents

Abstract

SUMMARY OF THE INVENTION: the first sample is heated to 1350 ° C, its weight loss is established, the additional sample is heated at a rate of 5-10 ° / min until a weight loss of at least 5% is calculated, and the ratio of the weight loss of the 1st sample to the 2nd is calculated. The magnitude of this ratio is indicative of heat resistance.

Description

The invention relates to the field of thermal analysis and can be used in the chemical and electrical industries, geology, and other industries.

The purpose of the invention is to increase the accuracy and rapid determination of the heat resistance of mica, in particular phlogopites.

The goal is achieved by a method of determining the heat resistance of mica; including heating the sample to 1350 ° C with subsequent determination of the weight loss of the sample, characterized in that the additional sample is heated at a rate of 5-10 ° / min until a weight loss of at least 5%, then the ratio of the weight loss of the 1st sample to the 2nd and by the magnitude of this ratio, heat resistance is judged.

The method for determining the heat resistance of mica is based on the use of relationships between the kinetic parameters of the thermal destruction process and the heat resistance of a substance

T0

or

R UL- + 2 1pTsT

K I mu K I m J)

ABOUT)

V

4ff

fe

Then

Rizh)

(2)

where T0 is the limiting temperature that determines the heat resistance of a substance, R is the universal gas constant, and b is the heating rate under experimental conditions. Tm temperature of the maximum rate of thermal decomposition reaction.

The method is carried out as follows. The initial sample is divided into two parts (1.2-2.0 g each). The first portion is calcined at 1350 ° C for 1-2 hours until the change in mass ceases during the calcination. The total weight loss W of the sample (in percent) is determined by the difference in the mass of the initial and calcined samples. The second part of the sample is heated with a predetermined value00

about

XY

at a speed (5 -10 ° / min) to a temperature T at which the change in mass is w - 0.05 W. At the same time, the speed dw / d g of the change in mass of the sample is recorded, the maximum value of which corresponds to the temperature Tm.

Knowing the degree of conversion of the sample a- "-W / W is 0.05, the heating rate of b, the temperature of which a is 0.05, and using non-linear programming methods, is not difficult by the ratio

- (1- ") 1 -p

1-p

A RT2 b E

-E / RT

(3)

determine E and A, which allows T0 to be calculated from formulas (1) or (2).

It should be noted that the use of formula (2) for the calculation of To allows not fixing the rate of change in the mass of the sample.

An example of the method. A phlogopite sample was taken at the Kovdorskoye field deposit (Murmansk region).

0

The initial sample was divided into two parts of 2 g. The first part was calcined for 1 hour at 1350 ° C. The total weight loss of the sample was W 3.72%. The second part warmed up at a rate of 10 ° / min until the moment when the weight loss was 0.05 W - 0.186%. The temperature of the sample was 1103 ° C. Using these data, it is easy to find by (3) p 0.815, A 2.55 x

111

xY s, E 84.2 kcal / mol. Therefore, according to (2), T0 is 949 ° C.

Claims (1)

SUMMARY OF THE INVENTION A method for determining the heat resistance of mica, including heating the sample to 1350 ° C, determining the loss of its mass, characterized in that, in order to increase the accuracy and expressness of the determination, an additional sample is used, which is heated at a speed 0 5-10 ° C / min until a mass loss of at least 5%, then the ratio of the mass loss of the first sample to the second is calculated and the thermal stability of the mica is judged by the value of this ratio. 5 5