First, the glass production process
Glass production is divided into raw material preparation, melting, forming, annealing and other processes. The abundant raw material for glass production is quartz sand or natural sand containing a large amount of silica, accounting for 60%~70% of the ingredients, and the rest are soda, limestone, feldspar, and rhombohedron containing Na2O, CaO, Al2O3, MgO. Magnesite. There are also auxiliary materials such as fluorite, borax, boric acid, and boehmite.
The melting of the glass takes place in the furnace. There are two main types of melting furnaces: one is a kiln, and the glass is contained in the crucible and heated outside the crucible. The other is a pool kiln in which the frit is melted and the open flame is heated on the upper side of the glass. The melting temperature of the glass is mostly between 1300 ° C and 1600 ° C. Most of them are heated by flames, and a small amount is heated by electric current, which is called electric melting furnace. Molding must be carried out within a certain temperature range. This is a cooling process. The molding method can be divided into two categories: manual molding and mechanical molding. Because of the labor intensity of artificial molding, high temperature and poor conditions, most of them have been replaced by mechanical molding. In addition to pressing, blowing, and drawing, mechanical molding has a calendering method, a casting method, a centrifugal casting method, a sintering method, and the like. Glass products must be annealed after forming. It is to keep warm or slowly cool for a certain period of time to eliminate or reduce the thermal stress in the glass to reach the allowable value.
In addition, some glass products can be rigidified in order to increase their strength. Including: physical rigidification (quenching), for thicker glass, tabletop glass, car windshield, etc.: and chemical rigidification (ion exchange), for watch glass, aviation glass, etc. The principle of stiffening is to generate compressive stress on the surface layer of the glass to increase its strength.
Second, the identification of major occupational hazards in glass production
Occupational diseases caused by glass production mainly include dust, high temperature, heat radiation and toxic substances.
1. high temperature and heat radiation
In the melting and forming workshop, the amount of heat and heat radiation is scattered from the melting furnace and the molten glass to the workshop. It is a typical high-temperature and strong radiation working place, and high temperature and heat radiation exist in the processes of melting, forming and annealing. The temperature of the glass furnace reaches 1560 ° C ~ 1580 ° C, and the surface temperature of the furnace is between 150 ° C and 395 ° C. The molten glass temperature is from 1080 ° C to 1290 ° C. In the production of flat glass, the surface temperature of the machine casing with vertical glass is above 150 °C; the surface temperature of the intermediate platform is 113 °C ~ 120 °C; the glass automatic machine can be heated to 350 °C ~ 400 °C; the temperature of the product during production Up to 450 ° C; the finished product temperature for annealing is 350 ° C ~ 400 ° C. In addition, the floor and walls of the workshop can be heated up to 60 °C due to the heating of temperature and heat radiation. In summer, some glass factories in southern China have been investigated with mechanical operation on or without groove: the temperature is between 40 °C and 50 °C, and the highest is above 70 °C; the thermal radiation intensity is 2.09J to 12.55J (cm2). .min). 6.5% to 30% of the operator’s working time is under high temperature and strong heat radiation conditions. At present, the slicing, cutting and trimming processes of most flat glass have been mechanized. However, in some factories producing window glass, the cutting process is still manual. In addition, the automatic operation of the ware glass and its assistants and the work place of the feeder are still in a high temperature environment. Because the art glass products are small in size, the heat radiation in the workshop is smaller than that in the flat or window glass workshop. The arrangement, the shape, the blower, the repair, the porter, etc. are different according to the distance of the operation site from the furnace. The degree of damage from thermal radiation also varies. Among them, the blower is strongly affected by heat radiation, and the radiation degree can reach 12.55J/(cm2.min), which is prone to heat stroke and the incidence of work injury increases accordingly. The molten glass can emit infrared rays. Under the long-term repeated action of infrared rays, there may be occupational cataracts, commonly known as masonry cataracts.
Due to a large amount of dust generated during the crushing, screening, transportation and batching of raw materials, workers may cause silicosis due to long-term inhalation of high concentrations of dust.
