Paper Keywords: secondary vocational school chemistry laboratory safety
Abstract: As the main carrier of experimental teaching, the quality of laboratory construction and management is directly related to the teaching quality. In order to ensure the normal teaching, the first thing to be solved is the safety of the laboratory. From the aspects of the management and implementation of laboratory safety system, the construction of laboratory safety facilities and laboratory safety, this paper expounds how to realize laboratory safety management to ensure good teaching quality.
? As the main carrier of experimental teaching, the quality of laboratory construction and management is directly related to the teaching quality. In recent years, students in secondary vocational schools are generally poor in quality, and their learning ability and awareness are low. Due to the influence of enrollment expansion, there are more students and the laboratory is relatively crowded than before. Therefore, in order to ensure the normal teaching and good teaching quality, the first thing to be solved is the safety of the laboratory.
? Our school is a national key secondary school, and all kinds of laboratories are basically sound and have begun to take shape. In the process of laboratory construction, our school first insists on? Safety first? The principle of combination? Practical, reasonable, economical and environmentally friendly? And other principles, from the rules and regulations, personnel arrangements, laboratory space, equipment, instruments, products and other aspects to do some exploration, especially safety measures.
1, leaders attach importance to it, the system is implemented, and personnel arrangements are in place.
? In the process of chemical laboratory construction, in order to reduce the acute chemical poisoning accidents caused by chemical experiments and improve the ability of teachers and students to deal with acute chemical poisoning emergencies, with the help of the security department, an emergency plan is formulated. The plan includes the following contents:
? I. Possible causes of acute chemical poisoning accidents
? Second, preventive measures.
? Third, the disposal procedures
? (1) Report in time
? (2) Start the emergency team.
? (3) On-site rescue:
? (4) Do a good job of obtaining evidence and protect the site and related evidence.
? (5) Operate according to the Emergency Plan for Handling Accidental Injuries of Campus Students.
? (6) matchmaking.
? (7) When necessary, the police will introduce people.
? In addition to the emergency plan, each laboratory also has laboratory safety operation procedures and a list of laboratory managers. The management of special personnel shall be implemented, and the measures of special personnel, counters and locks shall be implemented for dangerous chemicals. Our school has also established a laboratory management team with strong sense of responsibility and high professional quality. Laboratory staff are all certified, with strong safety awareness and orderly laboratory management.
2. The distribution of laboratory places is reasonable, and the best use is made to prevent time delay and avoid accidents.
? The supporting facilities of the laboratory are relatively complete, the experimental preparation is set separately from the student laboratory, different instruments are stored in different cabinets, and the experimental console is acid-resistant and alkali-resistant, which is very convenient to clean. The balance room and precision instrument room are made of shockproof marble, which is both beautiful and practical.
? In order to ensure the orderly progress of the experimental class, we attach great importance to the standardized education of the experimental class every day. In addition to the correct use of reagents and instruments used in class, special emphasis is placed on the cultivation of safety awareness and environmental awareness, so that students can understand safety, ensure safety spontaneously, protect property, and develop a rigorous and realistic scientific attitude and good behavior habits. In order to make students develop the concept of economy, environmental protection and safety in their hearts when doing any experiment, we should start from small things and start training and training from bit by bit. First of all, teachers should play a good demonstration role and exert a subtle influence on students, and then be strict in the experiment. This includes cultivating rigorous, earnest, objective and calm qualities in experimental attitude; Take drugs according to the prescribed dose, observe the experimental rules, do not take them out at will, do not taste them, do not carry out dangerous experiments without permission, do not dump experimental garbage at will, and save water, electricity, alcohol fuel, test paper, filter paper, etc. And take good care of the experimental instruments. After the experiment, dispose of the residue after the experiment as required, clean the experimental instruments, arrange the experimental table, and put away the experimental instruments and medicines. In particular, the waste liquid produced in chemical laboratories often contains acids, bases, heavy metal compounds, cyanide and arsenic-containing compounds. Generally, discharging laboratory waste liquid into sewers will not only do great harm to students, but also dilute students' awareness of environmental protection and form bad habits, which will affect the cultivation of green chemistry awareness and the development of green chemistry technology. Teach students good experience in experimental teaching and treat wastes harmlessly. For example, neutralization method is used to neutralize acidic or alkaline wastewater, and extraction method is used to recover phenols and heavy metals from soluble wastes with different solubility in two phases. This can not only cultivate students' awareness of green chemistry, but also enable students to learn the practical technology of green chemistry, save resources, turn waste into treasure and turn harm into benefit.
