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The laboratory shall maintain adequate ventilation, either through natural ventilation or by installing mechanical ventilation systems, to prevent the accumulation of harmful fumes generated during high-temperature operations. It is strictly prohibited to store flammable and explosive materials or gas cylinders in the vicinity of heating equipment to avoid fire or explosion hazards. In addition, appropriate operating procedures must be developed and posted in prominent locations for easy reference by laboratory personnel at all times. Common hazards associated with heating equipment include: lack of safety warning labels and operating procedures; insufficient clearance between heating units resulting in inadequate heat dissipation; proximity of heating equipment to electrical distribution panels; use of non-dedicated, unsecured power outlets for heating devices; storage of combustible materials near heating equipment; unattended operation of heating equipment; failure to disconnect power promptly after use; and failure to conduct regular inspections of heating equipment wiring for poor contact, aging, or damage. These risks must be rigorously prevented.

Before using the high-temperature laboratory electric furnace, carefully inspect the equipment to ensure it is in proper working order before commencing operation. First, clean any impurities from the furnace chamber to ensure there are no residues that could affect heating performance. Next, place the items to be incinerated on the furnace’s dedicated sample tray and close the furnace door. After connecting the power supply, verify that the indicator light illuminates, confirming that the power has been properly connected. At the same time, open the exhaust vent, insert the thermometer, and adjust the automatic temperature-control knob to gradually raise the temperature to the desired setpoint. During this process, prior to energizing the furnace, check that the lead wires and terminal connections are in good condition, that the furnace chamber is clean, and that there is no damage.

During operation of a high-temperature electric furnace, close attention must be paid to temperature changes, which should be monitored in real time via the display on the control panel or through thermometers and other instruments. In general, the furnace’s heating is automatically controlled by the control software; however, operators must remain vigilant to ensure that the temperature remains within safe limits. Once the set temperature is reached, the temperature-control knob should be adjusted until the green indicator light illuminates, signifying that the temperature has been attained and is stable. It is important to note that water or any liquid must not be allowed to come into contact with the furnace plate or heating elements, as this could cause short circuits or damage the heating components. During calcination, the material to be heated must be placed in a sound crucible or porcelain dish and introduced (or removed) using long crucible tongs; the material should be positioned as close as possible to the center of the furnace chamber, and care must be taken to avoid touching the thermocouple to prevent it from being broken. In addition, acidic or sulfurous volatile substances, as well as strongly oxidizing chemicals, must be pre-treated to allow all volatiles to escape completely before being placed in the furnace for heating.

During the heating process, the heating rate should be properly controlled to prevent sample breakage due to excessively rapid heating. Particular care must be taken when handling sensitive materials, such as quartz glassware, to avoid breakage that could result in serious lacerations. In addition, test specimens containing water or oil must be degreased and thoroughly dried before being placed in the furnace to prevent the generation of harmful gases or even explosions at high temperatures. Furthermore, when calcining samples, both the heating rate and the maximum furnace temperature must be strictly controlled to avoid spattering and subsequent corrosion that could contaminate the furnace chamber. Upon completion of calcination, the power supply must be disconnected, and the furnace door should not be opened immediately. The door may be opened only after the temperature has dropped to a specified range, at which point the calcined items can be removed and allowed to cool to a certain temperature before being transferred to a desiccator and further cooled to room temperature.

During the experiment, the experimental conditions should be continuously monitored, particularly parameters such as temperature changes and heating rate. Temperature variations can be tracked in real time via the display on the control panel or through thermometers, and relevant data should be recorded. Upon completion of the experiment, the heating element of the high-temperature electric furnace must be switched off, and the furnace door should not be opened until the temperature has dropped to a safe level. When opening the furnace door, exercise caution to prevent heat loss and potential burns. In addition, the main power switch, control power supply, timer, and other associated equipment should be turned off to ensure that all components have come to a complete stop. Before using a high-temperature electric furnace that has been stored for an extended period without operation, it must first undergo a drying process; the duration of drying should be determined based on the specific circumstances.

When using high-temperature laboratory electric furnaces, it is imperative to implement all necessary safety precautions and operate the equipment strictly in accordance with the prescribed operating procedures. Personnel must remain at their stations during operation. If, due to special circumstances, the furnace must be left running overnight, prior notification to the supervisory staff is required, along with the implementation of appropriate safety safeguards and emergency response measures. Upon completion of use, the power supply must be immediately disconnected, the power plug removed, and the furnace allowed to cool to a safe temperature before leaving. Newly used electric hair dryers, hot-air guns, soldering irons, and similar devices must not be stored immediately; they must be allowed to cool naturally, and their ventilation openings must not be blocked or covered. Heated items should be handled and retrieved only when the power is off and in a safe manner. The use of open-flame electric furnaces in the laboratory is prohibited without authorization. It is forbidden to use electric heating equipment to bake solvents, oils, plastic containers, or other flammable and combustible volatile substances. If toxic or harmful gases are generated during heating, the process must be conducted inside a fume hood.

