mo boi tron

8/3/2019 mo boi tron

1/23

TRNG I HC CNG NGHIP TP. HCM

TRUNG TM CNG NGH HA HC

Bi bo co thc hnh

ti:

M BI TRN

Ging vin hng dn: Ths NGUYN HU SN

Lp : HHD6LT

Nhm: 4

Thnh ph H Ch Minh, ngy 28 thng 12 nm 2011


2/23

NHN XT CA GIO VIN HNG DN

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Tp. H Ch Minh, ngy 22 thng12 nm 2011

Gio vin hng dnNGUYN HU SN


3/23

M U

M bi trn (MBT) ni chung cng nh cc vt liu bi trn ni ring c

ngha rt quan trng trong i sng, chng c tc dng nng cao hiu qu s

dng, tin cy v tui th ca cc my mc, ng c Hng nm th gii tiu

th khong 40 triu tn vt liu bi trn, trong m bi trn ch chim khong

5 % nhng l sn phm khng th thay th trong k thut cng ngh. Ring

Vit Nam hin nay, mi nm tiu th khong 20.000 tn m. Trong s cc MBT

hin nay, loi m sn xut t nguyn liu du khong v x phng ca cc axit

bo chim ti hn 99 %.

Cc vt liu bi trn qua s dng b thi vo mi trng mt cch babi cng nh b ri vi, r r l ngun ch yu gy nhim. Mc d cha c

thng k y nhng lng cht bi trn tch t trong mi trng chc chn

gy ra tc hi rt ln. Hin nay khi cc yu cu an ton mi trng ngy cng

tng, vic to ra cc sn phm bi trn c kh nng phn hy sinh hc cao thay

th cho cc sn phm bi trn gc du khong truyn thng ngy cng tr nn

cp thit. Cc sn phm ny thng i t este tng hp v c bit t du thc

vt (DTV), vn c kh nng phn hy sinh hc tt hn nhiu du khong thng

thng. Hn na DTV cn l ngun nguyn liu ti to c trong khi ti

nguyn du m ngy cng cn kit.

Hin nay trn th gii c kh nhiu cng trnh nghin cu vic ng dng

DTV lm nguyn liu sn xut MBT trong khi nc ta y l mt lnh vc rt

mi m.


4/23

PHN 1: TNG QUAN

I. L THUYT

1.1. Mc ch th nghim

Tm hiu c s ha hc ca qu trnh sn xut m bi trn.

Nghin cu sn xut m bi trn.

1.2. C s l thuyt

Cc thit b my mc khi vn hnh, cc b mt chi tit tip xc vi

nhau, cc b mt chi tit ny hon ton khng nhn bng nn khi tip xc chu

nh hng ca ma st s gy ra s cn tr chuyn ng, s nng ln ca thit

b, gy mi mn v lm gim cng xut ca ng c, thit b. hn ch s

nh hng ca ma st i vi cc thit b ngi ta to mt lp mng mng

cht bi trn gia cc b mt chi tit vi nhau, cht s dng to mt lp

mng mng c gi l cht bi trn. Cht bi trn c th dng kh, lng,

bn rn hay rn.

M bi trn l mt sn phm bi trn trng thi bn rn, c hnh

thnh do s phn tn ca cht lm c trong pha lng. Ging nh cc snphm bi trn khc, m bi trn vi chc nng lm gim s ma st gia hai b

mt chi tit ma st v mi mn khi hai b mt chi tit tip xc vi nhau. So vi

cc cht bi trn dng lng, m bi trn chim mt t l thp hn, khong 6%

sn phm bi trn.

