Treatment of clay minerals
AssigneeEnglish Clavs Lovering Pochin & Company, Limited
InventorsJan Ivan Bidwell, Roger William Adams, Walter Brian Jepson
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Abstract
The rheological properties of a clay are improved by forming a mixture of an aqueous suspension of the clay at a pH in the range 5 to 9 and a weakly positively charged inorganic hydroxy polymer of aluminum in a quantity such that there is present in the mixture not more than 10 mg of aluminum per gram of clay.
Claims20
A method of treating a clay in order to improve the rheological properties of the clay which method comprises forming a mixture of (i) an aqueous suspension of the clay containing less than 450 parts per million of dissolved silicate, expressed as SiO.sub.2, and at a pH in the range 5 to 9 and (ii) a weakly positively charged inorganic hydroxy polymer of aluminum in a quantity such that there is present in the mixture from 0.5 to 10.0 mg of aluminum per gram of clay, calculated on a dry weight basis;
- the inorganic hydroxy polymer of aluminum being represented by the formula:
- Al(OH).sub.n . (3-n)X.sup.-
- where 0.5 .ltoreq.n .ltoreq.2.8 and X.sup.- is Cl.sup.-, NO.sub.3.sup.- or 1/2 SO.sub.4.sup.2-,
- and being formed by combining an inorganic aluminum salt and a base selected from the group consisting of the carbonates and hydroxides of lithium, sodium and potassium.
A method of treating a kaolinitic clay comprising at least 70% by weight of particles smaller than 2 microns equivalent spherical diameter in order to improve the rheological properties of the clay which method comprises the steps of (a) forming a mixture of (i) an aqueous suspension of the clay which contains less than 450 parts per million of dissolved silicate, expressed as SiO.sub.2, which is at a pH in the range 6 to 8 and which has a solids content in the range 5 to 20% by weight solids, and (ii) a weakly positively charged inorganic hydroxy polymer of aluminum which can be represented by the formula:
- Al(OH).sub.n . (3-n)X.sup.-
- where 0.5.ltoreq.n.ltoreq.2.8 and X.sup.- is Cl.sup.-, NO.sub.3.sup.- or 1/2SO.sub.4.sup.2-,
- is present in a quantity such that the mixture contains from 1.0 to 7.0 mg of aluminum per gram of clay (calculated on a dry weight bases) and is formed by combining an inorganic aluminum salt and a base selected from the group consisting of the carbonates and hydroxides of lithium, sodium and potassium, (b) dewatering the mixture thus obtained, (c) resuspending in clean water the dewatered mixture of clay and hydroxy polymer of aluminum, and (d) dewatering the resuspended mixture.
Dependencies are inferred from the claim text.