. VA CONG N G H E MO-LUVEN KIM
-ESI
NGHIEN CUU QUY TRINH XAC DjNH CAC NGUYEN TO CU, AU, AG TRONG XJ THAI CUA NHA MAY LUYEN DONG
CN. P H A N T H A N H HA, C N . N G U Y E N D A N G HAI Vien Khoa hgc v Cung nghe Md-Luyen kim
_ ^ ai nguyen khodng san tren t h i gidi ndi chung I vd d Vidt Nam ndi ridng dang ngdy cang can -^ kigt, cdc giai phap s u d y n g h p p ly, t i l t kigm tdi nguydn dang d u a c ddy mgnh n h i m dam bao phdt t r i l n ben v u n g
Hdng ndm tai nha mdy luydn ddng Lao Cai thai ra khoang tren 20 ngan tan xi thai cd ham lupng Au=0,2 gft; Ag=0,2 g/t va Cu=0,9 % ngoai ra cdn nhieu nguydn t l khde n h u REO, S. . Vi vay vide xdy dung Quy trinh phdn tieh ehinh xdc xae dinh cdc nguyen td Cu, Au, Ag trong xi Id rdt quan trpng va rdt cdn t h i l t khdng nhung giup xac dinh l u p n g kim loai trong xT thai md cdn gdp phdn dinh h u d n g x u ly thu hdi cac kim logi quy nay. Trong nhung nam qua tai Vien Khoa hpc va Cdng nghd Md-Luyen kim da t n l n khai Be tai
"Nghien euu quy trinh xac t^nh cac nguyen td Cu, Au, Ag trong xf thai cua nha may luydn dong". K i t qua nghien c d u se la can e u khoa hoc 6i dp dung vdo thuc t l san xudt, tham khao k i t h p p thu hdi cdc nguyen td cd ich di kem cdn trong xi va cd hudng x u ly mdi trudng.
B d xae dmh ham lug-ng A u , A g , C u trong xi cd nhidu p h u a n g phap phdn tich: P h u a n g phap phan tieh khdi l u a n g , p h u a n g phap phdn tich t h i tfch, p h u a n g phap t r i e quang, p h u a n g phap kich hogt natron, p h u a n g phap quang pho phdt xa nguydn t u , p h u a n g phdp quang phd hdp thy nguydn t u ,
1. Mpt sd phuo-ng phap xac djnh ham lirp'ng C u , Au, Ag
1.1. Xac djnh ham Iwgng vang
P h u a n g phap xac djnh A u d a n gian, co dp chinh xac cao Id p h u a n g phap hon h i n g thuy ngan (Hg), xac c^nh vdng: Tidn x u ly qugng vdng d 650 °C
khoang 2h, sau do ldc qugng vang vdi Hg kim loai theo t i l d Hg' A u = 7 ' 1 , sau 3h tach Hg c h u a A u khoi qudng, t i l p theo hda tdeh Hg bdng dung dich HNO3 1:2 thu d u p e vdng sgch. Hodc xdc dinh Au bdng p h u a n g phdp xyanua. t i l n x u ly qudng Au bdng CaO vd N a O H d i n pH=10,5-11,0 sau dd xyanua hda qudng vang trong hop n h u a . V d i ndng do KCN=1 %, theo p h u a n g phap xoay trdn tren may n g h i i n bi s u khoang 72 h
T i l p theo XI mang hda dung djch xyanua vang bdng Zn dd thu hdi A u kim logi. Cudi cung Idm sach Au khoi cae tap c h i t bdng axit H2SO498 % va HNO3 65 % thu d u a c vdng tinh k h i l t . Xae dinh A u bdng p h u a n g phdp vang nghiem ( p h u a n g phdp c u d n g thuy): c h u y i n hda quang c h u a vang ra dang AUCI3, k h u Au^* v l Au° bdng NaaSOa, sau dd loc, r u a k i t tua, say khd tinh ra ham l u p n g A u trong mau. Ngoai ra cd t h i xae dinh Au bdng phuang phap Cupen (nung luyen): t i l n hanh phdi lieu quang vdng vdi S1O2, C, NaaCOa, Na2B407, KNO3 vd PbO...
theo ti Id thieh hpp. Nung p h i i lieu trong chen sdnh d 1 200 °C khoang 120 phut, Au tao thanh hpp kim vdi Pb Giai phdng A u khdi Pb bdng chdn x u a n g hay chen MgO d 1.100 °C khoang 60 phut.
