外文翻譯---金屬離子和閃鋅礦存在下的黃鐵礦浮選

1、<p><b>　　附A 英語論文</b></p><p>　　Pyrite flotation in the presence of metal ions and sphalerite</p><p>　　【Canada】 Q. Zhang, Z. Xu, V. Bozkurt, J.A. Finch </p><p><

2、b>　　Abstract</b></p><p>　　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 pH

3、 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

4、the pyrite was alone or with sphalerite. © 1997 Elsevier Science B.V.</p><p>　　Keywords: pyrite; sphalerite; flotation; mineral interaction; metal ions: </p><p>　　Introduction</p>&l

5、t;p>　　Sulphide mineral ores remain the major source of base metals. The flotation of</p><p>　　valuable minerals of copper, lead and zinc from pyrite, the main sulphide gangue, has</p><p>　　re

6、ceived considerable attention (Forssberg, 1985; Dobby and 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

7、 use of recycle water, the presence of semi soluble minerals and from superficial oxidation of sulphide minerals and steel grinding media. Their detrimental effect is associated with either depression of the target miner

8、als or activation of the unwanted mineral (e.g. pyrite).</p><p>　　1. Experimental section</p><p>　　1.1. Minerals</p><p>　　The sphalerite (Sp) and pyrite (Py) samples (37-74 txm size

9、 fraction) were isolated from ore samples from Brunswick Mining 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

10、a 5% HC1 solution to remove soluble impurities. Residual sulphur, formed as a result of the acid treatment, was removed by washing the samples with acetone, followed by de-oxygenated-distilled water. The product was then

11、 </p><p>　　1.2. Chemicals</p><p>　　Sodium iso-propyl xanthate [iprx, (CH3)2CHOCS2Na] from American Cyanamidwas further purified using standard procedures and stored in petroleum ether (Rao,1971a

12、,b), ACS reagent grade copper sulphate, zinc sulphate, ferrous sulphate and calcium chloride (Fisher Scientific) were used as received. Hydrochloric acid andsodium hydroxide used as pH modifiers were also of ACS reagent

13、grade.De-oxygenateddouble distilled water was used in all the experiments.</p><p>　　1.3. Microflotation</p><p>　　The set-up for conditioning the pyrite (Fig. 1) permitted the mineral to be treat

14、edalone (as mineral 1) or in the presence of sphalerite (as 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-oxyg

15、enated 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. Conditio</p><p>

16、　　1.4. Zeta-potential</p><p>　　Zeta-potential of pyrite was measured using a Lazer Zee TM Meter (Model 501: PenKem, Inc., USA). All measurements were conducted in a 0.1 M NaC1 background</p><p>

17、　　electrolyte solution. A 0.05 g sample of pyrite, alone or mixed with sphalerite (which</p><p>　　was of much greater size), was placed in a 100 ml beaker and mixed, for 5 min, with 80ml distilled water cont

18、aining the metal ions of interest. (In some of the experiments, apre-determined amount of xanthate was added at this stage and mixing continued foranother 5 min.) The coarse sphalerite particles were then allowed to sett

19、le andsupernatant containing the fine target mineral particles was taken for zeta-potential</p><p>　　measurement. The results presented in this paper are the average of three independent</p><p>

20、　　measurements with a typical variation of +2 mV. Repeat tests showed that theconditioning procedure was capable of producing reproducible mineral surfaces suitablefor studying the effect of various treatments.</p>

21、<p>　　1.5. FTIR-spectrum</p><p>　　The attenuated total reflectance (ATR) spectroscopic technique was used to characterizethe surface species on the mineral particles treated. (Sample preparation was t

22、hesame as used for the microflotation tests.) A sample of the mineral along with somesolution was taken using a pipette and placed on a strip of filter paper. This was repeatedtill the filter paper was covered by a thin

23、layer of particles. The sample was then liftedalong with the filter paper and pressed onto a zinc selenide (ZnSe) </p><p>　　For the purpose of IR band identification, the spectrum was also collected using<

24、;/p><p>　　external reflectance infrared spectroscopy (at a fixed incident angle of 45 °) using a</p><p>　　copper foil pre-treated in a 0.5 m M i PrX solution, rinsed with petroleum ether and d

