626
C. Wang et al.
Introduction
With the rapid development in the modern manufacturing industries such as automobile, electrical, chemical, and medical, the demand of lead and zinc is increasing
continuously based on its good physical and chemical properties. Most mined of
lead and zinc are extracted from lead and zinc sulfide minerals, such as galena and
sphalerite. However, in nature, most galena and sphalerite are commonly finely disseminated and intimately associated with each other or coexist with other sulfide
minerals, such as pyrite, chalcopyrite, molybdenite, and precious metals, gold or
and silver. Given the complex symbiotic relationship, the similar natural floatability,
and the inadvertent activation of metal ions, e.g., Pb
2+ , Cu
2+ , dissolved in the pulp,
the selective separation of galena, sphalerite, and pyrite is very challenging in the
production of high sulfur lead–zinc ore.
High alkaline preferential process (HAPP) is the most popular conventional flotation flowsheet for the beneficiation of high sulfur lead–zinc ores. In this process, high
alkaline conditions are required to recover the galena first and then sphalerite from
pyrite and other gangue minerals. Subsequently, the acidic process is usually used for
the recovery of pyrite. This method is very effective but has some disadvantages. In
high alkaline conditions, the froth is sticky and easier to carry slime and further affect
the concentrate grade. The recovery of previous metals is significantly reduced by
high alkaline pulp pH. The pipe is usually choked that can be attributed to the generation of CaSO 4 by the reaction between Ca
2+ and SO 4
2− . Besides, some environment
and economic problems are also inevitable. This method requires a large amount of
lime and sulfuric acid, which not only increase the reagents costs but also increase
the toxicity in the environment. In addition, a large amount of dust, acid, NO 2 /SO 2
and greenhouse gases will be produced during the production, transportation and
use of lime, which will be released into the atmosphere. Sulfuric acid, as a highly
corrosive chemical, is dangerous for operator’s safety. In addition, in fields of mineral processing, lots of acidic wastewater, heavy metal irons, residues, and harmful
gases, such as SO 2 , SO 3 , or H 2 S are generated from the usage of H 2 SO 4 that further
destroyed the environment. Therefore, it is of various environmental and economic
benefits of introducing an alternative process flowsheet for the beneficiation of high
sulfur lead–zinc sulfide ores.
Facing above shortcomings of HAPP, Fankou mine has investigated many methods to reduce lime and sulfuric acid dosage, including galena–sphalerite mixed flotation and iso-flotation flowsheet. However, considering those results and conclusions,
none of them was succeeded completely. In this study, a galena–pyrite mixed flotation flowsheet was tested as a novel scheme to effectively recover lead, zinc, and
sulfur with a relatively low lime doses and without the addition of sulfuric acid.
Figure 1 shows the process flowsheets for new and old schemes. In the new scheme,
galena–pyrite bulk flotation was conducted with the depression of sphalerite followed
by galena/pyrite separation and the re-flotation of sphalerite.
C. Wang et al.
Introduction
With the rapid development in the modern manufacturing industries such as automobile, electrical, chemical, and medical, the demand of lead and zinc is increasing
continuously based on its good physical and chemical properties. Most mined of
lead and zinc are extracted from lead and zinc sulfide minerals, such as galena and
sphalerite. However, in nature, most galena and sphalerite are commonly finely disseminated and intimately associated with each other or coexist with other sulfide
minerals, such as pyrite, chalcopyrite, molybdenite, and precious metals, gold or
and silver. Given the complex symbiotic relationship, the similar natural floatability,
and the inadvertent activation of metal ions, e.g., Pb
2+ , Cu
2+ , dissolved in the pulp,
the selective separation of galena, sphalerite, and pyrite is very challenging in the
production of high sulfur lead–zinc ore.
High alkaline preferential process (HAPP) is the most popular conventional flotation flowsheet for the beneficiation of high sulfur lead–zinc ores. In this process, high
alkaline conditions are required to recover the galena first and then sphalerite from
pyrite and other gangue minerals. Subsequently, the acidic process is usually used for
the recovery of pyrite. This method is very effective but has some disadvantages. In
high alkaline conditions, the froth is sticky and easier to carry slime and further affect
the concentrate grade. The recovery of previous metals is significantly reduced by
high alkaline pulp pH. The pipe is usually choked that can be attributed to the generation of CaSO 4 by the reaction between Ca
2+ and SO 4
2− . Besides, some environment
and economic problems are also inevitable. This method requires a large amount of
lime and sulfuric acid, which not only increase the reagents costs but also increase
the toxicity in the environment. In addition, a large amount of dust, acid, NO 2 /SO 2
and greenhouse gases will be produced during the production, transportation and
use of lime, which will be released into the atmosphere. Sulfuric acid, as a highly
corrosive chemical, is dangerous for operator’s safety. In addition, in fields of mineral processing, lots of acidic wastewater, heavy metal irons, residues, and harmful
gases, such as SO 2 , SO 3 , or H 2 S are generated from the usage of H 2 SO 4 that further
destroyed the environment. Therefore, it is of various environmental and economic
benefits of introducing an alternative process flowsheet for the beneficiation of high
sulfur lead–zinc sulfide ores.
Facing above shortcomings of HAPP, Fankou mine has investigated many methods to reduce lime and sulfuric acid dosage, including galena–sphalerite mixed flotation and iso-flotation flowsheet. However, considering those results and conclusions,
none of them was succeeded completely. In this study, a galena–pyrite mixed flotation flowsheet was tested as a novel scheme to effectively recover lead, zinc, and
sulfur with a relatively low lime doses and without the addition of sulfuric acid.
Figure 1 shows the process flowsheets for new and old schemes. In the new scheme,
galena–pyrite bulk flotation was conducted with the depression of sphalerite followed
by galena/pyrite separation and the re-flotation of sphalerite.