Coal Tar Pitch has been traditionally used for manufacturing Carbon Anodes and Electrodes for Aluminum and Graphite Industry. We manufacture Coal Tar Pitch strictly from good quality High Temperature Coal Tar by Latest Vacuum Flash Distillation Process. We match, monitor and control all the necessary Physical and Chemical properties that are important for the performance of Pitch. These properties include:-
Our team of experts deeply understands the importance of these properties and accordingly control and monitor feedstock blending, centrifuging and Distillation severity.
Kindly Note: We manufacture wide range for Coal Tar Pitches from Softening Point : 35 to 200oC with different Beta resin contant as per customer requirements.
Coal tar pitch is currently produced from coal tar, which is a byproduct of high temperature coking of coal in the manufacture of metallurgical coke. The tar predominantly contains a mixture of bi- and poly-condensed aromatic hydrocarbons and also compounds with heteroatoms in rings (predominantly nitrogen bases from the quinoline and acridine series, 1 % to 2 %) and phenols (1 % to 2 %). Upon distillation, 8 % to 12 % of a naphthalene fraction, 5 % to 9 % of an absorption fraction, and 21 % to 26 % of an anthracene fraction, which boiled away to 360 deg ?, are separated. The residual part of the tar is the pitch which contains nonvolatile and low volatile substances, whose average yield is around 2 % of the coking coal charge used for high temperature carbonizing.
The industrial production of coal tar pitch consists of the fractional distillation of the coal tar at a temperature around 400 deg C (Fig 1). By this method, the coal tar yields a series of liquid fractions suitable for different industrial applications and a residue which is solid at room temperature, called coal-tar pitch. Two different types of coal tar pitches are usually produced namely (i) binder grade, and (ii) impregnating grade. The main difference between these pitches resides in the quinoline insoluble content (much lower in the impregnating grade coal tar pitch) and in the softening point (around 110 deg C, for binder grade and around 90 deg C, for impregnating grade).
The heaviest coal tar distillation fraction, which distils between around 270 deg C to 400 deg C, is anthracene oil. This fraction, composed of 3 to 5 ring aromatic ring polycyclic aromatic compounds (PACs), has eluded all attempts at polymerization by conventional thermal treatments at atmospheric pressure. Its transformation into a pitch requires the use of specialized forms of treatment that allow the polymerization of low-molecular weight PACs to take place. Bhilai Cement has developed an industrial process to transform Crude Coal Tar into pitches. This process involves thermal oxidative condensation and subsequent thermal treatment and distillation until the pitch reaches the desired softening point (Fig 1).
This type of pitch is produced with the specific aim of fulfilling the requirements for binder and impregnations grades, mainly for carbon (C) anodes and graphite electrodes. For this reason, their use in other fields, such as precursors for advanced C materials, normally requires a pre-treatment of the commercial pitches in order to adapt their composition and characteristics for their further utilization.
For example, thermal treatment in an inert atmosphere and air-blowing are the processes generally used to reduce the emission of volatiles during pitch processing and also to increase pitch C value, without altering most of the fundamental characteristics of the pitch (e.g., wetting capacity, fluidity, etc.). Basically, thermal treatment can be considered as an interrupted carbonization (350 deg C – 450 deg C) which involves distillation, polymerization and even the formation of mesophase. The result is pitch which is able to generate carbons with a lower porosity, higher density and pre-graphitic order. All these improvements make thermally treated excellent precursors for matrices of different types of composites, C fibres, self-sintering graphites, etc. On the other hand, air-blowing has similar effects to thermal treatment but at lower temperatures (less than 350 deg C). This is since oxygen (O2) promotes the formation of free radicals which favour polymerization reactions. In this case, polymerization occurs via the formation of planar macromolecules and the formation of cross-linked structures. The latter prevents mesophase development during air-blowing.
Coal tar pitch, derived from by-product coke ovens, is the preferred material for use as a binder in the manufacture of carbon and graphite electrodes. Coal tar pitch is a coal conversion product. Its IUPAC name is "Coal Tar Pitch, High temperature”. Its CAS number is 65996-32-2 and EINECS number is 266-028-2. It is the shiny, dark-brown to black residue produced by distillation of coal tar.
