Safety measures and correct operation methods in chemical laboratories, safety is very important, which often hides the danger of accidents such as explosion, fire, poisoning, burns, cuts and electric shock. How to prevent these accidents and how to give first aid when they happen are the qualities that every chemical experimenter must have. 1. 1 The safe use of electricity often violates regulations, which may easily lead to serious accidents such as personal injury, fire, equipment damage, etc. There are many electrical appliances used in the physical chemistry laboratory, so special attention should be paid to the safe use of electricity. The following table lists the reaction of 50Hz alternating current passing through human body. In order to ensure personal safety, we must abide by the laboratory safety rules. (1) to prevent electric shock.

1) Don't touch the appliance with wet hands.

2) The exposed part of the power supply should be insulated (for example, the wire connector should be wrapped with insulating tape).

3) The metal shell of all electrical appliances shall be grounded.

4) During the experiment, turn on the circuit before turning on the power supply. At the end of the experiment, cut off the power supply first and then disconnect the circuit.

5) When repairing or installing electrical appliances, cut off the power supply first.

6) Electric probes should not be used to test high voltage electricity. Special protective measures should be taken when using high voltage power supply.

7) If someone gets an electric shock, quickly cut off the power supply and carry out rescue.

(2) Prevent fire.

1) should be consistent with the electricity consumption allowed by the laboratory.

2) The safe electrification capacity of wires should be greater than the power consumption. 3) If there are flammable and explosive gases such as hydrogen and gas indoors, sparks should be avoided. When the relay switches, it is easy to generate sparks, so be careful. When electrical contacts (such as electric plugs) are not in good contact, they should be repaired or replaced in time. 4) When the wire is on fire, immediately cut off the power supply, and use sand or carbon dioxide and carbon tetrachloride fire extinguishers to extinguish the fire. It is forbidden to use water or carbon tetrachloride to extinguish the fire.

(3) to prevent short circuit

1) All contacts in the circuit should be firm, and the connectors at both ends of the circuit elements should not touch each other to prevent short circuit. 2) Wires and electrical appliances should not be immersed in water or conductive liquid, such as bulb joints for heating in the laboratory.

(4) Safe use of electrical instruments 1) Know whether the power supply required by electrical instruments is AC or DC before use; Whether it is three-phase electricity or single-phase electricity and voltage (380V, 220V, 1 10V or 6V). Need to find out whether the power supply meets the requirements and the positive and negative poles of DC appliances.

2) The measuring range of the instrument should be greater than the measured range. If the size to be measured is unknown, the measurement should start from the largest range.

3) Check whether the line connection is correct before the experiment. The teacher can't turn on the power until he checks and agrees.

4) If abnormal sound, local temperature rise or burning smell of insulating paint are found during the use of electrical appliances, the power supply should be cut off immediately and the teacher should be reported for inspection. Chemical safety protection (1.2) antivirus.

Before the experiment, we should know the toxicity and protective measures of the drugs used.

2) Operation of toxic gases (such as H2S, Cl2, Br2, NO2, concentrated hydrochloric acid and HF, etc.). ) should be carried out in a fume hood.

3) Vapors such as benzene, carbon tetrachloride, ether and nitrobenzene can cause poisoning. Although they have a special smell, long-term use will weaken people's sense of smell, so they should be used under the condition of good ventilation.

4) Some drugs (such as benzene, organic solvents, mercury, etc. ) can enter the human body through skin, so contact with skin should be avoided.

5) Highly toxic drugs such as cyanide, high mercury salts (HgCl2, Hg(NO3)2, etc. ), soluble barium salt (BaCl2), heavy metal salt (such as cadmium and lead salt) and arsenic trioxide should be properly kept and used with special care.

6) It is forbidden to drink water and eat in the laboratory. Don't bring tableware into the laboratory to prevent poison pollution. Wash your hands before you leave the lab and eat.