Chc nng ca m bi trn:

o Chc nng bi trn b mt chi tit: L mt sn phm bi trn nn

chc nng c bn ca m bi trn l to ra mt lp mng ngn

cch s tip xc trc tip ca hai b mt chi tit, gim s ma st v

s mi mn. Khc vi du bi trn, m bi trn c kh nng bm

dnh v kh nng chu nhit cao hn, nn thng c s dng

trong cc trng hp nh thit b hot ng khng lin tc v cn

gi b mt bi trn trong thi gian di, thit b cn s bi trn lin

tc nhng khng th cung cp du bi trn lin tc cng nh khng

th gi du bi trn, thit b hot ng iu kin khc nghit nh


5/23

nhit cao, p sut cao, chu ti trng va p, ti trng ln v vn

tc chm.

o Chc nng bo v b mt chi tit: Cng nh du bi trn m bi

trn s to mt lp mng trn b mt lm vic ca cc chi tit my,gip ngn cn s tip xc vi mi trng m hoc sn phm gy n

mn, ngn cn s tc ng ca cc tc nhn gy n mn v oxy

ha.

o Chc nng lm kn: So vi du bi trn, m bi trn c tnh bm

dnh tt hn do c tnh bm dnh cao hn. c s dng lm

kn cc mi ghp, ren

1.3. Thnh phn ca m bi trn

MBT cha t 65 n 95% du gc, t 5 n 35% cht lm c v

t 0 n 10% ph gia.

Pha phn tn (cht lm c)

Pha phn tn gi vng th keo v hn ch s linh ng ca mi

trng phn tn. Rt nhiu tnh cht ca MBT c xc nh da vopha phn tn. Nu cht lm c chu nhit, m c th lm vic nhit

cao. Nu cht lm c khng b nh hng bi nc, m cng s c

tnh cht nh vy.

Cc cht lm c c th c phn lm hai nhm chnh: cht lm

c x phng mui ca axit bo bc cao vi cc kim loi (x phng

Li, Ca, Ba, Na, Zn ) v khng phi x phng (v c, hu c,

hydrocacbon).

Mi trng phn tn (du gc)

Du gc l thnh phn ch yu m nhim chc nng bi trn, v

th phm cht ca m ph thuc rt nhiu vo phm cht ca du gc

hp phn. Du gc c th l du gc khong, du gc tng hp hay du

gc ng thc vt.


6/23

Du gc khong l mi trng phn tn ch yu sn xut m

bi trn hin nay do gi thnh thp v to ra c m ph hp vi phn

ln cc ng dng trong cng nghip. Trong cc loi du gc du

naphten c a chung dng ch to m bi trn hn c.

Khi m bi trn cn lm vic cc iu kin khc nghit ngi

ta thng s dng mi trng phn tn l du tng hp vi cc tnh cht

hn hn so vi du khong (tnh cht nht nhit, tnh cht nhit thp

tt, bn nhit, bn chng oxy ha cao, khong nhit lm vic

rng). Du tng hp bao gm cc hydrocacbon tng hp, cc dieste,

polyalphaolefin (PAOs), silicon

Du thc vt c s dng lm mi trng phn tn nhm p

ng cc i hi v an ton mi trng ang ngy cng tr nn cp thit.

Cc du thc vt c th c bin tnh khc phc nhc im trc

khi s dng lm du gc.

Ph gia

Du gc thng khng p ng c yu cu lm vic ca MBT

nu khng c mt cc ph gia. Chnh v th ph gia c cho vo m

nhm tng cc tnh cht vn c hoc to ra cc tnh nng mi. Vic pha

ch ph gia vo m cn c kho st k lng hn ch nhng hiu

ng ph khng mong mun, m bo hiu qu ca ph gia m khng

ph hng cu trc m do vic cho qu nhiu ph gia gy ra.

Cc loi ph gia thng c cho vo m nhiu nht l:

Ph gia chng oxy ha (phenyl naphthylamin, di tert

butyl para cresol, ZDDP )

Ph gia c ch g (cc sunfonat kim loi nh natri, bari, nhm,

cc phenolat kim loi ) Ph gia cc p (dibenzyl disunfit, di n octyl photphit )


7/23

Ph gia bm dnh (polyisobutylen, ethylenpropylen copolyme

)

Ph gia th ng ha b mt kim loi (Cc phc hu c cha

nit hoc lu hunh, cc dn xut ca 2, 5 dimecapto 1, 3, 4

thiadiazon )

1.4. Phn loi m bi trn

Mc d, so vi nhu cu s dng cht bi trn th m bi trn chim t

l thp hn so vi du bi trn. Nhng phm vi v mc ch s s dng m

du bi trn vn khng th thay th c. Th trng m bi trn cng rt a

dng ty thuc vo mc ch s dng. Mt s cch phn loi m bi trn nh: Phn loi theo NLGI

Theo tnh nng s dng: m thng dng, m a dng, m c dng.

