Flotation Flowsheets: Key Types and Benefits in Mineral Processing

A flotation flowsheet should be as simple and flexible as possible, because changes in the ore often necessitate changes in treatment: the more flexible the flotation machine, the easier and quicker the changes can be made, not only in regard to flexibility in arrangement of cells, but also the ability to treat coarse as well as fine material. The flexible points of a “Sub-A” which should be convinced in flowsheet design are:

  1. Any cell can be used as a rougher, cleaner or recleaner.
  2. Middlings can be returned to any cell from any other cell without the use of pumps or elevators.
  3. There are no blowers or air pipes to change or regulate.
  4. Use of Flotation Cells makes it possible to install units between ball mill and classifier, or to add in any part of the circuit.
  5. Due to the distinctive gravity flow principle, the “Sub-A” Cells will treat a coarse product as efficiently as a fine product, which often becomes necessary where dumps, tailings or low grades ore are floated when their values do not permit the high cost of fine grinding.

 

Flotation_Flowsheet_A
For a bulk or one mineral flotation operation

 

Flotation_Flowsheet_B
For one mineral or bulk flotation operation where separate cleaner cell or cells are necessary to produce a high grade concentrate. Without changing launders, feed can be introduced into second or third cell, utilizing first or first two cells as cleaners. Cleaner’s tailings join the initial feed and recirculate through the machine.

 

Flotation_Flowsheet_C
When using amalgamation where reagents cannot be added to grinding mill and no conditioning tank is available, second cell is used as emulsifier or conditioner.

 

Flotation_Flowsheet_D
Used where minerals are closely associated and very fine grinding is required to free values. By reversing partitions in cleaner cell, cleaner tailings can be returned to grinding mill to use as “make up” dilution, giving further grinding to middling particles.

 

Flotation_Flowsheet_E
Treating ores where it is difficult to make a high grade concentrate, due to tendency of other minerals to float with minerals desired in concentrate.

 

Flotation_Flowsheet_F
Very often used on lead, lead-zinc and other base metal ores where grade of concentrate is of first importance, utilizing two stage cleaning or cleaner and recleaner circuit.

 

Flotation_Flowsheets_G
Where close association of desired mineral with other mineral or gangue, requires regarding of a middling product to produce high grade concentrate with low tailing.

 

Flotation_Flowsheets_1
Flotation Machine simplifies flowsheet designs, lowers the first cost of equipment, and at the same time reduces the cost of treating ores and produces a higher grade selective product. Flowsheet No. 1 is typical of a gold bearing sulphide ore, wherein a major recovery of gold values is made by means of the Mineral Jig, and subsequently recoveries of gold and sulphide values are made by means of a “Sub-A” Flotation Machine accounts for additional recovery of gold values to bring the total plant recovery to 90-97 percent of the gold contained in the ore. This is the simplest flowsheet used in separating one mineral from the gangue, and is recommended where important amounts of precious metals are contained in an ore. In larger plants, utilizing flotation for the recovery of ore base metal where precious metal values are of secondary importance, a similar flowsheet but with the substitution of the Flotation Cell in the grinding circuit would be applicable.

 

Flotation_Flowsheet_2
This flowsheet shows the use of a “Sub-A” Flotation Machines for selective flotation producing high grade lead and zinc products. The Unit Flotation Cell and Mineral Jig recover 73.2 percent of the gold and 61.4 percent of the lead in a concentrate that only concentrates 2.3 percent zinc. Additional lead recovery is made in the lead section to give a total recovery of 96.4 percent of the lead in the lead concentrate. The zinc flotation section recovers 68.8 percent of the zinc in a concentrate having average grade of 59.6 percent of zinc. High recoveries, simultaneous with high grade products are possible only through the use of a “Sub-A” Flotation Machines which are designed to incorporate not only superior mechanical features, but also to apply fundamental flotation principles with the highest efficiency.

 

Flotation_Flowsheet_3
This flowsheet shows the application of a “Sub-A” Flotation Machines in the non-metallic mineral industries and is typical of the flotation of fluorspar. In mills of this type an important consideration in plant design is the flexibility of the flow through a flotation machine in order to minimum installation costs, keeps the space required at a minimum and provide flexibility without necessity of major changes. The “Sub-A” Flotation Machine is easily adapted to these conditions, as shown in this flowsheet. A few slight modifications make it possible to discharge ‘o final tailings at the end of practically any number of cells that may be desired for rougher flotation and middlings can also be drawn off at desired points. Concentrates can be cleaned and recleaned as desired. A few simple changes which require only a few minutes to make result in the production of any grade of concentrate desired. The “Sub-A” Flotation Machines are used in non-metallic flotation for treating either coarse or fine materials. In some cases non-metallics all passing 325 mesh, are floated with the productions of high grade products since the machine actually floats minerals selectively, and does not contaminate products by conveying gangue slimes mechanically entrained with the concentrate. Selective action of the a “Sub-A” cells is distinctive and far more desirable than the classifier action so common with cells where air is introduced under pressure. On the other hand, on materials requiring coarser sizes for marketing purposes. The “Sub-A” Flotation Machines are used because they are the only machines that can satisfactorily handle such materials.

Flotation-Circuits

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