(2) explosion protection

When combustible gas is mixed with air, when the ratio of the two reaches the explosion limit, it will be induced by heat source (such as electric spark), thus causing explosion. See the following table (1)(20 degrees, 1 atmospheric pressure) for the explosion limit of some gases mixed with air.

Upper explosive limit and lower explosive limit of gas explosion.

(Volume%) (Volume%) (Volume%) (Volume%)

Hydrogen 74.2 4.0 acetic acid -4. 1

Ethylene 28.6 2.8 ethyl acetate 1 1.4 2.2

Acetylene 80 2.5 carbon monoxide 74.2 12.5

Benzene 6.8 1.4 water, coal and gas 72 7.0

Ethanol 19.0 3.3 gas 32.0 5.3

Ether 36.5 1.9 ammonia 27.0 15.5

Acetone 12.8 2.6

1) When combustible gas is used, the gas should be prevented from escaping and the room should be well ventilated.

2) When handling a large number of combustible gases, it is forbidden to use open flames at the same time, and prevent electric sparks and other impact sparks. 3) Some drugs, such as aluminum azide, silver acetylide, copper acetylide, perchlorate, peroxide, etc., are easy to explode when impacted and heated, so be careful when using them.

4) It is forbidden to put strong oxidizing agent and strong reducing agent together.

5) Peroxides that may be produced in ether stored for a long time should be removed before use.

6) Explosion-proof measures should be taken for experiments that are easy to cause explosion. (3) Fireproof 1) Ether, acetone, ethanol, benzene and other organic solvents. It is very easy to burn, so there should be no open flame, electric spark or electrostatic discharge indoors when it is used in large quantities. Don't store too much of these drugs in the laboratory, recycle them in time after use, and don't pour them into the sewer to avoid gathering and causing fire.

2) Some substances, such as phosphorus, sodium metal, potassium, calcium carbide, metal hydride, etc., are prone to oxidation and spontaneous combustion in the air. Some metals, such as iron, zinc, aluminum and other powders, have large specific surface area and are easy to oxidize and spontaneously ignite in the air. These substances should be stored in isolation from the air and should be used with special care.

If there is a fire in the laboratory, don't panic and put out the fire according to the situation. Commonly used fire extinguishers are: water, sand, carbon dioxide fire extinguishers, carbon tetrachloride fire extinguishers, foam extinguisher and dry powder fire extinguishers. You can choose to use it according to the cause of fire, as follows.

In several cases, you can't put out a fire with water:

(a) When sodium, potassium, magnesium, aluminum powder, calcium carbide and sodium peroxide catch fire, dry sand should be used to put out the fire.

(b) Flammable liquids lighter than water, such as gasoline, benzene and acetone, can be ignited by foam extinguisher.

(c) Dry sand or dry powder fire extinguishers should be used in case of fire where there are burning metals or melts.

(d) When electrical equipment or live system is on fire, carbon dioxide fire extinguisher or carbon tetrachloride fire extinguisher can be used.

(4) Burn protection

Strong acid, strong alkali, strong oxidant, bromine, phosphorus, sodium, potassium, phenol, glacial acetic acid, etc. It will corrode the skin, especially to prevent it from splashing into the eyes. Low temperature such as liquid oxygen and liquid nitrogen can also seriously burn the skin, so be careful when using it. In case of burns, it should be treated in time. 1.3 The safe use of mercury can be divided into acute and chronic types. Acute poisoning is mostly caused by high mercury salt (for example, at the entrance of HgCl2, 0. 1g ~ 0.3g can cause death. Inhalation of mercury vapor can lead to chronic poisoning, and the symptoms include loss of appetite, nausea, constipation, anemia, bone and joint pain, mental weakness and so on. The maximum safe concentration of mercury vapor is 0.1mg m-3-3, and the saturated vapor pressure of mercury at 20 degrees is 0.00 12mmHg.