Khi do A u ed r i t nhidu nguyen td can trd, mat khde hdm lupng cua chung r i t nho nen can t h i l t phai tach va Idm gidu Au. Trong nghidn c u u chon phuang phap c h i l t AuCr d u d i dang phdc lien hpp ion trong do thuoc t h u d l tgo phuc lien h p p ion la Tnoctyl methyl amonium clorua (TOMAC) cd cdng thuc R3CH3NCI (R:CaHi7). Phan dng xay ra n h u sau:
RaNCHa^CI + [ A u C U T =R3NCH3 [AuCU ]• + CV H u u c a N u d c H d u c a N u d c
CONG NGHIEP MO SQ 4 - 2 0 1 2
^ ^ _
45 NAM VI^N KHOA HOC U C O N G ., Dang c h i l t R3NCH3* [AuCU ]" hda tan tot trongdung mdl DIBK rdi xac dinh h d m l u p n g A u trong dung mdi ndy bdng phdp do phd A A S ,
1.2. Xac djnh ham lw(?7ig b^c
Bac ed t h i d u p c xdc d|nh bdng p h u a n g phdp phdn tich khoi l u p n g theo nguydn t i e C h u y i n hda quang bac ra dgng AgCI, k h u AgCI v l A g bdng khi H2 hay Zn kim logi, sau dd Igc, r u a k i t tua, s l y khd, nung cdn, tinh ra hdm l u p n g Ag C a c h l phan u n g ,
3Ag + 4HN03=3AgN03 + NO + 2H2O A g N O , + HCI=AgCli + HNO3
Hode xde d|nh A g b d n g p h u a n g p h d p c h u i n dO didn t h i , v d i didn c y c bdng gidy bgc trong dung dich d d m Na2B407 c d p H = 9 Xdc d|nh A g bdng p h u a n g phap c h u i n dp g i a n t i l p , s u d g n g phan d n g trao ddi g i u a A g v d i [Ni (CN)4j^', sau dd c h u i n dp l u p n g Ni d u p ' c tdeh ra t u a n g d u a n g v d i l u p n g A g b d n g d u n g dich E D T A , v d i c h i thi Murexit, tai d i i m t u a n g d u a n g , m d u v a n g chuydn thdnh m a u t i m . MiDt p h u a n g p h a p khac rdt d a n gian xdc dinh A g ed d d ehinh x d c va dp lap lai cao la p h u a n g p h d p q u a n g p h d h i p thu nguyen t u (F - A A S ) v d i c a c d i l u kien s a u : V a c h do dac t r u n g 328,1 n m , k h e do 0,7 n m , k h o a n g ndng d d A g tudn theo d m h luat L a m b e r - B e e r t u 0,25 + 2,50 ppm va sai sd t u a n g ddi t u 4 -^ 8 %
1.3. Xac djnh ham Iwgmg dong
Ddng cd thd d u p e xac dinh bdng p h u a n g phap chudn dp EDTA v d i chi thi P A N , d pH=5 Tgi didm t u a n g d u a n g mdu l i m tham c h u y i n thanh vang t u a i . Xdc dmh ddng d i / a tren phan u n g chudn dO complexon giua Cu^* v d i EDTA d pH=8 v d i c h i thj Murexit. Tai didm t u a n g d u a n g m d u chi thj thay d l i t u vang sang t i m .
Cu^* + H2Y=CuY- + 2 H * Cuind + H2Y^=CuY^- + 2 H * + Ind
V a n g T i m Xde dinh d d n g b d n g p h u a n g phdp t r i e q u a n g v d i c h i thi 2-2' - D i q u i n o l i n , trong d u n g djch d g m axetat, do m d u d b u d c s a n g 540 n m . H a m l u p n g d d n g t u a n t h e o d j n h ludt L a m b e r - Beer t u 0+25 p p m N g o d i ra cd thd x a c d j n h d d n g v d i Ditizon d p H = 9 , do m a u tai b u d c s d n g 5 8 0 n m . h a m lup-ng x d c d j n h t u 0 + 5 p p m .
Hodc cd t h i xdc djnh C u d y a trdn p h u a n g phdp chudn dp l l t - T h i o s u n f a t
2Cu^* + 4 r = 2 C u l + l2
Phan dng giai phdng ra l2 e h u i n dp I2 bdng Na2S203 vdi chl thj h i tmh b | t ta xdc dmh dug'c Cu^*.
1; + 2Na3S303=Na2S20e + 2Nal
Hodc xde dinh C u theo p h u a n g phap khdi l u p n g . d y a trdn k i t tua c h i t c i n phdn tich vdi t h u l c thu' phu h p p , Ipc, r d a , s l y vd nung k i t tua r l i cdn vd t u dd xdc dinh ra h d m l u p n g ddng trong mau phdn tich.
Khi h d m lup'ng d i n g n h d ndn xde dinh bdng p h u a n g phdp quang p h i h i p thu nguydn t d (F- AAS) v d i cdc d i l u kidn sau. V g c h do 324,8 nm, khe do 0,2 n m , p h a m vi tuydn tinh t u 0,1-8.0 ppm vd sai so t u a n g d l i t u 4 6 % .
