The effect of PAX/CMC addition order on chlorite/pyrite separation

Addition order of both PAX (potassium amyl xanthate) and CMC (carboxymethyl cellulose) was investigated to separate pyrite from chlorite. The investigation included both flotation and adsorption tests. The flotation results showed that CMC can depress the flotation of chlorite but was found not to be selective against pyrite. When pyrite was conditioned initially with PAX before CMC it was found that the CMC slightly depressed pyrite flotation. The depression effect of CMC on pyrite was significantly higher when pyrite was conditioned first with CMC before PAX. Flotation of chlorite was not influenced by order of addition of CMC and PAX. Adsorption tests showed that CMC and PAX compete in adsorbing on pyrite and the adsorption density of PAX decreases in the presence of the pre-adsorbed layer of CMC. PAX was found not to adsorb onto chlorite irrespective if chlorite was conditioned initially with or without CMC. Therefore there was no competitive adsorption on chlorite surface between PAX and CMC. PAX can assist to protect the pyrite surface when conditioned initially first and allow the benefits of CMC depression for chlorite.