BRICK AND CERAMIC PRODUCTION — production on production of a brick, ceramic tile, drain tubes, art ceramics, etc.
Basic processes of production of stonewares are production, preparation of raw materials, ceramic masses, molding, drying, roasting of semi-finished products of products. As raw materials in To - k.p serve clays and additives to them — ceramic waste, ashes, slag. Clay consists of kaolinite (Al 2 O 3 • 2SiO 2 • 2H 2 O) and various impurity in the form of quartz sand, feldspar, iron, etc. Extraction of clay is made in pits by excavators, bulldozers and other mechanisms. Processing of clay is carried out in crushing and grinding units, mechanical and automatic dosers and mixers. Waste of ceramics crushes in jaw breakers, spherical mills, sifts and mixes with crude clay. Molding of products is made on pressa in a plastic or dry condition of raw stock. Drying is made in compartment or tunnel driers. For giving to ceramics of water repellency of a product are glazed. Quartz sand, minium, yellow lead are a part of glaze. Leadless glaze contains compounds of boron or strontium, zirconium with stannic oxide. Roasting is made in furnaces at t ° 900 — 1000 °.
The silicate brick is produced from quartz sand and the burned lime. The main productions (crushing, roasting and a grinding of limestone, mixing of lime with sand, clearing of mix) are mechanized and are in many respects similar to ceramic production.
Working conditions in To. - to. items during the processing of raw materials, molding of products dry pressing and drying are not always favorable: processing can be followed by air pollution dust, carbon monoxide, sulfur dioxide gas, an average and high-frequency noise. Processes of loading and unloading of products are not always completely mechanized that demands use at separate operations physical. efforts. During the roasting of semi-finished products high temperature of air, infrared radiation, sharp fluctuations of a microclimate, air pollution by dust and combustion products takes place. At glass glazing of products air can become soiled lead.
The most adverse factor of working conditions is dust (see). Limy and quartz dust contains 25 — 30% of crystal silicon dioxide, in dust of clay — 60 — 70% of the general and 1 — 20% of crystal silicon dioxide. Dust is characterized by high dispersion: 40 — 70% of dust particles have diameter to 2 microns. Maximum allowable concentration of the dust containing from 2 to 10% of crystal silicon dioxide — 4 mg/m 3 , raise dust clays — 6 mg/m 3 .
At non-compliance with safety regulationss, long influence dust of quartz can cause development pneumoconiosis (see), silicosis (see), and dust of clay — silikatoza (see). Limy dust can render irritant action on mucous membranes of upper airways and skin. Diseases of a musculoskeletal system from physical are possible. overstrain. During the use of the lead containing glazes lead intoxication is possible (see. Lead )
Preventive actions on To. - to. items are directed to mechanization, automation, distance steering tekhnol. processes; sealing tekhnol. equipment, reduction of intermediate nodes and height peresypok, movements of materials across; the blocking of bunkers for dry materials excluding a possibility of their full emptying; aspiration from under shelters of places of release of dust; pneumatic cleaning of rooms; use of individual protection equipment. For noise control of a crusher and spherical mills cover with the soundproofing casings. A radical action for improvement of working conditions on sites of roasting is transition from ring furnaces to tunnel. For normalization of a microclimate carry out cooling of the arches of furnaces by input of a sprayed water to a zone of cooling, an air dushirovaniye in a working zone; observance of the rational drinking mode is shown.
At employment in To. - to. items are necessary preliminary, and in the course of work periodic medical examinations. The main contraindications to work at contact with dust — diseases of a respiratory organs, cardiovascular system; at contact with lead — diseases of blood, a liver, kidneys. Persons at whom occupational diseases are revealed shall pass after treatment to other work.
Bibliography: Petrova A. N. and Gosin N. N. Improvement of working conditions in the industry of construction ceramics, M., 1969, bibliogr.; Retnev B. M. Occupational health of workers at brick-works, M., 1965, bibliogr.; about N e, Occupational health in construction production, M., 1977, bibliogr.
L. I. Maximova.