Cement production

Cement production industry of construction materials.
The main prefabricated cement - clinker (included with most cements); raw material for clinker is limestone or chalk and clay. Additives introduced into the feed mixture, determine the grade of cement and contain up to 40% and above free silicon dioxide. Cement clinker get wet and dry.
The main adverse factors in cement production: air dustiness, sharp fluctuations of air temperature and significant thermal radiation, noise. Leading harmful factor is the dust, consisting of cement clinker, additives, ready cement and coal (see Dust).
At non-observance of rules of industrial hygiene at work cement production can cause diseases of the respiratory system: hypertrophic and atrophic changes of the mucous membrane of the nose, pharynx and larynx, pneumoconiosis (see); diseases of the skin, gastrointestinal tract and peripheral nervous system.
Workers in the production of Portland pozzolan and acid cement pneumoconiosis can occur through 7-9 years; they usually are difficult and often combined with tuberculosis. The workers involved in the manufacture of Portland cement and slag Portland cement, pneumoconiosis develop slowly, found with experience of more than 10-15 years and, as a rule, flow benign. Pneumoconiosis can be detected also working at the mill, transport and packaging, at least - furnace shops. Prevention and early detection of pneumoconiosis provides for medical examinations of workers (pre-employment and periodic).
In purposes of improvement of labour conditions cement production requires maximum elimination of manual labor, mechanization and automation of production, transportation and processing of raw materials, insulation dusty processes, shelter and transportation devices, sealing equipment, exhaust ventilation.
Means of individual protection from dust can be respirator (see)that you want to use in operations with high dust levels.

Cement production industry of construction materials. In the USSR cement production is concentrated mainly on large-scale highly plants. There are two ways of cement production: wet (most common in the USSR) and dry.
The main occupational hazards in cement production are dust, adverse weather conditions and noise.
Dust cement production consists mainly of particles sized up to 4 microns and contain SiO2 (20%to 80%), CaO, Al2O5, Fe2O3, traces of compounds Mn and hexavalent Chromium.
SiO2 is found in the associated and free state; free SiO2 is contained in the dust factories producing acid resistant and putstsolanovyj portlandtsement.
Workers are occupied by quarries and on separate sites of raw materials and transport packaging workshops, crane operators, to be affected by a sudden change of temperature, humidity and movement of air. In summer, these workers are not excluded the possibility of significant overheating of the body. In the furnace shops heat from the heated to 250-300 degree buildings furnaces comes to production facilities, air temperature in warm and transitional periods of the year at the stove reaches 50 degrees with relative humidity 35-77%. In the cold period of the year the temperature at the workplace in the furnace plants does not exceed 14-24° at a relative humidity of 30 to 60% .
In difficult conditions are lining works at hot furnace repair - air temperature inside the furnace reaches 40-80 degrees. The intensity of the thermal radiation at the workplace in the furnace plants varies from 0.5 to 5 cal·cm2/min. In mill shops in warm time of the year when grinding hot clinker temperature reaches 30 degrees and above.
Machinists crushers, raw and cement mills and their assistants are under the constant influence of the noise intensity 94-125 dB with the prevalence of medium and high frequencies (A. P. Filin). Diseases of nasal cavity, as well as dermatitis, erosion, ulcer at the cement plants are rare. Marked only hypertrophic and atrophic changes of the mucous membrane of the nose, pharynx and larynx.
Pneumoconiosis (see) among the workers of factories, manufacturing Portland cement and slag Portland cement, is found in the experience of 10 to 20 years and above, slow, benign. Among the workers involved in the production of Portland pozzolan and acid-proof cement, pneumoconiosis often develops mainly in the experience of 5-9 years, and may be combined with tuberculosis. Pneumoconiosis is seen in the working of the mill, and transport and packaging workshops and much less workers furnace shops.
To prevent the emission of dust into the workspace careful shelter covers technological equipment and aspiration of contaminated air from under a cover. Before release to the atmosphere of the aspirated air must be two-stage treatment in cyclones in conjunction with bag filters of heat-resistant fabric or electrostatic precipitators. Replacement of mechanical transport of dry dusty materials pneumatic transport with the right of its use eliminates the emission of dust from the transported material.
When a wet way of manufacture of cement for cleaning the exhaust from rotary kilns gases appropriate to apply battery cyclones and electrostatic precipitators. In the dry method for furnaces should be made dust precipitation chamber with the subsequent passage of gases through the cooling scrubber and two - or three electrostatic precipitator.
Cleaning dust settling on the equipment, floors and walls of the shop premises should be done with the help of pneumatic devices.
For individual protection of respiratory organs against dust used respirators (see)that should be used when running short of technological operations in dusty conditions.
Removal of excess heat is provided by aeration buildings furnace shops. For protection against radiation sources used screens, panels made of insulating material. Opportunities for the improvement of working conditions in cement production opened in connection with the introduction of remote control mechanisms and process automation. With the purpose of early diagnosis of pneumoconiosis and timely transfer of cases to work out of contact with the dust workers kiln, mill, and transport and packaging workshops should undergo periodic medical examinations.