25、ried with dry nitrogen. This treatment removes all dixanthogen components and leavescopper xanthate on the foil. The spectrum was collected using the same instrumentalparameters as in ATR experiments, and polished copper

26、 foil was used as background.</p><p>　　The experiments for the mixed-mineral system were designed to eliminate galvaniceffects which otherwise would complicate the analysis. This system is therefore differen

27、tfrom that encountered in practice, but nevertheless it is a step closer compared to thetraditional single mineral studies. Our focus in this work is to examine the effect of metal ions and a second mineral on xanthate i

28、nteraction with a target mineral (pyrite).The effect of galvanic interaction and redox potential was not examine</p><p>　　2. Results</p><p>　　2.1. Flotation</p><p>　　pyrite alone (i

29、.e. in the absence of metal ions and sphalerite) exhibited the well known flotation response: a minimum around pH 7, with increasing floatability in acid conditions and a maximum in alkaline (ca. pH 8) (Steininger, 1968;

30、Fuerstenau et al., 1985). The addition of cupric ions enhanced pyrite floatability significantly over the pH range 6 to 10. In contrast, in the presence of sphalerite along with metal ions, the floatability of pyrite dec

31、reased significantly over the whole pHrange, </p><p>　　the effect of ferrous ions on pyrite flotation. Similar to cupric ions,ferrous ions increased floatability of pyrite alone, in particular in alkaline me

32、dia with amaximum recovery at ca. pH 9. Again, in the presence of sphalerite, pyrite flotation was depressed. An activation effect of calcium ions (10 -5 M) on single pyrite flotation was found although it was less than

33、that of either cupric or ferrous ions (Fig. 4). Whensphalerite is present, however, pyrite is virtually unfloatable above pH 7.</p><p>　　The above flotation results all show a common feature: metal ions prom

34、oted flotation of pyrite alone, but the presence of sphalerite along with the metal ions depressed the floatability. </p><p>　　2.2. Zeta-potential</p><p>　　pyrite alone had an iso-electrical poi

35、nt (iep) at ca. pH 3. This value is lower than that reported by Fuerstenau and Mishra (1980), but similar to that by Fornasiero et al. (1992). The discrepancy appears to be related to the initial oxidation state of pyrit

36、e: the more oxidized the pyrite, the higher the iep. By comparison with the iep of pyrite oxidized to various degrees as reported by Fomasiero et al. (1992), the pyrite sample used in this study appears to be slightly ox

37、idized.</p><p>　　In the presence of iprX, the zeta-potential of pyrite decreased marginally (byinspection of the data points), probably reflecting adsorption of negatively chargedxanthate anions. A similar o

38、bservation was made by Fomasiero and Ralston (1992) although Cases et al. (1993) suggest a much larger decrease in zeta-potential in the presence of xanthate. Cupric ions increased the zeta-potential significantly, in pa

39、rticular above pH 6. This increase can be attributed to the adsorption of a cupric ion spe</p><p>　　the effect of the presence of sphalerite. The zeta-potential in the presence of cupric ions remained the sa

40、me whether sphalerite was present or not. The subsequent addition of iprx did not change the zeta-potential, which is in marked contrast to the case in the absence of sphalerite. By comparison with Fig. 5, copper ions ap

41、pear to be still adsorbed on pyrite in the presence of sphalerite, but subsequent xanthate adsorption did not occur. This finding is consistent with the observed flotation b</p><p>　　the zeta-potential resul

42、ts in the presence of ferrous ions and calcium ions, respectively. Similar to the case with cupric ions, these ions increased he zeta-potential of pyrite significantly. In the presence of sphalerite, however, the zeta-po

43、tential response resembled that of pyrite alone and the subsequent addition of iprX had little effect. This suggests that ferrous and calcium ions have much less affinity for pyrite compared to sphalerite and adsorbed pr

44、eferentially on sphalerite when thes</p><p>　　observed suppression of metal activation in the presence of sphalerite seems to depend on the metal ion: in the case of cupric ions, xanthate adsorption was supp

45、ressed while in the case of ferrous and calcium ions, adsorption of the metal ions was suppressed. The overall effect, however, is similar, namely, the presence of sphalerite retarded the flotation of pyrite.</p>

