Classification of hazardous chemicals
109 chemical elements form about 600,000 kinds of chemicals through different combinations, which can be divided into non-toxic and harmless edible chemicals, general chemicals and dangerous chemicals, among which about 30,000 kinds of dangerous chemicals have obvious or potential dangers.
Dangerous chemicals refer to highly toxic chemicals and other chemicals that are toxic, corrosive, explosive, combustible and combustion-supporting, and harmful to human body, facilities and environment.
Hazardous chemicals are classified into the following eight categories according to their hazardous characteristics.
The first category, explosives; Under the external action (such as heat, pressure, collision, etc.). ), a violent chemical reaction can occur, and a large amount of gas and heat can be generated instantly, so that the surrounding pressure rises sharply and an explosion occurs, causing damage to the surrounding environment;
The second category, compressed gas and liquefied gas; Refers to compressed, liquefied or pressure dissolved gas;
The third category, flammable liquids; Refers to flammable liquids, liquid mixtures or liquids containing solid substances;
The fourth category, flammable solids, spontaneous combustion items and flammable items when wet; Refers to solid substances with low ignition point, sensitive to heat, impact and friction, easily ignited by external fire sources, burning rapidly, and possibly releasing toxic smoke or gas;
The fifth category, oxidants and organic peroxides; Refers to a substance that is in a high oxidation state, strong in oxidation, easy to decompose and gives off oxygen and heat;
The sixth category, there are drugs; Refers to articles that accumulate to a certain amount after entering the body, and can have biochemical or biophysical reactions with body fluids and organs and tissues, disturb or destroy the normal physiological functions of the body, cause temporary or permanent pathological changes in some organs and systems, and even endanger life;
The seventh category, radioactive substances; Articles with radioactivity greater than 7.4x 104Bq/Kg;
Eighth category, corrosive products; Refers to a solid or liquid that can burn human tissues and cause damage to metals and other objects.
Requirements for safe storage of dangerous goods
According to the national standard General Rules for the Storage of Common Hazardous Chemicals, the basic requirements for the safe storage of hazardous chemicals are:
(1) Storage of hazardous chemicals must comply with national laws, regulations and other relevant provisions.
(2) Hazardous chemicals must be stored in a special hazardous chemicals warehouse approved by the public security department, and the storage quantity and quantity of hazardous chemicals in the warehouse managed by the distribution department must be approved by the public security department. Without approval, hazardous chemicals storage warehouses shall not be set up at will.
(3) Hazardous chemicals piled up in the open air shall meet the safety requirements of fire prevention and explosion prevention. Explosives, first-class flammable substances, flammable substances when wet and highly toxic substances shall not be piled up in the open air.
(4) The warehouses storing hazardous chemicals must be equipped with technicians with professional knowledge, and their warehouses and places should be managed by special personnel, and the managers must be equipped with reliable personal safety protection articles.
(5) The stored hazardous chemicals shall be clearly marked and shall comply with the provisions of GB 190. When two or more dangerous goods with different grades are stored in the same area, the performance mark of the highest grade dangerous goods should be hung.
(6) There are three storage methods for hazardous chemicals: isolated storage, isolated storage and separate storage.
(7) According to the performance of hazardous chemicals, hazardous chemicals shall be partitioned, classified and stored in warehouses. All kinds of dangerous goods shall not be mixed with taboo materials for storage.
(8) Smoking and open flames are strictly prohibited in the building area where hazardous chemicals are stored.
Enterprises that produce, process and sell chemicals must understand and master all safety information and precautions related to use, storage and disposal, and train and educate employees.
Enterprises producing dangerous chemicals shall establish and improve the main person in charge, the person in charge, the safety production personnel, the functional departments and the post safety production responsibility system.
Enterprises producing dangerous chemicals shall formulate safety education and training, labor protection articles (tools), health care articles, employees' safety facilities and equipment, fire prevention, anti-virus, explosion prevention and occupational health, safety inspection, hidden dangers rectification, accident investigation and handling, safety production rewards and punishments and other rules and regulations.
Enterprises producing dangerous chemicals should formulate post operation safety regulations (safe operation law) and operation safety regulations that meet relevant standards according to the characteristics of sanitary technology, process and equipment of dangerous chemicals and the dangers of raw materials, auxiliary materials and products.
Enterprises producing dangerous chemicals shall be equipped with full-time safety production management personnel. The knowledge and management ability of production safety of the main person in charge and the management personnel of production safety of dangerous chemicals production enterprises shall pass the examination. Special operations personnel shall pass the examination of the relevant competent departments and obtain the qualification certificate for special operations.
Characteristics of commonly used dangerous chemicals
strong acid
1 hydrochloric acid
Hydrochloric acid is an aqueous solution of hydrogen chloride gas. Commonly used hydrochloric acid contains about 35% hydrogen chloride, and its density is 1. 19g/cm. Pure concentrated hydrochloric acid is a colorless and transparent liquid with irritating smell. Industrial concentrated hydrochloric acid is often yellow because of impurities. Concentrated hydrochloric acid will produce white fog in the air, because the hydrogen chloride gas volatilized from hydrochloric acid contacts with water vapor in the air to form small droplets of hydrochloric acid. Hydrochloric acid is very acidic and corrosive.
2. Sulfuric acid
Pure concentrated sulfuric acid is a colorless viscous oily liquid, which is not volatile. The concentration of commonly used concentrated sulfuric acid is 98% and the density is 1.84 g/cm 3. Concentrated sulfuric acid has strong water absorption and can absorb moisture in the air when it comes into contact with air, so it is often used as a desiccant for some gases. Concentrated sulfuric acid can also take away water from paper, wood, clothes and skin (all carbohydrates) and carbonize them. Therefore, sulfuric acid is very corrosive to skin and clothes. If sulfuric acid accidentally gets on your skin or clothes, wipe it off with a cloth immediately, and then rinse it with plenty of water.
