TI U CHUN VI T NAM TCVN 6303 : 1997

Nhm sunfat k thut Technical Aluminum Sulphate

1 Phm vi p dng Tiu chun ny p dng cho nhm sunfat ngm nc ( cn c gi l phn n) c sn

xut t nhm hidroxit v axit sunfuric Cng thc phn t : Al2( SO4).nH2O. 2. Tiu chun trch dn TCVN 1694-75 Sn phm ho hc- Ly mu v chun b mu. TVN 4851-89 Nc dng phn tch trong phng th nghim. TCVN 1058-78 Ho cht. Phn nhm v k hiu mc tinh khit TCVN 1272-86 Thuc th v ho cht tinh khit c bit-phng php phc cht- xc

nh hm lng TCVN 4374-86 Thuc th-phng php chun b dung dch ch th TCVN 1055-86 Thuc th-Phng php chun b cc thuc th dung dch v hn hp ph

dng trong phn tch TCVN 3732-82 Thuc th- Phng php xc nh cn khng tan trong nc TCVN 2297-86 Thuc th axit nitric TCVN 3778-83 Thuc th-phng php xc nh asen TCVN 1056-86 Thuc th- Phng php chun b cc dung dch dng cho phn tch trc

quang v phn tch c khuych tn TCVN 5507-91 Ho cht nguy him- Quy phm an ton trong sn xut , s dng, bo qun

v vn chuyn 3 Yu cu k thut 3.1 Nhm sunfat k thut c chia thnh hai loi: - nhm sunfat k thut thng dng; - nhm sunfat k thut cht lng cao. 3.2 Cc ch tiu ho l ca nhm sunfat k thut phi ph hp vi mc quy nh trong

bng 1. Bng 1- Ch tiu v mc ca nhm sunfat k thut Tnh bng phn trm

Mc quy nh Tn ch tiu Nhm sunfat k thut thng dng Nhm sunfat k

thut cht lng cao

1. Dng bn ngoi

Dng ht, tm , mnh, vi kch thc khng xc nh. Mu tng c

Dng ht, tm, mnh, vi kch thc khng xc nh. Mu

2. Hm lng cn khng tan

trong nc, khng ln hn 3. Hm lng nhm quy ra

Al2O3, khng nh hn 4. Hm lng st quy ra Fe2O3,

khng ln hn 5. Hm lng asen quy ra

As2O3, khng ln hn 6. Hm lng kim loi nng

quy ra Pb, khng ln hn 7. Hm lng axit sunfuric t

do, khng ln hn

hay vng chanh hoc hng nht

0,500

15,000

0,040

0,001

0,005

0,200

trng c.

0,100

17,000

0,020

0,001

0,005

0,100

4. Phng php th 4.1 Quy nh chung 4.1.1 Nc ct dng phn tch phi theo cc quy nh trong TCVN 2117-77 4.1.2 Thuc th dng trong tiu chun ny l loi tinh khit ho hc ( TKHH) hay tinh

khit phn tch ( TKPT). 4.1.3 Cc php th phi tin hnh song song trn 2 mu cn 4.1.3 ng so mu phi l cng loi trong mt ln phn tch 4.1.5 Cn phn tch c chnh xc n 0,01 g. 4.2 Ly mu 4.2.1 L hng c ly mu L hng l lng sn phm c sn xut t cng mt t nguyn liu ban u, c

ng gi trong cng mt loi bao b v c gi n hay c bo qun ti cng mt a ch. 4.2.2 Trnh t ly mu ti mi l Nguyn tc ly mu tun theo quy nh trong lc ly mu ca TCVN 1694-75. Ni

dung ly mu nh sau: Cn c vo s lng n v bao gi ( ly khi lng chun tnh l 25 kg) c trong l

quyt nh s n v cn ly mu. Ti mi n v bao gi c chn s ly ra mt mu c trong n v, gi l mu ban u. T l bao c ly v lng mu ban u theo quy nh trong bng 2.