46、<p>　　2.3. Infrared spectra</p><p>　　Infrared spectroscopy was used to identify and quantify the surface species resulting from interactions between the minerals and iPrX. Fig. 9 shows the spectra obtai

47、ned withpyrite in the presence of cupric ions. (Only part of the spectral region, from 1350 to 950 cm -1, is shown, over which the characteristic xanthate bands appear.) A featureless spectrum was obtained for the pyrite

48、 conditioned in de-oxygenated water (a). Six broad bands at ca. 1267, 1256, 1142, 1088, 1026 and 1008 cm ~ were obs</p><p><b>　　Table 1</b></p><p>　　Positions of corresponding princi

49、pal bands (cm- 1 ) of copper xanthate and dixanthogen formed from ethyl and iso-propyl xanthates</p><p>　　Wavenumbe[cm-1]</p><p>　　Fig.3.3. FrlR/ATR spectra of particles treated with cupric (c),

50、 ferrous (d) and calcium (e) ions in the presence of 5 × 10 -5 M iso-propyl xanthate as compared to that untreated (a) and treated with xanthate only(b)</p><p><b>　　(b).</b></p><p

51、>　　The spectra of pyrite treated with the ferrous and calcium ions are shown in Fig. 3.3(For reference, the spectrum of pyrite treated with cupric ions is also included.) Spectra(d) and (e) showed similar features as

52、in the absence of these metal ions, but with someincrease in band intensity. In contrast to copper ions, no additional bands were observed,</p><p>　　3. Discussion</p><p>　　3.1. General observati

53、ons</p><p>　　3.1.1. Pyrite alone</p><p>　　The results show that the metal ions, Cu 2+, Fe 2+ and Ca 2+, activate pyrite. Theactivation is through either the formation of metal xanthate (copper),

54、 and/or a 'catalytic'effect of metal ions on dixanthogen formation (all ions studied). In the case of cupric ions, the formation of metal xanthate seems responsible for the increasedfloatability although the slig

55、ht increase in dixanthogen formation may be a contributing factor. Whether the copper ions were incorporated into pyrite lattice to indu</p><p>　　The dixanthogen bands were enhanced when metal ions were pres

56、ent. The observed enhancement appears to be related to the variable valencies of copper and iron ions. Ferric or cupric ions may initially be reduced to a lower oxidation state while adsorbed xanthate is oxidized to dixa

57、nthogen. In the case of ferrous and calcium ions, it appears that adsorbed cations (as confirmed by zeta-potential measurements) provided a high density of surface active sites which electrostatically attract negatively&

58、lt;/p><p>　　3.1.2. Mixed-minerals competitive adsorption</p><p>　　The presence of sphalerite did not materially affect pyrite flotation when metal ions were absent. However, with metal ions present

59、, sphalerite decreased pyrite flotation significantly, the floatability being even lower than for pyrite alone in the absence of Q. Zhang et al./ Int. J. Miner. Process. 52 (1997) 187-201 199 metal ions. This implies tha

60、t when in competition with sphalerite, adsorption of xanthate is not favoured on pyrite. Competition is either for activating ions which appears to b</p><p>　　These mineral competition effects are reminiscen

61、t of a previous study of ours where mixing pentlandite and pyrrhotite enhanced xanthate adsorption on pentlandite and retarded it on pyrrhotite (Xu and Finch, 1996). The interpretation offered was galvanic: in the presen

62、ce of xanthate, pentlandite had a lower open circuit potential than pyrrhotite and in a mixture became the main site for anodic oxidation of xanthate to dixanthogen. In the present situation, the minerals are not in phys

63、ical contact</p><p>　　3.2. Practical implications</p><p>　　Cupric ions are the activator of choice for sphalerite and selective flotation against pyrite is generally successful. Part of the mech

64、anism, from the observations here, may be that in addition to direct activation of sphalerite, there is depression of pyrite causedby the presence of sphalerite. It has been reported that addition of cupric ions appears

65、to retard the flotation of pyrite, which contributes to increased sphalerite concentrate grades (Xu et al., 1992).</p><p>　　The findings suggest that while metal ions can activate pyrite, in the presence of