Sulfuric acid is soluble in water, and at the same time, it releases a lot of heat, so when we prepare sulfuric acid solution, the temperature of the solution will rise very high. If water is poured into concentrated sulfuric acid, the density of water is less than that of sulfuric acid, and it will float on sulfuric acid. When it is dissolved, a large amount of heat will make water boil immediately, causing sulfuric acid droplets to splash around. In order to prevent accidents, when diluting concentrated sulfuric acid, it is necessary to slowly inject concentrated sulfuric acid into water along the wall of the device, and constantly stir it to make the generated heat spread rapidly. Never add water directly into concentrated sulfuric acid.
3. Nitric acid
Pure nitric acid is a colorless liquid with a pungent smell. The concentration of common concentrated nitric acid is 68% and the density is 1.4g/cm3. Similar to hydrochloric acid, HNO3 _ 3 gas can also volatilize in the air and combine with water vapor in the air to form nitric acid droplets and form white fog. Nitric acid can also strongly corrode skin and clothes, so be careful when using nitric acid.
alkali
1, sodium hydroxide
Pure sodium hydroxide is a white solid, which is easily soluble in water and releases a lot of heat when dissolved. The aqueous solution of sodium hydroxide has astringency and satiny, and sodium hydroxide exposed to the air easily absorbs water vapor and deliquesces. Therefore, sodium hydroxide can be used as a desiccant for some gases. Sodium hydroxide is very corrosive, so it is also called caustic soda, caustic soda or caustic soda. Care must be taken when using sodium hydroxide to prevent direct contact between skin and clothes.
2. Ammonia water
Pure ammonia water is a colorless liquid, and industrial products are pale yellow because of impurities. The concentration of ordinary ammonia water is generally 20-25% for industrial grade and 28-30% for reagent grade. Ammonia is easily decomposed and volatilized, releasing ammonia. Ammonia is a very irritating gas. High concentration, high temperature, rapid decomposition and volatilization of ammonia. Ammonia is corrosive to many metals. Therefore, when transporting and storing ammonia, corrosion-resistant containers are generally used, such as rubber barrels, ceramic cans or iron barrels coated with asphalt.
Strong oxidant
Commonly used strong oxidants are hydrogen peroxide (hydrogen peroxide), potassium permanganate, persulfate, etc. These strong oxidants are very corrosive to the skin, and the smell is irritating, so you must wear protective equipment when using them. At the same time, most strong oxidants are flammable, so attention should be paid to stay away from fire sources when using and storing.
organic solvent
1. Organic solvents are mostly toxic substances. Common organic solvents are Aston, clean washing water, waterproof white water, boiling water, acetone, isopropanol and so on. Strong volatility, pungent smell, skin contact or respiratory inhalation may cause allergies and even poisoning.
2. Organic solvents are flammable and should be stored at low temperature at ordinary times, and should not be close to fire sources or high temperature areas.
Principles of Safe Use of Hazardous Chemicals
1, labor insurance supplies; Labor protection articles are mainly used to protect people's eyes, respiratory tract and skin from direct harm by harmful substances. Commonly used labor protection articles include: acid and alkali resistant rubber gloves, acid and alkali resistant rubber shoes, goggles, masks, rubber aprons, dust masks, gas masks, etc.
2. When using chemicals with strong corrosiveness and strong oxidation, you must wear acid-resistant rubber gloves, acid-resistant rubber shoes, goggles, masks, rubber aprons and other labor protection articles. When pouring medicine, don't point the mouth of the container at yourself and others.
3. When using volatile, irritating and toxic chemicals, you must wear acid and alkali resistant rubber gloves and gas masks, and open doors and windows to make the site well ventilated.
4. When using any chemical substance of unknown nature, you can't take it directly with your hands, smell it directly with your nose and taste it with your mouth.
5. During storage, acid and alkali should be separated, substances with strong redox properties should be separated, and flammable substances should be kept away from fire sources and heat sources. When handling chemicals, it is necessary to check whether the transport vehicles are in good condition, liquid chemicals must be placed in a single layer, and workers must wear labor protection articles such as acid alkali resistant gloves, apron and acid-resistant rubber shoes.
6, in the process of use, if found dizziness, fatigue, difficulty breathing and other symptoms, indicating that there may be poisoning, should immediately leave the scene to a ventilated place, if necessary, sent to the hospital for treatment.
On-site treatment of chemical dangerous burns
Hazardous chemicals are flammable, explosive, corrosive and toxic, and accidents are prone to occur during production, storage, transportation and use. Because of heat, chemical stimulation or corrosion, skin and eyes are burned, and some chemicals can be absorbed from the wound, even causing systemic poisoning, so chemical burns should be paid more attention than boiling water burns or flame burns.
1, on-site treatment of chemical skin burns
Leave the scene immediately and take off the clothes contaminated by chemicals quickly; Regardless of acid, alkali or other chemical burns, immediately wash the wound with a large amount of running tap water or clean water 15-30 minutes; Don't apply ointment or mercurochrome or purple water to fresh wounds at will, and don't wrap them with dirty cloth.
2. On-site treatment of chemical eye burns
Rinse quickly with running water at the scene, and don't rush to the hospital without rinsing; When washing, your eyelids must be opened. If there is no washing equipment, you can also immerse your head in clean basin water, open your eyelids and turn your eyes back and forth for washing. When quicklime and caustic soda particles splash into eyes, they should be removed with cotton swabs first, and then washed with water.