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Technical Renovation of
the Metallurgical Technology in Guangxi Longtoushan
Gold Mine
1. Brief Introduction
The original designed scale of the mineral processing
plant of Guangxi Longtoushan Gold Mine was 100
tons/day; and a gold extraction process of whole
slurry cyanidation and zinc precipitation was
employed. Since there were many problems in its
flowsheet, the techno-economic indices was not
so good, and the mine run a difficult business.
Aimed at these problems, Changchun Gold Research
Institute suggested a reasonable technical renovation
plan. The major part includes: modifying the process
from the original amalgamation + cyanidation to
gravity seperation, using centrifugal concentrator
as the equipment to realize continuous operation
in hard rock gold mine. During the process of
cyanidation, assistant agent was added that improved
the leaching effecct, increased the leaching rate,
and improved the leaching recovery. A crusher
was added in the crushing system, which not only
lowered the particle size of crushing but also
increased the milling capacity to 200 tons/day
from 100 tons/day. In process of precipitation,
plate frame pressure filter was creatively used
to purify the pregnant solution, which achieved
better purification effect, enabled big treatment
capacity, and is simple and convenient in equipment
maintenance and operation, high in gold recovery
and good quality of gold slime.
2.Main Techno-economical Indices and Benefits
By using this technique, the production scale
of this mine was increased to 200 tons/ day, the
actual mineral processing recovery was increased
to 89.16% from previous 69.31% before the technical
renovation, the operation cost lowered to 105.70
yuan/ton from 145.54 yuan/ ton, and the accumulative
economic profit was 7,426,600 yuan.
Due to application of the centrifugal concentrator,
the concentrate grade reached 1% when the yield
of gravity separation was 0.15‰, and the recovery
up to 45%, and in turn, free gold in the ore was
effectively recovered.
3. Application Prospects
The successful application of centrifugal concentrator
in Longtoushan Gold Mine shows that the coarse
and mediam-sized gold greater than 0.04mm in the
ore can be fully recovered. Through practice and
renovation in Longtoushan Gold Mine, the working
life of the contrifugal drum of this equipment
is extended by several times, and the jointing
of the inner structures and the flushing mode
for sand discharging are all automatic. It has
the features of reliable in running, convienient
and safe in maintenance, and its operation cost
is low as well with the unit cost per ton of ore
being only 0.23 yuan. Therefore, it can be widely
applied in China to replace amalgamation operation
to completely eliminate mercury pollution from
gold mines for greater environment benefits.
The important merit of oxydol-assisted leaching
and conventional oxygen-rich leaching prevailing
in China is that there is no need to purchase
expensive oxygen making equipment (for present
scale of Longtoushan, 200 tons/day, the cost of
oxygen making equipment to be 400,000 yuan), and
also the dosage of oxydol is less (200 g/ ton),
the cost is low (0.31 yuan /ton), it is easy to
be applied in domestic gold mines.
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