66、sphalerite this may be less of a problem. Does this mean that inadvertent activation is not an issue? Not really. Two places where this activation may occur are: toward the end of a flotation bank where the sphalerite is

67、 exhausted, or in refloating a middling stream low in sphalerite. Recent work has shown the benefits of restricting the length of a flotation bank and limiting the use of recycle (Shannon et al., 1</p><p>　　

68、Lastly, knowing where metal ion activation effects are likely to occur may help design corrective action such as altering the pH modifier (e.g. using soda ash to remove m the metal ions as carbonate precipitates) or addi

69、tion of complexing agents, such as diethylene triamine (Marticorena et al., 1994).</p><p>　　4. Summary and conclusions</p><p>　　(1) Cu 2+, Fe 2+ and Ca 2+ all activated flotation of pyrite alone

70、. All ions promoted dixanthogen formation. In addition, Cu 2+ promoted xanthate chemisorption (forming copper xanthate).</p><p>　　(2) The presence of sphalerite along with these metal ions depressed pyrite f

71、loatability.</p><p>　　(3) The effect of sphalerite on pyrite flotation arises from the competition for eitherxanthate (in the case of Cu 2+) or activating species (Fe 2+ or Ca2+).</p><p>　　Ackno

72、wledgements</p><p>　　The authors wish to acknowledge the financial support of the Natural Sciences and Engineering Research Council of Canada, and the Canadian Mining Industry Research Organization who co-or

73、dinated the sponsorship of Cominco, Inco, Falconbridge, Noranda, Hudson Bay Mining and Smelting and Teck. We also wish to thank Drs. Stephane Brienne and Ram Rao for many helpful discussions.</p><p>　　Refere

74、nces</p><p>　　(1)Ball, B., Rickard, R.S., 1976. The chemistry, of pyrite flotation and depression. In: Fuerstenau, M.C. (Ed.),Flotation. A.M. Gaudin Memorial Volume, Vol. 1., AIMMPE, New York, NY, pp. 458-48

75、4.</p><p>　　(2)Bushell, C.H.G., 1962. Flotation theory and mill control, In: Fuerstenau. D.W. (Ed.), Froth Flotation--50th Anniversary Volume. AIMMPE, New York, NY, pp. 576-580.</p><p>　　(3)Case

76、s, J.M., Kongolo, M., De Donato, P., Michot, L.J., Erre, R., 1993, Interaction between finely ground pyrite and potassium amylxanthate in flotation, 1. Influence of alkaline grinding. Int. J. Miner. Process. 38,267-299.&

77、lt;/p><p>　　(4)Chang, C.S., Cooke, S.R.B., Iwasaki, I., 1954. Flotation characteristics of pyrrhotite with xanthate. AIME Trans. 199, 209-217.</p><p>　　(5) Fornasiero, D., Ralston, J., 1992. Iron h

78、ydroxide complexes and their influence on the interaction between ethyl xanthate and pyrite. J. Colloid Interface Sci. 151,225-235.</p><p>　　(6)Fornasiero, D., Eijt, V., Ralston, J., 1992. An electrokinetic

79、study of pyrite oxidation. Colloids Surfaces 62,63-73.</p><p>　　(7)Forssberg, K.S.E. (Ed.), 1985. Flotation of Sulphide Minerals. Elsevier, New York.</p><p>　　Fuerstenau, D.W., Mishra, R.K., 198

80、0. On the mechanism of pyrite flotation with xanthate collectors. In: Jones, M.J. (Ed.), Complex Sulphide Ores. IMM, London, pp. 271-278.</p><p>　　(8)Gebhardt, J.E., Richardson, P.E., 1987. Differential flot

81、ation of a chalcocite-pyrite particle bed by electrochemical control. Miner. Metall. Process. 40 (3), 140-145.</p><p><b>　　附B 中文翻譯</b></p><p>　　金屬離子和閃鋅礦存在下的黃鐵礦浮選</p><p>

