1. TIU LUN CC QU TRNH SN XUT C BN --------***--------- LUYN NHM Nhm thc hin Trnh quang Vinh Hong Th Lu Chu Vn Thin on Thanh Tun

2. PHN I GII THIU CHUNG V TNH HNH LUYN NHM HIN NAY TRN TH GII V VIT NAM I. TNH HNH SN XUT NHM TRN TH GII HIN NAY I.1 Gii thiu chung v nhm Nhm l mt kim loi mm, nh vi mu xm bc nh kim m, v c mt lp mng xi ha to thnh rt nhanh khi n trn ngoi khng kh. T trng ring ca nhm ch khong mt phn ba st hay ng; n rt mm (ch sau vng), d un (ng th su) v d dng gia cng trn my mc hay c; n c kh nng chng n mn v bn vng do lp xt bo v. N cng khng nhim t v khng chy khi ngoi khng kh iu kin thng thng Tng qut Tn, K hiu, S Nhm, Al, 13 Phn loi kim loi yu Nhm, Chu k, Khi 13, 3, p Khi lng ring, cng 2.700 kg/m, 2,75 B ngoi mu trng bc Tnh cht nguyn t Khi lng nguyn t 26,981538 .v. Bn knh nguyn t (calc.) 125 (118) pm Bn knh cng ho tr 118 pm Cu hnh electron [Ne]3s2 3p1 e- trn mc nng lng 2, 8, 3 Trng thi xi ha (xt) 3 (lng tnh) Cu trc tinh th hnh lp phng Tnh cht vt l Trng thi vt cht rn im nng chy 933,47 K (1.220,58 F) im si 2.792 K (4.566 F) Trng thi trt t t thun t Th tch phn t 10 10-6 m/mol 3. Nhit bay hi 293,4 kJ/mol Nhit nng chy 10,79 kJ/mol p sut hi 100.000 Pa ti 2.792 K Vn tc m thanh 5.100 m/s ti 933 K Thng tin khc m in 1,61 (thang Pauling) Nhit dung ring 897 J/(kgK) dn in 3,774x107 /m dn nhit 237 W/(mK) Nng lng ion ha 1. 577,5 kJ/mol 2. 1.816,7 kJ/mol 3. 2.744,8 kJ/mol 4. 11.577 kJ/mol 5. 14.842 kJ/mol 6. 18.379 kJ/mol 7. 23.326 kJ/mol 8. 27.465 kJ/mol 9. 31.853 kJ/mol 10. 38.473 kJ/mol 11. 42.647 kJ/mol 12. 201.266 kJ/mol 13. 222.316 kJ/mol I.2 Lch s ngnh Sn xut nhm Mc d nhm l nguyn t ph bin trong v tri t (8,1%), n li him dng t do v tng c cho l kim loi qu c gi tr hn vng (Ngi ta ni rng Napoleon III ca Php c cc b n bng nhm d phng cho nhng ngi khch qu nht ca ng. Nhng ngi khch khc ch c b n bng vng). V th nhm l kim loi tng i mi trong cng nghip v c sn xut vi s lng cng nghip ch khong trn 100 nm. 4. Khi mi c pht hin nhm rt kh tch ra khi cc loi c cha n. V ton b nhm ca Tri t nm trong cc hp cht nn n l kim loi kh nhn c nht. L do l nhm b xi ha rt nhanh v xt nhm l mt hp cht cc k n nh, khng ging nh g st, n khng b bong ra. Ngi khi nghip Vo cui th k th XIX, nhm l th kim loi qu, cn him hn c bc. Tng lng nhm sn xut M vo nm 1884 ch c 125 pound (01 pound tng ng 450 gram). Ti Trng Cao ng Oberlin Bang Ohio, Gio s Frank Jewett ch cho cc sinh vin thy mt mu nhm nh v ni vi h rng, bt c ngi no c th tm ra c phng php sn xut mt cch kinh t th kim loi qu ny th ngi s tr nn giu c. Charless Martin Hall l mt trong s nhng sinh vin . Say m vi cc mu kim loi t khi mi 12 tui, Hall nung nu trong lng kht vng sn xut nhm v ng bin ngi nh kho bng g nh ng sau vn nh mnh thnh mt phng th nghim th s hng ngy vi mnh vo nghin cu. Ti liu tham kho Sut trong thi gian hc v sau khi tt nghip, Hall lin tc mit mi vi cc th nghim trong nh kho v t ch to c mt ni nu kim loi bng cacbon phc v vic to ra xt nhm-alumina. u nm 1886, ng y dung dch cryolite c cha alumina (Al2O3) vo ni nu kim loi v cho dng in chy qua. Kt qu l ng thu c mt ng ln nhn nhng cht ng cng, ng cho chng ngui i, sau dng ba p vn ra. Trong m bi bc ln c thy mt vi mnh nhm nguyn cht. in phn nhm tiu tn mt lng in rt ln, chi ph in chim 25% gi thnh; lm chy 1 tn nhm cn khong 13,5 - 18,5 MWh tch nhm ra khi oxi trong alumina; mc tiu th thp nht l 13.500 kWh/tn nhm nh my in phn nhm Moral ca BHP Mozambic, cao l 16.292 Kwh/tn nhm nh my Bratsk Nga. V vy, sn xut nhm ch em li hiu qu khi gi in thp < 3 US cent/kWh. c c gi thnh h, cc cng ty thng c nh my in ring, hu ht