Theo phm vi s dng: m cng nghip v m ng c.

Theo nhit lm vic: nhit thng. nhit cao, nhit thp.

Theo cht lm c: m gc x phng, m gc hu c, m gc v c.

Theo thnh phn pha lng: m c ngun gc khong, m tng hp.

Theo kh nng chu ti: m chu ti trng thng, m chu ti trng

cao, m chu ti trng rt cao.

Bng1.1. Phn loi m bi trn theo NLGI

STT Cp NLGI xuyn kim lm

vic, 25oC/0.1mm

Dng ngoi

01 000 445- 475 Na lng

02 00 400-430 Cc mm03 0 355-385 Rt mm04 1 310-340 Mm05 2 265-295 Mm va06 3 220-250 Rn va07 4 175-205 Rn08 5 130-160 Rt rn09 6 85-115 Cc rn

Bng 1.2. Mt s loi m chuyn dng


8/23

Loi m c tnh k thut Cng dng

M dng c

- Chu nc tt

- bm dnh cao

- Chng mi mn, n mn

tt

- Bo qun tt

Bi trn cc cm st

trong cc dng c, mymc chnh xc nh v

tuyn in, h thng t

ng, ng h, cc my

quang hc, roto,...

M my in - Chu nc tt

- bay hi thp

- Chng n mn tt

- Chng mi mn tt

Bi trn cc ln, conquay ca my in.

M my cng c

- Bn nhit

- Chu nc tt

- n nh th keo tt

- Bn oxy ha

Bi trn trong khong

nhit lm vic tng

i rng i vi ccmy cng c, luyn kim,

thit b nng chuyn.

M my khoan

- Sn xut t du nng

- C nht cao

- Chu nc tt

- Chng mi mn

- n nh th keo tt

- Bn c hc v oxy ha

Gim mi mn v ma st

trong cc cc khoan,

im ta ca chng xoay

M my hng khng- Nhit nh git >160oC

- nht thp

Bi trn cc cm chi tit

trong my bay


9/23

M tu ha

- Bn nhit

- Chng mi mn tt

- Chng n mn tt

- Chu nc trung bnh

Bi trn cc trc, , c

cu phanh ca tu ha

M tu thy

- M nhm, nhit nh

git >80oC

- C tnh bm dnh tt

- Chu nc tt

- Chu n mn

Bi trn cc cm ma st

trong tu thy.

1.5. Cc ch tiu nh gi cht lng

Xc nh xuyn kim ca m (ASTM

D217)

Thit b o xuyn kim c m t

trn hnh bn.


10/23

Trnh t xc nh:

a m vo bung iu nhit nhit 25 0,5 oC.

Cho m vo ci gi m ri gi 60 ln (bng tay hoc bng my).

Sau khi gi, nhi m vo cc m dng o xuyn kim. ui ht

khng kh khi cc bng cch p cc xung nhiu ln. Dng dao gt bng

mt cc m sao cho khng c bt kh.

t cc m sao cho chp nn chnh gia v st b mt cc.

Th chp nn ri t do trong 5 0,1 s.

c xuyn kim trn bng ch s.

Xc nh nhit nh git (ASTM D566)

Thit b o nhit nh git c m t trn hnh di.

Trnh t xc nh:

- Nhi y m vo cc, gt bng ming, ch khng to bt kh.- Ly que kim loi lun vo cc t di ln sao cho lp m ch dnh vo

thnh cc.

- t cc v nhit k vo ng th, t ng th vo cc gia nhit. Nhit k

c t sao cho u nhit k chm 1/3 vo cc m.

- Khuy bnh v gia nhit vi tc 4 7oC/ pht. Khi t ti nhit

thp hn nhit nh git d on khong 17o

C th tc gia nhitkhong 1 1,5oC/pht. Nhit gia nhit k trong v ngoi ng th

chnh nhau khng qu 1,5oC.

- Nhit nh git c xc nh bng trung bnh cng s ch nhit

ca hai nhit k khi git m u tin nh xung.