Coal tar pitch contains a large number of substances. It is solid at room temperature and consists of a complex mixture of numerous polycyclic aromatic hydrocarbons (PAHs), their methyl and polymethyl derivatives, and heterocyclics, and shows a broad softening range instead of a defined melting temperature. The hydrogen (H2) aromaticity of coal tar pitch (ratio of aromatic to total content of H2 atoms) varies from 0.7 to 0.9.
Fig 1 Schematics of the production of coal-tar pitch and anthracene oil-based pitch
The aromatic hydrocarbons in coal tar pitch include acenaphthene, fluorene, 2-methylfluorene, 1-methylfluorene, phenanthrene, anthracene, cyclopenta[def]phenanthrene, fluoranthene, acephenanthrylene, pyrene, benzo(a)fluorene, benzo(b)fluorene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo[e]pyrene, benzo(a)pyrene, perylene, dibenz(a,h)anthracene, indeno(1,2,3-cd)pyrene, benzo(ghi)perylene, and anthantrene. Tar bases/N2 containing heterocycles in coal tar pitch include acridine, and carbazole. The sulphur (S) containing heterocycles in coal tar pitch include dibenzothiophene. The O2 containing heterocycles/furans in coal tar pitch includes dibenzofuran.
At room temperature, pitch appears as a uniform solid, which mainly consists of a mixture of PAHs with four or more aromatic rings. An important qualitative characteristic of pitch is its group composition evaluated based on solubility in different organic solvents namely (i) the concentrations of substances soluble in petroleum ether (gamma fraction), soluble in toluene but insoluble in petroleum ether (beta fraction), and insoluble in toluene (alpha fraction). In turn, the alpha fraction is subdivided into the fractions soluble in quinoline (alpha-2 fraction) and insoluble in quinoline (alpha-1 fraction). The group composition is primarily responsible for the technological properties of pitch such as softening temperature, dynamic viscosity, fluidity at a specific temperature, coking property, and the yield of coke residue.
Coal tar pitch is non-explosive and non-oxidizing in nature. It has affinity and binding capacities to other C products (e.g. petroleum coke). It typical physical properties are given in Tab 1.
|Physical state||Black solid||At room temperature|
|Melting point||deg C||65-150||Softening range|
|Boiling point||deg C||Greater than 360||at 1 kg/sq cm|
|Density||grams/cc||1.15-1.40||at 20 deg C|
|Vapour pressure||mm wc||less than 1||at 20 deg C|
|mm wc||less than 100||at 200 deg C|
|Water solubility||mg/l||Around 40||at 22 deg C|
|Flash point||deg C||Greater than 250|
|Auto flammability||deg C||Greater than 450|
Coal tar-pitch is a thick, black, viscid liquid formed during the distillation of coal, that upon further distillation yields compounds, as benzene, anthracene, and phenol, from which are derived a large number of dyes, drugs, and other synthetic compounds, and that yields a final residuum (coal-tar pitch) which is used chiefly in making pavements.
Coal tar pitch is a byproduct of turning coal into coke or coal gas. It is a sticky, dark brown or black liquid that resists flowing and has a very strong smell. The actual components that make up coal tar pitch vary because the chemicals in the coal it comes from differ. Even so, it coal tar pitch is primarily made up of a wide variety of different phenols and polycyclic aromatic hydrocarbons. While coal tar does have medicinal uses in treating some skin conditions, it is primarily burned as a low-cost fuel or further processed into other materials.
While there may be hundreds of different chemicals in coal tar pitch, phenols and polycyclic aromatic hydrocarbons make up two large classes of chemicals. Phenols are a complex classification of molecules that are typically very caustic and often harmful even in small quantities. Polycyclic aromatic hydrocarbons are dichotomous substances that are both extremely harmful to life and believed to be necessary for life to exist at all. They are present in nearly all air and food to some degree, although the concentration in coal tar pitch is much higher.
