Depósi o de in es igación de la Uni e sidad de Se illa
h ps://idus.us.es/
“This is an Accep ed Manusc ip o an a icle published by Else ie in
Hyd ome allu gy on July 2003, a ailable a : h ps://doi.o g/10.1016/S0304-
386X(03)00081-1 .”
1
Coppe eco e y om chalcopy i e concen a es by he BRISA p ocess
R. Rome o, A. Mazuelos, I. Palencia*, F. Ca anza
Depa amen o de Ingenie ía Química. Facul ad de Química. Uni e sidad de Se illa.
41071 Se illa, Spain
* Co esponding au ho . Tel.: +34-954-557182; ax: +34-954-557134
E-mail add ess: palencia @us.es
R. Rome o is p o esso o Compu e Sys em Dep ., A. Mazuelos is associa e p o esso
o Chemical Enginee ing Dep ., I. Palencia is p o esso o Chemical Enginee ing Dep .,
F. Ca anza is p o esso o Chemical Enginee ing Dep .
2
Coppe eco e y om chalcopy i e concen a es by he BRISA p ocess
R. Rome o, A. Mazuelos, I. Palencia*, F. Ca anza
Abs ac
The echnical iabili y o he BRISA p ocess (Biolixi iación Rápida Indi ec a
con Sepa ación de Acciones: Fas Indi ec Bioleaching wi h Ac ions Sepa a ion) o he
coppe eco e y om chalcopy i e concen a es has been p o ed. Two coppe
concen a es (wi h a coppe con en o 8.9 and 9.9 w %) wi h chalcopy i e as he
dominan coppe mine al ha e been leached wi h e ic sulpha e a 12 g/L o e ic i on
and pH 1.25 in agi a ed eac o s using sil e as a ca alys . E ec s o empe a u e,
amoun o ca alys and ca alys addi ion ime ha e been in es iga ed. Small amoun s o
ca alys ( om 0.5 o 2 mg Ag/g concen a e) we e equi ed o achie e high coppe
ex ac ions (>95 %) om concen a es a 70°C and 8-10 h leaching. Liquo s gene a ed
in he chemical leaching we e biooxidized o e ous i on oxida ion and e ic
egene a ion wi h a mixed cul u e o e ooxidan bac e ia. No inhibi ion e ec inhe en
in he liquo composi ion was de ec ed. The sil e added as a ca alys emained in he
solid esidue and i was ne e de ec ed in solu ion. The eco e y o sil e may be
achie ed by leaching he leach esidue in an acid-b ine medium wi h 200 g/L o NaCl
and ei he hyd ochlo ic o sulphu ic acid, p o ided elemen al sulphu has been
p e iously emo ed by s eam ho il a ion. The e ec o a iables such as empe a u e,
NaCl concen a ion, ype o acid and acidi y-pulp densi y ela ionship on he sil e
ex ac ion om an elemen al sulphu - ee esidue has been examined. I is possible o
ob ain o al eco e y o he sil e added as a ca alys plus 75% o he sil e o iginally
3
p esen in concen a e B (44 mg/kg) by leaching a leach esidue wi h a 200 g/L NaCl –
0.5M H2SO4 medium a 90°C and 10 w % o pulp densi y in wo s ages o 2 h each.
The inco po a ion o sil e ca alysis o he BRISA p ocess allows a echnology based on
bioleaching capable o p ocessing chalcopy i e concen a es wi h a apid kine ics.
Keywo ds: Chalcopy i e, BRISA, sil e ca alysis
1. In oduc ion
Coppe has mainly been p oduced by smel ing. Low-g ade o e deposi s o
coppe a e no amenable o co en ional py ome allu gical p ocessing; he
py ome allu gical ea men equi es lo a ion concen a es wi h a minimum coppe
g ade a ound 20%. In mos low-g ade deposi s chalcopy i e is inely dispe sed on py i e
and o he sulphides and he py ome allu gical ea men o hese o es would equi e
ex ensi e g inding and lo a ion o he sulphides o p oduce inely di ided concen a es.