? Pay close attention to each student's experimental process through laboratory managers and teachers who tutor students' experimental classes, and correct mistakes in time to prevent accidents.
? For example, when the alcohol lamp is used, there are often students who are not skilled or careless in operating it, which will cause the desktop to catch fire. Once, in an experiment about the properties of propionic acid, students began to flush the test tube without waiting for it to cool down, and a small crack appeared in the test tube. When heated, the test tube bursts and the reagent flows to the alcohol lamp and the table. Suddenly, the table was on fire, and the students knocked the alcohol lamp on the ground, and the ground began to catch fire. We always ask that a wet cloth must be prepared next to the alcohol lamp, so many students and teachers immediately put out the fire with a lot of wet cloth.
3. Drug safety management
? According to the characteristics of the experimental course, although the amount of dangerous goods is small, there are many kinds and high frequency of use, so the safety of products is very important. In order to ensure the safety and pollution-free of drugs, in the process of reagent storage, according to the different characteristics of reagents, under the conditions of sealing, avoiding light, low temperature, ventilation, isolation and fire prevention, they should not interfere with each other as much as possible, and they should be labeled for easy search and use. We should know the explosive mixture of common sense.
? Flammable, explosive, spontaneous combustion and strong oxidant drugs are often used in the laboratory, and experimental operations such as heating, combustion and distillation are often carried out, which is easy to cause fires. Therefore, it is very necessary to know and master the knowledge and technology about fire prevention and extinguishing.
? (1) fire control
? When heating flammable reagents, water bath and oil bath must be used. Never use an open flame. If the heating temperature is likely to reach the boiling point of the heated substance, zeolite must be added to prevent boiling.
? When volatile flammable reagents (such as ethanol, ether, acetone, etc.) are used. ), try to prevent volatilization, keep indoor ventilation, and do not dump or transfer such reagents near open flames.
? Configure fire fighting equipment and check its performance regularly.
? (2) Fire extinguishing
? If there is a fire in the laboratory, it should be put out 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. Can be used according to the cause of fire: ① metal sodium, potassium, magnesium, aluminum powder, calcium carbide and sodium peroxide are on fire, and dry sand is used to extinguish the fire; (2) When flammable liquids lighter than water, such as gasoline, stupid and acetone, catch fire, foam extinguisher can be used. (3) Where there are burning metals or melts, dry sand or dry powder fire extinguishers should be used.
4, all kinds of toxic gas poisoning symptoms and safety protection measures
See table 1 for poisoning symptoms and protective measures of toxic gases.
?
5. Pay full attention to the safety in experimental teaching.
? For experiments that are not conducive to safety or the safety items are not clearly defined in the experimental teaching materials, the experimental teachers will generally combine the students' reality and try their best to carry out green experiments or supplement the precautions without affecting the teaching content and objectives, so as to make the experimental process safe and environmentally friendly, which is also beneficial to the health of teachers and students.
? For example, in organic chemistry experiments, our school has made some changes in many experiments. In the distillation operation experiment, in order to let students learn to operate safely, we do it in two steps. The first step is to use water to make distilled water, and the second step is to use reagents to carry out experiments specified in the course. In this way, students are basically safe when doing the first step, which is convenient for students to effectively carry out the second step experiment on the basis of mastering the basic operation and being familiar with the instruments. Moreover, in this experiment, we changed the alcohol lamp into an electric furnace and the round-bottomed flask into a flat-bottomed flask, which made it easier for students to install and the experimental effect was better. There are many changes like this, some of which are put forward by students, which also exercise students' thinking and encourage their enthusiasm.
6. Safe discharge of waste liquid after experimental class.
? The amount of various acids and bases in the laboratory is very large, and the concentration of general waste liquid is small, so it can be directly discharged. High-concentration acid-base waste liquid should be stored separately, and it can be safely discharged after being neutralized regularly until the pH value is between 6. Number five and number eight. 5.
7. Conclusion
? To sum up, from the chemical experiment accidents in recent years, there are mainly the following kinds: corrosion and burn accidents, fire and explosion accidents, poisoning accidents and so on. Therefore, in addition to fully understanding the above safety knowledge, it is more important for the laboratory to do the following work for a long time:
? First, we must attach great importance to the safety management of laboratories, which is something to keep in mind every day; Second, there must be all kinds of simple and emergency drugs; Third, we should strengthen the precautions and operating procedures of the laboratory; Fourth, regularly check and update chemical experimental equipment and improve protective facilities; Fifth, strengthen laboratory management, transform old hydropower facilities and eliminate potential safety hazards; Sixth, strengthen safety training and reduce improper human operation.
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