l thu in nh Alcan c ti 11 nh my thu in vi tng cng sut 4.156 MW, Alcoa t sn xut c 25% lng in cho sn xut 5. Ti ch nhm S ti ch nhm t cc ph thi tr thnh mt trong nhng thnh phn quan trng ca cng nghip luyn nhm. Vic ti ch n gin l nu chy kim loi, n r hn rt nhiu so vi sn xut t qung. Vic tinh ch nhm tiu hao nhiu in nng; vic ti ch ch tiu hao khong 5% nng lng sn xut ra n trn cng mt khi lng sn phm. Mt thc t ph bin cho n u thp nin 1900 l vic ti ch nhm l khng mi. Tuy nhin, n l lnh vc hot ng trm lng cho n tn nhng nm cui thp nin 1960 khi s bng n ca vic s dng nhm lm v ca cc loi ung cui cng a vic ti ch nhm vo trong tm ch ca cng ng. Cc ngun ti ch nhm bao gm t c, ca v ca s nhm c, cc thit b gia nh c, contener v cc sn phm khc. I.3 Tnh hnh sn xut v s dng nhm hin nay trn th gii Tnh hnh sn xut nhm t nm 2000 n ht nm 2007 trn th gii: ( S liu ca IAI ) 6. Tnh hnh sn xut 8 thng u nm 2008 : 7. Nh vy Bc M v Chu u vn dn u v sn xut nhm hin nay. II. TNH HNH SN XUT NHM TI VIT NAM HIN NAY II.1 Phn b qung nhm v tnh hnh sn xut trong nc Vit Nam l quc gia c ngun nng lng di do vi nhiu m qung bauxite, l c hi rt tt cho vic pht trin nng lng mi v cc d n kim loi, to ra mt chu trnh sn xut t bauxite n sn phm nhm v hp kim. Tuy nhin hin ti, Vit Nam cha c ngnh cng nghip nhm ring vi quy m ln. II.2 Mt s nh my luyn nhm v sn xut thnh phm nhm l n Vit Nam II.2.1 Nh my luyn nhm Bo Lm-Lm ng( trc thuc Tng cng ty khong sn Vit Nam thuc Tp on Cng nghip Than v Khong sn Vit Nam ) Cng sut : 600.000 tn/nm. 8. D kin bt u hot ng nm 2009 II.2.2 Nh my nhm Asia Vina Taiwan (thuc Cng ty Thng mi tng hp Qung Bnh) Nh my nhm Asia Vina - Taiwan l mt trong 5 doanh nghip hng u Vit Nam k c doanh nghip c hn 100% vn nc ngoi v lin doanh v sn xut cc loi nhm thanh nh hnh t tiu chun cht lng quc t, c sc cnh tranh cao. Nh my hin c 3 dy chuyn cng ngh hin i sn xut cc loi nhm thanh, 2 h thng m hon thin sn phm, h thng c nhm nu li ton b d liu trong qu trnh sn xut, va trit tit kim nguyn liu t tin, va lm cho nh my gim thiu ph thi n mc cao nht, cng vi cc my kim tra cng ca thanh nhm, dy lp m sn phm v h thng kim tra c, l ho ca sn phm t yu cu chnh xc cao. Cng sut : T 3.500 n 3.700 tn sn phm/ nm Ngoi ra cn rt nhiu cc c s c nhm v ch to nhm thnh phm nh l . Tham kho : - http://www.world-aluminium.org 9. PHN II NGUYN LIU SN XUT NHM Qu trnh luyn nhm i t cc sn phm qung nhm ngho (boxit-nhm tn ti di dng Al2O3 trong phc hoc n cht) hoc t nhm ph liu. Qung nhm do cc khong nhm to thnh, c khong hn 250 loi khong nhm khc nhau nhng thng c s dng nhiu 8 loi sau: Tn khong vt Cng thc ha hc Hm lng Al2O3 (%) Corundum Al2O3 100 Diaspo, bmit Al2O3. H2O (AlOOH) 85 Spinel Al2O3. MgO 71 Hydraogilit, ghipxit Al2O3. 2H2O; Al(OH)3 65,4 Kianit, antalunit, silimanit Al2O3. SiO2 63 Caolinit Al2O3. 2SiO2.2H2O 39,5 Alunit K2SO4.Al2(SO4)3.4Al(OH)3 37 Nephelin (Na,K)2O.Al2O3. 2SiO2 32,3 35,9 Trong cc loi qung, Boxit l qung nhm quan trng nht, trong boxit nhm tn ti di dng diaspo, bmit, hydraghilit, ghipxit v i khi c caolinit v corundum. Thnh phn ha hc ca qung bxit dao ng kh ln: Al2O3: 35-60% SiO2: 0,5-25% Fe2O3: 2-40% TiO2: vt 11% nh gi cht lng qung nhm, ngi ta nh gia thng qua ch tiu gi l modun silic SiO2 = t s lng Al2O3/SiO2. t s ny cng cao qung cng tt. 10. phN III Quy trnh sn xut nhm I.Khi qut v cng ngh sn xut Nhm -Nm 1886, Hall ngi M v Heroult ngi Php ng thi pht minh ra ph- ng php in phn nhm trong dung dch mui nhm nng chy. T n nay,Al c sn xut vi quy m cng nghip, sn lng tng ln khng ngng,Al tr thnh kim loi c s dng ngy cng rng ri. C th ni, phng php in phn Nhm trong mi