The p oduc ion o hese concen a es is no a ac i e om an economical poin o iew
because o he in ensi e ene gy consump ion in g inding and he low eco e y. An
al e na i e o he ea men o hese deposi s in ol es a coa se g ind o p oduce a
oughe concen a e yielding low coppe concen a es (a ound 10% o coppe ) wi h an
impo an ene gy sa ing and a highe me allic eco e y. These concen a es, in which
chalcopy i e is he majo i y coppe -bea ing mine al, ha e o be p ocessed
hyd ome allu gically.
Among o he hyd ome allu gical p ocesses, he BRISA p ocess has been
de eloped and success ully applied in ecen yea s o he eco e y o coppe om
4
coppe concen a es (Palencia e al., 2002). The BRISA p ocess (Biolixi iación Rápida
Indi ec a con Sepa ación de Acciones: Fas Indi ec Bioleaching wi h Ac ions
Sepa a ion), de eloped o imp o e he kine ics o bioleaching o me allic sulphides, is
based on bioleaching by he indi ec mechanism. In he BRISA p ocess, he bioleaching
p ocess is pe o med in wo sepa a e s ages: (a) a chemical s age based on Eq. (1) and
(b) a biological s age based on Eq. (2) o he biooxida ion o e ous i on consumed in
he chemical s age. De ails o he BRISA p ocess ha e p e iously been gi en (Ca anza
e al., 1997a; Palencia e al., 2002). The ea men o coppe concen a es wi h
chalcopy i e as he dominan coppe mine al copes wi h he ac ha chalcopy i e is,
among he coppe sulphides, he mos e ac o y o leaching. The chemical leaching o
chalcopy i e by an acidi ied solu ion o e ic sulpha e (Eq. (1) ) p oceeds a a e y low
a e.
CuFeS2 + 2 Fe 3+ 2 Fe2+ + Cu2+ + 2 S (1)
2 Fe2+ +1/2 O2 + 2 H+ 2 Fe3+ + H2O (2)
The a e o his eac ion in he ange 50-110ºC ollows a pa abolic law. Mos
au ho s ag ee ha he dec ease in a e is due o he o ma ion o a ilm which builds up
on he su ace o he mine al and opposes he elec on ans e om chalcopy i e o he
e ic medium, necessa y o he edox eac ion. Wi h ega d o he na u e o his
passi a ing laye , he e a e wo basic hypo heses: elemen al sul u (Mille and Po illo,
1979) and an in e media e sulphide esul ing o m he ans o ma ion o he o iginal
chalcopy i e, i s eac i i y being lowe han ha o he la e (Pa ke e al., 1981; Ba iga
e al. 1987). To imp o e chalcopy i e leaching a e much e o has been made and

5
se e al ca alys s ha e been p oposed, sil e ion being he mos e ec i e one. I is well
known ha low concen a ions o sil e ion g ea ly accele a e he chalcopy i e leaching.
Se e al mechanisms ha e been p oposed o explain he ca aly ic ac ion o he sil e ion
(Mille and Po illo, 1979, Hi oyoshi, N., 2002) hei desc ip ion and discussion being
beyond he aim o his pape .
The use o sil e as a ca alys in he chemical s age o he BRISA p ocess is
possible as he sil e used o he ac i a ion o chalcopy i e emains in he leached
esidue as Ag2S ( he main p opo ion) and Ag0 (Mille and Po illo, 1979; P ice and
Wa en, 1986; Ba iga Ma eos e al., 1993; Ca anza, 1997b) and i could also be as
a gen oja osi e in some condi ions o empe a u e and acidi y (Palencia e al., 1998).
