by Yuri KALININ, Dr. Sc. (Tech.), Director General of the Scientific Production Complex "Carbon-Shungite", Vladimir KOVALEVSKY, Dr. Sc. (Geol. & Mineral.), Head of the Shungite Laboratory, Institute of Geology of the RAS Karelian Scientific Center (Petrozavodsk, Republic of Karelia)

Ancient carbon-bearing formations of Karelia are unique natural formations of the Proterozoic (about 2 bln years), which have no equals in the geological history of our Earth. The composition of these formations is characterized by a variety of carbon-bearing rocks--from the minimal content to appropriate carbon concentrations, meaning, first of all, shungites. They have been thoroughly studied for over 50 years at the RAS Karelian Scientific Center--the homeland of the mineral-using modern research methods. For these years, the mineral has revealed its secrets, has become known all over the world, proved to be a promising material and, at the same time, has remained unknown in many aspects, offering new breakthroughs.

Shungite rocks* have been actively studied by scientists for over two hundred years. The first fragmentary reports on "black lands" in the Olonets Territory was published in 1792 by the famous Russian natu-

* See: Yu. Kalinin, "Ecological Potential of Shungite", Science in Russia, No. 6, 2008.-Ed.

ral scientist Nikolai Ozeretskovsky, a member of the Petersburg AS. A half century later, in 1848, Nikolai Komarov, staff-captain of the corps of mining engineers, made public some other data after discovering large scale accumulations of a "resinous rock" near the settlement of Shunga, Medvezhyegorsk District. Sys-

tematic studies of the ancient carbon formations were commenced in 1879 by Alexander Inostrantsev, Professor of the St. Petersburg University. It was he who proposed to name this mineral by the place of its first discovery and classified it as the last in a series of natural non-crystalline carbon rocks not attributed to coal. In 1928-1937, during the geological and technical studies carried out by the public trust "Shungite", scientists obtained valuable data on the composition and properties of the rock and proved that this carbon-bearing raw material could be used in many sectors of national economy.

In 1956, shungite-related studies in the geology sector of the USSR AS Karelian-Finnish Base (later on the USSR AS Karelian Branch, today the RAS Karelian Scientific Center) were headed by the prominent petrographer Pyotr Borisov, Dr. Sc. (Geol. & Mineral.). In 1962, a year after establishing the Institute of Geology, there was set up a laboratory of non-metallic raw materials under his scientific supervision (since 1975, the shungite laboratory). First of all, it had to study carbonbearing slates of the Nigozerskoye deposit (Kondopoga). The first report prepared in 1962 showed that these rocks could be used to produce light fillers of a claydite type, later on named haydite. This stimulated development of the Nigozerskoye deposit. Nearby, the Kondopoga shungite plant was built, producing crushed stone supplied to the North-Western, Central, Baltic, and other economic regions of the USSR to produce haydite. Originally, gravel was widely used as a porous aggregate for concretes to manufacture supporting structures and assembly parts for house building, and also for heat-insulating fillings. And though, new highly efficient insulation materials ousted gravel from the top, its use at that time was economically feasible and important for the development of housing and industrial construction in the north-western part of our country.

In the 1960s, shungite rocks were tested as a mineral pigment (1965), raw material to manufacture silicon carbide and metal silicon (1967), durable material fillers to produce phosphorus, phosphoric, sulfuric, and other acids (1970). The certificate "Shungites--New Complex Raw Material" issued in 1971 proposed the first technological classification of this mineral and listed

possible spheres of its use: to manufacture phosphorus and single-piece thermal acid-resistant ware, as a substitute for graphite in foundry production, as a pigment in construction, as a filler for acid-resistant ware, facing material, haydite, ornament and touchstone. According to the authors, the "above-listed trends do not include all possible applications of the mineral, representing only the initial results of introducing these unique rocks to national economy."