trng nng chy chim a v ch yu trong cng ngh sn xut nhm. Sau y l lu trnh sn xut nhm hin nay: 11. II. SN XUT NHM OXIT C 2 phng php sn xut nhm oxit ch yu: - Phng php Baye - Phng php Kim thiu kt II.1.Phng php Baye - Phng php Baye thc cht l phng php dng dung dch NaOH ho tch bxit nhit cao v p sut,do K.I.Baye ngi A pht minh vo nm 1887. Sau y l s tm tt phng php Baye sn xut nhm oxit : 12. Boxit Ho tch tcla CaO NaOH Bn qung Lng lc dd NaAlO2 Khuy phn ho Al(OH)3 Nung Al2 O3 Dung dch ci C c v costic ho Mm Al(OH)3 13. Cc khu chnh ca qu trnh sn xut Nhm xit gm : 1.Ho tch bxit 2.Khuy phn ho dung dch NaAlO2 3.Nung Nhm hyrxit 4.C c dung dch ci v costic ho. II1.1.Ho tch bxit: - Bxit sau khi nghin nh trn vo vi Kim cho vo tcla(thit b ho tch). Trong tcla xy ra tc dng ca dung mi vi cc thnh phn ca bxit. - Nhm xit trong bxit phn ln dng ngm nc(hirxit) khi ho tch s tc dng vi NaOH to natri aluminat theo phn ng sau : Al(OH)3 + NaOH + aq = NaAl(OH)4 + aq AlOOH + NaOH + aq = Na Al(OH)4 + aq - St xit khng tc dng vi NaOH nn nm li trong b, Silic xit tc dng vi NaOH to ra Natri silicat ho tan vo dung dch theo phn ng: SiO2 + 2NaOH = Na2SiO3 + H2O - Natri silicat li tc dng vi Natri aluminat to thnh natri alumosilicat : Na2SiO3 + NaAl(OH)4 + aq = Na2O.Al2O3.mSiO2.nH2O + NaOH - Hp cht Natri alumosilicat ngm nc khng tan trong NaOH dng rn, ln vo cn . - Phn ng trn c ch l kh SiO2 trong dung dch nhng c hi l gy mt mt Kim v Al. Hm lng SiO2 trong bxit cng ln th hm lng mt mt kim v Al cng nhiu => phng php Baye ch p dng cho cc loi qung c hm lng SiO2 thp. 14. - Hiu sut ca qu trnh ho tch ph thuc vo nhiu nhn t : Nhit , thi gian, nng dung dch, t s rn lng, bn cht qung. II.1.2.Khuy phn ho dung dch natri aluminat. - Sau lng lc dung dch natri aluminat c em i khuy phn ho. Dung dch ny phn ho to ra nhm hirxit theo phn ng sau: Na AlO2 + H2O -> Al(OH)3 + NaOH - V c ch th qu trnh phn ho s c chia lm 2 giai on : + To mm Al(OH)3 + Pht trin mm - Nu nng cao t s costic th qu trnh to mm s ngng. Khi t s costic cao hn na th qu trnh s din ra theo chiu ngc li, tc l to ra natri aluminat. V vy phi khng ch nng kim thch hp. Gim nng kim s c li cho qu trnh khuy phn ho.Nhit cng c tc dng vi qu trnh khuy phn ho, nu gim nhit th qu trnh khuy phn ho s xy ra nhanh, nhng cc ht Al(OH)3 kt tinh s nh, khng c li cho vic lc ra sau ny. - Trong thc t sn xut, cn cho thm Al(OH)3 vo lm mm. S mm Al(OH)3 cho vo bng khong 1,5-2,5 ln trng lng Al2O3 c trong dung dch. - Mc ch ca khuy l lm cho nng dung dch ng u v ht tinh th lun trng thi l lng. - Sau khi khuy phn ho, dung dch c t s costic l 3,6-3,7.Kt tinh xong a Al(OH)3 i phn cp. Loi Al(OH)3 c c ht ln em i ra v nung, cn loi ht nh cho quay li mm kt tinh cho qu trnh sau. Dung dch ci sau khi khuy phn ho c em i c c v costic ho. 15. II.1.3.Nung Al(OH)3 Mc ch ca vic em nung l lm mt nc ca Al(OH)3 thu c Al2O3 theo phn ng: 2Al(OH)3 Al2O3 + 3H2O II.1.4.C c dung dch ci v costic ho - Sau khi lc, ly Al(OH)3 ra, dung dch ci cn li ch yu cha NaOH, nhng nng thp, khng p ng c yu cu ca dung dch tun hon. V vy em c c nng nng ln 300 g/l th dng li.Trong qu trnh vn hnh, mt lng CO2 trong khng kh tc dng vi NaOH trong dung dch to ra Na2CO3. Khi c c s kt tinh ra Na2CO3, em lc tch Na2CO3 ra. Sau dng Ca(OH)2 costic ho theo phn ng: Na2CO3 + Ca(OH)2 = 2NaOH + CaCO3 - Sau lng lc, thi b, dung dch em dng li. Mt s u nhc im ca phng php ny: -u im: Lu trnh n gin, cht lng sn phm tt, gi thnh h. -Nhc im: Ch thc hin vi qung bxit c hm lng SiO2 thp mi c li v mt kinh t. II.2. Phng php Kim thiu kt Khi hm lng SiO2 trong qung cao, dng