Sil e ion inhibi s he g ow h o e ooxidan bac e ia used o e ic i on egene a ion
in he biological s age o he BRISA p ocess; howe e , he sepa a ion o chemical and
bac e ial ac ions enables he use o his ca aly ic sys em because sil e is always in he
e ic leaching ci cui and i will ne e each he bio eac o . On he o he hand, since
p ac ically he whole amoun o sil e added as a ca alys emains in he esidue, i s
eco e y a low cos is equi ed in o de o make his p ocess comme cially a ac i e.
Figu e 1 shows he lowshee o he BRISA p ocess o he ea men o
chalcopy i e concen a es. I consis s o a s age o e ic leaching in which a sil e sal is
added. The solid esidue con ains elemen al sulphu and all he sil e added as a
ca alys . The eco e y o sil e is accomplished a e elemen al sulphu emo al.
The aim o his wo k is o es ablish he echnical iabili y o he ea men o wo
coppe concen a es wi h chalcopy i e as he dominan coppe mine al ia he BRISA
p ocess. In o de o do his, he di e en s ages o he p ocess ha e been sepa a ely
s udied:
 Fe ic sulpha e leaching o concen a es wi h sil e as a ca alys .
6
 Fe ous i on biooxida ion o leach liquo s.
 Sil e ex ac ion om he leach esidue.
2. Ma e ials and Me hods
2.1. Ma e ials
Two coppe concen a es ha e been s udied. Bo h we e oughe concen a es:
A: Roughe concen a e om Compañía Mine a del Pací ico (Chile)
B: Roughe concen a e om Indus ial Mine a Mejicana Sociedad Anónima (IMMSA)
ob ained om an o e om Compañía Mine a Cananea (Mexico).
2.1.1. Mine alogical and Chemical Composi ion
Samples o he wo ma e ials we e moun ed in polished sec ions o
mine alogical s udy using op ical mic oscopy and scanning elec on mic oscopy (SEM)
equipped wi h an ene gy dispe si e X- ay analyze (EDX). The mine alogical da a a e
summa ised in Table 1. Quan i a i e mine alogical composi ion was de e mined by
image analysis om op ical mic oscopy images. Image analysis showed ha he
concen a e con ained mainly chalcopy i e oge he wi h py i e and gangue. In bo h
concen a es gangue mine als we e mainly silica, silica es, i on oxides and aces o
i anium oxides, all o hem libe a ed om sulphide mine als. A ailable g anulome ic
da a a e shown in Table 2.
Samples we e also analyzed by we chemical me hods using eagen g ade
chemicals and dis illed wa e . The chemical analysis o concen a es is shown in Table 3
7
2.2. P ocedu e
2.2.1. Fe ic sulpha e leaching expe imen s
Leaching expe imen s we e ca ied ou in wo di e en ypes o eac o s unde
ba ch leaching condi ions, shake lasks and s i ed anks. In all cases e ic sulpha e
solu ions we e i s hea ed o he desi ed empe a u e and he eac ion was ini ia ed by
adding a d ied mine al sample.
Shake- lask es s.- Expe imen s we e ca ied ou in 250 mL E lenmeye lasks wi h 100
mL o e ic sulpha e solu ion. The lasks we e con inuously agi a ed on an o bi al
shake a 280 min-1 and he mos a ed by o ced ai ci cula ion.
S i ed ank leaching es s.- Expe imen s we e ca ied ou in a 7 L glass, ba led
he mos a ed essel mechanically s i ed wi h a six-bladed la disk u bine. The
solu ion olume was 4 L and he s i ing speed 800 min-1. Du ing each expe imen ,
samples o pulp we e aken pe iodically and, a e il a ion, we e analyzed o coppe ,
o al i on and e ous i on.
