Hot compress bag, medical hot compress bag and the principle of warming baby

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heating principle of warm baby

“warm baby” is a synthetic mixture of iron, vermiculite, activated carbon, inorganic salt and water. Vermiculite is an iron magnesium aluminosilicate mineral with the composition of Mg0 5 (H2O) 4mg3 [alsi3o10] (OH) 2 is named because it can expand rapidly when heated and bend in the shape of leech (leech). Vermiculite is generally brown, brown yellow or dark green, with 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 thermal insulation material. After a series of complex chemical treatments, the extracted vermiculite film is translucent. The thermal insulation performance of this film surface layer is excellent. It is suitable for making fireproof covering layer, roof heat protection, high-temperature gasket, expansion connector for furnace or boiler, heat protection layer of refrigerator and other household appliances, incubator and cable outsourcing layer
so what is the heating principle of “warm baby” we use? By collecting relevant data, the reaction principle of “warm baby” and the products after use were explored and identified

II. Principle analysis
“warm baby” uses the exothermic reaction of iron oxidation to generate heat. In fact, it is based on the principle of oxygen absorption corrosion of iron 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. The water vapor is liquefied into water droplets and flows out to contact with air and iron powder. Under the catalysis of sodium chloride, it reacts rapidly to generate iron hydroxide and release heat
the oxidation reaction rate of iron under natural conditions is slow. If this reaction can be accelerated, such as trying to increase the surface area of iron and using water, salt and activated carbon to form a primary battery to promote the reaction, the temperature required by the heating bag can be obtained and become the heat source of the heating bag
negative electrode: fe-2e – = Fe2 +
positive electrode: O2 + 2H2O + 4E – = 4OH –
total reaction: 2Fe + O2 + 2H2O = 2Fe (OH) 2
2Fe (OH) 2 + 2H2O + 3O2 = 4Fe (OH) 3 ↓
2Fe (OH) 3 = = = = Fe2O3 + 3H2O

III. exploration process design
1 experimental supplies
primary battery reaction tank, wire, sensitive ammeter, iron sheet, carbon rod, 5% NaCl solution, beaker, test tube, funnel, filter paper Iron stand, rubber dropper, glass rod, pH test paper, spoon, alcohol lamp, platinum wire, evaporating dish, residual mixture after baby warming (dark brown solid), NaOH solution, dilute HCl, AgNO3 solution, H2O, KSCN solution, clarified lime water, etc

2 experimental steps
① Principle Exploration:
[operation] connect the iron sheet and carbon rod with wires (connect a sensitive ammeter between the wires), insert them in parallel into the galvanic cell reaction tank containing 5% NaCl solution, and observe the experimental phenomenon
[phenomenon] the pointer of the ammeter deflects and reddish brown substances appear on the iron sheet
[Conclusion] iron and carbon can form a galvanic cell to accelerate the oxidation of iron and release heat faster

② product exploration
(1) take a small amount of samples and dissolve them with water, there are a large number of insoluble substances. Filter to obtain colorless and transparent filtrate, and divide the filtrate into four parts
[phenomenon] there is no obvious phenomenon when KSCN solution is added to the first filtrate. Add AgNO3 solution to the second part, and white precipitation appears. Add NaOH solution dropwise to the third part, and there is no obvious phenomenon. The fourth part makes a flame reaction, and the flame is yellow
[Conclusion] it shows that the sample can be partially dissolved, the product contains NaCl, and the filtrate dissolved in water does not contain Fe3 +, Al3 +, Mg2 +
(2) take a small amount of sample and add excess NaOH solution, there is a large amount of insoluble matter. Filter to obtain colorless and transparent filtrate. Take a small amount of filtrate into the test tube and add KSCN solution dropwise without obvious phenomenon. [Conclusion] the sample does not react with alkali
(3) take a small amount of sample, add excess HCl solution and filter to obtain golden clear filtrate. Divide the filter solution into two parts. One part is added with KSCN solution, and the solution immediately turns blood red
add another part of NaOH solution dropwise, and there is no obvious phenomenon at the beginning. Adjust the pH value of the solution to 7 with pH test paper to neutralize the remaining HCl solution with NaOH solution. Continue to drop NaOH solution, and gradually dark green precipitation begins to appear, oscillate, and the precipitation disappears. Continue to add NaOH solution to excess, and the precipitation part disappears and turns brown yellow. The upper layer is colorless and transparent solution, and the lower layer is accumulated with reddish brown precipitation. After filtration, the obtained solid is heated to obtain reddish brown solid. The solid is insoluble in water and soluble in acid to obtain brownish yellow solution, which is preliminarily determined as Fe2O3
[Conclusion] the dark green precipitation is a mixture of reddish brown iron hydroxide precipitation and white aluminum hydroxide (possibly magnesium hydroxide) precipitation. Continue to drop NaOH solution, the aluminum hydroxide precipitation gradually disappears, and finally the remaining reddish brown iron hydroxide precipitation
(4) collect the filter residue, dry it, get black powder, ignite it, it can burn, and the generated gas can turbidity the clarified lime water. It is preliminarily determined as carbon powder

③ problem design in the experiment
(1) why is the solid state of warm baby different before and after use? (before use, there is NaCl solution in it, and all substances do not react, so it is paste; after use, it is transformed into solid, so it is relatively hard)
(2) why does warm baby use double-layer packaging? (the outer layer is a conventional airtight outer bag, which is used to isolate the air. Oxygen is required to participate in the use, so the inner layer is a non-woven bag made of microporous breathable membrane)
(3) why can warm babies get hot and keep it for such a long time? (it releases heat through the slow oxidation of iron powder, then accelerates the oxidation through the principle of galvanic cell to convert chemical energy into electrical energy, and then uses vermiculite to maintain the temperature, so it can last for 12 hours, and the temperature of the whole process is basically constant)

3 exploration conclusion analysis
through the observed experimental phenomena, We come to the conclusion that the reaction principle of warm baby is to use the primary battery to speed up the oxidation reaction and convert chemical energy into heat energy. In order to make the temperature last longer, the product uses mineral material vermiculite to keep warm. Because the product cannot react before use, the bag material should be very special, which is composed of raw material layer, gelatin layer and non-woven bag. The non-woven bag is made of microporous breathable membrane. It also has to have a conventional airtight outer bag – gelatin layer. When in use, remove the outer bag and expose the inner bag (non-woven bag) to the air, and the oxygen in the air enters the inside through the breathable membrane. The time and temperature of heat release are controlled by the oxygen permeability rate of the breathable membrane. If the oxygen permeability is too fast, the heat will be released at once, and the skin may be scalded. If the oxygen permeability is too slow, there will be no temperature. After use, it is black brown solid, including carbon powder, NaCl solid, Fe2O3 solid and ma
gnesium aluminum salts.

iron powder encounters oxygen and is activated by brine. The combination reaction will generate heat and make iron oxidize rapidly in a short time. So heat is generated. When the iron powder is not consumed, it becomes iron oxide, and there is no heat.

chemical reaction iron powder meets air

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