The decree of the USSR Council of Ministers issued in 1972 stating "the necessity for complex studies of carbon-bearing non-metallic mineral deposits of Karelia--shungites--the estimated reserves of which make up hundreds of millions of tons" became highly important for its development. Numerous research and production enterprises of Karelia and the Soviet Union were involved in this work: the public enterprise "Rosorgtekhstrom", Leningrad Mining Institute, Dnepropetrovsk Iron and Steel Institute, Petrozavodsk Design-Technological Institute, Ural Nllstromproekt (Chelyabinsk), Gvozdev Research Institute of Concrete and Reinforced Concrete (Moscow), Special Design-Technological Bureau "Dezintegrator" (Tallin, Estonia), Research Institute of Bridge Engineering of the Leningrad Institute of Railway Engineers, Kucherenko Central Research Institute of Engineering Structures (Moscow), Engineering and Construction Institute (Leningrad), Leningrad Institute of Technology named after Lensovet, Petrozavodsk State University, and, finally, subdivisions of the Karelian Branch of the USSR AS-- Institutes of Geology, Biology, Forest, Economics, Water Problems of the North, with the first one as the

head organization in charge of a complex research of shungites.

This problem challenged at the laboratory of the Institute of Geology marked the second phase of shungite studies. In the early 1970s, an industrial geological classification of the mineral was worked out, composition of the solid phase and volatile compounds was determined, structural studies by means of electron microscopy and derivatography* were carried out, its primary properties--density, thermal expansion and thermal resistance, heating value, adsorption, acid and alkali interaction--were studied. At the same time, the laboratory experts proved: shungite rocks can be used to manufacture ferroalloys, fettle aluminum electrolyzers and in foundry technologies. These works were carried out with the assistance of the All-Union Institute of Aluminum and Magnesium (Leningrad). To solve field tasks, a special geological-technological station was built in the settlement of Tolvuya (Medvezhyegorsk District) near the shungite deposits. It was there that numerous carbon-based technologies were tested.

In the 1980s, a new search for shungite applications was started under supervision of Yuri Kalinin, who headed the laboratory from 1964. In particular, scientists established: highly carbonaceous compounds are efficient adsorbents in water treating processes, fit to

* Derivatography--a research method to study chemical and physicochemical processes in the matter in terms of changing thermal regime. It is based on the combination of differential thermal analysis and thermogravimetry.--Ed.

adsorb phenols, humins and oil products, while materials on their basis act as active catalysts in the processes of organic synthesis of cyclic hydrocarbons and decomposition of hydric dioxide, which is very important to organize environmentally friendly chemical plants. Besides, shungite was recognized as an active filler for a wide class of composition materials to impart to them new properties: enhanced durability, chemical resistance, and electrical conductivity.

Scientists also detected radio screening capacities of shungite rocks, which stimulated development of the technology of getting construction materials, allowing to protect man from technogenic electromagnetic radiation. These properties of non-metallic mineral resources attracted attention of a number of national ministries--radio electronic and aviation industries, medium machine-building and defense. As a representative of the interests of the above-listed ministries, the Central Design Bureau of Radio Materials (Moscow) entered into a contract with the Shungite Laboratory to develop industrial technologies of radio screening materials, to construct experimental structures and carry out their radio-technical tests. The pilot lot of radio screening materials manufactured at the Petrozavodsk Silicate Brick Plant was tested and successfully accepted by defense departments. Many screened structures in Petrozavodsk, Moscow, Leningrad, Penza, Kuibyshev and also in Bulgaria were built using bricks with the shungite filler.

In the late 1980s, the USSR Ministry of Industry of Construction Materials planning to organize large scale production of radio screening materials issued an order to carry out geological prospecting of the Zazhoginskoe shungite deposit in the Medvezhyegorsk District 5 km away from the navigable bay of Lake Onega, where a considerable part of the resource potential of highly carbonaceous formations of Karelia (over 30 mln tons) was concentrated. But the absence of an industrial chain, incorporating development of the deposit, extraction, its initial preparation (crushing and fractioning), storage and shipping, to the consumer hindered the use of this mineral. To solve this problem and ensure full-sale development of the Zazhoginskoe shungite deposit, one of the authors of this article left the Institute of Geology, handed over the laboratory management to Yevgeny Dyukkiev, Cand. Sc. (Chem.), and in 1991 established the Carbon-Shungite Company (from 1995 the laboratory has been managed by Vladimir Kovalevsky, Dr. Sc. (Geol. & Mineral.)).