In all es s, he wa e losses due o e apo a ion we e de e mined by weigh and
we e aken in o accoun du ing coppe eco e y calcula ions. A he end o he
expe imen , he slu y was il e ed using 0.45 m Millipo e il e s and he esidue, a e
being washed wi h dis illed wa e and d ied, was s o ed in a desicca o o sil e
eco e y. The leach liquo was analyzed o me als and was used o e ous i on
biooxida ion es s. Coppe ex ac ion was calcula ed om mass balance and analysis o
solids (concen a e and esidue). In ca aly ic es s, he leaching medium consis ed o
e ic sulpha e wi h sil e as sil e sulpha e. An aliquo o a solu ion o sil e sulpha e
in aqueous sulphu ic acid a pH 1.25 con aining 500 mg/L o sil e was added o he
e ic sulpha e solu ion. The amoun o ca alys is exp essed as millig amme o
Ag+/g amme o concen a e. Unless o he wise s a ed, he expe imen al condi ions we e:
8
ini ial pH o solu ion 1.25, e ic i on concen a ion 12 g/L and du a ion o he es 8 h.
A pH alue o 1.25 was chosen as he mo e sui able o he p ocess (Ca anza e al.,
1997b). P elimina y s udies indica ed ha he coppe ex ac ion was almos independen
o pulp densi y o bo h concen a es p o ided he e emains su icien e ic i on in
solu ion. Because all he expe imen s we e ca ied ou a low e ic i on concen a ion
(12 g/L) in ba ch sys ems, he s udied pulp densi ies need o be low. As men ioned
ea lie (Ca anza e al., 1997b) in a con inuous ope a ion he pulp densi y o leaching
migh be highe han he alues conside ed in his s udy. The e ec o he a iables such
as amoun o ca alys , empe a u e and ca alys addi ion ime was in es iga ed.
2.2.2. Fe ous i on biooxida ion
The cul u e used o e ous i on biooxida ion was o iginally isola ed om Rio
Tin o mine d ainage wa e s and i consis s mainly o Thiobacillus e ooxidans,
Lep ospi illum e ooxidans and some he e o ophic bac e ia mainly ela ed o
Acidophilium. S ock cul u es we e ou inely main ained a 31ºC on a modi ied
Sil e man and Lundg en 9k nu ien medium (Sil e man and Lundg en, 1959)
supplemen ed wi h coppe sulpha e (20 g/L) a pH 1.25; an aliquo o he cul u e was
ans e ed in o a esh medium e e y 8 days. The e ous i on biooxida ion was ca ied
ou bo h in ba ch and con inuous- low eac o s. De ails o he expe imen al p ocedu e
ha e been gi en in a p e ious pape (Palencia e al., 1998).
2.2.3. Sil e eco e y
The me hod ollowed o sil e eco e y consis ed o wo s ages:
1) Elemen al sulphu ex ac ion. The d ied sulphu -bea ing esidue om he e ic
sulpha e leach o he concen a e was placed on a i ed glass disk connec ed o a
15
empe a u es o 70-90°C, he leaching esidues ha ing a sil e con en o he o de o
ha o he o iginal concen a es (10-15 and 34-64 mg/kg Ag o concen a es A and B
espec i ely).
Table 8 shows ha he use o hyd ochlo ic acid lead o sil e ex ac ions highe han
hose achie ed wi h sulphu ic acid o he same concen a ion no ma e wha he sodium
chlo ide concen a ion o he leaching medium was. The e ec o he sodium chlo ide
concen a ion was negligible in hyd ochlo ic medium bu some posi i e e ec was
obse ed in sulphu ic medium as i inc eased om 50 o 200 g/L. Taking in o accoun
ha solid weigh losses we e highe in es s wi h hyd ochlo ic acid, i is pos ula ed ha
hyd ochlo ic acid is mo e e icien han sulphu ic acid o he dissolu ion o ja osi es,
which is equi ed o high sil e ex ac ion.
