DETERMINATION OF MANGANESE, NICKEL, LEAD, TITANIUM, VANADIUM, AND COPPER IN OILS OF THE TYUMEN FIELD BY A SPECTRAL METHOD

R. D. Glukhovskaya, L. S. Kolesnikova, Yu. A. Karbainov,
L. V. Peneva

(Presented by the scientific seminar of the Department of Analytical Chemistry)

In a previous communication (an article in this collection) it was shown that, when comparing various methods of sample preparation, two procedures proved to be the most rational: ashing the sample with sulfuric acid [1–3] and ashing in the presence of a collector—carbon powder [4–7]. The first method, as can be seen from Table 1, gives more reproducible results. This is apparently due to the fact that the dry residue with the collector is not completely ashed. The sintered coke residues were difficult to grind, and this could have caused an uneven distribution of the elements throughout the mass of the carbon powder. In this connection, the oil samples intended for the study were ashed by the sulfate method.

Analytical procedure. An oil sample (20–25 g) is placed in a quartz dish, an equal volume of sulfuric acid is added, and the dish is placed on an electric hot plate (with asbestos) and carefully heated. Gradually increasing the heating temperature, heating is continued until the evolution of sulfurous gas vapors ceases and a black spongy mass forms.

The dish is transferred to a slightly preheated muffle furnace, and the temperature is gradually increased to \(500 \pm 50^\circ\mathrm{C}\). Calcination is carried out until complete ashing of the dry residue; the dish is cooled, small amounts of spectrally pure carbon powder are added, the powder is moistened with alcohol, the walls of the dish are wiped with a glass rod with a polyethylene tip, and the material is transferred to a preweighed watch glass. This operation is repeated several times until all the ash has been quantitatively transferred from the dish. The watch glass with its contents is then weighed, and the weight of the concentrate is brought to 120–150 mg with carbon powder. The sample is thoroughly ground in the presence of alcohol. Part of the resulting sample is diluted with carbon powder by factors of 10 and 100 and ground again in the same way. To the resulting samples and standards, 5% spectrally pure sodium chloride is added; they are ground for 5–10 min and used to fill the channel of a crater-type carbon electrode.

On one plate, the spectra of the samples prepared in this way and of standards with concentrations from \(3 \cdot 10^{-5}\) to \(1 \cdot 10^{-2}\%\) are photographed three times on an ISP-28 spectrograph.

The excitation source used in the work was an alternating-current arc (current strength 10 A).

The standards were prepared by grinding carbon powder with oxides of the corresponding elements [8].

On an MF-4 microphotometer, the intensity of the analytical lines was measured: Mn — \(\lambda = 2801.06\ \text{Å}\), Ti — \(3088.03\ \text{Å}\), V — \(3185.4\ \text{Å}\); Ni — \(3050.82\ \text{Å}\); Cu — \(3247.54\ \text{Å}\); Pb — \(2833.07\ \text{Å}\); and from \(\Delta S = S_{\ell} - S_{\phi}\) and \(\lg C\) a calibration graph was constructed.

The percentage content of the elements in the oil being analyzed was calculated by the formula

\[ \% Me = \frac{(C_1 - C_0)\cdot n}{a\cdot H}, \]

where

\(C_1\) — content of the element in the oil sample (from the graph), %;
\(C_0\) — content of the element in the blank sample (from the graph), %;
\(n\) — weight of the concentrate, g;
\(a\) — dilution, \(H\) — sample weight, g.

The results of the determinations were processed by the method of mathematical statistics and are given in Tables 2, 3, 4, 5, 6, 7.

Table 1

Table 2

Results of spectral analysis for nickel content

Table 3

Results of spectral analysis for titanium content

Table 4

Results of spectral analysis for lead content

Table 5

Results of spectral analysis for copper content

Table 6

Results of spectral analysis for manganese content

Table 7

Results of spectral analysis for vanadium content

REFERENCES

1. S. P. Gusev, L. V. Grishina. Collection of scientific works of the Moscow Institute of National Economy. Issue 18, 112 (1961).

2. S. N. Aleksandrov, Ya. E. Shmulyakovskii, S. A. Alekseev. Chemistry and Technology of Fuels and Oils, No. 9, 69 (1958).

3. S. K. Kyuregyan. Emission Spectral Analysis of Petroleum Products. Moscow, “Khimiya,” 1969.

4. E. V. Ilyina, K. I. Taganov. Spectral Analysis of Lubricating and Fuel Oils for Monitoring Wear of Parts in Mechanical Engineering. TsINTI, 1956.

5. N. P. Gorozhankina, S. G. Soboleva. Application of Spectral Analysis of Oils to Increase the Reliability and Durability of Machines and Mechanisms. TsINTI, 1965, p. 86.

6. M. M. Marenova, S. K. Kyuregyan. Application of Spectral Analysis of Oils to Increase the Reliability and Durability of Machines and Mechanisms. TsINTI, 1965, p. 32.

7. A. I. Sokolov. Chemistry and Technology of Fuels and Oils, No. 2, 70 (1964).

8. Methods for Analysis of Chemical Reagents and Preparations. Moscow, issue 8, 10 (1964).