Diferenzas entre revisións de «Lignina»

 
== Importancia económica ==
A [[madeira]] moi lignificada ten unha gran duración e é unha boa materia prima para moitas aplicacións. É tamén un excelente combustible, xa que a lignina produce máis enerxía ao arder ca a celulosa. A pulpa de madeira de alto rendemento ou mecánica utilizada para facer papel de prensa contén a maioría da lignina presente inicialmente na madeira. Esta lignina é a responsable de que o papel de periódico se poña amarelo co tempo. <ref name="eero"/> A lignina debe ser retirada da pulpa de madeira antes de producir a partir dela papel branqueado de alta calidade.
Highly lignified [[wood]] is durable and therefore a good raw material for many applications. It is also an excellent [[fuel]], since lignin yields more energy when burned than [[cellulose]]. Mechanical, or high-yield [[wood pulp|pulp]] used to make [[newsprint]] contains most of the lignin originally present in the wood. This lignin is responsible for newsprint's yellowing with age.<ref name="eero"/> Lignin must be removed from the pulp before high-quality [[bleaching of wood pulp|bleached]] paper can be manufactured from it.
 
InNo [[Sulfiteproceso process|sulfitedo pulping]]sulfito para facer pulpa de madeira, lignina islignina removedé fromeliminada woodda pulppulpa ascomo [[sulfonatesulfonato]]s. TheseEstes [[lignosulfonateslignosulfonato]]s haveteñen severalvarias usesaplicacións:<ref>{{cite web|url=http://www.lignin.org/whatis.html|title=Uses of lignin from sulfite pulping|accessdate=2007-09-10}}</ref>
 
* [[Dispersante]]s no [[cemento]] de alto rendemento, tratamento de augas e tintes téxtiles.
* [[Dispersant]]s in high performance [[cement]] applications, [[water treatment]] formulations and textile [[dye]]s
 
* Aditivos en aplicacións especializadas da industria de extracción de petróleo ou en produtos químicos de uso agrícola.
* Additives in specialty [[oil field]] applications and [[agricultural]] chemicals
 
* RawMateria materialsprima forpara severalvarios chemicalsprodutos químicos, suchcomo asa [[vanillinvanilina]], [[DimethylDimetil sulfoxidesulfóxido|DMSO]], [[ethanoletanol]], o azucre [[xylitolxilitol]] sugar, ande [[humicácido acidhúmico]].
 
* Axente ambientalmente sostible para a supresión do po das estradas.
* [[Environmentally sustainable]] dust suppression agent for roads
 
A lignina eliminada polo [[proceso kraft]] (método do sulfato) xeralmente se queima para ser utilizada como combustible, fornecendo enerxía para mover o muíño para facer pulpa e os procesos asociados.
The first investigations into commercial use of lignin were reported by [[Marathon Corporation]] in [[Rothschild, Wisconsin|Rothschild]], [[Wisconsin]] ([[USA]]), starting in 1927. The first class of products that showed promise were [[leather tanning]] agents. The lignin chemical business of Marathon was operated for many years as Marathon Chemicals. It is now known as LignoTech USA, Inc., and is owned by the [[Norway|Norwegian]] company [[Borregaard]], itself a subsidiary of the Norwegian conglomerate Orkla AS.{{Citation needed|date=January 2012}}
 
MoreMáis recentlyrecentemente, lignina extractedlignina fromextraída shrubbyde willowsalgueiros hasarbustivos beenfoi successfullyutilizada usedcon toéxito producepara expandedproducir polyurethaneescuma foamde [[poliuretano]] expandido. <ref>[http://www.genesis.co.nz/Press+Releases/2007/GREEN+PLASTIC+PRODUCED+FROM+BIOJOULE+MATERIAL.html Green plastic produced from biojoule material] BioJoule Technologies Press Release, 12 July 2007.</ref>
Lignin removed via the [[kraft process]] (sulfate pulping) is usually burned for its fuel value, providing energy to run the mill and its associated processes.
 
En 1998, a compaía alemá ''[[Tecnaro]]'' desenvolveu un proceso para converter a lignina nunha substancia chamada [[Arboform]], a cal se comporta de xeito idéntico ao plástico para a inxección en moldes. Por tanto. pode utilizarse en moitas aplicacións en substitución do plástico, e cando o material sexa desbotado pode simplemente queimarse como se fose madeira. <ref>[http://www.msnbc.msn.com/id/28283260/ A greener alternative to plastics: liquid wood] from [[MSNBC]]</ref>
More recently, lignin extracted from shrubby willow has been successfully used to produce expanded polyurethane foam.<ref>[http://www.genesis.co.nz/Press+Releases/2007/GREEN+PLASTIC+PRODUCED+FROM+BIOJOULE+MATERIAL.html Green plastic produced from biojoule material] BioJoule Technologies Press Release, 12 July 2007.</ref>
 
In 1998, a [[Germany|German]] company, [[Tecnaro]], developed a process for turning lignin into a substance, called [[Arboform]], which behaves identically to [[plastic]] for [[injection molding]]. Therefore, it can be used in place of plastic for several applications. When the item is discarded, it can be burned just like wood.<ref>[http://www.msnbc.msn.com/id/28283260/ A greener alternative to plastics: liquid wood] from [[MSNBC]]</ref>
 
== Notas ==
188.165

edicións