In the 1990s, characterized by lack of funds, the laboratory focused on the studies of the structure and electro-physical properties of the shungite carbon. It was the time when the scientists received data, drastically changing their conception of this mineral, its properties and genesis.

According to the present-day conceptions, shungite is a non-graphitizing carbonaceous substance with a globula as its basic structural unit--a fullerene-like formation of-10 nm, consisting of fragments of closed 3D shells or smoothly bent packages of carbon layers covering a nano-size pore. In terms of molecular structure, shungite is a graphite-like structure deformed both in the layer plane and in the perpendicular direction to it in such a way that its hexagonal symmetry reduces to trigonal one. Periodicity breaches in graphene layers may be caused by noncarbon inclusions and presence of non-hexagonal carbon rings. In the rocks under considerations, there were identified higher fullerenes and fullerene-like structures, isolated or attached to minerals. Shungite-like carbon was found not only in Karelia. It is also found at the exit of pyrobitumens of the blast crater of Sudbury (Canada), formed as a result of falling of the comet (10 km in diameter) 1.85 bln years ago, and in some gold ore fields--Sovetskoye deposit, the biggest one in Russia (the Yenisei Range) and Ericson (Canada). However, only the Karelian deposit has such unique manifestation forms and giant industrial potential.

Shungite is one of the most intriguing types of a free carbon, generating numerous standpoints as to the genesis of the mineral. They all can be divided into two big groups--biogenous and abiogenous. According to some researchers (in particular, Inostrantsev), it is not a coal; while others, for example, Vladimir Timofeev, Professor of the Leningrad State University, on the contrary, think that it is a bituminous coal and has even signs of charcoal. Supporters of the biogenous theory compare

shungite and kerogen (organic polymer materials, one of the forms of a non-conventional oil) of the Precambrian from the chlorite zone, pyrobitumen and anthraxolite. According to the abiogenous theory, it could be a result of carbonization of hydrocarbons or products of active mantle degassing, and also as a result of deep burning processes or transformation of vanadium oil. There are other hypotheses too. For example, one of the most famous Russian specialists in geochemistry of sedimentary rocks Yakov Yudovich, Dr. Sc. (Geol. & Mineral.), believes that shungite could form as a result of mixture of biogenous and abiogenous processes. Moreover, some scientists contemplate a possibility of impact action on the process of its formation.

From our point of view, shungite carbon is resistant to conversion to graphite and is preserving stability of the fullerene-like structure for 2 bln years. No geological factors enabling graphite-like carbon to turn into shungite were identified. All these facts show that this mineral should be classified as an independent carbon family like graphite and diamond. It could not be formed by way of transformation of members of the graphite family in the surface zones of the Earth.

Shungite rock has a specific structure. Carbon molecules form an average size matrix with evenly distributed mineral formations (~1 urn). Other sedimentary rocks have no similar structures: neither by high dispersion of silicates, nor by the form of carbon distribution. Such structures can be found only among technical products--crystalline glasses produced by way of crystallization of high-viscosity homogeneous glasses. There are reasons to assume that the shungite rocks were formed in the same way from viscous chetnogenous magmas. In such seat, with S and C1 available, basite (a product of crystallization of melts) and shungite enter into different chemical reactions (including oxidation-reduction reactions) and liquidation (stratification, decomposition) processes generating new products--shungites of diverse composition from maximally saturated with carbon (up to 70 percent) to basites consisting of shungite ash, carbonate rocks, sulfides and salts. According to one of the authors of the article, the listed compounds enable us to consider shungites and rocks of the Zazhoginskoye formation as products of chemogenic carbonatite (magmatic) masses. This is a new perception of genesis and it should be considered in more detail, since carbonatites are a natural storeroom of many raw materials, where unusual discoveries have been made.