phng php Baye sn xut s khng c li v mt kinh t do lm mt mt nhm xit v kim. 16. Phng php kim thiu kt cho php ch bin mt cch hp l cc loi qung c hm lng Silic cao. Thc cht ca phng php l em hn hp Bxit - Na2CO3 v vi nung nhit cao, kt qu l nhn c sn phm thiu kt cha natri aluminat. Sau ho tch thiu kt phm trong nc, natri aluminat ho tan dng dung dch, cc hp cht khc nm li dng cn b. Lc tch b thu c dung dch aluminat th. Sau khi kh Silic s thu c dung dch aluminat sch.em cacbont ho bng kh CO2 s thu c Al(OH)3. Sau khi nung Al(OH)3 12000 C s c Al2O3.Lu trnh sn xut Al2O3 bng phng php kim thiu kt gm cc khu chnh sau: Thiu kt, ho tch thiu kt phm, kh silic, cacbonat ho, nung. 17. vi Xay nghin Bxit Xay nghin Phi liu Thiu kt Ngin thiu kt phm Ho tch Lng lc Kh silic Lng lc dd NaAlO2 sch Cacbonat ho Al(OH)3 Nung Al2 O3 dd ci C c X a Cn 18. II.2.1.Thiu kt: - Mc ch: bin nhm oxit trong qung boxit thnh natri aluminat (NaAlO2) d tan trong dung dch nc, cn li SiO2 trong bxit to canxisilicat (2CaOSiO2) kh tan. - Cho boxit, dd Na2CO3,CaCO3 cng hi liu vo my nghin, sau phn tch thnh phn ho hc ca nguyn liu nghin iu chnh cho ph hp vi yu cu thiu kt,bn qung ny cha 70% nc, dng m phun vo l thiu kt.Bn liu sau khi vo l c gia nhit, tri qua cc vng kh nc, nung nng, lm ngui.Ti vng thiu kt,phi liu tri qua cc bc sau: Bc 1:thiu kt nhit thp, xy ra cc phn ng: Na2CO3 + Fe2O3 = Na2O.Fe2O3 + CO2 Na2CO3 + SiO2 = Na2O.SiO2 + CO2 Na2CO3 +Al2O3 = Na2O.Al2O3 + CO2 - Nu nhit thp c th to Na2O.Al2O3.SiO2 Bc 2:thiu kt nhit cao, xy ra cc phn ng sau: Na2O.Fe2O3 + Al2O3 = Na2O.Al2O3 + Fe2O3 Na2O.SiO2 + 2CaO + Al2O3 = Na2O.Al2O3 + 2CaO.SiO2 Na2O.Al2O3.SiO2 + 4CaO = Na2O.Al2O3+ 2(2Na2O.SiO2) II.2.2.Ho tch thiu kt phm - Sn phm thiu kt sau khi nghin nh c a i ho a i ho tch. - Mc ch l chuyn natri aluminat t pha rn vao dd nc, cn tp cht khc vn pha rn tch khi dung dch,dung mi ho tch c th l nc,dd kim long, dd natri aluminat long. 19. - Khi ho tch thiu kt phm xy ra cc qu trnh sau: + natri aluminat ho tan vo dung dch + natri ferit b phn hu theo phn ng: Na2O.Fe2O3 + H2O = Fe2O3 + 2NaOH - St oxit nm li trong cn, Natri ferit thu phn lm tng lng NaOH c li cho qu trnh ho tch. - 2CaO.SiO2 thc t khng ho tan, nhng nu thi gian ho tch ko di, nng dung dch m c, nhit ho tch cao th canxi silicat cng bt u phn ng vi dung dch kim v qu trnh s phc tp. - Mt s natri silicat to thnh cng tan vo trong dung dch v vy cn em dung dch i kh SiO2 II.2.3.Kh Silic - Sau ho tch c dung dch Aluminat th, v trong dung dch cn nhiu SiO2. V vy cn kh SiO2 trc khi kt tinh Al(OH)3. - Qu trnh kh silic ca dung dch dch natri aluminat tin hnh trong otocla tng t nh tcla dng ho tch bxit theo phng php Baye. Nhit kh SiO2 khong 1700 C.Phn ng ch yu ca qu trnh kh SiO2: Na2O.Al2O3 +2(Na2O.SiO2) +4H2O= 4NaOH +Na2O.Al2O3.2SiO2.2H2O Sau khi kh SiO2 a dung dch i lng lc, kt ta a v trn cng qung v em i thiu kt. Dung dch ci em cacbonat ho. II.2.4.Cacbonat ho dung dch natri aluminat 20. - Mc ch: lm cho dung dch natri aluminat b phn hu, kt ta Al(OH)3 theo cc bc sau: +Trc tin, cho CO2 trong khng kh tc dng vi NaOH 2NaOH + CO2 = Na2CO3 + H2O do NaOH b trung ho, t s costic ca dung dch gim xung, hp cht natri aluminat tr nn khng bn vng m phn hu theo phn ng : Na2O.Al2O3 + H2O 2Al(OH)3 + 2NaOH m NaOH sinh ra li tc dng vi CO2 thc y phn ng phn ho natri aluminat tin hnh theo chiu thun.Sau khi c c Al(OH)3 ta em nung thu c Al2O3 theo phn ng: Al(OH)3Al2O3 + H2O III.Sn xut Nhm bng phng php in phn. - Khi c nhm oxit, cn dng Na3AlF6 v cc mui fluorua in phn nhm.Ta c s in phn Nhm: -B thng l hnh hp ch