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Flotation 3135 sets benchmark for collector performance in phosphate application

The Bottom Line

Partnering with one of the world’s largest phosphate mines for decades, Clariant develops a cationic collector that…

  • Increases concentrate BPL levels to a minimum of 70%
  • Delivers consistent froth stability
  • Reduces silicon dioxide levels to less than 3%
  • Offers superior reliability in adapting to varying feed ore grades
  • Is backed by Clariant’s continual support


Establishing high production reverse flotation plants to recover a sedimentary phosphorite ore, one of the world’s largest phosphate mines requires a highly selective collector to deliver high mineral recovery rates. The cationic collector must create a froth that is stable enough to float silicate gangue material, but it must not be so stable that it creates overflows in the froth launders.

Besides the siliceous gangue, the feed ore contains a high percentage of carbonaceous impurities. The mine also employs an anionic collector, often Clariant’s Flotinor V 2711, for carbonate removal. The cationic and anionic collectors must harmonize, working in synergy to achieve optimum flotation results.

The feed ore sent to flotation consists of roughly 57% bone phosphate of lime {BPL} (26.1% P2O5), high silicon dioxide (SiO2) reaching 20% and carbonaceous impurities. The mine established collector performance standards of a minimum of 70% BPL (32% P2O5) and maximum 3% SiO2 levels for the cationic and anionic collectors.

Additionally, feed ore priorities change daily, so the collector must readily adapt to these changing feed conditions. The mine is looking for long term partners to ensure the flotation plant’s success. Consistent collector quality is a must, and the collector supplier must work to develop new reagents as required.


A major phosphate producer on the world market today got its start more than 30 years ago, and Clariant was there. Processing a sedimentary phosphorite ore, the mine initially crushed and washed the run of mine for its final phosphate product. This was then turned into phosphoric acid for use in the making of fertilizer products.

For years, the very fine material – less than 200 µm in size – that could not be concentrated by washing was discarded as waste. To improve efficiency of the beneficiation plant and increase the amount of sellable phosphate concentrate, the mine decided to subject this fine material to a flotation process. The <200 µm feed was sent through a pilot plant for beneficiation.

Clariant worked with the mine in the 1980s to develop Flotigam 3135, a proprietary reagent that could meet target levels for the phosphate concentrate, while producing a manageable froth. Due to the fine particles in the flotation feed, froth stability was of great concern. If froth was too stable, it could not be transported easily to further process steps. Thick froth layers formed on the thickeners, and the recycled water sent back to the flotation process contained a significant amount of fines, which amplified the formation of stable froth and subsequently spoiled the flotation process.

When starting high production flotation plants just after 2000, the customer continued to use Clariant’s Flotigam 3135 as the standard collector, as it created the right froth stability regardless of feed ore conditions. It also harmonized well with anionic collectors used for removal of carbonaceous impurities. As the mine conducted trials with other cationic collectors for use when the highly selective Flotigam 3135 was not required, mine technicians relied on the Clariant reagent as reference collector because it consistently yielded optimum flotation results.

Today, the mine operates multiple flotation cells and processes roughly 6 million tonnes of feed ore, producing nearly 4 million tonnes of concentrate. Work stoppages at the flotation plants due to froth stability issues are unacceptable, as plant downtime costs the company more than 1 million euros per day.


Clariant began developing a cationic collector for the phosphate mine during pilot plant development. Technicians conducted in-lab trials on ore supplied by the mine. Multiple collector types were developed with the target of established the correct frothing properties to efficiently float the silicate and carbonate impurities.

After many trials and extensive analysis, Clariant technicians determined that Flotigam 3135 – an ether propyl di-amine – exhibited the right frothing selectivity characteristics. The reagent met customer targets and worked together with the anionic collector to deliver BPL levels of ≥ 70% (≥32% P2O5) and SIO2 levels of <3%.

Mine engineers subsequently ran trials with Flotigam 3135 through the pilot plant. Even with varying feed, Flotigam 3135 delivered reliable, consistent froth that maintained mineral recovery rates, so the mine selected it as the standard collector.

As the mine switched to the high production flotation plants, froth stability was increasingly important. At dosage rates of 250 to 350 grams/tonne of feed ore, the mine continued to use Flotigam 3135 as the standard collector and compared other collector performance to the Clariant product in subsequent trials. Flotigam 3135 stood as benchmark collector in which all other collector results must attain, a practice that continues to this day.


By using Flotigam 3135, this phosphate mine receives high recovery rates, consistent concentrate quality and avoids developing froth that is too stable. For this high production mine, Flotigam 3135…

  • Serves as the benchmark collector for mineral recovery and concentrate quality
  • Consistently produces a manageable froth
  • Avoids flotation plant shut-downs that can cost the mine millions of euros in lost productivity
  • Delivers target results of ≥ 70% BPL (≥ 32% P2O5) and < 3% SiO2
  • Provides high recovery rates in excess of 80%
  • Gives the mine long-term benefits, which have lasted nearly 30 years