Patent ID: 8011514

Claim:
A method for purifying clay from a clay-containing ore, comprising: a. providing a clay-containing ore comprising clay and one or more organic or inorganic impurities; b. contacting an aqueous slurry of the clay-containing ore with an amine-aldehyde resin comprising a silane coupling agent, and c. during or after the contacting step, separating the purified clay from the clay-containing ore by froth flotation of at least one organic or inorganic impurity; wherein the amine-aldehyde resin comprises a urea-formaldehyde resin prepared by: mixing formaldehyde, urea, triethanolamine and optionally ammonia reactants at an alkaline pH, heating the mixture to an elevated temperature for a time sufficient to obtain complete metholylation of the urea, the reactants being present in an amount of about 1.50 to 4.0 moles of formaldehyde, about 0.001 to 0.1 mole of triethanolamine, and about 0.0 to 0.5 mole ammonia, per mole of urea; and adding acid to lower the pH to within the range of about 4.9 to about 5.2 and adding urea until the molar formaldehyde to urea ratio is within the range of about 1.5:1 to about 2.5:1 and reacting for a time sufficient to reduce free formaldehyde to less than 2%.