(1) Do not expose mercury directly to the air, and the mercury container should be covered with a layer of water.

(2) Shallow porcelain plates should be placed under mercury-containing instruments to prevent mercury drops from scattering on the desktop and ground.

(3) All mercury transfer operations should also be carried out in shallow porcelain plates (filled with water).

(4) Before the experiment, check whether the mercury-containing instrument is firmly placed. The joint of rubber pipe or plastic pipe should be fastened.

(5) Thick-walled glassware or porcelain should be used as containers for storing mercury. Mercury should be temporarily filled in a beaker, not in a container to prevent it from breaking.

(6) If mercury falls on the table or the ground, firstly collect as many mercury beads as possible with a mercury suction tube, and then cover the spilled mercury with sulfur, and generate HgS by friction. It can also be oxidized with KMnO4 solution.

(7) Filter paper or cloth rubbed with mercury or amalgam must be placed in a porcelain jar filled with water.

(8) Mercury containers and mercury-containing instruments should be far away from heat sources, and it is forbidden to put mercury-containing instruments into the oven.

(9) Laboratories that use mercury should have good ventilation equipment, and laboratories that purify mercury should have special facilities.

(10) Do not touch mercury if there is a wound on your hand.

1.4 Use and Precautions of High Pressure Cylinders (1) Color Marking of Gas Cylinders

The common signs of gas cylinders in China are shown in the following table.

Gas category bottle body color label color words

Nitrogen black yellow nitrogen

Oxygen sky blue black oxygen

Deep blue red hydrogen

Compressed air black and white compressed air

Carbon dioxide black yellow carbon dioxide

Helium brown white helium

Liquid ammonia yellow black ammonia

Green grass, green and white chlorine

Acetylene white red acetylene

Chlorofluorocarbons, aluminum, white and black chlorofluorocarbons.

LPG-grayish red LPG

Crude argon black and white crude argon

Pure argon is grayish green. Pure argon (2) uses gas cylinders.

1) Install a matching pressure reducing valve on the cylinder. Turn the pressure adjusting handle counterclockwise until the screw is loose, and check whether the pressure reducing valve is closed.

2) Open the cylinder master valve, and the high-pressure gauge shows the total pressure of the gas stored in the cylinder.

3) Slowly turn the pressure adjusting handle clockwise until the low pressure gauge shows the pressure required for the experiment.

4) When stopping using, close the main valve first, and then close the pressure reducing valve after the residual gas in the pressure reducing valve is exhausted.

(3) Precautions

1) cylinders should be stored in a cool and dry place away from heat sources. Combustible gas cylinders should be stored separately from oxygen cylinders.

2) Handle the cylinder carefully and tighten the cylinder cap.

3) When in use, a pressure reducing valve and a pressure gauge should be installed. The valve screws of combustible gas cylinders (such as H2 and C2H2) are reversely threaded; Non-combustible or combustion-supporting gas cylinders (such as N2 and O2) are positive wires. In general, various pressure gauges cannot be mixed.

4) Don't let oil or flammable organic matter pollute the gas cylinder (especially the gas cylinder outlet and pressure gauge).

5) When opening the main valve, don't point your head or body at the main valve to prevent the valve or pressure gauge from rushing out and hurting people.

6) Don't use up the gas in the gas cylinder, so as to avoid danger when inflating again.

7) The cylinders in use shall be inspected once every three years, and the cylinders containing corrosive gases shall be inspected once every two years. Unqualified gas cylinders can no longer be used.

8) Hydrogen bottles should be placed in a special cabin far away from the laboratory, introduced into the laboratory with copper pipes, and equipped with a device to prevent backfire.

9) The gas in the cylinder can't be completely used up. Leave some gas to prevent the outside air from entering the cylinder. Generally, the residual pressure above 0.5MPa gauge pressure should be maintained.