nht, y ni cc m (2), khi than pha trn l cc dng(1).Gia hai cc l cht in phn Criolit-aluminat nng chy(4). Di tc dng ca dng in mt chiu, Al trong dung dch in phn tit ra v tp trung y b,cn oxit bay ra v pha cc dng, oxi ho cc than, to hn hp kh CO +CO2 thot ra ngoi. Trn b mt dung dch in phn v xung quanh b to ra lp v cng (6).Cho Al2O3(3) trn lp ny, c mt thi gian nht nh li y lp v cung cp Al2O3 vo trong b in phn. - phng php c mt nhc im l cc dng tn in nng, cht in phn d b bc hi. III.1.Cho Al oxit vo b in phn 21. -Trong qu trnh in phn, Nhm oxit l nguyn liu tiu hao ch yu thu c Al cc m v kh thot ra cc dng. V vy phi cung cp nhm oxit vo b qu trnh in phn c lin tc.C mt thi gian nht nh li cho nhm oxit vo b, bng cch p v lp v in phn hnh thnh trn b mt b, sau li ri nhm oxit ln trn lp v .Thao tc ny c th lm th cng hoc my chuyn dng. III.2.Thao tc cc dng -Qu trnh in phn tin hnh 9500 C, cc dng b n mn dn dn trong qu trnh in phn nn phi nh k li cc dng xung, cho thm h vo cc dng. III.3.iu chnh thnh phn cht in phn Thc t, do b cc than hp ph, do b bay hi, b cc tp cht khc phn ly,t l thnh phn cht in phn khng n nh v vy cn iu chnh thnh phn cht in phn. Khi mi cho chy b in phn, NaF trong Criolit b cc than hp ph, nhng sau mt thi gian khng b hp th na, lc AlF3 b mt i do bay hi v phn li bi phn ng: 2Na3AlF6 + 3Na2O = Al2O3 + 12NaF 2Na3AlF6 + 3H2O = Al2O3 + 6NaF + 6HF V vy, cn cho thm AlF3 gi n nh t s Criolit. III.4.Ra Al: 22. Al lng tch ly dn y b trong qu trnh in phn. C 3-4 ngy tho Al mt ln. m bo cn bng nhit, khng nn tho ht nhm b ra v thng li mt lng Al lng ng vi chiu cao nc nhm khong 15cm. IV.Tinh luyn Nhm. -Phng php in phn Crilit-alumin nng chy ch thu c Al c sch 99,5-99,7%Al gi l Al k thut. -Al th t b in phn cn cha nhiu tp cht gim cht lng nhm nn phi tinh luyn. - Cc tp cht c trong Al thng l:cht in phn, nhm oxit, nhm cacbit, than ln vo Al t b in phn,Fe,Si,Ti t nguyn liu vo Al trong qu trnh in phn, tp cht th kh do ho tan Al ch yu l Hir. - Hai qu trnh tinh luyn Al thng c p dng cho sn xut: + Clorua ho v nu tch + in phn 3 lp IV.1.Tinh luyn theo phng php clorua ho, nu tch( thin tch) -Mc ch :Kh tp cht phi kim loi v tp cht th kh. -Khi tinh luyn bng clorua ho, Al tho b in phn ra cho ngay vo thng cha, khng ch nhit 7500 C-7700 C, sc kh Clo vo Al khuy lng,khi mt phn Al b clorua ho to AlCl3 dng hi. Hi AlCl3 bao quanh cc ht rn phi kim loi, lm chng ni ln trn mt kim loi lng v vt ra ngoi. ng thi cc kh nh H2 cng b hi AlCl3mang i. - kh i mt s cc tp cht, ta dng phng php nu tch, vic nu tch c tin hnh trong l in tr, khng ch nhit 700-7100 C, y l c dc nht nh v c ch tp chung Al.Al s chy lng, v tp trung li, cc tp cht vn th rn hoc st nm li trn y l. 23. IV.Tinh luyn bng phng php in phn ba lp. - Qu trnh tin hnh trong b in phn c ba lp lng, thc cht ca phng php ny l Al cc dng ho tan theo phn ng in ho sau : Al - 3e Al3+ Ti cc m thu c Al sch theo phn ng : Al3+ + 3e Al - Cc nguyn t dng hn Al (Cu, Fe, Si,...) khng ho tan v tp trung li trong hp kim cc dng,cc kim loi m hn Al (Mg, Ca,...) s b ho tan cc dng chuyn vo cht in phn cc dng ion tng ng, chng nm li trong cht in phn ch khng phng in, bi v th in th tit ra ca chng cao hn ca Al.Do chnh lch v t trng, trong b in phn tinh luyn c ba lp(t di ln trn):hp kim cc dng, cht in phn, Al sch. 24. PHN IV X L DNG THI . * * * * * * * * * * Cng ngh sn xut nhm gm rt nhiu qu trnh phc hp, v vy m cht thi ca tng qu trnh u khc nhau v cc cht cha trong chng cng khc nhau ty thuc vo tng qu trnh. Mt cch tng i c th chia dng thi thnh 4 loi: + cht thi rn. + kh thi. + nc thi. + nh hng n vi kh hu. I. CHT