Other Binders - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 105

TABLE 6.1.2 (CONTINUED)
Selected Treatment Studies for Heavy Metals and Radionuclides Using
Phosphates; Includes Laboratory Studies, Field Trials, and Applications

Metal/
Metalloid
Studied

Media/
Conditions

Phosphate
Treatment

Mechanism/Solid Phases
Formed References

Pb Soil, pH 2.7 to 7.1 Bonemeal Formation of Pb and Zn

phosphates

62

Pb Soil Triple super-

phosphate,
phosphate rock

Formation of
pyromorphite-like
minerals

63

Pb, Zn Soil Phosphoric acid Not determined 64

Pb, Zn, Cd Mine wastes Apatite II™ —

commercial
apatite mineral
product
derived from
fish bones

Not determined 65

Pu Aqueous solution;

pH 5 to 8

Synthetic
hydroxyapatite

Theorized to be either ion
exchange or physical
adsorption

66

Sb Aqueous solution;

pH 6 to 11

Synthetic
hydroxyapatite

Not determined 14

Se Synthetic

hydroxy-
apatite, natural
fluorapatite

Substitution of Se species
for phosphate in
hydroxyapatite

67

Se 0.1M KNO 3

solution, pH 5 to
11.5

Synthetic
hydroxyapatite

Exchange of SeO 3 2- for
phosphate

68

Sr Aqueous solution Synthetic

hydroxyapatite

Incorporation of Sr into the
apatite structure;
exchange for Ca

69

Sr Aqueous solution Synthetic

hydroxyapatite

Substitution of Sr for Ca 70

Th Aqueous solution Synthetic

hydroxy-
apatite, natural
apatites and
phosphate rock

Sr substitution for Ca;
isolated cluster of UO 2 in
the apatite structure

71

Tc, As Aqueous solution Synthetic

hydroxyapatite
with SnCl 2

Reduction and sorption 14

(continued)