3. Lead poisoning
Lead glass for the production of protective rays, as well as some optical glass, crystal glass, artificial gemstones, etc., often added lead dan and other substances in the raw materials, so it can be contacted in the ingredients, mixing and melting process of such glass production. Lead poisoning may occur due to lead oxide dust and lead oxide vapor during prolonged contact. In order to eliminate bubbles, stones and streaks in the molten glass and improve the quality of the glass, it is necessary to add a clarifying agent, commonly used as AS2O3 (arsenic); in recent years, calcium fluoride and cryolite (Na3AIF6) have been used as accelerators for long-term exposure to the above-mentioned poisons. There is a possibility of causing corresponding poisoning. The thermos bottle, bulb, etc. are sealed with a gas lamp during production, and can be exposed to carbon monoxide. In addition, a small amount of auxiliary materials or coloring agents, such as nickel hydroxide, cadmium sulfide, etc., are used in the production of glass, and cadmium and nickel vapor which escape during the heating process may have harmful effects on human beings.
Compressed air is often used in automatic or mechanical glass bottles, so the airflow noise of compressed air is often the main source of noise in glass bottles. The noise property is steady-state continuous noise; the sound pressure level can reach 86~95dB(A), which is high frequency noise. Working in a high-noise environment for a long time can cause damage to the auditory organs and damage the systemic nervous system and cardiovascular system.
In addition, stab wounds, cuts, burns, etc. of the feet and hands are also more common.
Third, occupational disease hazard control measures
The fundamental way to prevent occupational hazards is to automate production from raw materials, melting to forming, keeping operators away from dust and heat.
1. Dust-proof measures in the raw material workshop
(1) Sealing the pulverizing, sieving, transportation, and batching equipment, and installing a local suction-type ventilation device to control the flying field of the dust.
(2) The wet operation, wet pulverization, and wet method can significantly reduce the occurrence of dust.
2. Heat treatment and cooling measures in the melting workshop
(1) Insulate the heat source to wrap the furnace body with insulation material to reduce heat dissipation to the workshop.
(2) Strengthen overall ventilation and promote organized natural ventilation.
(3) Partial ventilation should be provided at the working sites of artificial glass blowers, flat glass workers, such as cutting, guiding, and trimming.
3. mechanical equipment anti-noise, vibration
(1) Equipment that generates noise and vibration, do a good foundation for anti-vibration and add anti-vibration pads.
(2) Separate the noise-generating equipment separately to prevent noise from propagating into the work area.
4. Strengthen the protection of individual occupational hazards
For workers exposed to infrared radiation, wear protective goggles when handling.
Working in a hand-blown glass bottle factory, the main protection object is high-temperature protection, and the generation of particulate matter, hard object impact and other injuries.
Personal protective equipment recommended is:
For hand protection gloves, you can learn from Everprogloves, which is a safety glove supplier in China.
1. Eye protection: Before the operation, when the material is inspected, the substance may splash into the eyes, and protective glasses or goggles should be worn. Common brands of goggles are 3M, Honeywell, UVEX, etc.
2. Hand protection: Wear suitable high-temperature resistant gloves to protect your hands from high temperatures. High-temperature gloves can choose Kevlar high-temperature gloves, and some brands include DuPont high-temperature gloves and Honeywell high-temperature gloves.
3. Respiratory protection: When the temperature is high, the solution will emit some toxic and harmful gases such as heavy metal vapor. In order to protect the respiratory tract of workers from toxic substances, it is recommended that operators must wear respirators or gas masks, and at the same time have good ventilation.
4. Head protection: If conditions require, you can wear a helmet to protect your head from the risk of hard objects.
5. Body protection: If you are in contact with high-temperature work, you must wear high-temperature insulation clothing or high-temperature apron to ensure the possibility of burns. The high-temperature insulation clothing market has more conventional Ba Gu high-temperature insulation clothing, Delta high-temperature insulation clothing and Lakeland high-temperature insulation clothing.
6. Foot protection: Safety shoes with anti-smashing and anti-scalding should be worn during work. Such as Honeywell safety shoes.