Domtar Inc.

Leon Magdzinski

Manssur Yalpani

A product comprising, a water insoluble lignin material, at neutral or acid pH, having chemically bound a sulfur(S) content from at least 9.5%, and a phosphorus(P) content from 3.3 to 10%. At least 50% by weight of the S and P content is thiophosphate. In said lignin material the mole ratio S/P is at least 1.8 that of S to aromatic unit (S/Ar) is greater than 0.7, and the P/Ar ratio is from 0.3 to 0.8. The lignin material has chelating capacities for gold at pH 2 of at least 2.2 millimoles per gram of lignin material. On IR analysis the lignin material has infra-red absorption bands evidencing P.dbd.S, P--S or Ar--S, P--O--Ar, aromatic, CH.sub.2 --S, and P--O--C groups in the vicinity of 730-750, 640-670, 1080-1110, 1490-1510, 820-845, and 965-995 cm.sup.-1, respectively. In the absence of interferring IR bands, the sum of the intensity of the bands in the vicinity of 640-670 cm.sup.-1 and 730-750 cm.sup.-1 over the intensity of the band in the vicinity of 1080-1110 cm.sup.-1 is greater than 1. The product, substantially free from unbound sulfur, may be used in chelation, floatation processes, as flame retardant, and for agricultural uses. A method of making the above comprises heating a lignin product with at least an exact equivalent molar ratio of phosphorus pentasulfide (P.sub.4 S.sub.10). The reaction product must be specially treated to recover it.

Lignin having chemically bound sulfur and phosphorus groups mainly as

A product comprising lignin material having a N-content of at least 1.86% and a sulfur content of at least 3.1%, an IR in the vicinity of 1550 to 1670 cm.sup.-1 having a peak width of at least 60 cm.sup.-1. The product is also directed to such products being cross-linked and which are most suitable as chelating agents in basic medium. The product may also be used as flame retardant, for agricultural and other end uses. The invention is also directed at a method of making the above product which comprises heating a lignin containing material with thiourea H.sub.2 N--C(S)--NH.sub.2 : for example by heating in a solvent or melting.

Growing community of inventors

Montreal, Canada

Leon Magdzinski