The model’s choice of a laboratory flotation machine depends on three things;
- What work you want to do with the machine
- Who you have to operate the machine
- How much you have to spend
If its just for some ‘hot’ plant floats and some basic metallurgical testing onsite then my personal favorite is the old Denver D12 machines. They are robust, fairly simple and easy to maintain. Its also fairly easy to pick up second hand. You may even have other sites in your company who have a spare one and a word of caution here it is also important when using this cell to have someone with a lot of practice who can get repeatable results. A good flotation technician or metallurgist who can do repeatable float tests is worth their weight in gold. There are no short cuts there just practice, practice, practice many years ago when I was a graduate an old technician made me do 10 float tests in a row and get the same results before I was trusted to do real batch test work (this was after already doing many practice tests).
Over the years there has been a lot of work done on flotation test repeatability and trying to iron out errors related to machine design and human error. There are a lot of good papers out their on this work which a quick literature search will reveal. A lot of this work also lead to bottom driven cells designs (eg Leeds cell, JKTech cell) to make scraping more even. In the extreme are machines that are automated to the extreme such as the ‘Outotec-Geological Survey of Finland’ unit that has automated froth scraping and all kind of online measurements. If high repeatability is what you are after this may be an option if you don’t have an experienced technician and you have cash.
Finally some of the new ‘cheap’ cells on the market have rotors and stators that are made from rubber not steel or hard plastic. If you are doing a ‘hot float’ at a high pulp SG the mechanism starts to bend giving you all kind of problems with the results. They also tend to have quiet small motors so they can trip out under these conditions.