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Commonly used silica gel desiccant discoloration inquiry

发表时间:2015-05-11 10:59:20

With the development of trade in goods, a variety of desiccant is widely used in transportation and storage goods. In high school, we also learn and use a desiccant, such as lime, soda lime, sulfuric acid, anhydrous copper sulfate, etc. Now, let's escape from the scope of the study, meet in the life of common desiccant.

 

Silica gel desiccant

 

Silica gel is a kind of high pore structure of hydrated silica, processed by natural mineral purified granular or bead. Non-toxic, tasteless, odorless, stable chemical property, strong moisture absorption performance, is a highly active adsorption material. Usually is to use sodium silicate and sulfuric acid reaction, and the aging, acid soak and a series of post-processing process and system. The most appropriate moisture environment for room temperature (20 to 32), high humidity (60-90), it can reduce the environmental relative humidity to 40% or so. Silica gel is amorphous material, its chemical formula is mSiO2 · nH2O. And therefore is widely used in instruments, meters, instruments, leather, bags, footwear, textiles, food, medicine and other relative humidity of the storage and transportation of control environment, to prevent the goods be affected with damp be affected with damp, mildew and rust. For example, xylitol is in use. The only desiccant silica gel is recognized by the European Union is the only through the FDA certification of desiccant.

 Silica gel has a strong adsorption ability, drying effect on a person's skin. If the silica gel into the eyes, need a lot of water flushing, and find a doctor as soon as possible. After eating can drink some milk, this will soon be silica gel desiccant.

 

Silica gel desiccant type 1, there are four main pore silica gel desiccant: 2, coarse pore silica gel desiccant: 3, blue silica gel desiccant: 4, cobalt free color silica gel desiccant. The colorless transparent at about 4500-4800 yuan/ton. Blue and orange in 6800-7000 yuan/ton.

 

Clay desiccant

 

Clay mineral is a crystalline hydrated magnesium aluminum silicate minerals, has a unique layer chain structure characteristics, existing lattice replacement in its structure, crystal needle, fibrous or fiber collection. Has a unique dispersion, high temperature resistant, salt resistant and good colloid properties such as higher adsorption decolorizing ability. And has certain plasticity and cohesive force. It can serve as a kind of physical adsorption dryer, and shape changes after moisture absorption by deliquescence, contact with water is not hot, very few containing water-soluble substances, PH is 6 ~ 8 close to neutral. So does not cause the influence of metal corrosion and so on, in line with the advanced industrial countries of the "4 r" and "1 d" standard. Widely used in electronics, instruments, clothing shoes and hats, electrical and mechanical equipment, military products especially the ocean container transportation.

 Clay desiccant has the following characteristics: 1. The pure natural, non-toxic, tasteless, environmental pollution-free, 100% can be natural degradation, as its raw material clay, abandoned after won't cause pollution to the environment. 2. Strong moisture absorption ability: under the same conditions, than silica gel moisture absorption ability; Anti seepage after moisture absorption, can guarantee the desiccant packaging is always in the dry state. 3. To smell, can remove the formaldehyde in air and gaseous sulfur and other harmful gases. 4. Can be processed into rules of high-strength spherical particles, in use process does not produce dust.

 

Chemical composition: SiO268.7 % Fe2O31. 39% Al2O317. 22% CaO2.72 % Na2O1. The K2O0 15%. 3%

 

Mineral desiccant

 

Mineral desiccant is composed of several kinds of natural minerals, appearance is grey ball. It is non-toxic harmless, biodegradable and environmentally friendly desiccant. Moisture absorption rate is above 50%, twice as much as the ordinary silica gel. , using pure natural raw materials, refined mineral and active hygroscopic agent with green environmental protection, non-toxic, tasteless, no damage to the human body. Products at room temperature and under the general humidity adsorption performance is good, has the adsorption activity, static dehumidifying and odor removal effect and so on.