Hnh: Thit b o xuyn kim


11/23

Hnh: Thit b xc nh nhit nh git

Xc nh n nh keo (GOST 7142)

Thit b xc nh n nh keo c m t trn hnh di.

Trnh t xc nh:

- Pht mu m cn phn tch vo cc, gt bng mt, khng c to bt

kh.

- Khi nhit khng kh thp hn 15oC hoc

cao hn 25oC cn tin hnh phn tch trong

bnh iu nhit duy tr nhit 20

5oC. t 710 t giy lc khng tro ln mt

knh ri ln bn ca gi xuyn kim.

- Ph mt t giy lc thm du ln mt cc

ng m sao cho gia giy lc v m khng


12/23

c bt kh. p cc ng m v giy lc thm du xung chng giy lc

sch sn trn mt knh.

- t vin bi thp vo ch lm u piston.

Th trc thp n khi tip xc vi vin bi, sau treo qu nng ln trc

thp, c nh trc thp khng cho chuyn ng v bt u tnh thi gian.

- Sau 30 tho qu nng ra. Cn cc ng m cng giy lc thm du.

Phn trm khi lng du tch ra khi m c tnh theo cng thc:

10021

=

m

mmX

Trong :

- m1: Khi lng cc m v giy lc thm du trc phn tch.

- m2: Khi lng cc m v giy lc thm du sau phn tch.

- m: Khi lng m trc khi tin hnh o.

Xc nh bn c hc theo ASTM D1831

bn c hc c xc nh bng my Shell Roll theo ASTM D1831.

Theo trnh t nh sau:

- Ra sch vng bi, hai trc ln v hai ng thp hnh tr bng xng

cng nghip.

- Pht u 500,5 g m ln thnh trong mi ng thp, ch khng

to bt kh.- t trc ln vo ng thp hnh tr v xit cht np sau t ng

tr ln hai trc quay ca my Shell Roll.

- Khi ng my, iu chnh nhit phng my gii hn t 20 38oC.

- Sau 2 h ly m t ng thp hnh tr o xuyn kim.

- n nh c hc ca m l chnh lch xuyn kim trc v saukhi tc ng c hc trn my Shell Roll.

Hnh: Thit b xc nh n nh keo


13/23

II. THC NGHIM

2.1. S lc v quy trnh sn xut m

Qu trnh ch to m thng l qu trnh khuy trn, lin quan n vic

phn tn cc cht lm c vo dung dch v s ng nht cc ph gia hay cccht bin i.

Hnh: My Shell Roll xc nh bn c hc cam bi


14/23

Qu trnh c thc hin bng nhiu cch. Trong mt s trng hp, cc

cht lm c c nh ch to a vo bc hon thnh sn phm v sau

khuy trn vi du cho n khi t c cu trc mong mun ca du, trong

phn ln cc trng hp cht lm t l x phng kim loi, cht lm c chnh thnh thng qua cc phn ng trong qu trnh ch to m.

V d trong qu trnh ch to m x phng Liti, cc du con ln thy phn,

cc axit bo, glycerides c ha tan trong mt phn du v sau c x

phng ha vi dung dch hydroxide liti. Hn hp ny to thnh x phng litri

dng t m c a dn dn vo du khong v sau c gia nhit loi

nc. Sau khi loi nc hn hp li c ct a vo du to ra thnh phm

c c theo mong mun. Trong trng hp ny hn hp x phng-du s l

mt khi do vi cu trc c th.

Tip theo m c th qua mt s qu trnh b sung nh nghin trong thng

hay lm ng nht qu ci thin cu trc. Khi t c cu trc tt v c,

m c hon thnh v ng gi.

Qu trnh hon thin c th hoc khng lin quan n s loi cc kh xm

nhp vo trong qu trnh sn xut. Ngay trc khi rt m c lc b cc bi

tp c th c a vo t nguyn liu gc hay trong qu trnh sn xut m c

th nh hng n tnh nng hot ng ca m.

Nh vy, qu trnh sn xut trong cc loi m c bn u lin quan n

mt s bc trong su bc sau: x phng ha, loi nc, ct hn hp x phng

loi nc vo du nghin, loi kh, lc.

