Hand warmer is a synthetic mixture of iron, vermiculite, activated carbon, inorganic salts, water, etc. Among them, vermiculite is a ferromagnesian aluminosilicate mineral with the composition of Mg0.5(H2O)4Mg3(OH)2. It is named after it can expand rapidly when heated and bend into a leech shape. Vermiculite is generally brown, brown-yellow or dark green, with a greasy glass luster. About 80% of expanded vermiculite is used in the construction industry and is a good heat and sound insulation material. Vermiculite is the world's leading super insulation material. The vermiculite is subjected to a series of complex chemical treatments, and the extracted vermiculite film is translucent. The surface layer of this film has excellent thermal insulation performance, and is used to make fireproof coverings, roof heat protection, high-temperature liners, expansion joints for furnaces or boilers, household appliances such as refrigerators, heat-proof layers for incubators, and outer cladding for cables, etc. All suitable.
So, what is the heating principle of the "hand warmer" we use? Through the collection of relevant data, the reaction principle of "hand warmer" and the products after use are explored and identified.
Principle Analysis
"Hand warmer" uses iron oxidation reaction to generate heat. In fact, it is based on the principle that iron absorbs oxygen and corrodes in humid air. At the same time, using the strong adsorption of activated carbon, water vapor is stored in the loose structure of activated carbon, and the water vapor is liquefied into water droplets, which flow out to contact with air and iron powder, and react relatively quickly under the catalysis of sodium chloride to form iron hydroxide , giving off heat.
The oxidation reaction speed of iron is slow under natural conditions. If this reaction can be accelerated, such as trying to increase the surface area of iron, using water, salt and activated carbon to form a primary battery to promote the reaction, you can get the temperature required by the heating bag , become the heat source of the heating bag. It will not cause harm to the body, just don't burn it.