 

Mineral desiccant can be used as mineral desiccant into two kinds: 1, montmorillonite desiccant; 2, attapulgite desiccant; Montmorillonite desiccant for natural mineral raw material processing and become, appearance is broken, easy pulverization, the moisture absorption rate depends on the amount of montmorillonite content, its expansion after moisture absorption, easy broken bag, but its natural adsorption, non-corrosive, used for precision instrument, have the edge on the arms; For attapulgite desiccant is pure natural attapulgite mineral raw material and active, refined hygroscopic agent with adjustable, moisture absorption rate for globular appearance, easy packing, but it contains chlorine ion, without damage to the human body but have contact corrosion to metal products, generally not rust product dry.

 

Fiber desiccant

 

Desiccant - fiber is made of pure natural plant fibre through special techniques. Among them, especially the effect of fiber desiccant, convenient and practical, do not take up space. The moisture absorption capacity of 100% of its weight, is unmatched by ordinary desiccant, three times the ordinary silica gel desiccant. In addition, the product safety and health, price moderate, is the choice of many biological, health foods and drugs. Is choice of many biological, health foods and drugs. Natural plant fiber as hygroscopic carrier, can be 100% natural degradation, environmental desiccant; Moisture absorption rate, high moisture absorption rate; Outside the image of the thick paper, can be arbitrary cutting or cutting into various shapes, can be directly fill in bottle or other container.

 

Calcium chloride desiccant

 

Calcium chloride desiccant is made of high quality calcium carbonate and hydrochloric acid as raw material, through evaporation and concentration, reaction synthesis, filtering, drying process refined but become. Porous, lump or honeycomb solid white. Taste bitter, odourless. Aqueous solution is colorless, PH value of 7.0 + / - 0.5. Mainly used as the material of other kinds of inorganic chemical production calcium salt; Is also used as a desiccant, gas producing alcohol, ester, ether and acrylic resin as dehydrating agent. In the food industry as a calcium fortifier, curing agent, chelating agent, desiccant, etc. Calcium chloride desiccant with adsorption activity static dehumidifying and odor removal effect and so on. Not only adsorption speed, adsorption capacity, high, non-toxic, tasteless, no contact corrosion, no pollution of the environment, especially without damage to human body, widely used in oil seal, optics, medical, health food and military products.

 

Quick lime desiccant

 

Main ingredients for calcium lime desiccant, the water absorption ability is accomplished by chemical reaction, so water is irreversible. Regardless of the environment humidity is high and low, this product can keep 35% of the moisture absorption capacity is greater than the weight, more suitable for low temperature preservation, dry has excellent moisture absorption effect, and the price is low. Can be widely used in food, clothing, tea, leather, shoes, appliances and other industries. But quick lime desiccant with alkali corrosion, has gradually become obsolete.

 

Quick lime into hydrated lime (calcium hydroxide) after moisture absorption. Its shape will be from the particles into a powder. Volume will increase 2-2.5 times. Reactive CaO + H2O - Ca (OH) 2 as a result of lime desiccant moisture absorption is by quick lime into lime hydrate, its property has changed, so do not use again. If desiccant and effect, can be used for home food preservation or shoes dry. Because lime desiccant before moisture absorption for the particle shape, and after moisture absorption of powder, just look at the bag of desiccant have particles, knew that is available. Raw material quicklime (CaO) raw materials after reaction with water heating. When there are signs of burn is found, for the doctor to observe. Hydrated lime non-toxic (calcium hydroxide), but its aqueous solution has strong alkaline, will stimulate the mucous membrane, so after eating, please find the doctor observed after drinking lots of water or milk. As not burning garbage disposal within the family, because of the raw material of lime desiccant (lime) hot immediately contact with water, it is possible that it is forbidden to abandon more than in water.

 

Hope in my description, you can fully understand this kinds of desiccant. Desiccant used by humans, however, little is thousands of many tens of thousands, I use a winter vacation can't finish it. For the are of interest to you, your own investigation and summary, so as to better understanding the chemistry of a wealth.