metallurgy, occupational health

From Big Medical Encyclopedia

METALLURGY — the area of the equipment and production occupied with processes of receiving metals of ores and other materials, and also giving to metals and their alloys of a necessary form and properties. Value M. in the national economy is exclusively big — its products are necessary for all industries. It is accepted to divide M. on black and color.

In the past the greatest threat for health of metallurgists was posed hard physical work in the conditions of an adverse microclimate, by high concentration of dust, aerosols of metals and toxic gases. Cases of heavy overheatings of an organism and acute poisonings with carbon monoxide were frequent, the expressed intoxications were observed by metals, including. foundry fever (see).

For years of the Soviet power there was a radical improvement of working conditions of metallurgists due to improvement tekhnol, processes and the equipment, improvement of planning solutions of production buildings, implementation effective a dignity. - tekhn. devices, complex mechanization and automation of heavy works, rationalization of work-rest schedules, use of well-tried remedies of individual protection. Thanks to it in M. cases of fatal poisonings and serious occupational diseases are liquidated.

Scientific and technical progress in M. is followed by further implementation of new high-performance and economic processes with the maximum automation tekhnol, operations (production of metallizovanny iron ore pellets and direct smelting from them became, an extra oven alloying of steel, preferential continuous pouring of steel, release of hire with protective coatings from chrome, aluminum, paints and varnishes and plastic etc.). However, despite mechanization of many labor-intensive processes, in M. manual skills are applied still rather widely. An exercise stress in combination with high temperature of air cause tension of thermal control and funkts, shifts from cardiovascular and respiratory systems. Temperature drops of air together with intensive thermal radiation promote catarrhal diseases. Plentiful sweating leads to temporary, but considerable moisture loss, the strengthened consumption of salts and vitamins. Take place and other production factors, adverse for workers.

Ferrous metallurgy — subsector on production and enrichment of ore, production of ferrous metals (cast iron, steel and ferroalloys) and their roughing-out — receiving hire (see. Rolling production ).

One of the major adverse production factors at black M.'s enterprises is production dust (see), edges it is formed during the crushing, transportation and filling of burdening materials, at repair of metallurgical furnaces, mixers and ladles, during the cleaning of hire on sandpapers, etc. Depending on conditions of dust formation dust is presented by compounds of metals with carbon, quartz and other impurity which are a part of additives (selenium, chrome, nickel, vanadium, beryllium, etc.) - The aerosol of condensation which is formed in the course of melting and pouring of metals is characterized by complex chemical structure. The high degree of dispersion of an aerosol promoting penetration of particles into deep departments of respiratory tracts, and availability of toxicants in it cause the expressed irritating and all-toxic action on an organism, a cut it is aggravated with presence of gases at air of workrooms.

At enrichment of ore on production Wednesday also used reagents, at a stage of roasting and agglomeration — excess of heat and light-end products of burning of fuel or the raw materials can arrive.

Pyrometallurgical (high-temperature) processes of extraction of metals are carried out in furnaces and other melting units, in to-rykh use gaseous, liquid and solid fuel or electrical energy; e.g., in steel-smelting workshops where steel from cast iron and waste of ferrous metals is melted with addition of the alloying materials. Workers on these sites can be exposed to intensive influence of convection heat (see. Hot workshops ) and infrared radiation (see), noise (see), difficult aerosols of condensation and disintegration of metals and connections of the accompanying elements (see. Aerosols ), such gaseous harmful substances, as carbon monoxide (see), sulfur dioxide gas p other. Gross release of carbon monoxide in large metallurgical workshops can reach considerable sizes; in view of intensive dilution at the expense of the volume of rooms and their good airing of concentration of carbon monoxide, as a rule, do not exceed marginal size (20 mg/m 3 ). However on nek-ry sites aglofabrik, domain and steel-smelting workshops during the performance of separate operations the increased concentration of carbon monoxide are possible.

Sulfur dioxide gas is formed as a result of burning out of sulfur of ore, agglomerate and cast iron, and also from the sulfur-containing fuel oil used in fuel quality. Transfer of heating devices from black oil fuel on natural gas led to falloff of concentration of sulfur dioxide gas in a working zone (to the maximum allowable concentration level below).

The powerful heating equipment, the melted and heated metal, slag, agglomerate on the majority of sites of steel works cause the peculiar microclimate which is characterized by intensive infrared radiation in combination with high temperature of air during the warm period of year and cooling of rooms during the cold period. So, on sites of agglomeration of agglomerative factories infrared radiation of working can reach 1000 W/m 2 , and air temperature during the warm period of year to exceed outside on 1 — 5 °.

In domain workshops throughout a shift the microclimate is subject to jumps in connection with periodic production of cast iron and slag, in time to-rogo air temperature raises on 5 — 8 °, infrared radiation reaches 1700 — 3500 W/m 2 . In steel-smelting workshops temperature increase of air happens during pouring of metal, especially in barreling flights and the zone adjoining furnaces where intensity of infrared radiation can reach 2800 W/m 2 .

Nonferrous metallurgy — subsector of the industry on production and processing of non-ferrous metals and their alloys. Along with non-ferrous metals at color M.'s enterprises in passing make also other chemical connections. From ore it is removed apprx. 74 chemical elements. Working conditions in this industry of M. are in many respects similar to working conditions in black M.