THI RN I.1 Thnh phn Trong tng qu trnh u c nhng loi cht thi khc nhau a phn l t c ln bi qung v cc kim loi tp dng cc hp cht, ngoi ra cn c cc loi cht thi pht sinh ngoi qu trnh luyn. Qung a vo luyn nhm cn cha nhiu tp cht nh t, ,cc kim loi tp cht tn ti dng cc hp cht V vy trc khi a vo l luyn qung cn c x l s b.Qu trnh x l gm nghin, sng, tuyn ra qung lm sinh ra qung, bi qung ri vi,cn t, c sng, tuyn ra. Thnh phn ny cha t l kim loi thp c nhp vo dng thi em i x l. Qung sau khi x l c em i sn xut nhm oxit bng phng php Bayer ha tan ri ha tch trong Octola p sut cao. Phng php ny tiu tn nhiu 25. nguyn liu v hao ph nhiu kim loi v vy cn thi cng cha t l kim loi cao. khc phc nhc im trn ngi ta s dng phng php kim thiu kt gim t l kim loi i vo cn thi. Tuy nhin ni chung c hai phng php u c kim loi tht thot. Khi nung oxit nhm nhit cao cn c cht tr dung(thng l CaO). Cn thi ca qu trnh ny cha oxit silic,oxit nhm tht thot, cc kim loi nng, cn lng ca cc cht v c khcVi nhng loi cn c t l kim loi cao s c ti s dng thu hi kim loi. Oxit nhm sau khi lm sch c em i in phn s thu c nhm th. thu c nhm sch ta tip tc tin hnh in phn, s ln in phn cng nhiu th nhm cng tinh khit.Dung dch in phn l mui Criolit khng ha tan cc kim loi dng hn nhm. V vy bn in phn cha cc kim loi dng hn nhm. Thnh phn ny ch yu l cc kim loi nng v c hi. Ngoi ra trong qu trnh sn xut cn pht sinh cc ngun thi khc nh bao b ng ha cht c th cn dnh cc ha cht c hi, rt cn c x l k m bo an ton i vi sc khe cng nh mi trng. I.2 Qui Trnh X L i vi cht thi rn th hin nay hai phng php ph bin nht c p dng nhiu nc trn th gii l chn lp v thiu hy.trong thiu hy c cho l sch hn. Ngoi ra cn c phng php ha l hoc cng c th dng x lm nguyn liu cho ngnh xy dng nh p gch vin hoc lm vt liu ph cho sn xut xi mng. Tuy nhin c th khng an ton v trong x c cha mt lng nh kim loi nng c th gy nguy him i vi ngi s dng nu tip xc lu di vi cc sn phm ny. Cht thi rn trc tin s c phn loi v x l c hc gm: nghin, sang, tuyn tri mi c x l bng cc phng php khc. 26. I.2.1 Cng Ngh Chn Lp L bin php tiu hy c p dng rng ri trn th gii. Theo cng ngh ny cht thi rn c c nh dng vin hay khi v em chn lp bi chn lp. bi chn lp phi m bo cch xa khu dn c trn 5km, nn t n nh, chng thm tt, mc nc ngm thp,cch xa sng h. tng hiu qu chn lp th cht thi rn thng c ha rn trc khi chn thng qua vic thay i tnh cht ha l, tng sc bn, gim ha tan,gim lan truyn cht thi c hi. Vt liu ng rn ch yu l xi mng hoc c th trn thm mt vi cht v c khc tng n nh v kt cu. T l phi trn ph thuc vo tng loi cht thi c th. Thng sau khi ng rn ngi ta kim tra kh nng ha tan ri phn tch mu nc lc xc nh cc ch tiu c trng ri so snh vi tiu chun. Nu t tiu chun s c chn bi rc cng nghip, nu khng t tiu chun phi tng t l xi mng. Vit Nam hin nay cha c tiu chun ny. Theo tiu chun Nht Bn cht thi rn sau khi ha rn em ngm v khuy lin tc trong 6h trong nc ct sau em lc v phn tch. Tuy nhin nc ta hin nay vic ng rn cha c thc hin v cc tiu chun v chn lp sch cht thi cng nghip cha t c. 27. Bi chn lp rc thi rn : I.2.2 Thiu t y l qu trnh oxi ha cht thi nhit cao ph hp x l cht thi rn ( thng t 1200o C n 1300o C ) v cung cp oxi. Phng php ny ch hiu qu khi cc vt liu kh chy trong cht thi di 30%. C hai phng php thiu t . + t t nhin l trc tip t cht thi trong mi trng t nhin xa khu dn c, cch ny li gy nhim khng kh,khng tn dng c nhit v ch p dng vi cht d chy. + t trong l thiu s dng cc l t chuyn dng t. Cc l t ny s dng qui trnh t khp kn v c h thng tn dng nhit. Phng php ny sch v an ton c s dng nhiu cc nc pht trin. Tuy nhin nc ta phng php ny mi ch c p dng t cht thi y t nhng c s ln. Cn cc nh my luyn