Formulating copper concentrate from an ore body is a complex process that involves several stages of extraction and purification. Copper ore is typically found in deposits containing various minerals and impurities, and the goal of the formulation process is to isolate and concentrate the copper content to a desirable level.
The formulation begins with the mining of the copper ore from the ore body. Depending on the location and characteristics of the deposit, various mining methods such as open-pit mining or underground mining may be employed. Once the ore is extracted, it is transported to a processing facility for further treatment.
The first step in the formulation process is crushing and grinding the ore to reduce its size and facilitate the liberation of copper minerals from the surrounding rock. This is usually done using crushers and mills, which break the ore into smaller particles.
After crushing and grinding, the ore undergoes a process called froth flotation. In this step, chemicals known as collectors are added to the ore slurry to selectively attract and bind to the copper minerals. Air bubbles are then introduced into the slurry, causing the copper minerals to float to the surface while the non-copper minerals sink. This froth containing the copper minerals is skimmed off and collected as a concentrate.
The collected concentrate still contains impurities and other minerals, so it goes through further processing to increase its copper content. The concentrate is typically subjected to smelting, where it is heated in a furnace with fluxes, reductants and oxygen enriched air. This process melts the concentrate and separates the copper from other elements, producing a molten copper matte and slag consisting of Iron Oxide, Silica and Other Compounds. Normally at this stage the concentration of copper is around 65%.
Reaction in the smelting furnace is as follows:
CuFeS2 + SiO2 + O2 → Cu2S・FeS + 2FeO・SiO2 + SO2 + Reaction heat
To further purify the copper, the molten matte undergoes a refining process. Oxygen-enriched air is blown into the Converter furnace to oxidize the matte further to create blister copper with a grade of approximately 99%.
Reaction in the converter furnace is as follows:
Cu2S・FeS + SiO2 + O2 → Cu + 2FeO・SiO2 + SO2 + Reaction heat
The anode furnace plays a crucial role in the copper smelting and refining process. It is specifically used to further purify the copper obtained from smelting. The main purpose of the anode furnace is to remove impurities and separate them from the copper by reacting the impurities with flux and additives and converting it into slag. The slag floats on the top of molten copper which can be easily skimmed off.
Once the slag is removed the molten copper can be collected from the Anode Furnace in a separate vessel of casting moulds which is casted into Anode plates for electrolytic refining. The anode plates are approximately 1m x 1m x 0.05m in size and weigh 380 kg per plate.
During this process the Anode Plates and Stainless Steel Cathode plates are alternatively assembled in the electrorefining cell and an electric current is passed through it. This causes impurities to migrate to the anode, while pure copper is deposited on the cathode, resulting in high-quality copper metal. After about 10 days of electrolysis, the cathode is lifted out and stripped from the stainless-steel plate, resulting in the completion of refined copper (with grade of 99.99%) as a final product.
Once the refining process is complete, the copper is casted into various forms such as ingots or rods, which can be further processed into different products such as wires, pipes, or sheets, depending on the intended use.
Sulphuric Acid Plant is an integral component of the smelting and refining process of copper. Its primary purpose is to produce sulphuric acid, which is a valuable chemical compound widely used in various industrial applications by collecting So2 from the smelting furnace and then reacting it in catalytic converter to produce SO3 which is absorbed in water to make Concentrated Sulphuric Acid.
The Sulphuric Acid plant is also responsible for regenerating the sulphuric acid used in the electrorefining process. It treats the spent electrolyte, which contains dissolved copper and sulphuric acid, to recover the sulphuric acid for reuse in the electrorefining cell.
Copper slimes refer to the fine-grained residues or by-products generated during various stages of the copper smelting and refining process. This smile often contains significant amount of valuable metals like Gold, Silver, Copper and other trace elements.
This plant is designed to recover and extract these valuable metals from the slimes, allowing for their subsequent processing and reuse. This recovery process helps maximize the overall resource utilization and economic efficiency of the copper production operation.
This plant is also important from the Environmental Compliance point of view and recovers excess water from the slime which can be treated and can be reused within the production process.