The general "rule of thumb" is use columns for cleaning purposes not recovery and uses the conventional cells for metal recovery. Therefore if you use columns it is a good idea to scavenge the column tailings with a bank of conventional cells.

Do not use columns for roughing or scavenging applications. Columns can be used well in cleaning applications, as deep froth depths are used and a lot of scope for efficient frosh washing

I am doing some preliminary investigation into different processing methods, chrysocolla is the primary source for our copper values and as I understand it this presents special challenges for the processing.

All the advice you have received is valid. However the overriding rule is testwork, there are base metal plants operating with all columns. It does challenge the comfort zones of many metallurgists. In igneous phosphates i have used columns in all phases of flotation but this came about after lots of testwork and some hard discussions with the client. Granted it is a different commodity/mineral type.

I would talk to the suppliers such as Eriez, Metso Cisa or Xstrata Jamieson for more definite answers.

I used large diameter columns for roughing application (gold-pyrite flotation). They worked well. In fact they have been in operation for more than 20 years now. They are still working well. I see no reason columns should not be considered in roughing duty provided they are chosen, designed and operated correctly. I also saw rougher columns (gold pyrite), performing badly (not in operation anymore).

I agree with all comments and want to add some mineralogical insight. It may be not inefficient to use column cells in any operation with chrysocolla being a main Cu mineral. This type of cells is generally used for cleaning operations when you have good flotation kinetics dealing with good floating and well-liberated minerals. In other words, basically mechanically wash a rougher con or coarse material that floats like crazy from gangue. Copper connected with chrysocolla is usually badly floatable, and most likely poorly liberated and fine. All those characteristics do not benefit quick flotation. So, I would suggest using kinetics parameters and liberation analysis of copper minerals in flotation feed and rougher tails to determine needed fineness, possible kinetics and to choose cell type based on combined data.

I totally agree with you. Columns are great for froth cleaning and upgrading of concentrates; or in specialist applications (e.g. pre-float as below).

I used a column as talc pre-float prior to a gold pyite/arsenopyrite circuit, to scalp out carbonates prior to flotation followed by BIOX. The concentrate was very low in sulphide (we used no collector) and this was leachable for a satisfactory gold recovery; freeing up the rest of the circuit for processing of refractory ore types by flotation followed by BIOX.

In another application, the column concentrate was virtually pure sulphide, and gave a grade higher than that required for the final concentrate grade - giving us the option to pull the scavengers a little harder and work a little more on the cleaners. In a nutshell, the technology works - you just need to have the right application in mind. 

As with most specialty equipment, Column Flotation Cells have their place and indeed, with proper testing may work well in no-conventional circuits like talc pre-float. Test work is really necessary as points out, preferably on an existing flotation circuit so that scale-up is not a factor.

We are at the preliminary stages in investigating into the viability of this mining property, We are currently mapping and assaying to see if the overall quality and quantities of the ore justify further expenditures.

I am looking for final research about copper bioleaching especially bactech bioleaching process and information about commercial copper plant with 50-100 MT copper cathode per annually.

The use of columns in roughing is a nonconventional technology (used relatively recently at NICICO but still "exotic"). There is no compelling reason to move away from conventional technology for a small project.

The key factor will not be the flotation cell used, but rather the chemical conditioning that you use to make the chrysocolla hydrophobic. The mineral has variable flotation properties since it has an indeterminate copper concentration that ranges anywhere from about 20-35% Cu. Recoveries in conventional flotation tend to be unspectacular. Various processes have been used to try to activate chrysocolla, including sulfurization (moderately effective), thermal pre-treatment (effective but costly), acid pre-treatment (moderately effective) or use of non-conventional collectors such as octylhydroxamate (moderately effective but costly).

On the other hand the stuff leaches very well, so by far the most cost effective extraction route is just to dissolve the copper and use a hydromet process - for example by heap leaching where you don't even have to grind it.

You can design a column to perform a roughing duty just as you can a cleaning or scavenging duty, if you know the fundamental design parameters and dynamics of a column cell. I first designed and installed a column only plant to produce three separate copper, lead, zinc concentrates some 20years ago, never missed a beat.

The big advantages of columns over large cells etc is:

Air control over a wide range, no other cell offers this capability.
Inch perfect level control.
Full cell utilization all of the time.
Process control loops based on air addition rates.
No mixing mechanism-all done by counter-current flow
No blockages due to large particle settling.
Deep self-draining froth phase to give higher grade concentrate!

The myth about cleaning and large particle problems is just that-Myth!

Dear All

I will be very pleased if any body give this book (C.C. Dell, Release Analysis - A New Tool for Ore Dressing Research) to my mail id:  ashishkmr.osme@gmail.com

Research Intern

CSIR-NML, Chennai

India