Bng 2 - T l ly mu trong l

Tng s n v bao gi c trong l

S dn v c chn ly mu ban u

Khi lng mu ban u ly ra t mi n v c

chn, g

n 300 t 301 n 500 t 501 n 1500 t 1501 n 3001 t 3001 n 10 000

3 4 5 7 10

500 400 300 300 200

i vi l hng c trn 10 000 bao th cn phn thnh nhiu l nh c s lng n v bao gi nm trong khoang rquy nh trong bng 2. Sau tin hnh ly mu ring bit cho tng l nh ny.

4.2.3 To mu chung Trn u c c mu ban u c mu chung. Mu ny i din cho l hng. Mu phi

c bo qun ni kh ro. Trn bao b ng mu phi ghi r: - tn sn phm; - s l hng; - ngi ly mu - ngy, thng, v a im ly mu 4.2.4 Mu th nghim c chun b t mu chung, theo nguyn tc chia t mu ny cn

bo m khi lng phn tch thng ly khong 200 g. Phn cn li ca mu chung l mu lu c bo qun ni kh ro, trong thi gian t nht l 30 ngy khi cn em phn tch trng ti.

4.3 Dung dch mu phn tch Cn khong 25 g mu th nghim vi chnh xc 0,001 g cho vo cc dung tch 250 ml.

Thm 200 ml nc nng v 5 git axit sunfuric ( 1:1), khuy u v un si trn bp cch thu trong thi gian 30 pht. Lc dung dch qua giy lc khng tro. Ra cn trn giy bng nc nng nhiu ln cho ti khi khng cn ion sunfat trong nc lc( th bng dung dch bari clorua). Chuyn dung dch v nc ra vo bnh nh mc 500 ml v thm nc n vch, lc k. G cn li trn giy lc khng tro xc nh hm lng cn khng tan trong nc( 4.4).

Dung idhcj sau nh mc gi l dung dch mu phn tch . Dung dch ny c s dng xc nh cc ch tiu ho hc ca mu th.

Ch thch Trong trng hp ch xc nh mt ch tiu c th no , cho php dng lng cn ring r cho mi ln phn tch. Nhng trcd khi nh phn tch phi h tan mu bng nc theo t l rn : lng = 1 : 20 c th p dng c cng thc tnh kt qu cho ch tiu ti phn tng ng ca tiu chun.

4.4. Xc nh hm lng cn khng tan trong nc 4.4.1 Cch tin hnh Cho giy lc v cn ( 4.3 ) vo chn s bit khi lng, sy kh v nung 10000 C

500 C, cn n khi lng khng i. 4.4.2 Tnh kt qu Hm lng cn khng tan trong nc, tnh bng % theo cng thc:

g2 g1 X1 = . 100 G Trong g1 l khi lng chn khng, gam; g2 l khi lng chn v cn sau khi nung, gam; G l khi lng mu th ( mc 4.3), gam 4.5 Xc nh hm lng nhm oxit 4.5.1 Nguyn tc Xc nh nhm bng phng php chun complexon pH t 5,5 n 6,0 vi ch th

xylenol dacam vi cch chun thay th 4.5.2 Dng c v thuc th - buret: dung tch 25 ml; - bnh nn : dung tch 250 ml; - dung dch m axetat c pH t 5,5 n 6,0 : chun b theo bng 11 trong TCVN

1056-86 hay theo phn 2 trong TCVN 1272-86 ( phn quy nh cho dung dch m II) - trilon B, dung dch 0,025 M: chun b theo iu 3.2 trong TCVN 1272-86; - km axetat, dung dch 0,025 M: chun b theo iu 3.6 trong TCVN 1272-86; - amoni hidroxit, dung dch ( 1 : 3); - xylenol dacam , dung dch 0,1 %: chun b theo iu 2.5.25, bng 5 trong TCVN

4374-86 v iu lu v ch th ny phn 2 trong TCVN 1272-86; - amoni florua, dung dch 5 %. 4.5.3 Cch tin hnh Ly 10 ml dung dch mu th ( 4.3 ) cho vo bnh nn 250 ml. Nh vi git metyl , thm tng git amoni hidroxit cho n khi dung dch th chuyn t

sang vng. Cho tip 25 ml dung dch trilon B v un nng n khong 60 n 70 0C. Thm 10 ml dung dch m axetat, 5 git ch th xylenol da cam , chun bng dung dch km axetat cho n khi mu dung dch chuyn t vng sng sang hng. Tip tc thm 10 ml amoni florua v un si 5 pht.