10) cylinders must be sent for regular inspection before they can be inflated. 1.5 gas operation rules: pure oxygen can be obtained from electrolytic water or liquefied air, compressed and stored in steel cylinders for later use. The pressure of the steel cylinder just filled with oxygen from the gas plant can reach 15MPa, and oxygen pressure gauge is needed to use oxygen.

When using oxygen, the following rules must be observed:

(1) When handling steel cylinders, it is forbidden to load and transport them together with the oxygen meter.

(2) It is forbidden to use hydrogen in the same laboratory.

(3) Keep away from heat sources as far as possible.

(4) When using, pay special attention to the hands, tools, steel cylinders and the surrounding areas. The oil on the wrench can be washed off with alcohol and dried before use to prevent combustion and explosion.

(5) Oxygen cylinders should be used together with oxygen meters, and should be carefully protected. They should not be used on other cylinders casually.

(6) When opening the valve and adjusting the pressure, people should not stand at the air outlet of the cylinder, and their heads should not be above the bottle head, but on the side of the bottle to ensure personal safety.

(7) Before opening the cylinder master valve 1, you must first check whether the pressure regulating valve 4 of the oxygen meter is in the closed state (the handle is closed). When the pressure regulating valve 4 is open (handle is open), do not suddenly open the cylinder master valve, otherwise the oxygen meter will be damaged or other accidents will occur.

(8) Prevent air leakage. If there is air leakage, tighten the screw or replace the leather pad.

(9) When the pressure in the gas cylinder is lower than 0.5MPa, it can no longer be used and should be inflated.

