Lignosulfonate composition and process for its preparation

Ferromagnetic lignosulfonate.

Ferromagnetic iron lignosulfonate.

Ferromagnetic sulfonated tannin.

Ferromagnetic iron sulfonated tannin.

A process for the preparation of ferromagnetic composition, which comprises dissolving an iron compound and a material selected from the group consisting of lignosulfonate and sulfonated tannin in an aqueous medium and mixing the mixture in the presence of an alkali at a temperature up to 230.degree. C at a pH of at least about 5.5 to form a ferromagnetic composition, said iron compound being dissolved in an amount of at least twice the stoichiometric amount, as ferric iron, to react with the sulfonate groups of the material, said mixture being heated under conditions to obtain the iron in the ferrous and ferric states, and said material being substantially free of polyhydroxy, polycarboxy, and lactone-type non-lignin constitutents having molecular weight less than about 400.

A process for the preparation of a ferromagnetic composition, which comprises dissolving a water-soluble iron salt and a material selected from the group consisting of a lignosulfonate and sulfonated tannin in water in an amount to obtain up to 30 weight percent of the material and at least 9 weight percent iron, based upon the weight of the material, adding from 0.9 to 1.5 equivalents of an alkali metal hydroxide per equivalent of iron to the solution, and heating the mixture at a temperature in the range of 40.degree. to 230.degree. C for from 0.5 to 24 hours to react the iron with the material to form a ferromagnetic composition, said material being substantially free of organic constituents having molecular weights less than 400, and said mixture being heated with the iron being in ferrous and ferric states.

A composition comprising a material selected from the group consisting of lignosulfonate and sulfonated tannin combined with iron, said composition having a relative magnetic susceptability, when measured in a magnetic field of 240 oersteds, based upon the iron content thereof, is at least 60% of substantially pure iron.