Copper leaching (leaching of copper ore)
With a leaching agent to copper ore, or calcine valuable components such as copper in copper concentrate is dissolved in water and most of the impurities separation process, as the wet copper's first job.
Copper leaching agent may be dissolved copper minerals are many kinds of leaching agent, but actually only water, sulfuric acid, ferric sulfate solution, ammonia solution and chloride solutions in industrial applications. The most commonly used copper leaching agent is sulfuric acid. Containing quartz and more acidic copper oxide, generally preferable to sulfuric acid leaching, not only because sulfuric acid inexpensive, but also because of the acid sulfuric acid leach ore consumes less. Containing alkaline gangue (such as calcium carbonate and magnesium carbonate) higher copper oxide, liquid ammonia leaching is generally used. Mixed copper sulfate and ferric sulfate is appropriate mixture of extraction, sulfuric acid is mainly dissolved copper oxide minerals, iron sulfide minerals are dissolved copper. When dealing with some metallic copper-containing materials, can also be used ammonia leaching with sulfuric acid.
The method has been applied to industrial production or reach semi-industrial pilot phase methods are mainly sulfuric acid leaching, ammonia and chloride leaching medium leaching.
Sulfuric acid leaching of copper oxide and more direct leaching with dilute sulfuric acid, which is wet copper industry was the most common method. Precipitation of copper sulfide leaching solution is available, the hydrolysis (see precipitation), iron substitution (see substitution), or extraction with a solvent to extract an electrolytic deposition of copper from the solution. A solvent extraction electrowinning process developed rapidly and has become the main method to mention copper from leaching solution.
Sulfuric acid can be oxidized copper ore is dissolved out, such as dissolves malachite CuCO3 • Cu (OH) 2, chrysocolla CuSiO3 • 2H2O, azurite Cu3 (CO3) 2 (OH) 2, cuprite Cu2O , vitriol CuSO4 • 5H2O, etc; leaching time when extended, is also soluble secondary sulfide minerals such as chalcocite Cu2S. Such as the leaching agent containing ferric iron and iron-sulfur bacteria such as bacteria, can also press the leaching of chalcopyrite type:
Fe2 (SO4) 3 + CuFeS2 → 5FeSO4 + CuSO4 + 2S
Zambia Nchanga (Nchanga) Company Chingola (Chingola) plant with dilute sulfuric acid leaching of copper flotation tailings 0.6%, 2.25% copper stockpiled tailings and waste rock section. After the materials are pre-preg, sent slot (see leaching tank) leaching were two, each with four slot in the thick leached pulp washing countercurrent decantation pool, thickener underflow lime neutralization after the pump to the dam, thickener supernatant by filtration send extraction.

Way way wet copper leaching into percolation leaching and agitation leaching.
A percolation leaching leaching method has been widely used for coarser ore and has been blasting out of the ore body. Acid leaching agent is usually sprayed from the top of the seam, the solution of acid and acid soluble copper ore reacts copper sulfate leaching out through the seam. Percolation leaching include heap leaching, in situ leaching and tank leaching leaching.
(A) heap leaching. Including waste heap leach ore and ore heap leaching, the former is used to handle conventional low copper mining law abandoned ore, often open-air job, clustered rock piles (millions of tons), ore heap leaching agent from the surface sprinkle cloth; latter is the surface oxide ore heap fragmentation and poly mineralization, generally up to 10 to 500 000 t of scale, mine ore mine waste heap than the slightly smaller heap leaching.
(2) In situ leaching. Crushed ore with explosives first place, do not move the ore from the ore leaching agent spraying the surface. This method is used to process low-grade copper deposits in surface or underground copper deposit. It must be noted in the subsurface crack the case before the hydraulic pressure leaching. Whether it is in situ leaching or heap leaching, are required to have no leakage substrate (natural or artificial), in order to collect the leachate.
(3) slots Leaching. In the giant trough (e.g. length 25m, width 15m, depth 6m, the processing capacity of 3000 ~ 5000t ore), and sulfuric acid containing 50 ~ 100g / L was immersed crushed ore (less than 1cm). Leaching is often drained soaked through several cycles. After the first few leachate purification sent by electrowinning copper production, the subsequent leaching solution used to leach the next batch of fresh ore. Compared with heap leaching and in situ leaching, tank leaching solution of sulfuric acid leaching using darker and have a higher production efficiency.
Agitation leaching of finely ground copper-containing material with a leaching agent added together and stirred with a stirrer tank leaching, the particle size is less than 95% of the material was 75 / μm, leach solution containing sulfuric acid 50 ~ 100g / L. Agitation leaching efficiency higher. In general, in situ leaching and heap leaching time in years calculated trough Leaching time in days counted, while only 2 ~ 5h agitation leaching can be completed.
In addition to some of the oxidation of sulfide copper calcine and calcined after using agitation leaching beyond the general ammonia leaching and agitation leaching oxide leaching are used.

Solvent extraction and electrowinning (SX/EW) is a two-stage hydrometallurgicalprocess that first extracts and upgrades copper ions from low-grade leach solutions into a solventcontaining a chemical that selectively reacts with and binds the copper in the solvent. The copper is extracted from the solvent with strong aqueous acid which then deposits pure copper onto cathodes using an electrolyticprocedure (electrowinning).

SX/EW processing is best known for its use by the copper industry, where it accounts for 20% of world wide production

Leaching involves the use of aqueous solutions containing a lixiviant which is brought into contact with a material containing a valuable metal. The lixiviant in solution may be acidic or basic in nature. The type and concentration of the lixiviant is normally controlled to allow some degree of selectivity for the metal or metals that are to be recovered. In the leaching process, oxidation potential, temperature, and pH of the solution are important parameters, and are often manipulated to optimize dissolution of the desired metal component into the aqueous phase.

The three basic leaching techniques are in-situ leaching, heap leaching, and vat leaching. In the solvent extraction is a mixture of an extractant in a diluent is used to extract a metal from one phase to another. In solvent extraction this mixture is often referred to as the "organic" because the main constituent (diluent) is some type of oil.

The PLS (pregnant leach solution) is mixed to emulsification with the stripped organic and allowed to separate. The metal will be exchanged from the PLS to the organic they are modified. The resulting streams will be a loaded organic and a raffinate. When dealing with electrowinning, the loaded organic is then mixed to emulsification with a lean electrolyte and allowed to separate. The metal will be exchanged from the organic to the electrolyte. The resulting streams will be a stripped organic and a rich electrolyte. The organic stream is recycled through the solvent extraction process while the aqueous streams cycle through leaching and electrowinningprocesses respectively.