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Clariant's FLOTICOR SI 7021 replaces a competitor's anti-scaling agent

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Clariant’s FLOTICOR SI 7021 replaces a competitor‘s anti-scaling agent at an iron ore mine because it… 

  • Delivers similar anti-scaling performance 
  • Has no effect on process recovery of iron ore 
  • Maintains similar dosage rates and points 
  • Provides better cost performance, saving the mine money


An iron ore mining operation in Minas Gerais, Brazil recently conducted a review of the anti-scaling reagent for its sludge thickener circuit. Clariant responded to the bid request, which required a reagent with similar anti-scaling properties of the product used in the circuit. However, the operation wanted to reduce reagent cost, achieved by either lowering consumption or maintaining dosage levels but at a lower price per unit.

The water recovered from the sludge thickeners was recirculated back to the flotation tanks for the iron ore beneficiation process. Therefore, the new anti-scaling reagent could not affect mineral recovery performance of the flotation tanks.


This large multinational company mines a low-grade itabiritic iron ore in Minas Gerias. The high volume operation uses flotation beneficiation to produce high grade iron blast furnace and direct reduction pellets.

After the low grade ore is crushed and milled, it is sent through multiple flotation tanks for iron recovery. Post separation, the ore slurry is sent to two parallel large-diameter tank concentrate sludge thickeners. The sludge thickeners overflow at rates of 194,230 ft3/h (5,500 m3/h) and 45,909 ft3/h (1,300 m3/h) at tanks 1 and 2 respectively. To lessen the mine’s environmental impact, water from these tanks is recovered and sent back to the flotation plant via large diameter pipes.

To increase clarification efficiency at the sludge thickeners, the mine adds lime at this stage, increasing the MgCO3 and CaCO3 of the overflow sent back to the flotation tanks. This results in scaling inside the return pipes, which, if not addressed, can lead to an increase in pipe pressures, additional stress on the pumps and production interruptions.

To counteract this issue, the mine used a competitive anti-scaling reagent. In 2011, the mine distributed a bid notice, searching for a new reagent that would deliver the same anti-scaling properties as the competitive reagent, while at the same time reduce costs.


Clariant scientists worked with the mine to better understand its processes, how it addresses scaling issues inside the return pipes and the overall objectives of the company. Since the mine recirculates overflow from the sludge thickeners to the flotation tanks, the first critical step was to ensure the anti-scaling reagent would not lower iron recovery levels.

Clearly understanding the operation’s needs, Clariant offered the mine’s technicians two anti-scaling reagents for lab trials. Both products were tested in laboratory flotation tests and data analysis showed neither reagent lowered mineral recovery levels. With a better cost performance, FLOTICOR SI 7021 was selected to advance to the next stage of trials.

During these blank trails, the sludge thickener tanks were equipped with test coupons to evaluate the anti-scaling effectiveness of both the competitive reagent and FLOTICOR SI 7021 . For a period of one month, the mine used the competitive anti-scaling reagent, and they collected and analyzed data retrieved from the test coupons.

The mine then tested FLOTICOR SI 7021 for three months. Clariant’s reagent was added at sludge thickener #1 at 4.8 gal/hr (18.0 l/h) [dosage rate of 3.3 ppm]. A second dosage point inside the compartment that receives overflow from sluge thickener #2 was established with a flow rate of 1.3 gal/hr (5.1 l/hr) [dosage rate of 3.9 ppm]. Test coupons were gathered and evaluated after 30, 60 and 90 days.

Analysis of the FLOTICOR SI 7021 test coupons showed the same anti-scaling properties as the competitive anti-scaling reagent at a better cost performance.


FLOTICOR SI 7021 met the mining operation’s objectives of delivering anti-scaling properties while improving cost performance, so it is now the reagent of choice for the sludge thickeners. The reagent is also being tested for use in the mine’s concentrate thickeners.

For this iron ore mining operation, FLOTICOR SI 7021… 

  • Has no effect on the mineral recovery rates of the flotation circuit 
  • Exhibits proven anti-scaling properties in the overflow return pipes 
  • Helps to keep the sludge thickener circuit operating at peak efficiency 
  • Delivers a better cost performance than the competitor’s product 

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Copyright © Clariant International Ltd, 2013.


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