2. N p i d u n g v a k d t q u a n g h i e n c u u 2.1. Phan huy mau
2.1.1 Phan huy mau Au, Cu
C d r i t nhieu each phan huy m a u , song u u thd t l t nhdt v i n Id p h a n huy bdng c u d n g thuy vi nb co tinh oxy hda m g n h , cd kha nang hda tan hau h i t cdc khoang vdt c h u a A u , C u
Can 25-50g m a u d e m nung d 400°C-600''C sau khi d l ngugi hda tan bdng H C l dgc, t i l p theo bdng c u d n g thuy Neu m a u c h u a lup'ng Idn silicat thi t r u d c tien hda tan b i n g HF rdi bdng HCl va culi^
cung bdng c u d n g thuy sau do Ipc r u a qua may Ipc hilt chdn k h d n g , djnh m u c trong binh 250 ml bdng HCl 2IVI Hut 50ml d u n g d u n g djch nay vao pheu c h i l t d u n g tich 100ml, cho 5ml dung mdi DIBK ehua 1 % T O M A C . O ^ y ndp p h l u c h i l t , ldc ddu trong 2 phut, chuyen pha h u u c a vdo I n g nghiem;
d l do p h i h i p thy cua A u , Dung dich cdn lai hut mpt lup'ng d e m di do p h d cua C u .
2.1.2 Phin huy mau Ag
C d n 25-50 g m § u cho vdo ede thuy tinh cao thdnh cd l i p canh k h u l y chju axit, them vao c6c 150ml HNO3 65 % phan huy m i u d 150 °C, khoang 2-2,5 h ddn khi d u n g djch cdn 1/5 t h i tich, Sau dd Ipc r u a q u a m a y Igc hut chdn khdng, djnh m d c dung djch thu d u p c trong binh 100ml bdng HNO3 2 % vd d e m do p h d h i p thu cua A g .
m CdNG NGHIEP MO SO 4 - 2 0 1 2
45 NAM VIEN KHOA HOC VA C A N G NGHE MO-LOYEN KIM _E^
2.2. Cac dieu kien do pho cua Cu, Au, Ag tren may AA-300
V g c h do C u 3 2 4 , 8 n m ; A u 2 4 2 , 8 n m ; A g 328,1 n m ;
Od n h a y Cu 0,025 p p m ; A u va Ag 1,0 ppm;
Khe do Cu 0,2 nm, A u vd A g 0,7 n m , C u d n g dd den HCl C u va A u 12 mA; A g 4 mA, L u u l u o n g khi C2H2, Cu 1.8 l/p, Au 1,4 1/p, Ag 2,0 l/p;
Tdc dd ddn m d u : C u vd A u 5ml/p; A g 4,5 ml/p;
T h d i gian do" 5-=-7 gidy eho ea C u , Au vd A g . 2.3. Khao sat cac dieu kien toi wu cho qua trinh phan huy miu
2 3 1- Anh hudng cua nhiet dd den hieu suit phan huy miu
Nghien e d u anh h u d n g eua nhiet dp d i n higu s u i t phdn huy m d u . Tien hdnh khao sdt each phdn huy mdu, ca mdu chudn ndi bg va m d u Idy trdn bai thai cua nha mdy, D i l u kien thi nghidm n h u sau Kich t h u d c hat xl < 0,063 m m , t h d i gian phdn huy 5h, ty Id R/L 1/3, nhidt dd phan huy thay ddi' 50°C , 75°C 100°C 125°C , 150°C K i t qua d u p c bidu didn trdn H 1
H. 1 Anh hifdng cua nhiet dd den hieu suit phan huy mau.
Anh h u d n g cua ty Id m d u so v d i dung mdi hda tan (ty Id R/L) ddn hieu s u i t phan huy mau, Dieu kien thi nghidm myc 2.3.1 c h i thay doi ty Id R/L t u 1/1-1/3. K i t qua d u a c b i l u d i l n tren H 2
2.3.3 Anh h u d n g cua t h d i gian d i n hieu suat phdn huy mau.
D i l u kign thi nghidm n h u muc 2.3.1 chi thay ddi t h d i gian phan huy mdu 2-7h tinh t u khi dgt 125°C.
K i t qua d u a c b i l u dien tren H.3.
H.2. Anh hwd'ng cua til$ R/L din hieu suit phan huy mau
H.3. Anh hwong cua Ih&i gian din hieu suit phan huy miu 2.3.4. Tinh ket qua
a) Ham l u p n g cua Cu, A u vd Ag d u a c tinh bdng
% theo cdng t h d e IT 100
% M e = C ^ ff (1) Tai d a y Me - Ky hidu cua Cu, A u va A g , C - Ndng dd eua Me tim d u p e theo d u d n g chudn, hay theo phan mdm cai san cua may, tinh theo ppm, W - T h i tich dung djch mdu d u p c dmh m d c , theo ml; V - The tich dung dieh mau Idy dd xde dinh, theo ml, a - L u p n g mdu can, theo p p m .
b) Ham l u a n g cua Au va A g d u a c tinh bdng g/t theo edng thuc"
g / t M e Q = % M e x 1 0 ' ' (1) Tgi day: Meg - Ky hieu cua A u vd Ag.
3. K d t l u a n
D d tai da dgt d u p c mye tieu d l ra. Xay d u n g d u a c quy trinh phdn tich chinh xde cde nguydn to
(Xem tiep trang 34)
