Some chemicals commonly used in paper production are H2O2, NAOH. The product's uses are for bleaching, cooking pulp... If you want to buy wholesale or retail H2O2, NAOH, please contact Loc Thien Chemical Company for the fastest order support.
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THE ROLE OF NAOH AND H2O2 IN PAPER PRODUCTION
The essence of pulping technology is to use chemicals to dissolve non-cellulose fiber components in the raw material, releasing cellulose in the form of powder (fiber). There are two main pulping technologies:
Kraft technology: is the technology of cooking pulp with alkali. Alkali is a mixture of NaOH and Na2S that has the function of dissolving lignin and semicellulose to release cellulose fibers. At that time, the wastewater (cooking liquid containing cooking chemicals and natural compounds in wood, mostly lignin) will contain a lot of alkali (high pH) and have the characteristic smell of sulfur compounds (thiols and sulphide-mercaptans), COD index and color (due to lignin) are very high.
In terms of pulp, if bleaching is required, it will consume more bleaching chemicals than pulp cooked by sulphite method. This is the most popular technology in the world and also in Vietnam. A complete pulp mill includes all the stages as presented below.
Kraft process flowchart, wastewater sources and pollutants
In this chain, water, energy and chemicals are circulated to the maximum. The raw material (wood chips, bamboo) flows from left to right through the stages of cooking, screening (removing knots, uncooked pieces), washing, bleaching with oxygen, washing before going to the bleaching stage with chemicals. Clean water is almost only used to wash the pulp in the final stage of the pulp cooking process, then goes upstream to wash the raw pulp, the waste water here has a very high concentration of chemicals and organic matter and is black in color, so it is called black liquor.
The black liquor is concentrated to the point of combustion, Na2SO4 is added and sprayed into the recovery furnace operating under sufficient conditions to reduce sulfate to sulfide, the organic part will burn to generate heat used to produce steam for the factory, ash-slag are Na compounds converted into Na2CO3 and Na2S. Dissolving this ash-slag will yield green liquor, reacting with lime will regenerate white liquor which is a mixture of NaOH + Na2S to be used again to cook the pulp. According to the kraft technology diagram, the black liquor evaporation system and the chemical recovery boiler play the role of recovering 95% of the chemicals used to cook the pulp and treating over 90% of the pollutants of the entire pulp factory.
In Vietnam, there are currently only two factories with this system, namely Bai Bang Paper Company (now Vietnam Paper Corporation) and An Hoa Paper Company, which was put into operation in 2011, although in principle, all new pulp mill projects must have this system. In addition, in Vietnam, there are about 100 small factories that only cook pulp with alkali, and when using bamboo as raw material, people only soak it in alkali for about 5-6 days. This method is called "cold alkali" and is imported from Taiwan and China, mainly for the production of votive paper.
Sulfite technology: This technology uses sulfite salts, cooked in an acidic environment. This technology has a stronger effect than Kraft on the durability of cellulose fibers, however the product has a higher whiteness, this technology is not popular in Vietnam.
Other bleaching applications are becoming more important as hydrogen peroxide is seen as an environmentally better alternative to chlorine-based bleaches.
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Representative office: 140/53 Vuon Lai, An Phu Dong Ward, District 12, Ho Chi Minh City
Warehouse 1: Group 6, Phuoc Hung Hamlet, My Xuan Commune, Tan Thanh District, Ba Ria - Vung Tau Province
Warehouse 2: Phuoc Thai, Phuoc Binh Commune, Long Thanh District, Dong Nai Province
Warehouse 3: Tan Dong Hiep B Industrial Park, Di An, Binh Duong
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