Abstract: Carboxyl-containing fructans such as carboxymethylinulin can be successfully used to prevent deposition of scale composed of, for example, calcium, barium and strontium salts of sulphuric acid and carbonic acid in oil extraction. In the oil extraction method, 0.5-200 ppm of a carboxyl-containing fructan that contains 0.3-3 carboxyl groups per mono-saccharide unit is incorporated in the process water, in the process equipment or in the oil-containing formation.

Abstract: Dispersions of pigment, such as calcium carbonate, titanium dioxide and types of clay, can be effectively stabilized by the use of carboxyl-containing fructan in an amount of 0.05-10% by weight, based on the dispersion, which fructan contains 0.5-3 carboxyl groups per mono-saccharide unit. The carboxyalkyl groups are in particular carboxymethyl groups, but the carboxyl groups can also be carboxyl groups obtained entirely or partially by oxidation. The carboxymethylfructan gives results which are comparable to or better than those obtained with the polyacrylates which are less desirable from the standpoint of health and environment.