Cc bc tin hnh c bn trn c s dng ch to ton b cc loi

m. Trong nhng quy trnh sn xut nht nh mt vi bc c th c thc

hin ng thi, trong khi cc quy trnh khc chng c phn chia theo th

t c th tng bc.

Thit b chnh cho qu trnh sn xut m gm c thng np liu thch hp

cho x phng ha. Thng thng thit k c b phn gia nhit v c gn cc b

khuy trn. Qu trnh gia nhit c th l t trc tip hay bng hi nng. Cc bkhuy thng l loi c hai chc nng do n c hai b cnh quay theo hng


15/23

ngc nhau mt b cnh c gn vi li dao no gt nhng khi x phng

t hai bn thnh ca thng np liu.

Thng thng cc thng sn xut m c dng m. tuy nhin khi sn xut

mt vi loi m c th dng thng kn hay thng chu p y nhanh qu trnhx phng ha hay t phn ng theo yu cu. sau khi c x phng ha m

c lm mt cng nh khi chng c gia nhit bng phng tin lm mt l

thng hai lp. Tc lm mt sau khi x phng c to thnh l rt quan trng

cho s hnh thnh cu trc tt ca nhiu loi m, bi vy i hi vic phi khng

ch nhit mt cch cht ch.

Nh cp trn cu trc c th b bin i trong qu trnh nghin.qu trnh nghin c th vn tin hnh lin tc ng thi vi qu trnh lm mt

hoc chng c th thc hin ring r. Nu qu trnh nghin c thc hin ring

r th cc bm tc ln, cc thit b ng nht, cc my nghin theo c th

c s dng thng thng. Mc ch ca cng on nghin l lm ph cu trc

dng si hay ci thin b phn tn ca x phng vo dung dch bi trn. Qu

trnh nghin trong thng s ph dc cc cu trc dng si, nhng qu trnh

nghin bng thit b ng nht ha hay cc loi my nghin khc i hi phi cithin s phn tn.

Trong qu trnh sn xut m c th b sc kh. Nhn chung s sc kh

khng lm gim tnh nng bi trn ca m nhng chng nh hng n hnh

dng bn ngoi. ci thin cc yu cu ca khch hng mt vi loi m gn

y c loi kh. C rt nhiu thit b c s dng cho mc ch ny,

nhng v c bn chng u ging nhau theo cch gin cc mng m mng trong chn khng. Mi trng chn khng s ui kh v lm cho m sng ra rt

nhiu.

Cng on sn xut cui cng l lc. N c thc hin vi cc b lc

dng li hay cc dng chuyn dng trn th trng. Kch c li lc s dng

thay i da trn mc ch s dng cui cng ca sn phm m. Mt s loi m

thng dng r tin c th lc s b qua li 40 mesh: Tuy vy m s dng trong

hu ht cc ng dng bao gm s bi trn cc trc c phn t quay i hi li

lc c kch c 100 mesh hay mnh hn.


16/23

Tm li: quy trnh sn xut m gm cc cng on nh sau:

X phng ha, trn du vi x phng, thm ph gia, loi nc:

C17H35COOH + Me(OH)x = (C17H35COO)xMe

Thm ph gia

Loi nc

Ct hn hp x phng loi nc v du

Nghin, to bng, mn, ng nht

Loi kh

Lc

Bao gi sn phm

Khi pha trn cc loi m cn phi xem xt tnh tng hp ca chng. Nu

chng khng c tnh tng hp th khng c pha trn. Cn c s tay k thut

tra cu.

2.2. Thc hnh

Trang thit b

- My khuy c c b iu chnh tc khuy

- Bp in

- Becher 500ml

- Nhit k 200oC

Thc hnh

Th nghim 1 : Kho st thnh phn nguyn liu n c ca m bi

trn

- Giai on x phng ha: Nhit tin hnh phn ng 85-100oC trongkhong thi gian 30 pht.


17/23

- Giai on ng nht to m bi trn: Sau khi x phng c gi n nh,

nht thi c cho vo v ng nht ha ti nhit 120-130 oC trong

khong 1,5 gi.

