1、附 A 英语论文 Pyrite flotation in the presence of metal ions and sphalerite 【 Canada】 Q. Zhang, Z. Xu, V. Bozkurt, J.A. Finch Abstract The effect of Cu 2+, Fe 2+ and Ca 2+ ions on pyrite floatability with xanthate as a function of PH in the presence and absence of sphalerite was studied. In the alkaline
2、pH region, these ionsactivated the pyrite when alone but not when sphalerite was present. Zeta-potential measurementsand infrared surface characterization confirmed the different interaction with xanthate dependingwhether the pyrite was alone or with sphalerite. 1997 Elsevier Science B.V. Keywords:
3、pyrite； sphalerite； flotation； mineral interaction； metal ions: Introduction Sulphide mineral ores remain the major source of base metals. The flotation of valuable minerals of copper, lead and zinc from pyrite, the main sulphide gangue, has received considerable attention (Forssberg, 1985； Dobby an
4、d Rao, 1989). Recently, there has been growing suspicion that metal ions play a role in limiting selectivity of sulphide flotation. These metal ions result from the use of recycle water, the presence of semi soluble minerals and from superficial oxidation of sulphide minerals and steel grinding medi
5、a. Their detrimental effect is associated with either depression of the target minerals or activation of the unwanted mineral (e.g. pyrite). 1. Experimental section 1.1. Minerals The sphalerite (Sp) and pyrite (Py) samples (37-74 txm size fraction) were isolated from ore samples from Brunswick Minin
6、g and Smelting (New Brunswick, Canada) by alternate use of a shaking table and a Mozley separator. The single minerals obtained were treated three times with a 5% HC1 solution to remove soluble impurities. Residual sulphur, formed as a result of the acid treatment, was removed by washing the samples
7、 with acetone, followed by de-oxygenated-distilled water. The product was then dried in a vacuum oven at 70C and stored under nitrogen. For both sphalerite and pyrite, X-ray diffraction analysis showed that no significant amounts of other mineralogical phases were present. Chemical analysis indicate
8、d a purity over 97% for pyrite while sphalerite contained 63.8% Zn and 2.8% Fe. The sample of this size range was used inthe flotation and IR studies. For zeta-potential measurements, it was further ground (in an agate mortar and pestle) to ca. 20 immediately prior to use. 1.2. Chemicals Sodium iso-
9、propyl xanthate iprx, (CH3)2CHOCS2Na from American Cyanamidwas further purified using standard procedures and stored in petroleum ether (Rao,1971a,b), ACS reagent grade copper sulphate, zinc sulphate, ferrous sulphate and calcium chloride (Fisher Scientific) were used as received. Hydrochloric acid
10、andsodium hydroxide used as pH modifiers were also of ACS reagent grade.De-oxygenateddouble distilled water was used in all the experiments. 1.3. Microflotation The set-up for conditioning the pyrite (Fig. 1) permitted the mineral to be treatedalone (as mineral 1) or in the presence of sphalerite (a
11、s mineral 2), where the two minerals were in separate compartment but shared the same solution. One gram of mineral was conditioned for 10 min in 30 ml of de-oxygenated water at a given metal ion concentration, after which the supernatant was replaced with a premeasured amount of xanthate stock solution, and conditioning continued for another 10 min.
