Fenugreek Gum: Depressant Galactomannan: The effect of a new polysaccharide on the depression of talc and the flotation of a nickel–copper sulfide ore

The depressant galactomannan was extracted and purified from fenugreek powder.

The effect of the depressant fenugreek gum galactomannan (KGM) on the depression of talc and the flotation of a nickel–copper sulfide ore have been investigated through microflotation, batch flotation and industrial flotation tests, zeta potential and infrared spectrum measurements. The flotation results indicated that KGM had a straining influence on the depression of talc while had little effect on nickel minerals flotation. Compared with the depressant carboxymethyl cellulose (CMC) and guar gum, the KGM increased the nickel recov- ery dramatically, it not only negated the need for a talc removal process, but also achieved a significant decrease in the depressant consumption by half. Zeta-potential and infrared spectrum measurements illustrated that chemical adsorption was seen between KGM and talc, and a possible weak physical adsorption was seen between KGM and pentlandite. This was the reason why KGM had high depression selectivity for talc and little depression effect on nickel minerals.

Conclusions

(1) Microflotation tests indicated that the depressant KGM had a weak effect on pentlandite flotation, while it could effectively depress the easy-floating talc.

(2) The results of locked cycle tests indicated that the effective flotation separation of nickel–copper minerals from the Ni/ Cu sulfide ore was realized by using KGM as depressant. Compared with guar gum, the KGM increased the recovery of nickel in nickel concentrates by 2.61% and copper in copper concentrates by 4.18%.
(3) The industrial flotation results indicated that KGM was a high performance depressant for the depression of talc. Compared with the original plant setup (CMC), the KGM decreased the depressant consumption by half, negating the need for a talc removal process. It not only realized the separation of nickel/copper minerals, but also increased the recovery of nickel (18.15%) and copper (18.02%).

(4) Zeta-potential and infrared spectrum analysis indicated that KGM could selectively and strongly adsorb on talc surfaces through chemical adsorption while a weak physical adsorption happened between KGM and pentlandite. This was the reason why KGM had high depression selectivity for talc and little depression effect on nickel–copper minerals.

Kaile Zhao a,b,⇑, Guohua Gu a, Changliang Wang b, Xiying Rao b, Xiaohui Wang b, Xiaxu Xiong a a School of Minerals Processing and Bio-engineering, Central South University, Changsha 410083, China

b Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Sciences, Chengdu 610041, China