alum water principle and its preparation method of aluminum sulfate

Alum is a familiar folk purifying agent , which is a kind of aluminum sulfate and potassium sulfate complex salt . Then it is how to use water purification , and its use What is the principle . But also how to use it produced . We together look.
Alum water principle
Alum can be ionized in water, two metal ions : KAl (SO4) 2 = K + + Al3 + + 2SO4 4 -. And Al3 + is easily hydrolyzed  carbon black powder to form colloidal aluminum hydroxide Al (OH) 3: Al3 + + 3H2O = Al (OH) 3 ( gel ) + 3H +. Aluminum hydroxide colloid strong adsorption capacity , can absorb impurities suspended in the water , and the precipitate formed , the water clarification. Therefore , a better purifying agent is alum .
Aluminum sulfate alum was prepared using 1 , aluminum sulfate is added in an excess of ammonia , to obtain aluminum hydroxide precipitate potassium sulfate and ammonium sulfate solution, a 2 , a solid aluminum hydroxide was filtered , washed with dilute sulfuric acid obtained by adding an appropriate amount of aluminum sulfate , evaporation and  iron oxide yellow crystallization 3 , to the filtrate was added an excess of potassium hydroxide and heated , the ammonia evaporated to give potassium sulfate solution , evaporation and crystallization . Due to the use of the prepared aluminum sulfate alum ( potassium aluminum sulfate ) will affect the body iron, calcium absorption components , leading to osteoporosis , anemia, and even affect the development of nerve cells . Therefore , it is now generally used for drinking water alum . Of course, the same rationale containing aluminum ions chloride, aluminum chloride is not used for drinking water purification.

The amount of lubricant some introductory

Lubricant actual processing plastics with a variety of effects, such as the kneading , rolling processing , to prevent adhesion polymer cartridge , inhibition of friction and heat, reduce kneading torque and loads, thus preventing polymer material thermal degradation . In the extrusion molding, to improve mobility , the barrel and the polymeric material to improve adhesion of the mold , to prevent and reduce the  impact modifier retentate . Another film can improve the appearance and luster. From processing machinery perspective, mixing, rolling , slush molding , etc. , the external lubricant has an important role in extrusion, injection molding, lubricants is more effective.
The amount of lubricant is generally 0.5 % to 1% , selection should pay attention to the following aspects : ( 1 ) the flow properties of the polymer molding technology needs have been met , the primary role of lubrication considerations to ensure that internal and external balance ;
( 2 ) external lubrication is valid , it can be in the molding temperature, the surface layer of the plastic film to form a complete liquid prevail , so the melting point of the lubricant outside the molding temperature should be close, but to a difference of 10 ℃ ~ 30 ℃ order to form a complete film ;
( 3 ) When the lubricant is selected in production , so as to be meet the following requirements:
( 4 ) compatibility with the resin medium size, internal and external lubricating balance ; non-blooming , easy to scale ;
( 5 ) Small surface gravity , viscosity, at the interface scalability, and easy to form the interface layer ;
( 6 ) as far as possible without compromising the excellent performance of the polymer does not affect the performance of the secondary processing of plastics ;
( 6 ) itself is excellent in heat resistance and chemical stability , in the processing does not decompose volatile ;
( 7 ) non-corrosive , does not pollute the film , there is no toxicity.
However, the simple use of a lubricant is often difficult to achieve the purpose , to be used in combination of several lubricants , lubricating composite developed rapidly in recent years , the inganic pigments  choice can be viewed from multiple perspectives lubricant.
Commonly used lubricants are stearic acid , butyl stearate , oleamide , ethylene bis stearic acid amide and so on .
Many substances can be used as a lubricant waxes such as natural paraffin, liquid paraffin ( mineral oil ) , microcrystalline wax , etc., but the effect is mixed. Natural wax mostly used external lubrication , the lubricant can be used as a variety of plastic , mold release agents, the general amount 0.2 ~ 1phr, but the compatibility , thermal stability and dispersibility is not good , the amount can not be too large , preferably lubricants and used ; while white oil mostly used PVC, PS internal lubricants, lubricating properties, good thermal stability , the general amount 0.5phr. they are drug-free , can be used for food packaging. Another Microcrystalline wax : in Plastics Processing is also used as a lubricant , the amount of 1 ~ 2Phr, thermal stability and lubricity better than normal paraffin .
Low molecular weight polymers are widely used heat stabilizer for foaming board  as a lubricant such as polyethylene wax, low molecular weight polypropylene , its internal and external lubrication are better, and non-toxic . PVC and polyethylene wax materials suitable for extrusion, calendering , the dosage is usually 0.1 ~ 1phr, to improve processing efficiency, prevent the film adhesion, improved dispersion of the filler or pigment , compatibility and transparency is not very good ; irregular low molecular weight polypropylene can be used as the structure rigid PVC, PE lubricant performance, can improve the dispersibility of other additives .