Tables 9 and 10 show he e ec o he acidi y-pulp densi y ela ionship on he sil e
ex ac ion o leached S- ee concen a e A in sulphu ic and hyd ochlo ic media
espec i ely. In bo h cases he acid demand o comple e sil e ex ac ion inc eases wi h
an inc ease in he pulp densi y. As al eady shown (Table 8), he subs i u ion o
hyd ochlo ic acid by sulphu ic acid o equal concen a ion leads o a no iceable dec ease
in sil e ex ac ion. Table 10 shows ha o a pulp densi y o 1 (w/ %) he use o 0.25
M sulphu ic acid leads o sil e ex ac ions o he o de o hose ob ained wi h 0.1 M
hyd ochlo ic acid. Consequen ly, om a echnical poin o iew hyd ochlo ic acid can
be subs i u ed by sulphu ic acid which ep esen s bo h economic and handling
ad an ages.
Resul s o he e ec o he acidi y-pulp densi y ela ionship on he sil e ex ac ion
o leached S- ee concen a e B, shown in Table 12, con i m he e ec obse ed o
concen a e A (Tables 9 and 10): he demand o acid o comple e sil e ex ac ion
inc eases wi h an inc ease in he pulp densi y. Wi h 0.5 M sulphu ic acid, he use o

16
pulp densi ies highe han 5 (w/ %) leads o an impo an dec ease o he sil e
ex ac ion, he esidues ha ing e y high sil e con en . Tes s wi h 5 and 10 (w/ %)
pulp densi y we e ca ied ou again wi h in e media e acid addi ion, he sil e ex ac ion
being simila o hose ob ained wi hou acid addi ion. The e o e, he p oblem was
supposed o be ela ed o he equilib ium o he eac ion and no only o he lack o
acidi y. Wi h he pu pose o con i ming his hypo hesis, and ge ing close o he
condi ions o a con inuous ope a ion, wo-s age leaching es s we e pe o med. Resul s
o one o hese es s a e summa ized in Table 13. A mass balance o sil e in he whole
p ocess ( e ic sulpha e leaching, elemen al sulphu ex ac ion and sil e eco e y)
allows us o s a e ha i is possible o ob ain o al eco e y o he sil e added as a
ca alys plus 75% o he sil e o iginally p esen in he concen a e (which is e y
in e es ing as his concen a e con ains 44 mg/kg o sil e ). To calcula e he a e age
acid consump ion, es s wi h 5 and 10 (w/ %) o pulp densi y we e selec ed. The
a e age acid consump ion was 32 g o sul u ic acid pe kg o concen a e.
4. Conclusions
The esul s ob ained in his wo k show ha chalcopy i e concen a es can be
e ec i ely leached by he BRISA p ocess wi h as kine ics and a high coppe eco e y.
Two oughe coppe concen a es ha ing 8.9 and 9.9 w % Cu wi h chalcopy i e as he
dominan coppe -bea ing mine al and mino con en s o o he s sulphides ha e been
es ed. The e ic sulpha e leaching was ca ied ou in agi a ed ba ch condi ions wi h 12
g/L Fe3+ and pH 1.25 using sil e as a ca alys . High coppe ex ac ions (>95 w %) we e
ob ained by ac i a ing concen a es A and B wi h 0.5 and 2 mg Ag/g o concen a e
espec i ely a 70ºC and 8/10 h leaching. Liquo s gene a ed in he e ic sulpha e
17
leaching we e sil e - ee and he e ous i on was e ec i ely biooxidized bo h in s a ic
and low condi ions a 31ºC. The biooxida ion s age egene a es he leaching agen
( e ic i on) equi ed in he chemical s age. Sil e has been e ec i ely eco e ed om
esidues by leaching hem wi h an acid-b ine medium wi h 200 g/L o NaCl and 0.5 M
sulphu ic acid p o ided elemen al sulphu had been p e iously emo ed. High sil e
ex ac ions (abo e 98 w %) was ob ained in 1h a 70ºC o bo h concen a es. I is
possible o ob ain o al eco e y o he sil e added as a ca alys plus some o he sil e
o iginally p esen in he concen a e by inc easing empe a u e o 90ºC p o ided ha
he acid was no limi ing.
