What is heap leaching copper?
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials.
How do you leach copper ore?
The leaching reagent (dilute sulfuric acid) is sprayed through sprinklers on top of the heap pile and allowed to trickle down through the heap, where it dissolves the copper from the ore. The resulting “pregnant” leach solution of sulfuric acid and copper sulfate is collected in a small pool.
Which copper mineral leaches the fastest in a heap leach?
Chalcopyrite Leaching
Chalcopyrite Leaching The foregoing data show that the rate of dissolution is faster when the mineral is more finely ground, that the rate increases with an increase in temperature, and that the rate of dissolution is more rapid in ferric chloride than in ferric sulphate.
What is heap leach ore?
Heap leaching is an industrial mining process of separating precious metals, copper, and other minerals, from ores. It involves a series of chemical processes, through which the mineral ores are piled into the form of a heap, and a leach solution is spread over the ore surface to leach metal from the heap.
What is meant by heap leaching?
Definition of heap leaching : a mining process in which metals are leached from a pile of crushed ore by a percolating solution (as of sodium cyanide)
What is heap leaching process?
Heap leaching involves stacking of metal-bearing ore into a heap on an impermeable pad, irrigating the ore for an extended period of time with a chemical solution to dissolve the sought-after metals, and collecting the leachant as it percolates from the base of the heap.
How do you clean raw copper ore?
Soak in muriatic acid (hydrochloric) approximately 1 hour. Sometimes toilet bowl cleaners contain this acid. This soaking removes all the green/brown oxidation from copper, plus any calcite is dissolved. Rinse well and brush the copper and rock again to remove any further loose rock.
What chemicals are used in heap leaching?
Lixiviants are chemical solutions used in leach mining to enhance dissolution of metals in ores. Sulphuric acid and cyanide salts are the most common demonstrated lixiviants used in heap or vat (tank) leaching processes applied under atmospheric conditions.
What is used in copper leaching?
The principal copper-bearing mineral in the ore is chrysocolla. Dilute sulfuric acid solutions containing from 30 to 35 grams per liter of acid are used to leach the ore.
Why is heap leaching bad?
The fluids remaining after the leaching process commonly contain elevated concentrations of metals and radioactive isotopes, posing a significant risk to nearby ground and surface water sources (IAEA, 2005). Additionally, the low pH of ISL mining wastewater can result in acidification of the surrounding environment.
How do you heap a leach?
What is Heap Leaching?
- Mine the ore.
- Crush the ore (if necessary)
- Agglomerate the ore (if necessary)
- Place the ore on a lined pad.
- Irrigate the ore with the appropriate lixiviant to dissolve the metals (leachate)
- Collect the leachate in a pond or tank (pregnant or value bearing solution)
When did heap leaching begin?
Large-scale heap leaching can be said to have started in 1980 when three major copper projects were commissioned in Chile, and, at approximately the same time, a large number of gold projects were commissioned in the United States.
How much copper is produced from heap leaching?
In 2011 leaching, both heap leaching and in-situ leaching, produced 3.4 million metric tons of copper, 22 percent of world production. The largest copper heap leach operations are in Chile, Peru, and the southwestern United States. Although heap leaching is a low cost-process, it normally has recovery rates of 60-70%.
What is heap leaching in mining?
QUICK LINKS. Heap leaching is an industrial mining method to dig out precious metals and copper compounds from ore. The mined ore is crushed into tiny chunks and heaped on an impermeable plastic and/or clay lined leach pad where it may be irrigated with a leach solution to melt the valuable metals.
What is the acid heap leaching method for nickel ore?
Nickel ores. This method is an acid heap leaching method like that of the copper method in that it utilises sulfuric acid instead of cyanide solution to dissolve the target minerals from crushed ore. The amount of sulfuric acid required is much higher than for copper ores, as high as 1,000 kg of acid per tonne of ore, but 500 kg is more common.
What is being done to study the leaching of copper?
The United States Bureau of Mines at its Southwest Experiment Station, in cooperation with the department of mining and metallurgy, University of Arizona, has undertaken a study of these fundamental factors involved in the leaching of copper ores.