Unique properties of the compound are dependent on its specific structure. Thanks to the shungite matrix, the contact surface between carbon and silicates, comprising the mineral, reaches 20 m²/g. As a consequence, oxidation-reduction reactions between them are very intense and undergo at lower temperatures, as compared with conventional processes, and higher efficiency. For example, when smelting casting iron in blast furnaces to synthesize silicon, 1 kg of shungite carbon

is equivalent to 3-4 kg of coke carbon. Or another example: silicon carbide is usually produced at 1,600-2,500 °C. If we use nongraphitic carbon as a raw material, these figures will become 300-500 °C lower.

Shungite rocks, as compared with graphite, are more chemically resistant in aggressive environment, for example, in melts of aluminum electrolyzers. They also have high sorption properties, sometimes leaving behind activated carbons. This was registered, for example, in the course of purification of drinking water from free radicals and oil products. Besides, the intensive reducing reaction of compounds determines antioxidant properties of water infusions. In addition, they are able to regenerate their sorption properties.

The recent phase of research is associated, first of all, with studies and use of products of deep modification of shungite rocks, based on the modern fundamental knowledge on the structure and properties of the mineral. What is meant here is thermal processing, changes of oxidation-reduction potential of the environment, initiation of catalytic processes of carbon transformation and growth of noncarbon automorphoses.

In the recent years, in the course of studies of thermal and baric transformations of shungite rocks, scientists developed a method of their nanostructuring resulting in the fusion of hollow globules into larger particles and growth of nanofibrous silicon carbides, which, in their turn, break the shungite monolith into separate nanosize components. This method provided the basis for a technology patented in 2008 (authors--Vladimir Kovalevsky and Alexander Safronov) allowing to produce a brand new product--shungiton containing hyperfullerene carbonic structures and nanofibrous silicon carbides. According to the expert opinion made by ZAO Innovations of Leningrad Institutes and Enterprises (St. Petersburg), it has no direct analogues in the world practice. Joint works carried out together with OOO Bummash Tekhnolog (Petrozavodsk) revealed: adding of 10 percent of the filler, increases strength of thermoactive composite materials by 45 percent given a considerable increase of durability factors (over 20 percent). The Research Institute of Tire Industry (Moscow), where the new product was tested, confirmed its fitness to be used in tire resins. It was also proved (in conjunction with the RAS Moscow Institute of Metal Engineering and Materials Science named after A. Baikov and Perm Scientific-Technical Center OOO Novomet) that carbon-bearing fillers change the structure and properties of aluminum and stainless steel. In 2010 commercialization of shungite on studies was included in the list of top 10 promising innovative projects of the Republic of Karelia.

Today shungites are widely used in metallurgy, in particular, in blast-furnace smelting of casting iron. It is used as a raw material to synthesize metal silicon, i.e. it acts as an alloying additive. Synthesis of Si from the Karelian mineral is more efficient, as compared with the traditional technology. During smelting of cast iron, shungite is used in the blast process for placing SiC, which precipitates on the walls of a furnace thus creating a kind of protective shell. This method of "treatment" of production facilities is applied at almost all iron-and-steel works of our country and in Germany.

The primary perspectives of practical use of this valuable raw material are associated with elimination of environmental problems. Radio screening materials are used in public health care, for example, two shungite treatment rooms are arranged at the Military Medical Academy named after S. Kirov (St. Petersburg) to treat liquidators of the accident at the Chernobyl Nuclear Power Station, employees of nuclear plants and oil refineries, patients suffering from cardiovascular diseases. To sum it up: the adaptation effect of electromagnetic deprivation (isolation) of patients in shungite rooms shows in a significant reduction of the rehabilitation period after intoxication and acute diseases. Screening from electromagnetic smog activates the immune system. Similar treatment rooms were organized at health resorts in Petrozavodsk, Pyatigorsk, Sochi, Nizhni Novgorod and other cities.

Shungite, able to purify water from various organic and some inorganic substances, is actively used in the treatment of drinking water. In the town of Pushkino (Moscow Region) this material is used in municipal water intake filters. It is also used in household appliances, filters purifying water from oil products, in agriculture to increase crops and resistance of plants to different diseases, and as a fodder additive to the diet of fur animals, pigs and barndoor fowl.

Illustrations supplied by the authors