Acknowledgemen s
The au ho s exp ess hei app ecia ion o Compañía Mine a del Pací ico and
Compañía Mine a Cananea o making a ailable he samples used in his s udy.
18
Re e ences
Ba iga Ma eos, F., Pe eda Ma ín, J., Palencia Pé ez, I., 1993. Bac e ial leaching o a
bulk lo a ion concen a e o chalcopy i e-sphale i e. Bio eco e y 2, 195-218
Ba iga, F., Palencia, I., Ca anza, F., 1987. The passi a ion o chalcopy i e subjec ed o
e ic sul a e leaching and i s eac i a ion wi h me al sul ides. Hyd ome allu gy 19, 159-
168.
Ca anza, F., Palencia, I., Rome o, R., Iglesias, N., 1997a. Applica ion ields o he
BRISA p ocess. In luence o he o e mine alogy on he p ocess lowshee . In:
Aus alian Mine al Founda ion (Ed.), P oceedings o he In e na ional
Biohyd ome allu gy Symposium IBS97-BIOMINE 97 “Bio echnology Comes o Age.”,
Sydney, Aus alia, 4-6 Augus , 1997, M2.1.1 – M2.1.10.
Ca anza, F., Palencia, I., Rome o, R., 1997b. Sil e ca alyzed IBES p ocess:
applica ion o a spanish coppe -zinc sulphide concen a e. Hyd ome allu gy 44, 29-42.
Du izac; J.E., Jambo , J.L., 1984. Fo ma ion and cha ac e iza ion o a gen oja osi e
and plumboja osi e and hei ele ance o me allu gical p ocessing. In: Pa k, W.C.,
Hausen, D.M., Hagni, R.D. (Eds.), Applied mine alogy in he mine als indus y. The
Me allu gical Socie y o AIME, Los Angeles, Cali o nia, pp. 507-530.
19
Hi oyoshi, N., A ai, M., Miki, H., Tsunekawa, M., Hi ajima, T., 2002. A new eac ion
model o he ca aly ic e ec o sil e ions on chalcopy i e leaching in sul u ic acid
solu ions. Hyd ome allu gy 63, 257-267.
Mille , J.D., Po illo, H.Q., 1979. Sil e ca alysis in e ic sul a e leaching o
chalcopy i e. In: XIII In . Mine al P ocess, Cong ., Wa saw, Poland, pp. 691-742.
Palencia, I., Rome o, R., Ca anza, R., 1998. Sil e ca alyzed IBES p ocess:
Applica ion o a spanish coppe -zinc sulphide concen a e. Pa 2. Biooxida ion o he
e ous i on and ca alys eco e y. Hyd ome allu gy 48, 101-112.
Palencia, I., Rome o, R., Ca anza, F., Mazuelos, A., 2002. T ea men o seconda y
coppe sulphides (chalcoci e and co elli e) by he BRISA p ocess. Hyd ome allu gy 66,
85-93.
Pa ke , A.J. Paul, R.L., Powe , G.P., 1981. Elec ochemical aspec s o leaching coppe
om chalcopy i e in e ic and cup ic sal solu ions. Aus . J. Chem. 34, 13-34.
P ice, D.W. , Wa en, G.W., 1986. The in luence o sil e ion on he elec ochemical
esponse o chalcopy i e and o he mine al sul ide elec odes in sul u oc acid.
Hyd ome allu gy 15, 303-324.
Sil e man, M.P., Lundg en, D.G., 1959. S udies on he chemoau o ophic i on bac e ia
Fe obacillus e ooxidans. An imp o ed medium and ha es ing p ocedu e o
secu ing high yields. J. Bac e iol. 77, 642-64.
