Preacidification heap leaching of copper ore is crushed to -8mm refers copper ore, mixed with water and concentrated sulfuric acid, copper in the ore is reacted with sulfuric acid to produce a soluble copper sulfate. Part of the secondary copper sulfide also produces soluble copper sulfate. The pre-acidification reaction is as follows:
CuSiO 3 ·2H 2 O+H 2 SO 4 +2H 2 O 
CuSO 4 ·5H 2 O+SiO 2
Cu 2 S+H 2 SO 4 + O 2 +4H 2 O CuSO 4 ·5H 2 O+CuS
The earliest application of this method was the Lo Aguirre mine located 30 km from Santiago, Chile. Its process can be summarized as follows: after the ore is crushed to -6mm, it is mixed with concentrated sulfuric acid and water to control the ore moisture content to 11%, pile up (let the ore sit and mature), and the pile height is 2.4m. Dilute with dilute sulfuric acid, extract with leaching solution, and return the leaching water phase (containing 0.5g ∕L, H 2 SO 4 8g ∕L); the saturated organic phase is back extracted with sulfuric acid, and the stripping solution contains copper 50g ,L, acid 130g∕L, electrowinning, electrowinning tail liquid returned for back extraction. In said hydrometallurgical copper in this method a thin layer leaching.
The pre-acidification heap leaching cycle is only 6d. At this time, the leaching rate of copper oxide is 88%-90%, and the leaching rate of secondary copper sulfide is about 50%. The remaining 50% of copper sulfide in the ore is sent to the permanent storage yard for recovery.
CuS+Fe 2 (SO 4 ) 3 CuSO 4 +2FeSO 4 +S
The immersion period of the permanent yard is 120d and the spray intensity is 3L/(h·m 2 ).
The mine has two steps of pre-acidification heap leaching and conventional heap leaching. The total recovery rate of mixed ore of copper oxide and copper sulphide is 80%-90%, the cost is low, and the annual output of copper is 17000t. It is the most successful ore pre-acidification heap leaching. The precedent.
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