XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3043
would be broken. At this time, Cu2+ and NH3 could be
quickly released by the copper ammonia complex, which
supplied Cu2+ in the solution and stabled the effective con-
centration of Cu2+ in the solution [6,7].
Cu2+:ZnS
(s) +xCu2+(aq) →
Zn(1–x)CuxS(s)+xZn2+
(aq) (1)
Cu(OH)2: nZnS(s)+xCu(OH)2(ppt) →
(ZnS)n·xCu(OH)2(surf.) (2)
(ZnS)n·xCu(OH)2(surf.) →
Znn-xCuxSn·xZn(OH)2(surf.) (3)
Znn–xCuxSn·xZn(OH)2(surf.) →
Znn–xCuxSn(surf.) +xZn(OH)2 (4)
New Theory of Precise Activation of Sphalerite And
Synchronous Depression of Iron Sulfide Was Proposed
Solution chemistry calculation and experiment verifi-
cation showed that there was a large amount of Cu(NH3)
n2+ in the copper-ammonia system under low alkali con-
ditions. Through zinc-ammonia complex, ammonia pro-
moted the dissolution of zinc hydroxide on sphalerite
surface, reduced the covering of zinc hydroxide on mineral
surface and reduced surface hydrophilicity, thus promot-
ing the replacement reaction of active components and
improving the effect of selective activation. The reaction
was shown in Equation 5. The XPS analysis was shown in
Figure 2, which revealed that the copper ammonia complex
reduced the content of ZnO/Zn(OH)2 on the surface of
the mineral by 18.75%, and the adsorption capacity test
showed that the adsorption rate and adsorption capacity of
Cu2+ on minerals were significantly increased. Meanwhile,
the slow-release effect of copper ammonia complex further
promoted the replacement activation. As a result, sphalerite
was precisely activated. In addition, copper ammonia com-
plex could also depress the flotation of iron sulfide minerals
simultaneously, and the flotation test showed that the recov-
ery of iron sulfide minerals was significantly reduced under
this system. The results of adsorption capacity test showed
that the adsorption capacity of copper sulfide decreased and
the adsorption capacity of hydroxyl remained unchanged in
the copper ammonia complex system. XPS analysis showed
that the content of copper sulfide on the surface of iron sul-
fide minerals decreased, while the content of hydroxylated
iron remained unchanged. The above results showed that
NH3 could react with Cu(OH)+ to form copper ammo-
nia complex and OH–, and increase the concentration of
Figure 1. Diagram of Cu2+ store—release process of copper
ammonia complex
Figure 2. XPS of Cu2p
3/2 and Zn2p
3/2 on sphalerite surface
in system of copper sulfate and copper ammonia complex
respectively
would be broken. At this time, Cu2+ and NH3 could be
quickly released by the copper ammonia complex, which
supplied Cu2+ in the solution and stabled the effective con-
centration of Cu2+ in the solution [6,7].
Cu2+:ZnS
(s) +xCu2+(aq) →
Zn(1–x)CuxS(s)+xZn2+
(aq) (1)
Cu(OH)2: nZnS(s)+xCu(OH)2(ppt) →
(ZnS)n·xCu(OH)2(surf.) (2)
(ZnS)n·xCu(OH)2(surf.) →
Znn-xCuxSn·xZn(OH)2(surf.) (3)
Znn–xCuxSn·xZn(OH)2(surf.) →
Znn–xCuxSn(surf.) +xZn(OH)2 (4)
New Theory of Precise Activation of Sphalerite And
Synchronous Depression of Iron Sulfide Was Proposed
Solution chemistry calculation and experiment verifi-
cation showed that there was a large amount of Cu(NH3)
n2+ in the copper-ammonia system under low alkali con-
ditions. Through zinc-ammonia complex, ammonia pro-
moted the dissolution of zinc hydroxide on sphalerite
surface, reduced the covering of zinc hydroxide on mineral
surface and reduced surface hydrophilicity, thus promot-
ing the replacement reaction of active components and
improving the effect of selective activation. The reaction
was shown in Equation 5. The XPS analysis was shown in
Figure 2, which revealed that the copper ammonia complex
reduced the content of ZnO/Zn(OH)2 on the surface of
the mineral by 18.75%, and the adsorption capacity test
showed that the adsorption rate and adsorption capacity of
Cu2+ on minerals were significantly increased. Meanwhile,
the slow-release effect of copper ammonia complex further
promoted the replacement activation. As a result, sphalerite
was precisely activated. In addition, copper ammonia com-
plex could also depress the flotation of iron sulfide minerals
simultaneously, and the flotation test showed that the recov-
ery of iron sulfide minerals was significantly reduced under
this system. The results of adsorption capacity test showed
that the adsorption capacity of copper sulfide decreased and
the adsorption capacity of hydroxyl remained unchanged in
the copper ammonia complex system. XPS analysis showed
that the content of copper sulfide on the surface of iron sul-
fide minerals decreased, while the content of hydroxylated
iron remained unchanged. The above results showed that
NH3 could react with Cu(OH)+ to form copper ammo-
nia complex and OH–, and increase the concentration of
Figure 1. Diagram of Cu2+ store—release process of copper
ammonia complex
Figure 2. XPS of Cu2p
3/2 and Zn2p
3/2 on sphalerite surface
in system of copper sulfate and copper ammonia complex
respectively