SU1206651A1 - Method of analysing material chemical composition - Google Patents

Description

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The invention relates to the field of the investigation of the chemical and physical properties of substances and concerns the analysis of materials for the content of elements forming volatile halides.

Known methods of high-temperature vacuum extraction to determine the gas-forming impurities, such as the method of determining oxygen, which consists in melting the sample to be analyzed in a graphite crucible in a melt (bath) of another material, such as nickel, with carbon, extracting oxygen from the melt as carbon monoxide and quantifying carbon monoxide using a gas analyzer ij,

High-temperature vacuum extraction methods allow the analysis of a wide range of materials, the sensitivity of the determination of impurities is 10 -10%, the accuracy of determination at this level of concentrations is 15-20%.

The disadvantage of high-temperature extraction methods is the narrowness of the range of detectable impurities, they can only be used in analytical chemistry of gas impurities and carbon.

The closest to the invention is a method for analyzing the chemical composition of a material, which consists in melting an analyzed sample in a melt (bath) of another material, on the surface of which is liquid slag from a metal halide, extracting impurities from the analyzed sample in the form of a volatile halide and quantifying it using gas analyzer. The method allows determination of a wide range of metallic and non-metallic impurities 2.

The disadvantage of this method is that the crucible material always contains a certain amount of the impurity being analyzed, which, interacting with the liquid metal halide slag and forming a volatile halide, creates a background in the analysis, which reduces the sensitivity and reproducibility of the analysis results.

at temperatures up to 200-250 ° C, gas fluorides: As, B, C, Cr, Ge Ir, Mo, Nb, 0s, P, Pd, Ru, Re, Sb Si, Ta, and, V, W. As a material The crucible can also be used in the following 5 fluorine-containing materials, for example, fluorapatite Ca (PO) uG, lepidol (5140.0) (F, OH) 2parisite, Ca (Ce, La, ...) 2 (CO3) h Fg, Rowlandi Y, Fe si207l F, gumite ZMVD510 Mg

The purpose of the invention is to increase the accuracy of 55 () 2 and others. These are natural mineness and sensitivity of the analysis. The goal is achieved by the fact that, in the method that involves 10

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c in the extraction of impurities from the sample in the form of a volatile halide and its subsequent quantitative determination using a gas analyzer; a fluorine-containing substance, such as fluorophosphate, is used as the crucible material.

In this case, the impurity to be analyzed, even if it is in the crucible material, is removed as a volatile halide during the process of preheating the crucible and evacuating the resulting gases, and the preheating of the crucible is performed. mainly at temperatures above the analysis temperature. After heating and subsequent cooling, the crucible, which is a source of gaseous halide during heating, is loaded with the sample to be analyzed and heated in vacuum. The analysis of released halide gas impurities are carried out in a known manner.

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In this case, the constancy of the rate of supplying halogen gas to the sample to be analyzed is provided, the stability and the rate of progress of the reaction are higher, which makes it possible to significantly increase the accuracy and sensitivity of the analysis.

Fluorine-containing material crucibles can be manufactured by known methods, for example, by mechanical, machining, casting, pressing, etc. The melting point of these crucibles is much higher than the extraction temperature.

Fluoroflogopit has a composition expressed by the formula KHg-AlSigOi jF, and

is a natural mineral (mica) with so pl. 1270-1330 ° C.

The proposed method is possible

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define all elements forming

о / at temperatures up to 200-250 С gaseous fluorides: As, B, C, Cr, Ge, Ir, Mo, Nb, 0s, P, Pd, Ru, Re, Sb, Si, Ta, u, V, W. Other crucible-containing materials, for example, fluorapatite Ca (PO) g, lepidolite (5140.0) (F, OH) 2parisite, Ca (Ce, La, ....) 2 (CO2) g Fg can be used as the crucible material. , Roulandite Y, Fe si207l F, gumite ZMVD510 Mg

55 () 2 and others. These are natural mineral substances, when heated, they produce gaseous fluorine, i.e. meet their requirements. Nevertheless, artificial fluorine-containing materials with a sufficiently high melting or decomposition temperature, which emit gaseous fluorine when heated, for example, fluoroplastic, can be used with the same success, but its melting point is rather low (), which limits its use.

Example 1. Analyze the content of phosphorus in titanium containing 0.001%. P, 4.7% A1 and 2% V in a copper bath. A sample of titanium chips weighing 0.5 g is placed in a fluoroflogopite crucible pre-heated in vacuum at 1,100 ° C for 2 hours. The analysis is carried out at 900 ° C, the phosphorus recovery time is 20 minutes, the determination is carried out on an MX-7301 mass spectrometer . The phosphorus content in titanium is 0.00095 + 0.00010%. The phosphorus content, measured in a known manner, 0,0009210,00030%. The relative standard deviation of the results (S), calculated according to the 10 definitions, is 30%. When analyzing this sample in a known manner.

Thus, the reproducibility and sensitivity of the determination of phosphorus in titanium by the proposed method is increased by approximately three times.

Example 2. Analyze the content of boron in pure iron containing 0,0017% Century. The crucible from

Compiled by A. Zhavoronkova. Editor I. Nikolaichuk Tehred A.Ach

8701/43 Circulation 778

VNYIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Under

Branch PSh1 Patent, Uzhgorod, st. Project, 4

206651

fluoroflogopite with a copper bath weighing 2.3 g is degassed at 1230 ° C, then the temperature is reduced to 1150 ° C, the extraction furnace is connected to a 5 mass spectrometer tuned to a mass of 48 amu. (BF), and a weight of iron weighing 0.23 g is dropped. After melting the weight, boron dissolved in the bath interacts with fluorine to form BFj, the ionic current of which is fixed by a mass spectrometer. Experiments on the determination of phosphorus and boron are carried out only using fluoroflogopite crucibles. .

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When heated in a crucible, a homogeneous molten bath is formed - the metal being analyzed. At the same time, due to the decomposition of the crucible material, fluorine gas appears in the extraction furnace. At an extraction temperature, a reaction occurs between the impurity dissolved in the bath material and fluorine to form a gaseous product, for example:

p + 3/2) FF, (g); in + 3/2. F (g) BFg (g).

The proposed method ensures the constancy of the rate of supplying the halogen gas to the sample to be analyzed, higher stability and speed of the reaction, as a result of which the accuracy and sensitivity of the analysis are increased.

Mr. Z. Zimokos

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Claims (2)

1. METHOD FOR ANALYSIS OF THE CHEMICAL COMPOSITION OF THE MATERIAL, which consists in melting the sample in the crucible, extraction of the impurity from the melt in the form of a volatile halide with its subsequent quantitative determination · one of the known methods, characterized in that, in order to increase the accuracy and sensitivity of the analysis, as crucible material using a fluorine-containing substance. 2. The method according to claim 1, characterized in that fluorophlogopite is used as the fluorine-containing substance. ί 1206651