ngui n khong t 60 n 70 0C. Tip tc chun bng dung dch km axeteat n khi mu ca dung dch chuyn t vng chanh sang hng. Ghi th tch V ca km axetat tiu tn cho ln chun ny

4.5.4 Tnh kt qu Hm lng nhm oxyt, tnh bng % theo cng thc: V . 0,0012745 . 500 .100 X = G . 10 Trong

V l th tch dung dch Zn ( CH3COO)2 0,025 M dng chun ln th 2, mililit( tng ng th tch EDTA 0,025M wocj gii phng t nhm complexonal ) ( 0,0012745 g l khi lng Al2O3 tng ng vi 1 ml EDTA);

G l khi lng mu, gam. 4.6 Xc nh hm lng st oxit 4.6.1 Phng php so mu bng my ( phng php trng ti) 4.6.1.1 Nguyn tc St ( III ) kt hp vi O- Phenantrolin to thnh mt phc mu cam hay vi 2-2

dipiridin cho phc mu thm. o cng mu ca dung dch 4.6.1.2 Dng c v thuc th - my so mu lm vic c vng nh sng c bc sng t 500n nm n 540 nm. - giy cng g - axit sunfuric : dung dch ( 1 : 1 ) trong nc - hidroxylamin hidroclorua: dung dch 100 g/l. Chun b theo iu 2.35 TCVN 1055-

86; - O-Phenantrolin( 1-10- phenantrolin) : dung dch 3g/l. Chun b theo iu 2.61

TCVN 1055-86 - 2,2- dipiridin: dung dch 0,5 % trong ru chun b theo iu 2.27 TCVN 1055-86; - dung dch m amoni axetat: ho tan 100 g amoni axetat vo khong 600 ml nc,

lc. Thm 200 ml axit axetic bng vo dung dch lc. Pha n 12lit. - dung dch chun st A : ho tan 0,702 g phn st ( II ) amoni [ Fe( NH4)2( SO4)2. 6

H2O ] vo 50 ml nc c cha 10 ml dung dch axit sunfuric 10 %. Chuyn vo bnh nh mc 1000 ml v thm nc n vch . Mt mililit dung dch chun st A cha 0,1 mg st ( Fe) . Dung dch pha xong phi c ng trong bnh PE v ch dng trong vng 2 ngy.

- Dung dch chun st B: ly 100 ml dung dch chun st A vo bnh nh mc 1000 ml. Thm nc n vch , lc u. Mt mililit dung dch chun st B cha 0,01 miligam st ( Fe). Ch chun b trc khi dng

- Xy dng ng chun a) trong 6 bnh nh mc dung tch 50 ml c nh s, ln lt cho dung dch chun

st B theo lng nh sau:

Bnh nh mc, s Th tch dung dch chun st B cho vo, ml

Hm lng st tng ng, mg/ 50 ml

0 1 2 3 4 5

0,0 1,0 2,0 3,0 4,0 5,0

0,00 0,01 0,02 0,03 0,04 0,05

b) tip theo, cho vo mi bnh cc dung dch sau: - nc ct : 20 ml; - hidrylamin hidroclorua : 1 ml; - O-Phenamtrolin hay 2,2 dipiridin : 5 ml. Lc u, thm tip vo mi bnh dung dch amoni hidroxit pH dung dch trong mi bnh

chuyn v khong 3,5 4,0 ( th bng giy cng g ). Lc k, sau thm 5 ml dung dch amoni axetat v thm nc n vch, lc k. yn dung dch 15 pht. o mt quang bc sng 510 nm ( knh lc mu xanh lc), dung dch trong bnh s 0 l dung dch so snh.

c) dng ng cong chun: v ng cong chun ph thuc gia mt quang v hm lng st tnh bng mg/ 50 ml dung dch.

