Сhromatographic methods for the study of organic extractants of transformer oil

THE PURPOSE. In order to control the technical condition of oil-filled electrical equipment, a number of new analytical methods have recently been created to determine the ultra-low concentrations of impurity compounds in transformer oil. An analysis of the literature data showed that at this stage of the analytical procedure significant errors may occur that worsen the quality of control of the technical condition of oil-filled electrical equipment, and in some cases make its results meaningless. The published literature practically does not discuss the problem of sample preparation of transformer oil, which negatively affects the quality of analytical control, that is, the reliability of the results and, accordingly, the diagnosis of oil-filled electrical equipment. METHODS. The paper discusses a sample preparation system for transformer oil, which is based on various methods for extracting target components from it. The adsorption process is used, the preparation of chemical derivatives, various types of extraction, liquid, gas, solid phase and fluid, as well as using low temperatures, extraction in microwave, magnetic, electromagnetic and centrifugal fields. It is shown that liquid extraction with an organic solvent is widely used from all sample preparation methods, with the help of which furan compounds resulting from the destruction of paper insulation are extracted from transformer oil. The disadvantages of sample preparation using liquid-phase extraction and the possibility of using solid-phase extraction on various adsorbents for this purpose are discussed. RESULTS. The results of an experimental study of the sorption properties of various organic solvents with respect to porous materials differing in the structure of their surface are presented. We used zeolite-bearing rocks of the Tatar-Shatrashansky deposit, synthetic zeolites NaX-13A. Using the ascending variant of liquid column chromatography, the absolute retention values of standard extractants were determined and their dependence on the length of the sorption layer of the porous material was found. CONCLUSIONS. It was shown that the highest retention times for all studied adsorbents are observed for organochlorine extractants, chloroform, carbon tetrachloride, dichloroethane, trichlorethylene. For N. Hexane is a relatively small interaction. Histograms are given of the effect of the retention time of standard sorbates (extractants) on their physicochemical nature.

Removing copper and nickel from contaminated water with vermiculite-sungulite materials

The environmental impact of non-ferrous metallurgy sites is a well-studied and thoroughly described phenomenon characterizing industrially developed areas. New techniques are being developed and adopted to help reduce the amount of metal compounds released in the environment by the industry. The so-called fugitive sources of pollution, which include polluted areas surrounding industrial sites, have been a recent focus of attention. This paper considers the possibility to use vermiculite-sungulite materials obtained by concentration of tailings produced by a phlogopite mine in Kovdor (Murmansk Region) as a sorption material to be used for removing heavy metals from contaminated ponds of the Monchegorsk Industrial Area in the Murmansk Region. A series of experiments has been conducted during which sampled water was treated with vermiculite-sungulite materials. This sorption treatment technique was established to be efficient. Some resultant solutions have residual concentrations of metals <10 mcg/L, with the purification efficiency exceeding 85%. The factor determining the process of removing nickel and copper from contaminated water includes pH, which is reached as a result of water interacting with the above materials. In the equilibrium state, provided the рН level in the system is maintained above 8.5, vermiculite-sungulite materials can keep metals sorbed thus preventing their migration from the sorption layer. The findings show that due to the use of finely dispersed materials the concentrations of copper and nickel can be lowered from 10 mg/L to a few micrograms. This research study was funded and supported by Kola MMC.

Photochemical production of gold films on the surface of fabric materials

A technology for producing gold films on the surface of fabric materials has been developed, which provides for preliminary wetting of the fabric product with aqueous solutions of gold (III) chloride. In this case, a sorption layer of gold chloride is formed on the surface of fabric materials. Then, when drying these products under sunlight, physicochemical and photochemical processes occur, leading initially to the formation of monovalent gold chlorides, which, having semiconductor properties, provide the release of elemental gold. After washing of by-products on the surface of the material remains an ultra-thin film of gold, which has a sufficiently strong grip on the base. Since the proposed technology does not require special equipment it can be used to apply functional films of gold on various products of technical, household and medical purposes.

Physico-chemical models of galena flotation system

Main idea to prevent the ground contamination by heavy metals is to extract them maximally with minimum consumption of chemical reagents. So, a perfect studying of pulp ionic structure, an adjustment of the sulphuric ores flotation parameters and modelling of minerals selectivity variables, by using the thermodynamic method of analysis, the behavior of lead xanthenes surface state in solution and experimental investigation results, allow obtaining quantitative physico-chemical models of minimum necessary xanthenes concentration of lead sulphide complete flotation.The optimal pH values, ensuring a complete flotation of galena agree with the potential of zero or minimum charge of its surface, and the optimal composition of the collector sorption layer consisting both of chemisorbed xanthenes and physically adsorbed dixanthenes.In additional, it was obtained quantitative models for the necessary xanthenes concentration of lead sulphide complete flotation in the case of different oxidation products from the galena surface in pH values from 7,0 up to 12,0.The models derived can be used as the criteria for functional units of automation systems to control and regulate the flotation process in mineral processing plants. All these should conduct to increasing of metals extraction degree with minimum chemical reagents consumption and providing good environmental protection.