- Cc t l thnh phn kho st cho trong bng sau:

Bng 3.3. T l nguyn liu kho st sn xut m bi trn

MuDu thc

vt (ml)

Lithium

hydroxit

(ml)

Nht(ml)

T l

VO: LiOH:

Nht

Hm

lng cht

lm c

(%)

01 30 45 90 1:1.5:9 21.702 45 45 90 1:1:6 25

03 30 52.5 80 1:1.75:8 25.6

04 30 52.5 100 1:1.75:10 21.6

05 30 55.5 90 1:1.85:9 24

Th nghim 2 : Kho st nh hng thi gian x phng ha n c

- Tin hnh kho st nh hng ca thi gian x phng ha n ln kim

ca m bi trn cc khong thi gian sau: 30 pht, 60 pht v 120 pht.

- Thnh phn kho st l thnh phn ti u t th nghim 1

- Nhit x phng ha : 90-100oC.

- Giai on ng nht x phng v nht: Nhit :120-130oC, thi gian 90

pht.

PHN 2: BO CO THC HNH

I. THC NGIM

1.1. Kho st nh hng ca t l x phng ha

Bng: kho st t l x phng ha


18/23

T nhng kt qu thu c ta thy rng vi t l 1:7 gia LiOH v du

da th ta thu c sn phm x phng tt nht.

1.2. Kha st nh hng ca t l x phng v du gc

Bng: Kho st t l x phng v du TV

T l (%)

x phng /du da

X

phng

Du

gcNhn xt

18 9 41 c cao, mu nht, hi sn.

22 10 40 c cao, hi sn.

24 11 39 c tt, mu vng dp

T nhng kt qu th c bng trn ta thy rng vi t l 24% xphng trong hn hp m ta thu c sn phm tt nht.

1.3. Kha st nh hng ca thi gian ln qu trnh x phng ha

Bng: nh hng ca thi gian ln qu trnh x phng ha

T l LiOH Du daTgian

(phut)Nhn xt

1:7 7.15 42.85 30 M mn p

1:7 7.15 42.85 60 Kh, c sn

1:7 7.15 42.85 120 It sn, d mn km, kh

T nhng kt qu thu c ta thy rng vi thi gian x phng ha

khong 30pht ta thu c sn phm x phng tt nht (chu l trong thi gian

x phng ha ta loi trit nc d thu c sn phm x phng tt nht).

1.4. Kho st nh hng ca nhit ln qu trnh c ha

T l LiOH Du da Nhn xt

1:4 12.5 37.5 Nhiu sn, Khng mn, qu tm

1:5 8.4 41.6 It sn, cha mn, mu cha p

1:7 7.15 42.85 Khng sn, x phng vng ng, p


19/23

Bng: nh hng ca nhit ln qu trnh c ha

T nhng kt qu thu c bng trn ta thy rng vi nhit khong

ln hn 1800C ta thu c sn phm m tt nht.

1.5. Kho st nh hng ca nhit ln qu trnh x phng ha

Bng: nh hng ca nhit n qu trnh x phng ha

T kt qu trn ta thy rng gia n x phng ha khong nhit t

85-1050C l tt nht.

II. NHN XT CHUNG

T cc s liu thc nghim c c trong qu trnh ngin cu i nh

hng ca t l, thi gian v nhit ca tng qu trnh ta thu c sn phm

m tt nht da vo bng sau:

T l (%)

x phng/ dunhn

X

phng

Du

gc

Nhit

(0C)

Nhn xt

24 11 39 120 Long, nhiu sn.

24 11 39 140 Long, nhiu sn.

24 11 39 160 c km, sn.

24 11 39 180Vng ng, p, c cao, khng

sn.

T l NaOH Axit stearic Nhit (0C) Nhn xt

1:7 7.15 42.85 70 Hi sn, thi gian lu, cha mn.

1:7 7.15 42.85 80 Khng mn, thi gian lu.

1:7 7.15 42.85 90 It sn, cha mn.

1:7 7.15 42.85 100Khng sn, x phng vng ng,

p.1:7 7.15 42.85 110 Hi sn, vng p.


