Dry ice is not ice, but a solid form of carbon dioxide. It is often used to create a cloud effect on the stage. This is because after the dry ice is placed at room temperature, the dry ice will vaporize as the air pressure decreases and the temperature increases. And dry ice in the sublimation process will absorb heat, so that the temperature around the stage is reduced, the water vapor in the air will take the dust particles in the air as a medium, condensed into small droplets, large area looks like a cloud.
However, if dry ice is not used properly, it will freeze people. Because when dry ice comes into contact with the human skin, sublimation will occur, and in the process of sublimation, dry ice will absorb a lot of heat. When directly contact with the human body, it will cause the human skin tissue frostbite.
In daily life, take dry ice, be careful not to direct contact with the hand when handling dry ice, otherwise, it will freeze the skin, and will stick to the skin, so be sure to use tools to handle dry ice. If it is very short contact, cotton gloves can play a role in preventing frostbite. But if you touch for too long, you can 't use cotton gloves. The correct treatment method is: Enter the 22 ℃ - 25 ℃ room, or immerse the hands in 38 ℃ - 42 ℃ warm water, quickly increase the body temperature, but not with fire, cold water soaking or rubbing with snow, and try to raise the wound and keep warm.
In general, dry ice is stored for a short period of time, even if stored in a dedicated dry ice freezer, can only be stored for 5 to 10 days. After the shelf life, dry ice will form ice mass and even gasifies. In addition, do not store dry ice in a container with good sealing performance and small volume, because dry ice is extremely easy to volatilize and generates a gas that is 1,000 times larger than the solid area, which will bring great pressure to the sealed container.
For dry ice used for preservation, the best way to deal with it is to discard it directly to make it naturally volatilize, in order to avoid the danger of improper storage. If you want to continue to store it, you can use a dry thermos. A vacuum layer is arranged between the thermos bottle liner and the outer bottle wall for heat insulation, so that the gas generated by the volatilization of dry ice can be released from the gap between the bottle stopper and the bottle wall, so that the internal pressure is reduced, and the method is safer.http://www.wxytgas.com/