Solid coal tar pitch is extruded into small rods and, for this reason, is often referred to as "pencil pitch." In the aluminum industry, coal tar pitch is used as a binder in the manufacture of electrodes that primarily consist of petroleum or anthracite coal. As these electrodes are heated at high temperatures over a period of weeks, the ingredients in the electrodes are converted to carbon. For this reason, coal tar pitch is also often referred to as "carbon pitch" or "binder pitch." Additional synonyms for coal tar pitch include "roofing pitch" because of its use in the roofing industry and "target pitch" because of its use in the manufacture of clay targets.
The American Conference of Governmental Industrial Hygienists (ACGIH) and the Occupational Safety and Health Administration (OSHA) have each established a permissible 8-hour time-weighted-average (TWA) exposure level of 0.2 mg/m3 for the volatiles that are emitted from coal tar pitch ("coal tar pitch volatiles"). This number represents the average airborne exposure in any 8-hour work shift of a 40-hour work week which shall not be exceeded. According to OSHA, it is also the highest level of exposure an employee may be exposed to without incurring the risk of adverse health effects. OSHA considers engineering controls, such as ventilation and automation, the best method for controlling exposure to coal tar pitch volatiles. Respiratory protection to limit inhalation exposure and protective clothing to prevent dermal exposure to coal tar pitch and coal tar pitch volatiles are also recommended, although maintaining exposures below the TWA level is preferable. Issue Date: 1/30/2017 2 Revision: 0 Acute, or short-term, exposure to coal tar pitch has been associated with several health effects. For instance, coal tar pitch is a phototoxic substance. This means that dermal contact with coal tar pitch in the presence of ultraviolet light (sunlight) can result in a skin reaction similar to an exaggerated sunburn, as well as blisters. Short-term exposure in the absence of sunlight may also irritate the skin and cause other skin conditions such as dermatitis and acne. Additional health effects associated with short-term exposure to coal tar pitch include eye and respiratory tract irritation; severe burns from exposure to hot liquid coal tar pitch; and respiratory difficulty, convulsions, and possible cardiovascular collapse from exposure to airborne concentrations of coal tar pitch mist or vapor significantly beyond the 8-hour TWA workplace exposure limit of 0.2 mg/m3. Several agencies, including the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP) and the ACGIH, have evaluated coal tar pitch with respect to its carcinogenicity and concluded that it is a human carcinogen. Other agencies, such as the National Institute for Occupational Safety and Health (NIOSH) and the Agency for Toxic Substances and Disease Registry (ATSDR) have also evaluated the potential health effects associated with coal tar pitch. These evaluations, particularly those from the NTP, NIOSH and ATSDR, are not limited to coal tar pitch, but rather include assessments of health effects associated with other products derived from coal, including soot, coal tar and creosote, as well as other industries from which coal tar is derived, including gas works and coke ovens. It is important to distinguish between the potential hazards posed by exposure to coal tar pitch and those posed by exposure to different derivatives of coal. When the available scientific and medical literature is limited to coal tar pitch, chronic (or long-term) exposure to coal tar pitch above the 8-hour TWA workplace exposure limit of 0.2 mg/m3 and in the absence of proper personal protective equipment has been associated with cancers of the skin, lung and bladder. The risk of lung and bladder cancer has largely been associated with studies of aluminum industry workers employed for many years in a particular industrial process that continuously bakes coal tar pitch 24 hours a day at temperatures in excess of approximately 900 to 950 degrees Celsius. Similar exposures are not expected among the general population. The risk of skin cancer has largely been associated with historical studies and anecdotal reports of workers who did not follow good personal hygiene practices. In particular, the studies and reports suggest that exposed workers did not regularly bathe or wash contaminated clothing. Similar exposures are not expected among workers today who follow good personal hygiene practices and wear proper personal protective equipment. Much of the data relating to skin cancer also derives from animal studies using dermal administration. There is no evidence in the published literature that low level or incidental exposure to coal tar pitch causes skin cancer in animals, but continuous dermal exposure for long periods of time has been shown to cause skin cancer in mice. There are no long-term ingestion studies or inhalation studies with coal tar pitch. There is no evidence in the scientific literature that low level or intermittent exposure to coal tar pitch causes any type of cancer in humans. There is also no evidence in the scientific literature that low levels of coal tar pitch in soils, sediments, groundwater, surface water, or drinking water cause cancer in humans exposed to these media. Besides cancer, long-term exposure in the absence of good personal hygiene practices can also affect skin pigmentation and may cause skin growths. Additional data also suggests that coal tar pitch is both a mutagen and a reproductive hazard, which means that long-term exposure to the substance may cause genetic defects, may harm an unborn child and may damage fertility.