82、　　【加拿大】Q、張 Z、許 V 博茲庫爾特 J、A 芬奇 </p><p>　　摘要：研究了在閃鋅礦存在和不存在的情況下，Cu2+、Fe2+和Ca2+離子時(shí)對于黃藥浮選黃鐵礦的可浮性與PH的關(guān)系的影響。在堿性PH范圍內(nèi)，單獨(dú)作用時(shí)，這類離子能活化黃鐵礦，但當(dāng)存在閃鋅礦時(shí)，卻不會活化。ξ電勢測定和紅外表面特性證實(shí)，與黃藥相互作用的不同取決于黃鐵礦單獨(dú)存在還是與閃鋅礦一起存在</p><p&g

83、t;　　關(guān)鍵詞： 黃鐵礦 閃鋅礦 浮選 金屬離子 </p><p><b>　　引言</b></p><p>　　硫化礦石仍是基本金屬的主要來源。該浮選寶貴的礦產(chǎn)銅，鉛和鋅從黃鐵礦，主要硫化物煤矸石，已獲得了相當(dāng)?shù)年P(guān)注(Forssberg, 1985; Dobby and Rao, 1989). 最近，人們越來越懷疑，金屬離子在限制硫物浮選選擇性的作用。這些

84、金屬離子，是由于使用循環(huán)水，礦物質(zhì)和可溶性半從硫化礦物和鋼鐵表面氧化研磨介質(zhì)的存在。他們的不利影響是與任一目標(biāo)礦物或有害礦物（如黃鐵礦）激活抑郁癥</p><p><b>　　1 實(shí)驗(yàn)</b></p><p><b>　　1．1 礦物</b></p><p>　　從礦樣中分選出閃鋅礦(S)和黃鐵礦(Py)樣品(粒級37～7

85、4)。用5％HCl溶液處理所得單礦物3次，脫除可溶性雜質(zhì)。用丙酮再用脫氧蒸餾水脫除酸處理產(chǎn)生的殘余硫。在～70℃的真空爐中干燥產(chǎn)品并貯存于氮?dú)夥罩?。X-射線衍射分析表明，閃鋅礦與黃鐵礦二者均未存在大量其它礦相?；瘜W(xué)分析顯示，黃鐵礦的純度>97％，而閃鋅礦含63．8％Zn和2．8％Fe。在浮選和IR研究中采用這種粒度范圍的樣品。對于ξ電勢測定，要進(jìn)一步用瑪瑙研缽和研杵磨至約20μm并在磨后立即用于測定。</p><

86、;p><b>　　1．2 化學(xué)藥品</b></p><p>　　用標(biāo)準(zhǔn)法進(jìn)一步掙化異丙基納黃藥【PrX，(CH3)2CHOCS2Na]并貯存在石油醚中。使用ACS(美國化學(xué)學(xué)會)試劑純的CuS04、ZnS04、FeS04和CaCl2。用作pH調(diào)節(jié)劑的HCI和NaOH 也是ACS試劑純的。全部實(shí)驗(yàn)都使用脫氧重蒸餾水。</p><p><b>　　1．3

87、小型浮選</b></p><p>　　調(diào)和黃鐵礦的裝置(圖1)可單獨(dú)處理礦物(礦樣1)或者有閃鋅礦存在時(shí)處理礦物(礦物2)，其中，兩種礦物分隔在兩部分，但共用同樣的溶液。在30ML脫氧水中．在已知金屬離子濃度下，將1g礦物攪拌lOmin，此后，用預(yù)定量的黃藥貯備液取代上清液，并繼續(xù)攪拌lOmin。用200r／mln的實(shí)驗(yàn)室振搖</p><p>　　機(jī)進(jìn)行攪拌。為保證在混臺礦物試

88、驗(yàn)中，分開兩部分的礦物共用同樣的溶液，燒瓶中溶液的水平保在玻璃壁頂部以上(圖1)。黃鐵礦以及上清液則移入改進(jìn)的海力蒙浮選管，再用74ml／min的空氣流速進(jìn)行2min的浮選。在過濾和干燥后，將浮游物與尾礦分別稱重，并計(jì)算回收率。</p><p><b>　　1.4 ξ電勢</b></p><p>　　用拉澤奇計(jì)（lazer ZeeTM Meter）(501型)測定黃

