Angouran zinc demonstration
plant
A demonstration plant, designed, constructed and operated by BATEMAN
for the Iran Zinc Mines Development Corporation (IZMDC), confirmed the
process route selected for the feasibility study on a proposed refinery
for the Angouran Mine, which could produce 100 000 t/yr of zinc from
an ore feed of 473 000 t/yr. The plant was located at IZMDC's research
centre, about 20 km from Zanjan in north west Iran.
The tests provided an insight into the distribution
and accumulation of elemental impurities during the various process
stages, essential for optimised plant design and enhanced process control,
and to determine the capital cost of the full scale plant. During the
five-week test, nearly 20 t of 12 different blends of ore were processed
to produce more than 2 t of zinc cathode assaying between 99,99 and
99,995 % purity.
This achievement confirmed BATEMAN's extensive experience in the refining
of zinc that the attainment of super-high grade (SHG) zinc cathode is
contingent on the use of high-quality reagents and avoiding the contamination
of the electrowinning (EW) solutions. Careful management of the entire
reagent supply chain proved to be vital.
The Angouran ore consists mainly of carbonates of
zinc, lead and calcium, some troublesome minor elements such as arsenic
and cadmium and quartz, mica and other silicates. It is considered to
be high grade, averaging 23 % zinc.
The demonstration plant comprised circuits for repulping
the ore, acid, weak-acid and neutral leaching, residue filtration, copper,
cadmium, cobalt and nickel removal, basic-zinc-sulphate precipitation,
tailings neutralisation, solvent extraction (SX), EW and reagent mixing
and distribution.
The demonstration plant was constructed by modifying
an existing hydrometallurgical plant, producing about 120 t/yr of zinc
cathode. Modifications included installing new leaching, SX, EW, tailings-neutralisation
and electrolyte-cooling circuits. The SX circuit used DEHPA diluted
with kerosene as the organic phase and featured Bateman Reverse-Flow
Mixer Settlers incorporating extraction, stripping, scrubbing and organic
regeneration. Bateman Pulsed Columns were also used to test the SX unit
operations.
As protection against inclement weather, which during
winter features sub-zero temperatures, the plant was housed in a roofed
building with an area of about 1 600 m². A boiler room, metallurgical
and analytical laboratories, equipment and electrolyte storage, water
treatment facilities, power supplies and motor control centre were also
provided.
An Iranian contractor in partnership with BATEMAN's
engineering-design team took three months to complete the modifications
and commissioning took seven weeks. Local personnel, including masters-degree
students, were trained during the commissioning and ramp-up phases and
were retained as operating staff during the test campaign. Assays were
performed in the on-site laboratories by recruiting temporary personnel
from IZMDC and Iranian academic institutions.
More information may be obtained from
Tony Cau, General Manager, Copper, Zinc & Light
Metals on
+61-7-3320-333 or email basemetals@batemanengineering.com;
or
Richard Klue, BATEMAN Business Manager, Lead
& Zinc, on +27-11-899-2651 or email basemetals@batemanengineering.com.
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