Process for removing impurities from kaolin clays

A process for removing colored impurities from clay comprising the steps of:

• a) blunging the clay with a dispersing agent, or a combination of dispersing agents, in water to form an aqueous clay dispersion;
• b) treating the aqueous clay dispersion with a conditioning composition comprising at least one conditioning agent and at least one conditioning additive, wherein
• (i) the at least one conditioning agent is represented by the formula:
• R−C(=O)N(R″)−OM
• wherein R is linear or branched C2-C18 alkyl, linear or branched C2-C18 alkenyl, C6-C20 aryl, substituted aryl, C7-C26 aralkyl or substituted aralkyl;
• R″ is H, C1-C12 alkyl or aralkyl;
• and M is hydrogen, an alkali metal or ammonium, wherein the substituted aryl or substituted aralkyl are substituted on aryl with hydroxy, C1-C6 alkoxy, or C1-C6 alkyl, to form a conditioned dispersion;
• and
• (ii) the at least one conditioning additive is a fatty acid represented by the formula:
• R−C(=O)OM
• wherein R is a C10-C18 alkyl, C6-C20 aryl, substituted aryl, C7-C26 aralkyl or substituted aralkyl, and M is hydrogen, an alkali metal or ammonium, wherein the substituted aryl or substituted aralkyl are substituted on aryl with hydroxy, C1-C6 alkoxy, or C1-C6 alkyl, to form a conditioned clay dispersion;
• c) flocculating the conditioned clay dispersion by treatment with a flocculating agent comprising a water dispersible organic polymer, to form flocculated impurities;
• and
• d) removing the flocculated impurities to form a purified clay dispersion.

A process for removing colored impurities from clay comprising the steps of:

• a) blunging the clay with a dispersing agent, or a combination of dispersing agents, in water to form an aqueous clay dispersion;
• b) treating the aqueous clay dispersion with a conditioning agent represented by the formula:
• R−C(=O)OM
• wherein R is C10-C18 alkyl, C6-C20 aryl, substituted aryl, C7-C26 aralkyl or substituted aralkyl, and M is hydrogen, an alkali metal or ammonium, wherein the substituted aryl or substituted aralkyl are substituted on aryl with hydroxy, C1-C6 alkoxy, or C1-C6 alkyl;
• c) flocculating the conditioned clay dispersion by treatment with a flocculating agent comprising a water soluble or water dispersible organic polymer containing hydroxamic acid groups or salts thereof, to form flocculated impurities;
• and
• d) removing the flocculated impurities to form a purified clay dispersion.

A process for removing colored impurities from clay comprising the following steps:

• a) blunging the clay with sodium silicate and sodium polyacrylate in water to form an aqueous clay dispersion;
• b) treating the aqueous clay dispersion with a oleic acid fatty acid and calcium chloride,
• c) flocculating the conditioned clay dispersion by treatment with hydroxamated polyacrylamide of molecular weight of about 10-20 million, to form flocculated impurities;
• and
• d) removing the flocculated impurities to form a purified clay dispersion.

A process for removing colored impurities from kaolin clay comprising the following steps:

• a) blunging the clay with sodium silicate and sodium polyacrylate in water to form an aqueous clay dispersion;
• b) treating the aqueous clay dispersion with a mixture of C8-C10 hydroxamic acid and C12 alcohol;
• c) flocculating the conditioned clay dispersion by treatment with hydroxamated polyacrylamide of molecular weight of about 10-20 million, to form flocculated impurities;
• and
• d) removing the flocculated impurities to form a purified clay dispersion.