89、鐵礦的ξ電勢。全部在0.1MNaCl的背景電解液中進(jìn)行測定。將單獨(dú)的或與閃鋅礦（粒度較大）混合的0.05g黃鐵礦樣品置于100ml燒杯中，并與含有所研究金屬離子的80ml蒸餾水混合5min。(有些實(shí)驗(yàn)，在此步加入預(yù)定量的黃藥并繼續(xù)混合5min)，再使粗閃鋅礦顆粒沉降，取含細(xì)粒目標(biāo)礦物的上清液進(jìn)行ξ電勢測定。本文所示結(jié)果是3次獨(dú)立測定的平均值，一般變動±2mV。重復(fù)試驗(yàn)表明，該制作程序能夠產(chǎn)生可再現(xiàn)的適于研究各種處理效應(yīng)的礦物表

90、面。</p><p>　　1．5 FTIR-光譜</p><p>　　有衰減全反射(ATR)光譜法來檢測所處理的礦粒上的表面物質(zhì)形態(tài)的特征。(樣品制作與小型浮選試驗(yàn)的相同)。用吸管吸取礦物及若干溶液的試樣，放在濾紙條上，重。復(fù)此步，直到濾紙被顆粒薄層罩蓋，然后提起樣品以及濾紙，壓在ZnSe ATR晶體上。用帶有基線水平ATR 取樣裝置的IFS一</p><p>　　

91、66FTIR光譜儀獲得IR光譜。用清潔的ATR晶體作本文光譜背景。利用波數(shù)分辨率4cm-1。的MCT檢測器，積累200次掃描獲得該光譜，未示出任何基線校準(zhǔn)。作為校核，求得與10-4M黃藥溶液接觸的ZnSe晶</p><p>　　體的光譜：在本文所示光譜范圍內(nèi)未見有特征譜帶。．用丙酮清洗晶體，用紫外線照射10min(分解任何殘余黃藥)，用100％ 乙醇淋洗，每次測定之后用過濾的干燥氮?dú)獯蹈?lt;/p>&

92、lt;p>　　為了檢驗(yàn)IR譜帶，同時(shí)也采用在05mM 。iPrX溶液中預(yù)處理過的用石油醚淋洗的并用干氮干燥過的銅薄片，借助外部反射紅外光譜(固定入射角45。)收集到該光譜。這樣處理消除了所有復(fù)黃藥組分并留下黃原酸銅在薄片上。使用與ATR實(shí)驗(yàn)相同的儀器參數(shù)，并用拋光的薄片作背景收集該光譜。 </p><p>　　設(shè)計(jì)了混合礦物系統(tǒng)實(shí)驗(yàn)“消除電流效應(yīng)，否則，會使分析復(fù)雜化。因此，此體系與實(shí)踐中遇到的不同，但盡管

93、如此，它是逐漸接近類似于傳統(tǒng)單礦物研究的。本文的焦點(diǎn)是探討金屬離子和第二種礦物對黃藥與目標(biāo)礦物(黃鐵礦)相互作用的影響。尚未研究電作用和氧化還原電勢的影響，但為了比較，采用低固液比的脫氧水來保持氧化還原電位相對恒定。在混合礦物體系中，即使使用XPS半定量分析也難以定量測定個(gè)別礦物上金屬離子或黃藥的吸附量。為此，用ξ電勢測定作為提供現(xiàn)場半定量的令人滿意的資料的分析工具。</p><p><b>　　2 結(jié)

94、果</b></p><p><b>　　2．1 浮選</b></p><p>　　單獨(dú)黃鐵礦(即無金屬離子和閃鋅礦)顯示出眾所周知的浮選特性：在酸性條件下，可浮性增大，在pH7左右雖小，在堿性(約pH8)中最大，在pH6～10時(shí)，添加Cu2+可顯著提高黃鐵礦的可浮性。比較而言，在闖鋅礦以及金屬離子存在下，在整個(gè)pH范圍內(nèi)，黃鐵礦的可浮性顯著下降，在pH&g