20/23

Stt Nguyn liu Khi lng (g)

1 Du da 40

2 LiOH 6

3 Du nhn 195

6 Nc 60 (ml)

III. TR LI CU HI

1. S khc nhau c bn gia m Li v Ca

M liti c nhit nh git cao, t tan trong nc, t x phng liti ngi

ta sn xut cc loi m dng nhit thp n cc loi m dng nhit cao.

Khong nhit m m liti c php s dng l t -60 ti 140 oC, m liti c

tnh n nh c hc v tnh n nh keo tt.

M Ca l loi m c s dng ph bin, lu i v r tin nht. M

canxi tng hp c x phng canxi ca du th hoc m ha hc. Trong thnh

phn ca m canxi nht thit phi c mt ca nc, v nc to tinh th hydrat

ca x phng canxi. Nh vy nc trong m canxi to ra cu trc khng gian

m. Nu loi nc th cu trc ca m b ph v, lm m t phn ra thnh du

nhn v x phng. y nc ng vai tr l cht ph gia n nh th keo cam canxi. Nu m c hm lng nc thp hn 0.5% th m c hin tng phn


21/23

r, cn nu hm lng nc ti 5% (cao hn mc quy inh) nhng khng nh

hng ti tnh cht s dng ca m, hm lng nc trong m thch hp nht l

1 3%. M canxi c u im : gi tnh thp, tnh chng xc v chng mi mn

cao, bo v kim loi tt, th keo tng i n nh, mc chu nc p ng nhucu m bo cho vic s dng rng ri trong cuc sng. Nhc im ca m

canxi: Nhit nng chy thp nn c hn ch v phm vi s dng. 100 oC m

b mt nc nn khung cu trc bt u b ph v dn. Nhit cng cao tc

phn hy cng nhanh. Cho nn nhit cho php s dng l khong 50-70oC.

M canxi c tnh n nh c hc thp khi bo qun trong kho, bao b, hay trong

iu kin mi trng m cc c cu tm dng lm vic trong mt thi gian di.

M canxi ch yu dng lm m chng ma st, ngoi ra cn dng lm m bo

qun rt tt v n c tnh nng chu nc, thi tit m v nh sng nhng nhit

khng qu 50oC.

2. ngha ca qu trnh x phng ha ?

Qu trnh x phng ha quyt nh trc tip n cht lng x phng v

gin tip n cht lng sn phn m. Qua qu trnh kha st th ngim ta thy

rng cn mt t l du da v Li(OH) va thu c cht lng x phng

tt nht. Nu qu trnh x phng ha qu t thi gian th nc s khng b loi

trit , nh hng n cht lng sn phm m. nu qu trnh x phng ha c

nhiu sn s nh hng n c cng nh cht lng sn phm m thu c.

Vy nu xt v mt tng th ca ton b qu trnh, th gian on x phng

ha l mt gia on ch cht, quyt nh n cht lng sn phm. y cng l

giai on c ngha nht trong ton b qu trnh.

3. ngha ca ch tiu im nh git i vi cht

lng ca m nhn?


22/23

Nhit nh git c xc nh theo ASTM D 566 (vi m c nhit

nh git khng vt qu 288oC) hoc D 2265 (vi m c nhit nh git ln

hn 288oC) l nhit ti git m lng u tin nh ra khi cc di cc iu

kin tiu chun.Nhit nh git khng c tc dng nhiu trong vic d on cc iu

kin lm vic ca m, n cho php phng on gii hn nhit cao khi lm

vic vi MBT. M x phng liti c nhit nh git khong t 150 200oC.

4. Trnh by cc thang o ca xuyn kim?

c ca m c c trng bi xuyn kim su ca mt cn

kim loi tiu chun ln vo m (tnh bng mm/10) mt iu kin tiu chun vkhi lng, thi gian v nhit . xuyn kim c xc nh theo ASTM D

217 hay ASTM D 1403.

xuyn kim c phn loi bi vin du m quc gia Hoa K (NLGI)

nh bng sau :

Bng: xuyn kim theo NLGI

NLGI xuyn kim Trng thi

000

00

0

1

2

3

445 475

400 430

355 385

310 340

265 295

220 250

Na lng

Na lng

Na lng

Mm

Kem

Hi cng


23/23

4

5

6

175 205

130 160

85 115

Hi cng

Hi cng

Cng

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