4.6.1.3 Cch tin hnh Ly 25 ml dung dch mu th chun b trn ( 4.3 ) cho vo bnh nh mc dung tch

50 ml ri thm 1 ml hidroxylamin hidroclorua, 5 ml dung dch O-Phenantrolin hay 2,2-dipiridin. Lc u, thm amoni hidroxit pH dung dch trong bnh chuyn v khong t 3,5 dn 4,0 ( th bng giy cng g ). Thm nc n vch mc v lc u.

ng thi lm mt mu trng. Sau 15 pht, o mtk quang ca dung dch mu so snh vi dung dch trng. 4.6.2.6 Tnh kt qu Hm lng st oxit ( Fe2O3), tnh bng % theo cng thc sau: a. 100 . 1,4297 a . 0,14297 X3 = = 1000 . G G Trong : a l lng st c trong 50 ml dung dch mu ghi c theo ng cong chun, mg; G l lng mu th tng ng th tch ly xc nh, gam; 1,4297 l h s tnh chuyn Fe thnh Fe2O3. 4.6.3 Phng php so mu bng mt 4.6.3.1 Nguyn tc So snh cng mu ca dung dch phc st ( III ) thioxianat ca mu th, vi dung

dch chun. 4.6.3.2 Dng c v thuc th - pipet; - cc thu tinh 100 ml; - ng so mu dung tch 100 ml; - bnh nh mc 500 ml; - axit nitric theo TCVN 2297-78 : dung dch pha long ( 1: 1); - amoni thioxianat: dung dch 15 %; - ung dch chun st A v B chun b theo 4.6.1.2. 4.6.3.3 Cch tin hnh

Ly 10 ml dung dch mu th (iu 3.2 ) vo mt ng so mu (ng s 1), thm 1 ml dung dch axit ntic. un trn bp cch thu si khong 5 pht. ngui v thm 5 ml dung dch amoni thioxianat vo ng. ng thi cho vo mt ng so mu khc c cng kch thc (ng s 2 ) ln lt thm:

- 10 ml nc ct; - 1 ml dung dch axit nitric; - 5 ml dung dch amoni thioxianat. Dng microburet cho ng thi vi lng bng nhau: dung dch chun st vo ng 2 v

nc ct vo ng 1. Sau mi ln thm nc hay dung dch chun st B , lc u mi ng v so snh cng mu ca hai ng trn nn trng.

Nu cn chnh lch th tip tc cho thm nc v dung dch chun st B vo cc ng tng ng ri so mu li . Ch lc u mi khi cho thm. Tip tc tiin hnh cho n khi quan st thy cng mu ca dung dch trong hai ng bng nhau.

Ghi th tch dung dch chun st dng. 4.6.3.4 Tnh kt qu Hm lng st oxit, tnh bng % theo cng thc: V . 0,01 . 100 . 1,4297 V . 0,0014297 X3 = = 1000 . G G Trong : V l th tch ca dung dch chun st B d cho vo ng s 2, mililit; G l khi lng mu tng ng th tch dung dch mu ( 4.3 ) ly, gam; 1,4297 l h s tnh chuyn Fe thnh Fe2O3 4.7 Xc nh hm lng asen 4.7.1 Hm lng asen c xc nh theo TCVN 3778-83 v thm cc ni dung sau: a) s dng ducngj c xc nh asen c cc ng thu tinh ng knh bng 10 mm; b) khng cn x l trc cc mu th nh trong phn 2 trong TCVN 3778-83; c) giy tm thu ngn bromua c chun b theo iu 2.33 trong TCVN 1055-86; d) giy ( hoc bng ) tm ch axetat c chun b theo iu 2.24 trong TCVN 1055-86 e) chun b thang so snh asen tiu chun ( quy ra As) trong khong 0,001 mg/ml n

0,005 mg/ml vi tng nc thay i 0,001 mg/ml. C th chun b thang d phng trong khong 0,0001 mg/ml n 0,001 mg/ml vi tng nc thay i 0,0002 mg/ml;

f) lng dung dch mu th chun b theo iu 4.3 cn thit cho mi ln phn tch l 30 ml;

g) tin hnh xc nh asen theo cc mc 3.3.1 v 3.3.2 trong TCVN 3778-83 . Tip theo thc hin iu 3.3.3 trong TCVN 3778-86 nh sau:

Ly 30 ml dung dch mu th ( 4.3) cho vo bnh phn ng ca dng c xc nh asen. Ln lt thm:

- dung dch axit clohidrric 20 % : 20 ml; - dung dch thic ( II ) clorua 0,4 % : 5 ml; - dung dch kali iodua 10 % : 5 ml;

- dung dch niken clorua : 1 ml; - bt km kim loi : 5 g. ng ngay np bnh, lc trn cn thn vi vng ri yn 1 gi nhit phng, sau

ly giy tm thu ngn bromua ra v so snh cng m u to thnh trn giy vi mu ca thang chun.

4.7.2 Tnh kt qu Hm lng asen tnh bng % theo cng thc sau: 1,32 . a 0,132 a X4 = = 10 . G G. trong a l hm lng asen tm c trn thang chun, mg/ml; G l khi lng mu tng ng th tch dung dch mu ( 4.3 ) ly, gam; 1,32 l h s tnh chuyn As thnh As2O3. 4.8. Xc nh hm lng kim loi nng 4.8.1 Nguyn tc So snh cng mu ca huyn ph hp cht sunfua trong ng mu vi cng mu

cia huyn ph ch sunfua trong ng chun. 4.8.2 Dng c v thuc th - ng so mu dung tch 100 ml; - bnh nh mc 100 ml; - amoni hidroxit: dung dch 10 %. Chun b theo iu 2.6 TCVN 1055-86; - axit axetic : dung dch 30 %. Chun b theo iu 2.18 TCVN 1055-86; - hidrosunfua: dung dch bo ho. Chun b theo iu 2.59 TCVN 1055-86; - nc axit ho: dng amoni hidroxit hoc axit axetic chnh pH ca 2000 ml nc ct

n khong 3 4. Nc axit ho s c dng thay nc ct trong sut qu trnh xc nh kim loi nng;

- dung dch chun ch A: chun b theo iu 2.16.2 TCVN 1056-86 c dung dch cha 1 mg ch trong 1 l dung dch

- dung dch chun ch B : cho 10 ml dung dch chun ch A vo bnh nh mc 100 ml, thm nc n vch 100 ml, lc k. Dung dch B cha 0,01 mg ch / 1 ml , dung dch B chun b phi dng ngay trong ngy.

4.8.3 Cch tin hnh Ly 10 ml mu chun b trn ( 4.3)cho vo ng so mu (ng s 1), ri thm khong 30

ml nc, lc u. Thm 10 ml dung dch hidrosunfua, lc u. ng thi trong mt ng so mu khc (ng s 2) thm ln lt:

- 10 ml dung dch hidrosunfua; - 40 ml nc. Dng 2 microburet cho ng thi 1 lng bng nhau : dung dhc chun ch B vo ng 2 v

nc ct vo ng 1. Sau mi ln thm, lc u mi ng v so snh cqng mu ca hai ng trn nn trng. Tin hnh tip tc cho n khi mu ca hai ng bng nhau.

Ghi th tch dung dch chun ch B thm vo ng 2 4.8.4 Tnh kt qu Hm lng kim loi nng qui ra ch, tnh bng % theo cng thc sau: V. 0,01 . 100 0,001 . V X5 = = 1000 . G G Trong V l th tch ca dung dch chun ch B cha 0,01 mg ch / ml cho vo ng so mu s 2,

ml; G l khi lng mu th, tng ng th tch dung dch mu ( 4.3 ) ly xc nh, g. 4.9 Xc nh hm lng axit sunfuric t do 4.9.1 Nguyn tc Chun axit t do bng natri hidroxit vi ch th phenolphtalein 4.9.2 Dng c v thuc th - bnh nn dung tch 250 ml; - axit sunfuric: dung dch 0,1 N; - natri hidroxit: dung dch 0,1 N; - natri florua : dung dch 4 % trung tnh; - phenolphtalein: dung dch 1 % trong cn, chun b theo iu 2.1.36 trong TCVN