Protective X-ray 1.6 X-ray absorbed by human tissues is harmful to human health. Generally, soft X-rays (longer wavelength and lower penetration) used for crystal X-ray diffraction analysis are more harmful to human tissues than hard X-rays (shorter wavelength and higher penetration) used for hospital fluoroscopy. Light cause local tissue burns. If exposed for a long time, it will lead to the decline of white blood cells and hair loss. Severe radiation sickness occurred. But if appropriate protective measures are taken, the above hazards can be prevented. The most basic one is to prevent all parts of the body (especially the head) from being exposed to X-rays, especially direct X-rays. Therefore, it is necessary to block the window of the X-ray tube with lead skin (the thickness is more than one millimeter) in order to limit the X-ray to a small local area as far as possible and prevent it from scattering to the whole room, especially to the light. When temporarily not working, the windows should be closed, and personnel should leave the X-ray laboratory as far as possible when unnecessary. The room should be well ventilated to reduce the influence of harmful gases produced by high voltage and X-ray ionization on human body. Emergency measures First aid measures Remove the patient from the poisoning scene immediately, take off the contaminated clothes, thoroughly wash the contaminated skin, hair and nails with soapy water (not hot water), and change clothes immediately. Wash the skin with soap and water. If taken by mistake, immediately induce vomiting, take orally 1%-2% soda water for gastric lavage, and then send it to hospital for emergency treatment. Specific antidotes include pralidoxime and atropine. The leakage was absorbed by sand and buried in an open place. The polluted ground is neutralized with lime, then washed with plenty of water, and the diluted sewage is put into the wastewater system. Fire extinguishing methods can be sprayed with water, dry powder, foam, etc. Keep the container cool with water, spray water to disperse steam, drive away escaped materials, and prevent the fire from being ignited again. Measures for the Administration of Highly Toxic Chemicals in Guangdong Province (Guangdong Safety Supervision [2003] No.242) Article 14 Highly toxic chemicals must be stored separately in a special warehouse with anti-theft alarm devices. Strictly implement the "five pairs" system of double receiving and sending, double bookkeeping, double locking, double transportation and double use. The management system of precursor chemicals is 1. Objective To establish a management system for the use and storage of precursor drugs. 2. Applicable to the safety management of precursor drugs in our company. 3. The responsible person's security department, security team, purchasing department and users. 4. Procedures According to the relevant provisions of the NPC Standing Committee's Decision on Drug Control and the Regulations on Drug Control in XX Province, combined with the actual situation of this enterprise, this system is formulated. 4. 1 The production, management, transportation and storage of precursor chemicals must comply with relevant national laws and regulations, and a management team for the use of precursor chemicals shall be established, with the main leaders as the team leader. And identified 1-2 full-time and part-time managers of precursor chemicals. 4.2 Conduct regular political review of liaison officers, warehouse managers and users of precursor chemicals, and conduct regular education and training for the above-mentioned personnel. 4.3 Every time you buy precursor chemicals, the liaison officer will bring the application form for the purchase and use of precursor chemicals in this city, as well as the last purchase certificate and the actual purchase situation. Go to the management office of precursor chemicals of the Municipal Public Security Bureau to apply for the purchase certificate. The purchase voucher is valid for one month, and each voucher can only be purchased once. If the purchase is not made on time, the expired purchase certificate shall be returned to the original issuing authority within 7 days after the expiration of the validity period, and the original issuing authority shall cancel it. The purchase voucher shall not exceed the amount specified in the purchase voucher. 4.5 The purchase voucher can only be used by the purchasing unit indicated on the voucher. The purchasing unit shall send personnel to the sales unit to purchase, and shall not give the purchase voucher to other units or individuals for use in any form, or ask other units or individuals to purchase it on their behalf. 4.6 The purchased precursor chemicals must be used by the unit, and shall not be transferred or lent to other units or individuals for use. Do not apply for purchase and use certificates for other units. 4.7 After the precursor chemicals arrive at the unit, the liaison officer must be present to supervise the unloading and warehousing. After the quantity is checked correctly, the deliveryman, warehouse keeper and supervisor shall sign the Registration Certificate Book of Precursor Chemicals respectively. 4.8 Precursor chemicals must be stored in a separate warehouse with double locks. Entry-exit account registration is clear, comprehensive and accurate. Irrelevant personnel are not allowed to enter the warehouse of precursor chemicals. Warehouse keepers and liaison officers should check the usage and inventory of the current month every month, and send the inventory information to the management office of precursor chemicals before the 5th of each month. If any discrepancy is found in the inventory, it shall be reported to the management office of precursor chemicals immediately. The management office and the user enterprise will review it. If it is found stolen, it should be reported to the public security organ immediately. 4.9 The user department (workshop) must issue a requisition form for precursor chemicals, which shall be signed by the person in charge of the user department (workshop) and then collected from the warehouse. When leaving the warehouse, the liaison officer must go to the scene to supervise. After checking the quantity, the receiver, warehouse keeper and supervisor shall sign the registration book of precursor chemicals in and out of the warehouse respectively. After leaving the warehouse, the consignee will send the precursor chemicals to the user department (workshop) accompanied by the liaison officer. Users of precursor chemicals should establish registration accounts and bind them separately for future reference. If the precursor chemicals are stored in the tank, pumping them into the high-level tank from the tank (that is, pulling them out of the tank) is regarded as leaving the warehouse. Make a warehouse registration. 4. 10 The user department (workshop) shall reasonably collect precursor chemicals according to the use plan of the day. In principle, whoever uses precursor chemicals will collect them, and the person in charge of collection will be off duty, and precursor chemicals will be regarded as unused. The person in charge of the user department (workshop) shall arrange for two people to return the redundant precursor chemicals to the warehouse, and the warehouse administrator shall register the returned precursor chemicals as raw materials. The returner and the warehouse keeper should sign the register respectively. The warehouse shall not temporarily store general-purpose raw materials, and the user department (workshop) shall not store precursor chemicals in the department (workshop) without permission. If the user department (workshop) uses the returned precursor chemicals again, it shall go through the formalities for obtaining them again in accordance with the provisions of Article 9. Where precursor chemicals are used, attention should be paid to the recovery and treatment of the residual liquid after the use of precursor chemicals. 36980.68868688662