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Flotigam K2C excels in reverse flotation application producing high quality magnesite concentrate

The Bottom Line

Clariant works with a leading supplier of refractory materials to…

  • Provide supporting technical information for the company’s mine feasibility study
  • Deliver the right high-efficiency collector to meet the stringent 98% magnesium oxide concentrate grade
  • Optimize the process to adapt to varying feed ore grade quality


A global refractory materials supplier wanted to begin mining and refractory plant operations in northeast China to produce its high-grade, fire-proof products. Initially, the company’s European operation tasked Clariant with providing the necessary supporting documentation for the feasibility study, so the customer could obtain the financing for ore mining and production.

Prior to starting mining operations, the customer established a minimum target magnesite concentrate quality of 98%. With an ore feed grade of 95-96%, the mine required the chemistry to remove silica impurities to improve concentrate grade at production capacities reaching 38 metric tons per hour.

As operations progressed, the customer sourced magnesite ore feed from external suppliers. Experiencing inconsistent feed quality from these outside sources, the customer needed Clariant to optimize the reverse flotation circuit to maintain consistent concentrate grade and production levels.


In the mid-1990s, a global leader in the refractory materials market entered into a joint venture with a Chinese investment company to develop refractory production operations in northeast China. Magnesite ore feed, to make the company’s high quality refractory bricks, initially was supplied solely from a company-owned mine. A small percentage of the bricks was produced for domestic consumption, while the vast majority was shipped to companies throughout the world.

The mine’s crushing and screening equipment and ball mills ground flotation circuit feed size to less than 8 mm. Using a reverse flotation process, the conventional flotation stirrer cells with self-air suction were designed to produce a magnesite concentrate with a minimum 98% magnesium oxide grade at a production capacity reaching 38 t/hr.

Mine feed material consisted of 95-96% magnesite with silica dioxide impurity levels ranging from 3 to 4%. The high efficiency collector served both as a collector and frother to reduce impurity levels to less than 0.4%.

As mine ore reserves were depleted, the refractory company purchased raw ore feed on the open market to supplement the mine’s production. This resulted in inconsistent feed grades with varying impurity levels, which required close monitoring of concentrate grade quality. To maintain concentrate grade with fluctuating feed quality, Clariant recommended the addition of a frother to supplement impurity removal.


Prior to the mine’s inception, Clariant worked with the joint venture to ensure successful operations. Clariant provided the supporting technical information that proved the ore could be mined for producing a high quality magnesite concentrate required for the refractory’s smelters.

Before running material through the flotation circuit, Clariant technicians conducted internal lab tests to select the best high efficiency collector, designed to meet the customer’s magnesite concentrate with 98% target magnesium oxide grade. After analyzing lab results, Flotigam K2C was recommended as the best collector.

The customer’s technical staff further evaluated Flotigam K2C in its own laboratory tests and determined it provided the required collector and frother properties to produce the target concentrate grade. The collector was injected as a liquid into the conditioning tanks at a rate of 660 g/ton. As required to ensure the desired level of frothing, Montanol 800 was also injected at a 50 g/ton dosage.

As the company introduced ore purchased from other mines, feed grade quality varied. In most cases, only the collector Flotigam K2C was required to provide the frothing property that ensured a high quality concentrate. However, Clariant’s solution of combining Flotigam K2C with the Montanol 800 frother on an as-needed basis has helped the mine to achieve on-spec and stable flotation, even with varying feed grade.

Consistent Results

From providing the required chemistry for feasibility studies to optimizing the process when adapting to varying feed quality, Clariant continually works to achieve concentrate grade targets in the most efficient method possible.

For this refractory materials company in China, Flotigam K2C…

  • Consistently produces high grade concentrate of 98% magnesium oxide
  • Reduces silica dioxide impurity levels to less than 0.4%
  • Provides the flexibility to adapt to varying feed conditions which maintaining concentrate quality
  • Works alone or in conjunction with Montanol 800 to provide the required frothing properties
  • Allows the company to charge a premium price for its concentrate
  • Enables the company to make high grade refractory bricks for supplying demand from its global customer base


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