Many non-ferrous metals have the expressed toxic properties and contents them in air at the industrial enterprises is regulated by GOST No. 12.1.005 — 76 «SSBT. Air of a working zone. The general sanitary and hygienic requirements» in the form of maximum allowable concentration. Nek-ry non-ferrous metals and their connections, napr, cadmium, nickel, chrome, arsenic, having cancerogenic properties, at impact on an organism of working can cause the remote effects that is considered at their rationing.

Content of non-ferrous and rare metals in ores is very insignificant that causes the necessity of processing at the mining and processing enterprises of huge amounts of ore.

Benefication is carried out by hl. obr. by a floatation method with use of various reagents, a part to-rykh or products of their decomposition can cause intoxications.

The production environment of the enterprises of color M., in addition to aerosols of metals and their connections, can become soiled some other the harmful substances which are emitted from the used raw materials or at the expense of applied in tekhnol, process of additives. Heat treatment of sulfide ores and concentrates is followed by allocation of a large amount of sulphurous anhydride, ground mass to-rogo is used for production by a chamois to - you or elemental sulfur. At hydrometallurgical methods of receiving non-ferrous metals the used reagents and components tekhnol, solutions can be a source in air of a working zone of harmful substances and pollution of integuments. In aluminum production (see. Aluminium industry ) the melted cryolite emits fluorides, influence to-rykh can cause professional fluorosis (see).

In gold mining, tin, zinc and other productions of color M. dust of production rooms has complex chemical structure and may contain arsenic (see), lead (see), is lame (see) and other impurity. Electrolysis processes and hydrochemical treatment of non-ferrous metals are followed by allocation of fog sulphuric acid (see), chlorine (see), hydrogen chloride and some other harmful substances.

As for color M. typically simultaneous presence at the production circle of group of harmful substances, during the carrying out a dignity. control it is necessary to consider a possibility of their combined influence.

Prevention of occupational diseases and improvement of working conditions in M. substantially depend on the level of mechanization and automation tekhnol, processes, widespread introduction to-rykh sharply reduces the volume of manual operations, allows to exempt workers from hard work and to bring them out of a zone of influence of heat, harmful gases, noise, vibration etc. For protection against infrared radiation use the developed panels, cabins and rooms of radiation cooling, different types of screens, installation for air conditionings (see).

The main measures of fight against dust — wet drilling using additives of surfactants or dry drilling with a local suction of dusty air and the subsequent its cleaning, hydroirrigation during the dredging, transportation of ore and its crushing by preparation for enrichment, rational ventilation of excavations and workshops of crushing, and also use of individual protection equipment. At extraction of ore workers can be affected also by the gases which are formed during the blasting and due to operation of cars with diesel fuel. For the purpose of prevention of poisonings it is necessary to air development after explosions, to apply special absorbers of exhaust gases of diesels or to replace them with electric motors.

Reduction of concentration of dust is reached also thanks to localization of sources of a pylevydeleniye and the organization effective local exhaust ventilation (see) (the shelter of the razmolno-crushing equipment of agglomerative tapes, conveyors), to moistening of the crushed materials, the maximum reduction of extent of transport communications and numbers of overloads of loose materials on them.

In workshops of flotation and on hydrometallurgical sites improvement of working conditions is reached by implementation of less toxic reagents, automation and distance steering tekhnol, process, uses of the tight equipment, implementation of the closed transportation of solutions and a pulp, hygienic improvement of the equipment (ore and thermal melting instead of mine furnaces, roasting in furnaces of a fluidized bed instead of multihearth furnaces, dehydration by means of vacuum filters and automatic centrifuges of continuous action instead of filter presses etc.), mechanization of heavy works.

In pyrometallurgical workshops big gigabyte. measures for normalization of an industrial microclimate due to restriction of excess heat releases (effective heat insulation of the heated equipment and communications, reduction of an open surface of the melted materials and timely export them from the workshop, etc.), and also use of the means of an industrial heat-shielding from thermal radiation working (shielding, rational placement of jobs and an air dushirovaniye) matter. During the cold period of year in addition use electric and gas infrared radiators for local heating.

According to the existing order of the Minister of Health of the USSR are carried out preliminary at revenues to work and periodic medical examinations of the workers occupied at the metallurgical enterprises. Control of the state of health of workers is exercised in relation to specifics of production (1 times in 12 or 24 months) by the commission of specialists doctors taking into account the established list of contraindications and a lab. researches. A number of privileges is established to the workers of metallurgical productions having harmful working conditions: additional issue and the shortened working hours, the state pension on favorable terms and in preferential sizes, the right for free receiving to lay down. - professional, food, vitamin drugs, etc.

Bibliography Berg I. A. The accident prevention in ferrous metallurgy, M., 1954; Questions of hygiene and professional pathology in nonferrous and ferrous metallurgy, under the editorship of S. V. Miller and M. S. Sadilova, Sverdlovsk, 1971; Kokorev N. P. Occupational health in ferrous metallurgy, M., 1965; Levina E. N. General toxicology of metals, JT., 1972, bibliogr.; Mindlin G. Ya. To the characteristic of operational injuries in nonferrous metallurgy, Zdravookhr. Grew. Federations, No. 10, page 11, 1973; H and in r about c to and y V. K. Occupational health, page 360, M., 1974; The Guides to occupational health, under the editorship of F. G. Krotkov, etc., t. 3, page 192, M., 1961; The Reference book on occupational health, under the editorship of V. D. Karpov and V. E. Kovshilo, L., 1979; Technical progress in ferrous metallurgy of the USSR, under the editorship of L. E. Lukiç, M., 1974.

A. A. Kasparov, A. V. Ilnitskaya, R. A. Kuchersky