sulfuric acid usage in copper leaching

[bluebirdiran]

Well it seems you are all off the mark by a long way. You have to keep the pH of the slurry of copper powder and sulfuric acid solution at about 1.5 to 2 for maximum recovery of copper in the ore. You have to keep mixing it for about 1 to 2 hours for Malachite and a bit longer for chrysocolla type of ores. Azorite is also soluble . These are the main soluble copper compounds found in copper ore. The ore has to be well crushed preferably to less than 20 mesh. Leaching works only on so called oxide ores. Sulfide ores will not leach unless you do bioleaching. So how much sulfuric acid you will need depends on the assay of the ore. The more calcium in the form of Lime and magnesium in the form of dolomite you have in the ore , the more acid you will need to neutralize these elements first and then dissolve the copper content. What you get after filtration of the slurry is copper sulfate. Now if you decide to do cementation by adding iron scrap you will get a brown powder precipitating. For each kg of expected copper, you will need slightly bigger amounts of iron scrap. You cannot do electrowining on this product. you can smelt it and get copper matte of about 96% purity. The other choice is to do electrowining of the solution provided you can enrich the copper content of the solution to at least 35 g/l and an acid content of about 180 g/l if I remember correctly. You will need about 2 volts DC for this at an ampere density of about 200A/m2. This is direct electrowining which is not recommended because you will not get 99.99% pure copper at the cathode barring other likely problems. So you have to do what is called solution extraction using an organic oil called by the commercial name of Lix. This is too complicated to do at home I think.

 

[kjavanb123]

Hi bluebirdiran,

First I like to welcome you to the greatest communities online. This was an old project and very first ones before I got hooked on e-waste. Thanks so much for your informative post. The price of copper is in the lowests nowdays, so any types of leaching would make it unprofitable for home scale.

Regards
Kj

 

[Ayham Hafez]

Hi bluebirdiran,

First I like to welcome you to the greatest communities online. This was an old project and very first ones before I got hooked on e-waste. Thanks so much for your informative post. The price of copper is in the lowests nowdays, so any types of leaching would make it unprofitable for home scale.

Regards
Kj

I'm trying to find away for recovering copper from copper sulphate electrolyte used in electrolysis copper refining cell without making cementation, then purify the solution to get pure dilute sulphuric acid to use it again.

Incase copper electrolyte solution has about 50 grams copper per liter and about 150 ml of sulphuric acid per liter, and some other impurities such as nickel, iron tin and silver.

Can I simply make electrowining by using lead as an anode and stainless steel sheet as cathode to get copper from solution? Will silver and other base metals formed on the cathode? If not how I can purify the sulphuric solution from them after finishing electrowining?