【文档说明】四川省成都七中高一英语外研版必修四素材(文章)Module 1 Glass Recycling .docx,共(2)页,15.492 KB,由小赞的店铺上传
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GlassRecyclingGlasshastheleastvolatilepricingofallthepostconsumerrecyclingcommodities.Composedofsandan
dpotash;bottleglassismadefromreadilyavailableandinexpensiverawmaterials.Tobecompetitive,recycledglassmustmainta
inapricethatcompeteswiththeseabundantrawmaterials.Tradedasflint(clear),amber(brown),emerald(green)ormixedc
olorbrokenglass.Thepricedependsonthecleanlinessandcoloroftherecycledproduct.Cleanflintcullet(anotherwordforbrokenglass)is
usuallythemostdesirableformofrecycledglassscrap.Mixedcolorbrokenglasswithceramicsorstonesmixedinitistheleastdesirablegradeofculletb
ringingthelowestprice.MostRecyclerscolorsortandbreakorcrushandscreenbottlesbeforesellingtheirproduct.Mo
dern,highproductionbottlemanufacturingrequiresverycleananduniformfeedstock.Overthepastdecadetherehasbeenagrowthintheglassbenefactio
nsector.Theseareintermediateprocessorsthatreceiveglassfromrecyclingprogramsandrunitthroughaseriesofstepstoremoveanycontaminants(
rocks,ceramics,metalcaps,etc.)andprovideauniformfeedstocktothebottlemanufacturers.Thesepreprocessorprovideanexcellentmarketforrecyclingprogramsth
atdonothavethevolumeorabilitytoproduceglassfordirectmilldelivery.Glassbeneficiationplantsusesophisticatedopticalsortingmachinestoseparatethegl
assintothethreecolortypes.Theymayalsox-raytheglasstodetectanyrocksorceramicswhicharethenremoved.Magnetsandeddycurr
entseparatorsareusedtoremovedmagneticandnon-magneticmetalcontaminationfromcapsandlids.Theendproductisauniformlysizedloadofgroundg
lassthatisfreeofcontaminantsreadilyacceptablebybottlemanufacturers.Lowergradesofrecycledglassthataretoomixedorcontaminated,maybeusedinconcreteorin
roadpavingmaterialcalled"Glasshalt".Insomeareaswherethereisanoverabundanceoflowgradeglassitisusedtocoverov
ertherubbishinthelandfillinplaceofsand.Thisisnottrulyrecyclinganditishopedthatbettersortingtechnologywillsoonmakethismaterialusa
blefornewbottles.Glassrecyclingsavesenergybecauserecycledglasscanbeprocessedatalowertemperaturethanblendi
ngnewglassfromrawmaterials.Also,recycledglassisusuallyclosertothebottleplantsthanthesourcesofpotash,themostexpensivecomponentingl
assbottlesandjars.Bout32%ofenergycanbesavedbecauseofitslowmeltingpoint.Itiseasiertomanufacturenewglasswarefromrecycledglassthanfromrawmaterial,wh
ichcanalsoreduceairpollutionby20%,andwaterpollutionby50%.