Briquetting

BRIQUETTING (from English brick), the production of briquettes, i.e., coal or ore fines or peat pressed into lumps. Of greatest importance both in industrial and sanitary-hygienic respects is the briquetting of hard coal. The production process, the essence of which consists in mechanically mixing coal fines with a binding substance—resin and pitch—and pressing the mixture, begins with the preliminary processing of the material. The coal is subjected to sorting and washing, then crushing in disintegrators. Resin and pitch are first broken manually with crowbars, then crushed and ground in crushers, disintegrators, or edge-runner mills. The crushed materials in certain proportions are mechanically fed into mixing apparatuses, whence, after thorough mixing, they proceed via conveyors into special mixer apparatuses, in which the mixture is fused and brought into a plastic state using superheated steam. From the mixers, the mixture is fed by a conveyor to briquette presses, whence finished briquettes of a definite size and shape emerge. After drying in drying ovens for 1.5 to 2 hours, the briquettes are transported on carts and stacked in piles. Briquetting is predominantly a dusty production. Along with coal dust, which is released in large quantities, especially characteristic of briquetting is resin and pitch dust, to the harmful effects of which workers are exposed during all processes associated both with the preliminary processing of the binder and with the mixing of the mass and the transport of dry briquettes. In those rooms where the heating and melting of the mass take place, vapors containing, along with fresh tar particles, caustic gases—benzene, ammonia, sulfur—are added to the dust. Pitch and resin dust, especially in combination with caustic gases, possessing a very strong irritating effect, causes a number of skin diseases typical of briquetting, including the skin cancer of briquette workers (first described by Zweig in 1909). Among briquette workers, the following are fairly common: "tar skin," which, according to Oppenheim, is characterized by a brown coloration of uncovered parts of the body (resin impregnation) and increased pigmentation, comedones (due to the clogging of the excretory ducts of the sebaceous glands by resinous substances and dust); hyperkeratotic processes—tar folliculitis and acne (Bliashko); tar itch eruption (Teerkratze); erythematous nodules; pustular eruptions; eczemas. These and similar skin lesions, especially comedones and warts, often (predominantly in workers with long service) lead to the formation of the so-called "briquette cancer," localized most frequently on the face. — Preventive measures. Along with strict observance of general sanitary rules for the arrangement and maintenance of work premises—maximum mechanization of production processes, sealing of equipment, local extraction of dust and vapors, rational general ventilation. Personal hygiene measures—rational special clothing, strict observance of cleanliness and tidiness by workers (showers, baths, frequent changes of underwear and clothing). Great benefit is derived from daily lubrication of exposed parts of the body with ointments, as well as with a thin slurry of clay (Lehmann). Timely removal of hyperkeratoses and warts.