95、t;5時(shí)，回收率比單獨(dú)黃鐵礦而無銅活化的低。這種可浮性下降表明在兩種礦物共用相同的溶液時(shí)對黃藥有競爭用。顯然．當(dāng)銅活化閃鋅礦時(shí)，消耗大部分黃藥，剩下濃度低于不存在閌鋅礦時(shí)的黃藥濃度用于黃鐵礦浮選。這間接地證實(shí)，在有閃鋅礦而無銅離子時(shí)，黃鐵礦浮選作用保持不變，因?yàn)?，在不存在活化的金屬離子時(shí)，閃鋅礦對黃藥不作用。這意味著，在此條件下，閃鋅礦的存在對黃鐵礦浮選影響</p><p><b>　　很小。</

96、b></p><p>　　研究了亞鐵離子對黃鐵礦浮選的影響。與Cu2+相似，F(xiàn)e2+會增大單獨(dú)黃鐵礦的可浮性，尤其在堿性介質(zhì)中，最大回收率在約pH9年。再者，在閃鋅礦存在下，黃鐵礦浮選受抑制。發(fā)現(xiàn)了Ca2+(105-M)對單獨(dú)黃鐵礦浮選的活化效應(yīng)，盡管比Cu2+或Fe2+的影響小。但是，當(dāng)存在閃鋅礦時(shí)，在pH7以上，黃鐵礦實(shí)際上不可浮。</p><p>　　以上的所有浮選結(jié)果表明一個(gè)

97、共同的特點(diǎn)：金屬離子促進(jìn)單獨(dú)黃鐵礦浮選，但閃鋅礦及金屬離子會減弱可浮性，</p><p><b>　　2．2 ξ電勢</b></p><p>　　單獨(dú)的黃鐵礦等電點(diǎn)(iep)在pH3左右。此值與文獻(xiàn)中該值的差別與黃鐵礦的初始氧化態(tài)有關(guān)：黃鐵礦愈氧化，iep愈高。與氧化至各種程度的黃鐵礦的iep比較，本研究所用的黃鐵礦樣品似乎屬于微弱氧化。</p><

98、;p>　　在iPrX存在下，黃鐵礦的ξ電勢有一定程度下降，可能反映出帶負(fù)電的黃原酸根陰離子的吸附，進(jìn)行了類似觀測，發(fā)現(xiàn)在黃藥存在下， 電勢有很大下降。Cu2+ 顯著增大ξ電勢，尤其在pH6以上時(shí)更是如此，這種增大可歸因于cu 在帶負(fù)電的黃鐵礦表面上的吸附。在堿性pH時(shí)加入黃藥，ξ 電勢顯著下降，這種下降可能是由于吸附了帶負(fù)電的 PrX離子和／或部分地從黃鐵礦表面脫除了吸附Cu2+。Cu2+的存在下， PrX增大黃鐵礦的浮選回收率說

99、明前者是更可能的情況，即表面上Cu2+ 的存在吸引了帶負(fù)電的iPrx。</p><p>　　研究了閃鋅礦的影響，Cu2+存在時(shí)的ξ電勢在閃鋅礦是否存在時(shí)是一樣的。隨后加入 PrX不會改變ξ電勢。在閃鋅礦存在下，Cu2+ 似乎仍然被黃鐵礦吸附，但后來不發(fā)生黃藥吸附。此結(jié)果與所觀測的浮選行為一致，即當(dāng)存在閃鋅礦時(shí)，黃鐵礦浮選顯著減弱。</p><p>　　研究發(fā)現(xiàn)，F(xiàn)e2+和Cu2+的存在與

100、Cu2+相似，它們會顯著增大黃鐵礦的ξ電勢。但是在閃鋅礦存在下，ξ電勢的特性與單獨(dú)黃鐵礦相似，后來加入 PrX有微小影響。這意味著，F(xiàn)e2+和( 對黃鐵礦比閃鋅礦的親和力小得多，當(dāng)兩種礦物存在于相同溶液時(shí)，它們優(yōu)先吸附在閃鋅礦上。所觀測到的在閃鋅礦存在下金屬活化的抑制作用的競爭機(jī)制似乎取決于金屬離子：在Cu2+的情況下，黃藥吸附受抑制，而在Fe2+和ca 的情況下．金屬離子的吸附被抑制了。但是，總效應(yīng)是類似的，即閃鋅礦的存在延緩了黃鐵礦