20
Table 1
Mine alogical da a o he ma e ials
Concen a e
Majo mine al phase
Mino mine al phase
T aces
Chalcopy i e
(w . %)
Py i e
(w . %)
Gangue
(w . %)
A
27
44
29
Co elli e, bo ni e,
chalcoci e
Molybdeni e,
ennan i e
B
24
31
43
Bo ni e, chalcoci e
(1.5%), co elli e
(0.5%)
Sphale i e,
e ahed i e,
ennan i e,
molybdeni e
Table 2
G anulome ic da a o he concen a es
Concen a e
Pa icle size (m)
d10
d20
d50
d80
d90
d100
A
1.7
2.9
26.6
98.7
131.8
251.2
B
2.0
3.1
9.0
37.9
60.0
142.5
Table 3
Analy ical da a o he ma e ials
Elemen
Concen a e A
Concen a e B
Cu (w . %)
8.9
9.9
Fe (w . %)
31.4
21.4
S (w . %)
32.0
25.3
Zn (w . %)
0.02
0.1
Pb (mg/kg)
80
260
Ag (mg/kg)
12
44
Au (mg/kg)
1.9
0.5
As (mg/kg)
30
5000
Sb (mg/kg)
0.9
0.1
Bi (mg/kg)
3.4
n.d.
Hg (mg/kg)
3.3
n.d.
Cd (mg/kg)
3.0
-
Insolubles (w . %)
24.0
34.9
n.d. no de ec ed

21
Table 4
Leaching o concen a es A and B (shaken lasks, pH = 1.25, 8h, pulp densi y: 2 (w/
%) o A and 1.5 (w/ %) o B)
Concen a e
[Fe3+]
(g/L)
Tempe a u e
(º C)
Cu
ex ac ion
(%)
Solid
weigh
loss
(w . %)
Residue
Cu con en
(w . %)
Fe2+
(g/kg o
concen a e)
A
0a
70
6.0
6.0
9.0
14
A
12
25
5.8
3.3
8.8
17
A
12
70
14.4
7.2
8.3
133
B
0b
70
12.8
3.1
9.0
21
B
12
25
10.8
3.6
9.2
15
B
12
70
20.7
6.7
8.5
179
a Assay pe o med wi h a pulp densi y o 5 (w/ %) and 6 h
b Assay pe o med du ing 6 h
Table 5
E ec o empe a u e on he ca aly ic e ic sulpha e leaching o concen a e A (s i ed
anks, pH = 1.25, pulp densi y: 2 (w/ %), e ic i on concen a ion: 12 g/L, [Ag+] = 0.5
mg/g concen a e, 8 h)
Tempe a u e
(ºC)
Cu ex ac ion
(%)
Solid weigh
loss
(w . %)
Residue Cu
con en
(w . %)
Fe2+
(g/kg o
concen a e)
60
90.3
16.4
1.04
379
70
97.5
20.6
0.28
379
80
94.5
16.2
0.61
384
90
86.5
8.9
1.36
350
Table 6
E ec o empe a u e on he ca aly ic e ic sulpha e leaching o concen a e B (s i ed
anks, pH = 1.25, pulp densi y: 1.5 (w/ %), e ic i on concen a ion: 12 g/L, [Ag+] = 2
mg/g concen a e, 10 h)
Tempe a u e
(ºC)
Cu ex ac ion
(%)
Solid weigh
loss
(w . %)
Residue Cu
con en
(w . %)
Fe2+
(g/kg o
concen a e)
60
82.1
17.9
2.13
358
70
95.3
19.2
0.58
366
80
82.2
20.7
2.25
358
90
67.8
16.9
3.88
414
22
Table 7
E ec o empe a u e on he sil e ex ac ion o leached sulphu - ee concen a e A (0.1
M HCl, 200 g/L NaCl, 1h, pulp densi y: 1 (w/ %), ini ial solid Ag con en : 1369
mg/kg)
Tempe a u e
(ºC)
Ag ex ac ion
(%)
Solid weigh loss
(w . %)
Residue Ag con en
