Froth flotation was the key process in extracting the valuable minerals from the waste rock. The basic principal is to blow air through a mixture of ground ore/water/chemical reagents. The valuable minerals stick to the bubbles which rise to the surface to be collected Terminology used here.

Quartz flotation equipment

  • Concentrate – Ore with the waste rock removed, for shipping to smelter
  • Collect/collector/ activated – Process of making selected mineral(s) stick to the froth/bubbles. The collector is the chemical that makes this happen
  • Frothing agent – Chemical used to make bubbles stable (and not burst)
  • Depress/depressant – Process of making selected mineral(s) not stick to the froth/bubbles. The depressant is the chemical that makes this happen
  • Gangue – Waste minerals, e.g. quartz
  • Fines – Ore ground to the consistency of fine sand

Heteropolar – Molecule with water-repellent (non-polar) and water-soluble (polar) parts

Hydrophobic – Molecule (or part of) that is water-repellent (the opposite is hydrophilic) To extract the valuable minerals, the ore had to be ground to a powder – in the

Flotation Machines

. After initial crushing, the ore was washed to remove impurities (‘primary slimes’) such as clay and soluble salts which would clog up the flotation and fine grinding process.

The last grinding stages before flotation were done wet – this was essential as it prepared the ore for the reaction with the chemical reagents. The ore/water mixture was called pulp. The pulp was then fed into the froth flotation tanks.

The Bubbles….Creating the Froth

A key part of the floatation process was blowing air through the pulp to create bubbles. These bubbles would rise to the surface, with the ore minerals stuck to them, allowing the collected ore to be removed. A chemical had to be added to keep the bubbles stable so they could rise to the surface without bursting – just like adding dishwashing liquid to water. The frothing agent used most at Britannia was steam-distilled pine oil.

Floating the Minerals

To make any mineral floatable, it has to be made water-repellent (hydrophobic). When this happens, it can stick to the frothing agent in the bubbles and be carried to the surface to be removed. It sticks to the bubble because, being water-repellent, the molecules have more of an attraction to air than water. Minerals by the nature of their molecular structure are not water-repellent, so they must be coated with a thin film of water-repellent chemical. This is done by adding a ‘collector’.

In the early days of flotation, oil was used as the collector (oil and water don’t mix, so oil coated minerals were water-repellent), but as this often coated the gangue (waste) minerals too it wasn’t a high yield process. It also wasn’t possible to do selective flotation, i.e. remove different types of sulphides independently. Mill no. 1 used this process – Elmore Bulk Oil Flotation and was one of the first on the continent installed in 1912 (600 ton capacity).

For sulphide minerals, a common collector is the xanthate group of chemicals. Like the frothing agent, xanthates are heteropolar. This means that they have a water-soluble (polar) end, which is attracted to the wet surface of the sulphides, and a water-repellent (non-polar) end which sticks to the bubbles. At Britannia, xanthates were used from 1926 (replacing coal tar and creosote) – they are still used in flotation today.

Flotation Machines

In the early days of flotation, Britannia used two types – Mineral Separation and Forrester. In 1931, the Forrester type became solely used as it gave higher grade concentrates and decreased costs. The early Mineral Separation machines agitated the water as it introduced air. It wasn’t a very efficient machine though. The later Forrester was an ‘air-lift’ machine, using compressed air to blow bubbles at the base of a V-shaped trough. The mineral-laden bubbles rose to the top where they overflowed into collection channel.

The Britannia Deep Cell system was developed by Mr A C Munro, Mill Superintendent. This was a modified version of the Southwestern Machine. It was used in the bulk flotation process, where flotation happened in 8 feet deep cells (5’ wide x 100’ long), unlike conventional cells at the time which were shallower. For the Britannia ore, it gave a 95% recovery rate, however it never caught on in the general mining industry.

Bulk Flotation

This was the first flotation stage and was pioneered at Britannia. It separated all the sulphides from the gangue minerals. This can be done when the ore is ground to a coarser level than when trying to separate the sulphides from each other. This saves money as it meant the hard waste rock didn’t have to be unnecessarily ground finely. Powerful reagents could also be used which didn’t hamper selective flotation. Potassium ethyl xanthate (collector) and pine oil (frother) were used as key reagents at this stage.

Categories: Beneficiation Plant Tags: , , , ,

One Response to “ Quartz flotation equipment ”

  1. Demand:Titanium Processing Plant | Materials: Titanium Ore | Customer from USA Says:

    We are looking to BUY the following SAND TYPE PROCESSING plants (NOT ROCK): 1. Titanium Processing Plant – throughput capacity 250 tons per day 2. Magnetite separator and concentrator plant – throughput capacity 2,600 tons per day 3. Magnetite- titanium leaching treatment plant- throughput capacity 85,000 Tons per month We are looking for complete and existing solutions; NOT custom designed. Production output needs are stated above. At this time, I do not have any additional information. Please let us know if this is something you can help us source out. Thank you for your time.

Products Quick Links