Patent Number: 044420285
Section: claims

1. A method for incorporating radioactive phosphoric acid solutions in concrete comprising: (a) first neutralizing a phosphoric acid solution containing Cobalt-60 with Ca(OH).sub.2 and thereby forming a precipitate, said precipitate having the formula Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2 and the crystal structure of hydroxyapatite, and then  (b) mixing said precipitate with portland cement and thereby forming concrete. 2. The method of claim 1 wherein said phosphoric acid solution contains 6% phosphoric acid. 3. The method of claim 1 wherein said precipitation is carried out at a pH of from 7.5 to 8.5. 4. The method of claim 1 wherein the precipitate and the portland cement are mixed in proportions by weight ranging from 3:1 to 1:1. 5. The method of claim 1 wherein the precipitate is separated from the supernate and dried before the mixing with portland cement.