Different types of high-temperature laboratory furnaces have distinct operational precautions. For instance, when operating a high-temperature tube furnace, it is essential to ensure that the surrounding area is free of flammable and explosive materials as well as corrosive or other hazardous gases, and to maintain effective heat dissipation outside the furnace. It is strictly prohibited to load or unload materials, or to open the furnace lid for rapid cooling, when the furnace tube temperature exceeds 100°C; such operations should only be performed after the furnace chamber has cooled down naturally. If the furnace is operated under gas flow, the gas flow rate must be continuously monitored and adjusted to maintain stability, and an anti-backflow device and an exhaust-gas collection system should be installed at the exhaust outlet. When a corundum tube is used in a high-temperature tube furnace, the flanges at both ends of the tube must be supported by a supporting frame to prevent vertical stress from causing bending or fracture of the tube at high temperatures due to thermal expansion and pressure. The electrical connections of the temperature-control system should be inspected regularly to ensure good contact, with particular attention paid to verifying that the connection points of the heating elements are securely fastened.

Muffle furnaces, as another common type of high-temperature laboratory electric furnace, also require careful attention to operating precautions. Muffle furnaces consume substantial amounts of electricity and must be powered through a dedicated circuit breaker. Flammable and explosive materials are strictly prohibited from being stored in the vicinity. During operation, the heating rate and maximum furnace temperature should be carefully controlled to prevent sample spatter that could corrode and contaminate the furnace chamber. New furnaces should first be baked at low temperatures for several hours to avoid thermal shock or cracking of the furnace lining. Prolonged operation at high temperatures should be avoided to protect the furnace chamber. After use, the furnace door should not be opened until the temperature has dropped below 200°C. Muffle furnaces must not be operated beyond their specified service life; any extension of service requires prior approval.

As another commonly used heating device in the laboratory, the oven has certain specific precautions for its operation. The oven should be placed in a dry, level indoor location to prevent vibration and corrosion, and the surrounding area must be free of flammable or explosive materials as well as corrosive and other hazardous gases. Safe electrical practices must be observed: install a power switch with sufficient capacity based on the oven’s power consumption, use appropriately rated power cables, and ensure a reliable grounding connection. When loading samples, they should be arranged at a reasonable spacing; no samples should be placed directly on the heat-dissipation plates to avoid obstructing the upward flow of hot air. Only after confirming the material properties may the operator proceed with drying; common flammable items such as paper sheets, labels, adhesive bottles, and plastic cups are strictly prohibited from being placed inside the oven. Drying of flammable, explosive, volatile, or corrosive substances is also forbidden. When drying cleaned laboratory glassware, any excess water should be thoroughly removed before placing the items in the oven. For ovens equipped with forced-air circulation, the fan must remain on throughout the heating-up and temperature-holding phases; otherwise, temperature uniformity will be compromised and the heating elements may be damaged. Upon completion of operation, the power supply must be promptly disconnected to ensure safety. Both the interior and exterior of the oven should be kept clean, and the operating temperature should never exceed the oven’s maximum rated temperature. To prevent burns, dedicated tools must be used when inserting or removing samples. The oven chamber should be kept clean to avoid cross-contamination between dried items.

Electric thermostatic water baths and oil baths are among the most commonly used heating devices in laboratories, and their operating precautions must be observed carefully. When filling the bath with water or oil, the liquid level must never fall below the heating element to prevent damage to the element. After turning on the power, the heating indicator light will illuminate; set the temperature to the desired value. During operation, continuously monitor the water or oil bath for any signs of leakage. For applications requiring relatively low working temperatures—i.e., when the set temperature is close to room temperature plus 5°C—it is advisable to use a two-step setting procedure: for example, if the desired working temperature is 37°C, first set the thermostat to 35°C, wait until the temperature overshoots and then begins to decline, and subsequently set it to 37°C. This approach can reduce or even eliminate temperature overshoot and help the bath reach and maintain the target temperature more quickly. Avoid splashing water or oil onto the control box to prevent electrical leakage. If the bath will remain unused for an extended period, drain all water or oil to prevent rusting. Throughout operation, the bath must be supervised at all times to avoid dry heating.

In summary, the proper use of high-temperature laboratory electric furnaces is not only critical for the accuracy of experimental results but also directly affects the safety of laboratory personnel. Therefore, when operating such furnaces, it is imperative to strictly adhere to the operating procedures and pay close attention to all safety precautions. Moreover, different types of high-temperature laboratory electric furnaces have their own specific operational requirements; thus, procedures must be tailored to the particular circumstances of each application. Only in this way can the safe and efficient operation of these furnaces be ensured, thereby providing robust support for research activities.