Environmental Information Long-term toxicity to fish is expected to be minimal. It is also not expected to be toxic at the limit of water solubility. Coal tar pitch is immobile and does not appreciably leach to groundwater. It is also very poorly soluble in water. Coal tar pitch that is released or disposed in the environment is likely to remain unchanged for many years. When coal tar pitch is seen in soil, it is usually present as distinct pieces or chunks of black, hard material, which is not likely to be contacted in the same way as is soil. Exposure Coal tar pitch is an industrial product and is not sold directly to consumers or for direct consumer use. Exposure to coal tar pitch is primarily limited to occupational settings, such as tar distillation, roofing and aluminum smelting. In these settings, occupational exposure to liquid, solid, heated or vaporous coal tar pitch is controlled by the use of enclosed processing systems, industrial hygiene controls and personal protective equipment. Each industrial facility should also have a thorough training program for employees and appropriate work processes, as well as safety equipment in place to limit exposure. Workers should follow the recommended safety measures in the relevant Safety Data Sheet (SDS). Information Sources Data is compiled from a variety of sources, including publicly available documents, internal data and other sources such as, but not limited to, Safety Data Sheets (SDS). For additional information regarding this product, including its physical and chemical properties, transport information and regulatory information, please refer to the applicable Safety Data Sheet (SDS)
Coal tar pitch and binding agents obtained from it are the most important components in the production of various C materials. The favourable combination of high coking ability and low viscosity in a molten state is mainly responsible for the high level of the physico-mechanical properties of anode pastes obtained on their basis, electrodes for steel furnaces, low ash pitch coke, fireproof materials, tapping hole mixes, C fibers, coal graphite and construction materials for different purposes, electrical products, and roofing and other C materials, which are used in different branches of industry such as in ferrous and non-ferrous metallurgy, electrode industry, the production of semiconductor materials and integrated micro-circuits, chemical apparatus and machine building, electrochemistry, atomic power engineering, aircraft building, and rocket production
Solid coal tar pitch is extruded into small rods and, for this reason, is often referred to as ‘pencil pitch’. In the aluminum industry, coal tar pitch is used as a binder in the manufacture of electrodes which primarily consist of petroleum or anthracite coal. As these electrodes are heated at high temperatures over a period of weeks, the ingredients in the electrodes are converted to C. For this reason, coal tar pitch is also often referred to as ‘C pitch’ or 'binder pitch'. Additional synonyms for coal tar pitch include ‘roofing pitch’ because of its use in the roofing industry and ‘target pitch’ because of its use in the manufacture of clay targets.
Coal-tar pitch is used in the manufacture of graphite electrodes for steel arc furnaces. It is also used to impregnate and strengthen refractory brick (for lining industrial furnaces), and in surface coatings, such as pipe-coating enamels and black varnishes used as protective coatings for industrial steelwork and as antifouling paints for boats. It is also used as a component in the manufacture of activated C, C refractory for blast furnace lining and tap-hole clays. Hard pitch is used as a binder for foundry cores. It is also used to produce pitch coke, which is used as the C component of electrodes, carbon brushes, and carbon and graphite articles.