kim th cha c iu kin tip cn cng ngh ny. Cng ngh ny c nhiu u im : kh nng tn dung nhit, x l trit khi lng, tng i sch, khng tn t chn. Nhc im ca cng ngh ny l chi ph ln, d to ra sn phm ph nguy him. II.2.3 Cng Ngh Ha L. L cng ngh x l s dng cc qu trnh bin i ha l . Cng ngh ny ch c hiu qu vi nhng nh my c qui m ln, ph hp thu hi cc cht thi rn c cha cc kim loi nng hay cc dung mi hu c.Mt s bin php ha l c bn sau. 28. + Trch ly : l qu trnh tch cc cu t ra khi hn hp nh dung mi c kh nng ha tan chn lc mt s cht c trong hn hp , cc sn phm trch ly c ti s dng cho cc mc ch khc. + Chng ct : L qu trnh hn hp cht lng bay hi thnh tng pha cu t t tch c cc cht cn tch + Oxi ha kh : S dng cc tc nhn oxi ha kh tin hnh cc phn ng oxi ha kh chuyn cht thi c hi thnh cc cht khng c hoc t c hn.Thng s dng mt s cht oxi ha sau : Na2S2O4 , KmnO4 , K2Cr2O7 , H2O2 x l mt s kim loi a ha tr . II- KH THI II.1 Thnh Phn Hn Hp Kh Kh thi ca qu trnh sn xut nhm cha nhiu loi kh v bi. Trong nhiu nht l bi qung t khu nghin v tuyn qung. CO2, CO t qu trnh in phn, t nhin liu v mt lng nh t cc thit b vn chuyn trong nh my , hi nc thot ra t octola c tnh kim , ngoi ra cn c cc kh Cl2, F2, H2 t qu trnh in phn v tinh luyn nhm . Mt lng nh hi kim loi thot ra t cc l luyn v tinh luyn. cc nc SNG, oxit nhm c sn xut t nhiu loi nguyn liu khc nhau do lng kh thot ra rt ln v cha hm lng bi cao. Nu s dng Alunit sn xut nhm oxit th kh ra cn cha c SO2 . Bi thot ra t qu trnh nung vi, thiu kt, nung oxit nhm v gia cng chun b nguyn liu. Cc hp cht sunphua thot ra khi v hon nguyn Alunit Sau y l bng thng k hm lng bi t mt s thit b : 29. NGUN KH tH TCH KH RA T MI THIT B ( M3 /H) HM LNG BI C TRONG KH KHI CHA LC (G/M3 ) Cc l thiu kt 100.103 300.103 40 150 L nung oxit nhm 10.103 - 72.103 200 - 700 L ng nung vi 40.103 5 y l hnh nh kh thi thot ra t l luyn II.1.1 Qui Trnh X L Bi. Cc kh ra t l thiu kt v cc l nung c lm sch bng h thng lc bi gm cc thit b lc in kiu ngang, qut ht, my bm, thp ra v lm ngui . Sau y l s h thng thit b lm sch kh ra t l thiu. 30. K: kh dng cacbonat ha . 1 : thit b lc in kh kiu y ngang . 2 : qut ht. 3 : thp ra . 4 : my bm. 5 : thp ra lm ngui . 6 : thit b lc in m. Kh t l nung oxit nhm c a qua thit b lc in kh(1) sau qua qut ht (2) a vo thp ra (3), phn kh sch c y ra kh quyn, bi lng xung y thp. Thp ra lm ngui c phun nc theo chu trnh kn i khi dng dung dch phun l kim yu. Phn kh ra t l thiu kt dng vo qu 31. trnh thm cacbon c dn qua thp ra lm ngui v thit b lc in m. Nc c phun vo thp ny khng hi li m chy thng ra ngoi. Hm lng bi trong kh sau thit b lc khong 0,02 n 0,1 g/m3 . Kh ra t cc b in phn c ht qua phu chp ri lm sch bng phng php ra kh s dng dung dch Na2CO3 long khong 4% - 6% kh HF thu dc NaF: HF + Na2CO3 = NaF + NaHCO3 HF + NaHCO3 = NaF + H2O + CO2 . Thng s dng d Na2CO3 . Khi dung dch hp th NaF t 35 40 g th em ch to Criolit. Phng php ra kh bng dung dch Na2CO3 long s dng trong cc thit b khc nhau , thp ra rng, thp ra c m, thp bt Mc d ch yu kh ra khi b in phn dc ht qua phu chp tuy nhin vn cn mt phn kh vo xng qua qut ht c y ra ngoi lm bn mi trng . Mt s nh my th nghm lm sch kh ny bng h thng thp rng c ng knh 6m, pha trn m rng ln 10m, tng chiu cao ca thp khong 20m, vn tc dng kh trong thp khong 5m/s. HF c trong kh ra d c lm sch trong thit b lm sch kh ri n bi v cui cng l cc ht nha v cng nh . Bi khng thu hi c hon ton v mt phn trong chng c kch thc qu nh ( di 3m ). Gn y lm sch cc ht bi v nha qu nh ngi ta s dng cc thit b lc in kiu ng c hiu sut thu bi ti 90% . Sau kh c lm sch trong thp ra rng loi cc kh tp cht trong c kh HF . Ngoi ra cn c cc thit b lc trng lc cng dng thu cc ht bi nh . 