The design of the plant was patterned after Japan's Tamano smelter and refinery plant, considered as one of the world's most efficiently-run smelters. The flash smelting process developed by Outokumpu Oy of Finland and modified by the Mitsui Mining and Smelting Company, was adopted for more flexibility in processing different grades of copper concentrate, high recovery of sulfur, and reduced power and oil consumption.
Copper concentrate, the basic feedstock undergoes a smelting and refining process in which impurities are removed and refined copper is extracted. Precious metals and other byproducts are also recovered in the process.
PASAR has expanded its smelter capacity to 720,000 mtpy of concentrates in early 2006. In May 2007, PASAR will complete a brownfield conversion from conventional starting sheet electrorefining to ISA process. Refinery capacity will be increased from 172,500 mtpy to 215,000 mtpy of coppr cathodes.
Copper concentrate, the basic feedstock undergoes a smelting and refining process in which impurities are removed and refined copper is extracted. Precious metals and other byproducts are also recovered in the process.
PASAR has expanded its smelter capacity to 720,000 mtpy of concentrates in early 2006. In May 2007, PASAR will complete a brownfield conversion from conventional starting sheet electrorefining to ISA process. Refinery capacity will be increased from 172,500 mtpy to 215,000 mtpy of coppr cathodes.
SMELTING PROCESS
Copper concentrates of various grades from all over the world are unloaded by a luffing crane and transferred to the concentrate storage house via the conveyor belt. These concentrates are laid into beds in the blending house. Silica sand, coke, coal and slag concentrate are added to the blended copper concentrates before resulting mixture is fed into the flash dryer to remove moisture.
The dry blended concentrates together with preheated oxygen-enriched air are fed into the flash smelting furnace with electrodes (FSFE) through a single jet burner.
In the FSFE, oxygen reacts with iron and sulfur to form oxides. Excess iron combines with oxygen and silica to form molten slag, while sulfur oxidizes and exits through the uptake to the acid plant for sulfuric acid production.
Untreated iron and copper remain as sulfides and form a heavier molten material called matte which collects at the bottom of the furnace, while slag containing most of the oxidized impurities floats on top. The molten slag is skimmed off, granulated with seawater, and hauled to the granulated slag stockpile.
The matte which contains 55-60% copper is tapped into a ladle and fed to the converter furnaces for further upgrading into blister copper, which contains 98-99% copper. It also contains precious metals such as gold and silver and minute amounts of impurities.
From the converter furnace (CF), blister copper is transferred by ladle to the anode refining furnace. The resulting fire-refined copper is cast into anodes which contain 99.5% copper, by a 28-mold Outukumpu Oy (OKO) casting wheel at the rate of 90 tons per hour.
The solidified anodes are cast for use as starting sheet anodes or commercial anodes before these are transferred to the refinery tank house for electrolytic refining. The smelter processes 720,000 mtpy of concentrates. Integral to the process is pollution abatement, such that gases containing sulfur oxide - generated in the FSFE and CF - pass through the gas ducts to the waste heat boiler, electrostatic precipitator, and acid plant for conversion into sulfuric acid. Waste acid from the acid plant is treated in a neutralization plant to produce gypsum.
The dry blended concentrates together with preheated oxygen-enriched air are fed into the flash smelting furnace with electrodes (FSFE) through a single jet burner.
In the FSFE, oxygen reacts with iron and sulfur to form oxides. Excess iron combines with oxygen and silica to form molten slag, while sulfur oxidizes and exits through the uptake to the acid plant for sulfuric acid production.
Untreated iron and copper remain as sulfides and form a heavier molten material called matte which collects at the bottom of the furnace, while slag containing most of the oxidized impurities floats on top. The molten slag is skimmed off, granulated with seawater, and hauled to the granulated slag stockpile.
The matte which contains 55-60% copper is tapped into a ladle and fed to the converter furnaces for further upgrading into blister copper, which contains 98-99% copper. It also contains precious metals such as gold and silver and minute amounts of impurities.
From the converter furnace (CF), blister copper is transferred by ladle to the anode refining furnace. The resulting fire-refined copper is cast into anodes which contain 99.5% copper, by a 28-mold Outukumpu Oy (OKO) casting wheel at the rate of 90 tons per hour.
The solidified anodes are cast for use as starting sheet anodes or commercial anodes before these are transferred to the refinery tank house for electrolytic refining. The smelter processes 720,000 mtpy of concentrates. Integral to the process is pollution abatement, such that gases containing sulfur oxide - generated in the FSFE and CF - pass through the gas ducts to the waste heat boiler, electrostatic precipitator, and acid plant for conversion into sulfuric acid. Waste acid from the acid plant is treated in a neutralization plant to produce gypsum.
REFINING PROCESS
PASAR uses the conventional starting sheet technology in its refinery. Refined copper anodes are suspended in-between thin copper starting sheets inside electrolytic cells. These electrolytic cells are filled with electrolytic solution consisting of copper sulfate and sulfuric acid. Electric current is passed through the poles of the anode starting sheet circuit.
The direct electric current causes the copper molecules in the anodes to dissolve, ionize, and migrate through the electrolyte solution and deposit as copper molecules onto the starting sheets. Copper deposition continues until the starting sheet thickens into a full-grown cathode with 99.99+% copper purity. This process takes anywhere from 6 to 7 days, depending on the refinery's cycle, current density and efficiency.
The electrolyte solution used during the refining process is decopperized through an electrowinning or reverse electrolysis process. The purified electrolyte solution is recycled back into the system. Recovered copper is fed back into the CF at the smelter.
During the refining process, the insoluble metals in the anodes, such as gold, silver, selenium, and tellurium, settle at the bottom of electrolytic cells. This precipitate called slimes is sent to a leaching tank where copper is recovered. The recovered copper is fed back into the CF, while the decopperized slime is processed into doré metal and selenium powder.
The direct electric current causes the copper molecules in the anodes to dissolve, ionize, and migrate through the electrolyte solution and deposit as copper molecules onto the starting sheets. Copper deposition continues until the starting sheet thickens into a full-grown cathode with 99.99+% copper purity. This process takes anywhere from 6 to 7 days, depending on the refinery's cycle, current density and efficiency.
The electrolyte solution used during the refining process is decopperized through an electrowinning or reverse electrolysis process. The purified electrolyte solution is recycled back into the system. Recovered copper is fed back into the CF at the smelter.
During the refining process, the insoluble metals in the anodes, such as gold, silver, selenium, and tellurium, settle at the bottom of electrolytic cells. This precipitate called slimes is sent to a leaching tank where copper is recovered. The recovered copper is fed back into the CF, while the decopperized slime is processed into doré metal and selenium powder.
RAW MATERIAL SUPPLY
PASAR sourced all its copper concentrates requirements from copper mines in the Philippines during its first few years of operation. However, in 1987, PASAR began diversifying its sources of raw material not only to ensure a continuous supply but also to achieve the correct concentrate blend required for more efficient processing operations.
Today, PASAR's copper concentrates are supplied by large mines in Indonesia, Papua New Guinea, Canada, Australia, Argentina, Brazil, and Chile. PASAR continues to purchase copper concentrates from some Philippine mines as available.
Today, PASAR's copper concentrates are supplied by large mines in Indonesia, Papua New Guinea, Canada, Australia, Argentina, Brazil, and Chile. PASAR continues to purchase copper concentrates from some Philippine mines as available.
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