Abstract: A method for removing heavy metals from brines used as well servicing fluids in which the heavy metal is oxidized to a higher, stable oxidation state of +3 or greater, the oxide or variants thereof of the oxidized metal is formed resulting in a generally water insoluble precipitate which is then removed by filtration leaving the brine free of deleterious amounts of the heavy metal.

Abstract: A process for preparing a form of carboxymethyl cellulose which exhibits superior rheological and fluid loss characteristics in aqueous calcium chloride solutions which comprises conducting causticization of high molecular weight cellulose in the absence of oxygen, at a temperature less than 350.degree. C., in an aqueous solution containing 86.9.+-.2% by weight isopropanol, at an isopropanol-water solution to cellulose weight ratio from 2 to 1 to 7.5 to 1, and in the presence of sufficient alkali metal hydroxide such that the alkali metal hydroxide to monochloroacetic acid molar ratio during the subsequent etherification of the alkali cellulose is greater than 2.00 to 1, wherein the monochloroacetic acid utilized contains less than about 2% by weight dichloroacetic acid.