plastic flame retardant technology introduction

Plastic applications continue to expand at the black iron oxide  same time increasing its heat and combustible and easily ignite, brought to mankind unexpected danger and loss. Therefore, from the late 1960s, people began to pay attention to and emphasizes natural and synthetic materials, flame resistance, flame retardant additives began as an important class of first chemical fiber, plastics industry rise. Retardants abroad since the 1970s began to develop rapidly, consumption and varieties rose sharply, there are around 6 to 8 percent growth rate. Many of the additives in the plastics industry in flame retardant consumption has moved up to No. 2, second only to the great variety of plasticizers. . Flame retardant additive and reaction is usually divided into types: additive flame retardant used for thermoplastics, is currently the world's largest production of flame retardants, flame retardants accounted for 90% of total. More reactive flame retardant for thermosetting plastics; flame retardants according to the chemical structure can be divided into inorganic and organic flame retardants, inorganic flame retardants are antimony compounds, inorganic boron compounds, inorganic phosphorus flame retardant, inorganic hydroxides, organic flame retardants include organic halogenated flame retardants and organic phosphorus flame retardant. Antimony flame retardants. Antimony prices high, heavy smoke, while halogen flame retardant antimony trioxide is essential gn3t}? ^. Bm
Synergists, so trioxide particle fineness requirement is getting smaller, not only can greatly reduce the amount of increase flame jf? V [{! K |
Sex, but also greatly reduce the amount of smoke. Are generally in the fineness of several microns to 0.01μm, as developed by Seiko Co., Ltd. of Japan Patox average particle size of 0 .01 ~ 0 .02 μm. Guizhou Rong Jiang Fenghua developed chemical antimony antimony oxide ultrafine pure activity, with an average particle size of 0.02μm, content of 99.999%. PolycomHuntsman developed "N% vVu` PNyacoIADP480 a particle size less than 0.1μm antimony pentoxide, adding 1% in the PP up a good flame retardant, and not?)? L? AVQIp
Be of PP impact strength, transparency, etc. impact. Another use of antimony trioxide and aluminum hydroxide, zinc borate, fluoride {C?? O @?? WS
Borate complex, not only can reduce the amount of antimony trioxide and the amount of smoke is also greatly reduced. In short ultrafine seek) E??. OaP
Antimony substitutes and reduce the amount of smoke is antimony flame retardantsdevelopment focus. ? G?} 7?? 50
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- Brominated flame retardants. Brominated flame retardants despite heavy smoke, because of environmental issues by the magnesium hydroxide  EU restrictions; but because flame-g?? NpH? YB
Performance is good, with less impact on product performance is small, quite a long time in the future is still the main flame. With? ~ PpN? DLFL
International technical progress the development of brominated flame retardants on the new feature is to continue to improve and increase the molecular weight of bromine content. Such as the U.S. Ferro's PB-68 is mainly composed of brominated polystyrene, the molecular weight 15000 containing 68% bromine. Belfast bromine chemical companies and Ameribrom companies were developed poly Pentabromophenol acrylate bromine content of 70.5% \ MW 30000 ~}-n? DdMa / -
80000. These flame retardants particularly suitable for all kinds of engineering plastics, migration, compatibility, thermal stability, flame resistance, etc. are much better than many small molecules flame retardants, may become future replacements. - Phosphorus flame retardant. Phosphorus flame retardants are mostly liquid, mainly used in PU, PVC and other plastics. United retardant properties of polymers is much better than the linear polymer, so thermoplastics plus $? _ZQ]?? F
Adding a small amount of a crosslinking agent work becomes part of the polymer network structure, not only can improve the dispersion of the flame retardant, there are benefits BqOve? S2xU
Combustion in the condensed phase polymer produced coking, effectively improve the flame retardancy and PVC stabilizer for cable  mechanical products can increase sexual? O-YGEjeG?
Energy, weathering, heat resistance, etc., such as soft PVC quaternary ammonium salt in a small amount, so that the heat of the fire-retardant material to form a crosslinked> a ~: z?-Jiz
Material. Radiation may also be used to join metal oxides and crosslinking methods, but also allows the polymer to pay. W #?? VTZE; d
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 - Directly generate retardant monomer technology. Directly before the polymerization of the monomer having a flame resistance, so that the resulting 1? Wo? FI?;
Polymer become retardant materials, but also flame retardant in a way.

Security plasticizer

PVC is mainly used in packaging wrap film, which, after adding phthalate soft, high transparency, good self-adhesive. Phthalates past that is relatively safe, in limiting the amount added can be used for a food packaging. However, due to widespread use of plastic products and plastic packaging, as time goes by. Phthalates from plastics and other substances gradually transferred to the external environment. Commonly found in airborne particulates, rivers and soil. Many countries of the atmosphere, lakes, rivers and soils have been detected in different concentrations of phthalates. Japan in the 30 rivers 86 monitoring points detected DEHP, the United Kingdom, China and other scientists are also the atmosphere, rivers and environmental sewage detected DEHP, results show that our environment is subject to different levels of DEHP contamination. Phthalates through the respiratory tract, gastrointestinal tract and skin absorption into the body, so that people from the normal intake of food and water will inevitably be some of DEHP, however, under normal circumstances, the amount of intake is difficult to exceed the safe limit.

In the published research papers on the toxicity of DEHP, the researchers through animal experiments (mainly rodents), in vitro experiments or epidemiological survey methods, gradually prove DEHP cause reproductive system damage, liver toxicity, renal toxicity, it There are some uncorroborated potential hazards, including teratogenicity, carcinogenicity. Given these potential health risks, the EU issued a directive 1999/815/EC, the EU member states use by children under three years of age in contact with the mouth of toys and other children's products (such as baby pacifiers, teething, etc.) in the poly vinyl chloride plastics plasticizer content restrictions, requirements contained six kinds of PVC phthalate plasticizers (DEHP, DINP, DNOP, DBP, DIDP, BBP) the total content shall not exceed 0.1% . As the plasticizer in PVC products generally used in an amount of 2% to 70%, which indicates that plastic toys actually disable the DEHP plasticizer, which is still in development stages in order to protect children.

DEHP there are other potential health risks. The myocardial cells in vitro in soaked in DEHP may cause its rhythm abnormalities. However, in the heart of the body and did not find this phenomenon, said long-term exposure to DEHP may cause arrhythmia lacking basis.