Coal tar pitch is an industrial product which is typically dispatched in bulk to customers as either a liquid or a solid. It is often supplied to customers via rail in either tanker cars (liquid pitch) or hopper cars (solid pitch).
|COAL TAR PITCH||DESCRIPTION|
|Aluminium Grade Binder Coal Tar Pitch (Both Liquid and Solid)||It is unique in its properties to act as an improved Binder having excellent Compatibility with carbonaceous aggregrates of different origin & nature to provide superior grades of electrodes either in situ or in Soderberg type. This product helps to impart technical properties and produce top class anode quality. The Binder is used besides the Aluminium industries also in Refractory, Foundry Chemicals and selected pigment manufacture.|
|Graphite Grade Binder Coal Tar Pitch||Improved chemical compatibility between carbonaceosaggregrate (CPC) and the pitch - it is possible to manufacture long durable and best performing graphite electrodes. Mnufactured electrodes can be used in high capacity electric arc furnaces in hassel free operation.|
|Impregnated Coal Tar Pitch||Carbon and graphite electrodes are finally impregnated with special types of pitch to increase strength and density. Impregnation pitch or Zero QI pitch is used for smooth penetration in micro pores of electrodes for decreasing porosity and to increase strength & electrical conductance, resulting in more durable and best performing graphite electrodes. This zero QI Pitch also has applications in Defence.|
|MesophaseCoal Tar Pitch||Mesophase pitch is being synthesised from pure coal tar. Mesophase pitch is used to make high technology products, such as carbon fibres, binders for|
|Refractory Grade Coal Tar Pitch||This pitch is used in manufacture of manufacturing carbon bricks mixture, tap hole mass, ramming mass, sealing fluids. It helps to impart technical properties and is of top quality.|
|Ultramarine Blue||This type of pitch is used as reducing agent as well as a heat source in the manufacture of ultramarine blue.|
|Coal Tar Pitch for Industrial Crucible and Blocks||This product is used in manufacturing of industrial silicon carbide blocks, crucible and as a binder for casted material.|
|Pitch Creosote Mixture||The main ingredients are superior grade binder pitch processed from coal tar generated in high temperature|
|Dehydrated Coal Tar||temperature carbonisation of bituminous coal. The selected quality of binder pitch is then cut back by mixing with specific type and ratio of coal tar oil/solvents to achieve the specific properties required for downstream application as defined below. It is not merely half cooked coal tar that is generally marketed as ordinary dehydrated coal tar.|
|COAL TAR PITCH IN LIQUID FORM||DESCRIPTION|
|CODE NO||TYPE||APPLICATION & USES BY DOWNSTREAM INDUSTRIES|
|BC- CTP - 01||Refractory Binder||Resinous binder for taphole clay, mudgun mass & ramming mass manufacture|
|BC- CTP - 02||Special Refractory Binder||Low viscous tar is used for making refractory composite.|
|BC- CTP - 03||Coal Tar for Special Grade Refractory Mass Formulation||Special tar formulation used for refractory clay making in high dimension furnace|
|BC- CTP - 04||Special Coal Tar Formulation for Construction Compounds||Used by the construction chemical manufacturers for insulation & expansion joint fillers and waterproofing etc.|
|BC- CTP - 05||Coal Tar compound for Refractory & Construction Chemical products manufacturing||Used by refractory products manufacturers. Also used by paint industries for industrial paints manufacturers. Extensivly used for anti corrossive insulation for under earth/water structures and metallic & non-metallic structures and cables.|
|BC- CTP - 06||Solvent mixed Coal Tar formulation having consistency of Paint and polymers||Extensively used by paint industries and also by coating and insulating sheet manufacturers.|
|BC- CTP - 07||Coal Tar & aromatic solvant mix having paint consistency||It is a solvent based coal tar have the consistency of paint. Used by paint manufacturers & as a good insulating paint.|
|BC- CTP - 08||Coal Tar formulation for Refractory & Foundry Chemicals||Used by Refractory & foundry Chemicals manufacturers|
|BC-CTP - 09||Coal Tar formulation for Refractory & Foundry Chemicals||Used by Refractory & foundry Chemicals manufacturers|
|BC-CTP - 09||A Special Coal Tar Formulation||Used by Carbon & Graphite manufacturers|
|BC-CTP - 10||Coal Tar Coating manufacturing base product||Used in coal tar based insulating and anti corrosive coating manufacturing purpose.|