The last years have been very successful for the Iron ore mining industry with increased volumes and market price. The major driving force is the rapid economical expansion in China. To meet this growth the mining industry invests in both new production capacity and in processes to improve the quality of the Iron ore concentrate (magnetite/hematite).

Low grade iron ores has to be processed to a certain level of iron grade to meet the requirements from the steel producers.

Magnetic separation is used in the concentrating process of magnetite. There is always a mineralogical limit which sets the possible maximum iron grade; this differs between ores from different deposits. In many cases magnetic separation is not enough to give the wanted quality of iron ore concentrate.

Silica and phosphorus are the two most important impurities to be reduced. Especially phosphorus has to be reduced to a very low level.

Flotation is a well known technique which gives the opportunity to get further purification. Silicates are removed with cationic surfactants and anionic surfactants are used for the removal of phosphorus minerals.

The silica and phosphorus minerals become hydrophobic by the adsorbed surfactants and when air is dispersed in the mineral slurry in the flotation cell, froth will be formed containing the hydrophobic tailing minerals. The froth is separated and the iron ore sink is concentrated.

Akzo Nobel has extensive experience of flotation of both silica and phosphorus from magnetite ores and offers flotation reagents for both applications.

Silica flotation reagents are collected under the family name LILAFLOT® and the reagents for phosphorus reduction belong to ATRAC® family.

Akzo Nobel has a specialised application group and a mineral flotation laboratory for development of reagents. Every ore and process is unique and tests are required to find the optimal flotation reagents. During the development work the parameters of importance are identified and the optimal reagent is developed with respect to that. Examples of important parameters are content of fine particles (slime), process water quality and process temperature.

Successful properties for flotation reagents are high efficiency and selectivity. The losses of iron oxide must be minimized in the flotation and the reagent has to be efficient in removal of impurities at low dosage. Akzo Nobel also gives assistance to get the approvals from authorities for handling and usage of flotation reagents at the mine site.

This work is done in co-operation with the mining companies and flotation equipment suppliers. In the end the result will be a customised flotation reagent of standard type or a highly tailor made solution.