32. III NC THI III.1 Ngun Nc thi Nc thi trong luyn kim cha nhiu tp cht v c . Nc ra khu tuyn qung cha cc oxit kim loi, mui Aluminat, mui silicat, cc tp cht v c khc v t , cht rn l lng. Nc t qu trnh ha tan v ha tch octola, ra sn phm v lng gn sn phm cha kim, kim loi,mt s cht ha tan nh As, F Dung dch in phn cng thng xuyn c thay ra, dung dch ny cha mt s kim loi tan trong qu trnh in phn. Nc lm sch kh v lm ngui x cha cc cht rn l lng, kim loi nng , c th c c hp cht ca S . sn xut 1 tn oxit nhm thi ra khong 3m3 nc thi cc loi. tinh luyn 1 tn nhm sch thi ra khong 30m3 nc thi. Nc thi cha cc kim loi nng gy bnh vim lot d dy, d dy,h hp,ung th mu v cc bnh ng rut . III.2- Qui Trnh x L . Nc thi c x l qua nhiu bc. Ban u nc thi c lc s b bng h thng thit b lc loi b cn b v cc cht rn l lng. Trong cng nghip ngi ta thng s dng cc b lc vi lp vt liu lc c th dng ht nh thch anh, than cc, si nghin Ty thuc vo loi nc thi m la chn vt liu lc. Sau nc thi c a i kh cc cht c hi gm cc kim loi nng, mui, kim, F 33. x l kim thng dng cch trung ha bng cc axit to mui. kh F dng sa vi to kt ta CaF2 . Kim loi trong nc thi c kh bng nhiu cch nh kt ta, in ha, sinh hc,trao i ion. Trong kt ta l phng php ng dng nhiu nht. + Phng Php Trao i Ion. y l phng php dng Ionit ( nha hu c tng hp ), cc cht cao phn t c gc hyrcacbon v cc nhm chc trao i ion cc qu trnh trao i c tin hnh trong cc ct cationit v anionit + Phng Php in Ha. Phng php ny da trn c s ca qu trnh oxi ha kh tch cc kim loi trn cc in cc nhng trong nc thi cha kim loi khi cho dng in mt chiu chy qua . T tch c ion kim loi ra khi nc thi m khng cn b sung ha cht. Phng php ny thch hp x l nc thi c nng kim loi cao trn 1mg/l. Tuy nhin phng php ny cn chi ph ln. +Phng php Sinh Hc. Phng php ny da trn nguyn tc mt s loi thc vt, vi sinh vt trong nc s dng kim loi nh cht vi lng. Ni chung phng php ny kh p dng trong cng nghip v ch x l c nc c nng cht thi thp, v phng php ny cng rt tn din tch. +Phng Php Kt Ta Ha Hc. 34. Phng php ny da trn phn ng ha hc gia cht a vo nc thi vi kim loi cn tch, PH thch hp s to kt ta v tch c kt ta khi nc thi mt PH nht nh ca dung dch nng kim loi vt qu nng bo ha th kim loi s to kt ta. Rt t kim loi to kt ta PH=7 hay trong mi trng axit m phn ln PH trong khong kim yu hoc kim. iu chnh PH ngi ta thng dng sa vi, s a hoc xt. Nu nc thi cha hm lng kim loi cao cn x l ti ngun thu hi kim loi to c hi tun hon li nc v gim hm lng kim loi trong dng thi trc khi x l tp trung. IV NH HNG N VI KH HU Ni chung mi trng lm vic trong cc nh my luyn nhm cng nh luyn kim u rt bi v n, khng kh nng, ngt ngt. 35. Qu trnh nghin v tuyn qung gy n, rung v sinh ra bi. gim n v rung c th tng khi lng thit b hoc to lp m gim rung di thit b. lp t cc h thng ht bi, thng gi bn trong nh my. Cc nh my cng phi t xa khu dn c gim gy n ti khu dn c. Nhit pht sinh t cc l nung v thiu kt, cc kh pht tn ra t qu trnh nung, hi kim loi, oxit kim loi t l tinh luyn, b in phn pht tn ra mi trng gy nh hng ti sc khe cng nhn vin. Ni chung ch c th khc phc phn no nhng vn trn bng cch tng cng p dng khoa hc k thut, cng ngh, my mc hin i nhm gim thiu s r r, pht tn cc cht c hi ra ngoi. Tng cng c kh ha, t ng ha trong cc cng on, hn ch vic con ngi tip xc trc tip vi cc qu trnh nguy him. 36. Ti liu tham kho 1 K thut mi trng NXBKHKT 2 X l nc cp sinh hot v cng nghip nguyn th thu thy 3 X l nc thi - NXB Xy Dng 4 Webside : moitruong.xaydung.gov.vn 5 www.techmartvietnam.com.vn Nhng ngi thc hin : Trnh quang Vinh Hong Th Lu Chu Vn Thin on Thanh Tun --------------------- Lp QLMT