Long term-stabilized magnesium hydroxide suspension for covering iron mineral, a process for its production and application

A long term stabilized magnesium hydroxide suspension adapted to cover pellets of several kinds of materials to avoid their agglomeration when treated at temperatures of between about 900° C. to 1,000° C., which comprises a solids content of about 55%;

• a water content of about 44%;
• a viscosity of about 1,000 cp.;
• an average particle size of about 2.0 microns;
• a Mg(OH)2 content of about 55%;
• a chloride content of about 0.30%;
• a calcium content of about 0.45%;
• a pH of about 11.7;
• an equivalent magnesium oxide content of about 38%;
• a specific gravity of about 1.47;
• and including at least one anionic polyelectrolyte as a dispersant agent, at a concentration of about 40%, in an amount of about 1%, by weight, on a dry basis and an adherent compound having a concentration of at least about 30% in an amount of about 1.5% to 2.0%, by weight, on a dry basis;
• adapted to being stored for at least three months without substantial agitation and without experiencing substantial settlement, while avoiding the formation of solid, hard substrate.

A process for the production of a long-term stabilized magnesium hydroxide suspension from magnesium hydroxide solids, which comprises the steps of:

• a) washing the magnesium hydroxide solids;
• b) filtering and repulping the magnesium hydroxide solids to obtain agglomerated solid particles having less than about 0.6% of chloride values;
• c) dispersing the agglomerated solid particles by comminuting in dispersing equipment to reduce their particle size to provide a dispersed product;
• d) grinding the dispersed product to further reduce the particle size so that at least the 50% of the ground product has a particle size of about 2 microns;
• e) adding an adherent compound, at a concentration of at least about 30% in an amount of about 0.5 to about 5%, by weight, on a dry basis;
• f) dispersing the product of step e) in the dispersing equipment and;
• g) adding at least one anionic polylectrolyte as a dispersant agent, at a concentration of at least about 25%, in an amount of about 0.5 to 2.5%, by weight, on a dry basis.