4374-86. 4.9.3 Cch tin hnh Cn khong 0,5 g mu vi chnh xc 0,001 g. Cho mu vo bnh nn ( bnh 1) cha

sn 20 ml n 30 ml nc ct ha tan mu, sau thm chnh xc 10 ml dung dch axit sunfuric. un si 1 pht n 2 pht. ngui n nhit phng. Thm 10 ml dung dch natri florua, 3 git ch th phenolphtalein, ri nhanh chng chun bng natri hidroxit cho n khi xut hin mu hng bn trong 1 pht.

ng thi tin hnh chun mt dung dch kim tra trong bnh khc( bnh 2) gm cc ho cht ging nh bnh 1 nhng mu th c thay bng nc ct.

4.9.4 Tnh kt qu Hm lng axit sunfuric t do tnh bng % theo cng thc: ( V1 V2) .0,1 .100 V1 V2 X6 = 49,035 . = 0,490359 . 1000 G G trong V1 l th tch dung dch natri hidroxit tiu tn khi chun dung dch cha mu th, ml; V2 l th tch dung dch natri hidroxit tiu tn khi chun dung dhc mu kim tra, ml; 49,0359 l ng lng gam ca axit sunfuric trong phn ng chun ny,g; G l khi lng mu th,g. 5. Ghi nhn, bao gi, vn chuyn, bo qun

5.1 Ghi nhn 5.1.1 V tr Nhn c ghi trc tip ln bao b ng sn phm hoc in ln giy v gn km vi bao b

ng hoc oc in km vi giy chng nn cht lng l hng cp cho khch hng. 5.1.2 Ni dung Nhn ghi phi c cc ni dung sau: - tn sn phm; - loi ( ghi hm lng danh ngha ca sn phm ); - tn c s sn xut hay c s cung cp; - khi lng mt n v bao gi( khi lng tnh); - tn tiu chun p dng; - k hiu l hoc thi gian sn xut hoc s hiu hp ng giao nhn l hng ny. Ch thch- c th kt hp ni dung ghi nhn vi ni dung ghi nhn an ton. 5.2 Bao gi 5.2.1 Bao gi ng sn phm phi chu c mi trng axit mnh. Bao gi cha sn

phm phi c kh nng gi kn hn ch ti a vic lt kh m vo bn trong bao gi sut qu trnh vn chuyn, bo qun sn phm.

5.2.2 Cc loi bao gi Cc loi bao gi sau y c th c dng tu theo lng sn phm ng bn trong: a) ti lm bng giy craft nhiu lp mng mng PE hay PP: cho php ng sn phm vi

khi lng khng qua 25 kg; b) ti dt t si tng hp v c lp mng chng m bn trong: cho php ng sn phm

vi khi lng khng qu 50 kg; c) thng nha cng hoc kim loi c lt lp ph chu axit: cho php ng sn phm vi

khi lng khng qu 250 kg. 5.3 Vn chuyn Sn phm ng trong bao gi c th c vn chuyn bng phng tin vn ti thng

dng. Khi vn chuyn sn phm phi c ch ring bit hay phi cch ly tt vi hng ho khc.

5.4 Bo qun 5.4.1 Sn phm phi c bo qun ni kh, mt, thong gi, c che ma nng. 5.4.2 Sn phm ch c xp chng ln n hau khng qu 40 lp v phi c cch ly vi

nn kho 5.4.3 Nn nh ni bo qun nn lm bng hay c ph vt liu chu axit 6 .Quy tc an ton khi lm vic vi nhm sunfat 6.1 Nhn cnh bo Trn cc bao gi ng sn phm dng bt, phi dn nhn cnh bo vi ni dung sau: a) biu trng cho loi ho cht n mn: loi s 5, ph lc IV ca tiu chun TCVN 5507-

1001. b) Cc dng ch cnh bo nm trong khung vin en v ghi r:

NHM SUNFAT HO CHT HI DA

Trnh bm vo da v mt Trnh ht bi m bc ln

6.2 Trang b bo h cc nhn Khi lm vic vi nhm sunfat, phi s dng: - gng tay cao su; - qun o bo h; - khn qung c; - m trm u; - ng chu axit; - knh bo v mt; - khu trang m.