(mg/kg)
25
78.3
0.7
299
25*
88.0
3.5
248
50
97.1
3.7
42
70
98.9
5.5
15
90
99.3
6.5
10
* Assay pe o med du ing 6 h
Table8
E ec o he NaCl concen a ion in chlo ide and sulphu ic media on he sil e ex ac ion
o leached sulphu - ee concen a e A (70ºC, 1h, pulp densi y: 1 (w/ %), ini ial solid
Ag con en : 715 mg/kg)
[NaCl]
(g/L)
[Acid]
(M)
Ag ex ac ion
(%)
Solid weigh
loss
(w . %)
Residue Ag
con en
(mg/kg)
50
0.05 (H2SO4)
79.4
3.6
153
100
0.05 (H2SO4)
80.2
3.0
146
150
0.05 (H2SO4)
80.2
3.8
147
200
0.05 (H2SO4)
86.0
3.3
103
50
0.1 (HCl)
97.7
5.5
17
100
0.1 (HCl)
98.6
5.6
11
150
0.1(HCl)
98.6
5.1
11
200
0.1(HCl)
98.4
5.8
12
Table 9
E ec o he acidi y-pulp densi y ela ionship in chlo ide medium on he sil e
ex ac ion o leached sulphu - ee concen a e A (70ºC, 200 g/L NaCl, 1 h, ini ial solid
Ag con en : 1369 mg/kg)
Pulp densi y
(w/ %)
[HCl]
(M)
Ag ex ac ion
(%)
Solid weigh loss
(w . %)
Residue Ag con en
(mg(kg)
1
0.1
98.9
5.5
15
5
0.1
99.0
4.8
14
10
0.1
96.9
4.6
45
10
0.2
99.3
6.9
10
23
Table 10
E ec o he acidi y-pulp densi y ela ionship in sulphu ic medium on he sil e
ex ac ion o leached sulphu - ee concen a e A (70ºC, 200 g/L NaCl, 1h)
Pulp densi y
(w/ %)
[H2SO4]
(M)
In i ial Ag
con en
(mg/kg)
Ag ex ac ion
(%)
Solid weigh loss
(w . %)
Residue Ag
con en
(mg/kg)
1
0.05
715
86.0
3.3
103
1
0.25
715
96.0
5.5
31
1
0.5
715
98.6
6.3
11
1
1
715
98.8
5.7
9
5
0.5
582
98.6
9.8
9
10
0.5
649
98.4
7.5
11
20
0.5
649
95.4
7.5
32
Table11
E ec o empe a u e on he sil e ex ac ion o leached sulphu - ee concen a e B (200
g/L NaCl, 0.5 M H2SO4, pulp densi y: 1 (w/ %), 1 h, ini ial Ag con en : 3118 mg/kg)
Tempe a u e
(ºC)
Ag ex ac ion
(%)
Solid weigh loss
(w . %)
Residue Ag con en
(mg/kg)
70
98.0
3.0
64
80
98.9
7.0
37
90
99.0
10.0
34
Table 12
E ec o acidi y-pulp densi y ela ionship on he sil e ex ac ion o leached sulphu -
ee concen a e B (200g/L NaCl, 70 ºC, 2 h, ini ial Ag con en : 2536 mg/kg)
Pulp densi y
(w/ %)
[H2SO4]
(M)
Ag ex ac ion
(w . %)
Solid weigh loss
(w . %)
Residue Ag con en
(mg/kg)
1
0.05
97.1
3.7
78
1
0.25
98.3
3.8
44
1
0.5
98.3
4.1
44
5
0.5
94.5
3.2
144
10
0.5
87.0
3.4
342
24
Table 13
Two s ages sil e ex ac ion o leached sulphu - ee concen a e B (200g/L NaCl, 0.5
M H2SO4, 90ºC, pulp densi y: 10 (w/ %))
Time (h)
Ini ial Ag con en
(mg/kg)
Final Ag con en
(mg/kg)
Ag ex ac ion
(%)
2 (1s s age)
2536
83
97.0
2 (2nd s age)
83
14
99.5