[Abstract] This paper briefly introduces oxidizing leaching of red alloy in dilute sulphuric acid media and pilot effect taking microbubble neutralizing tank as leaching equipment.
Key words: red alloy Leaching   Self-heating  Microbubble neutralizing tank
I. Preface
In recent years, a kind of multielement raw material containing copper, cobalt, iron etc (above 70% copper, the rest are iron, cobalt, and etc.) enters into the domestic market. It is commonly known as red alloy because it presents red after removing the oxide layer. The pilot results show that it is an ideal technical solution to use air as oxidizing agent in dilute sulfuric acid media and microbubble neutralizing tank as leaching equipment.
II. Raw material conditions
Initial condition is black or brownish black spherical particle, with diameter of 5～8mm. Particle size of 90 percent is 4-30 mesh. List 1 is chemical compositions.
Chemical composition of red alloy ％ List 1

III. Leaching test
(I)   Laboratory test
1.  Red alloy can be leached smoothly in dilute sulfuric acid media taking air as oxidizing agent, and leaching efficiency is more than 99.5%.
2.  Acidity after leaching is between 10～25g/l.
3.  Extraction temperature at 75℃～85℃ can get high leaching speed.
4.  The leaching agent has favorable filtering performance.
(II)   Leaching reaction mechanism
(III)   Pilot equipment
Microbubble neutralizing tank consists of reactor, water-gas ejector, liquid-gas separator (buffer) and circulating pump.
The equipment is equipped with other parts as follows:
①.Spiral-flow solid-liquid separator.
② Acid mist condenser.
③ Liquid level controller.
④ Drain outlet.
(IV)   Pilot process
Materials: use red alloy in original state, no requirement on particle size.
Pre-leaching solution: H2SO4160～210g/l; reaction temperature: 75℃～85℃;
Solution replacement speed: 4～7l/min; acidity of leaching liquid: 15～30g/l
IV. Conclusion and prospect
1. Daily average leaching capacity is 460kg (design standard>500kg);
2. Leaching power consumption of ton alloy is about 450kwh (design standard≤400kwh);
3. The equipment can realize self-heating start and operation if there are some problems.
4. Low acidity oxidation leaching process of red alloy in H2SO4 medium is feasible.

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