Pyrrhotite is a prevalent gangue mineral found in non-ferrous sulfide ores, including those of copper, lead, and zinc. Its non-stoichiometric crystal structure, characterized by variable iron-to-sulfur(Fe/S) ratios, leads to complex crystal-chemical behavior. Additionally, the unstable bonding state at its surface makes it highly susceptible to oxidation when exposed to oxygen in the flotation pulp. These characteristics often impede the selective flotation separation of valuable minerals, presenting a significant challenge in the efficient recovery of non-ferrous metals. During the oxidation process, iron ions migrate from the bulk to the mineral surface, where they coordinate with O₂, OH⁻, and H₂O to form an outer layer of iron oxyhydroxide(FeOOH), while leaving behind an iron-depleted, sulfur-enriched sublayer. This process is influenced by the pulp’s pH and oxidation-reduction potential(Eh), leading to the progressive oxidation of monosulfide species within the sublayer to disulfides and polysulfides, thereby continuously altering the surface chemistry of pyrrhotite. Under mild oxidation conditions, surface metal-hydroxyl complexes are formed, which modify the surface charge and result in a positive zeta potential. In contrast, xanthate collectors are present in solution as negatively charged anions, which facilitates their electrostatic adsorption onto pyrrhotite. This interaction undermines the efficiency of depression and complicates the separation of pyrrhotite from target minerals. Under conditions of intensified oxidation, Fe(OH)₃ precipitates form on the mineral surface. The pronounced hydrophilic nature of Fe(OH)₃ results in the formation of a dense hydrophilic film, which markedly diminishes mineral floatability and significantly impedes the flotation of pyrrhotite. It is important to note that pyrrhotite primarily exists in two crystalline forms: non-magnetic hexagonal pyrrhotite and magnetic monoclinic pyrrhotite. The inherent crystallochemical differences between these forms result in distinct surface oxidation kinetics, surface electrical properties, and adsorption affinities for flotation reagents. Consequently, the two polymorphs exhibit differing flotation behaviors within the same flotation system, thereby substantially complicating the separation of valuable non-ferrous sulfide minerals. The detrimental impact of pyrrhotite on flotation separation is primarily exhibited through two mechanisms: (1)its oxidation process depletes dissolved oxygen(DO) in the pulp, which is crucial for the surface oxidation activation of target sulfide minerals during flotation;(2) galvanic interactions occur when pyrrhotite is in contact with other sulfides in the pulp, thereby modifying the surface chemistry of the associated minerals. In industrial applications, synergistic strategies can be implemented to selectively depress or activate pyrrhotite flotation. These strategies include controlling its oxidation rate by adjusting pH levels or adding antioxidants, regulating pulp DO through staged aeration or the use of redox modifiers, and modulating the electrochemical interactions between pyrrhotite and target sulfide minerals.
铜、铅和锌等有色金属硫化矿中经常共生磁黄铁矿,磁黄铁矿的存在会对硫化矿物浮选分离造成严重干扰。如:广西大厂矿田105号矿体原矿中磁黄铁矿含量为38.5%,铅锌硫难以分离,严重影响了精矿质量,为了稳定生产长期使用氰化钠进行锌硫分离(邱显扬等,2011;郑文军,2019);广东大宝山矿业有限公司铜选厂磁黄铁矿含量高达39.6%,导致平均铜回收率在68%以下,远低于正常值(邱显扬等,2011;胡文英等,2018);安徽铜陵冬瓜山铜矿磁黄铁矿含量为14.36%,使得铜回收率仅为74.6%(邓禾淼,2022;李沛原等,2021)。磁黄铁矿是一种缺铁(铁空位)的非化学计量硫化铁矿物,其分子式为Fe(1-x)S,其中0<x≤0.125;由于铁空位数和铁空位层排布的不同,磁黄铁矿晶体结构可划分为3个晶系:六方晶系、单斜晶系和斜方晶系。其中,最常见的是六方磁黄铁矿(5C,非磁性)和单斜磁黄铁矿(4C,磁性)(图1),约70%的硫化矿床中同时存在这2种晶型的磁黄铁矿(Tang et al,2022)。
由于磁黄铁矿本身的晶体化学性质多变,且极易氧化,往往对目的矿物的浮选产生巨大干扰,成为有色金属矿浮选的一大难题。生产实践和前人研究表明,磁黄铁矿与铜、铅、锌硫化矿物浮选分离的难点有3个:(1)不同矿床和不同位置产出的磁黄铁矿的性质存在一定的差异,在可浮性和磁性上甚至会有截然相反的表现。沈洪涛等(2022)发现单斜(4C型)磁黄铁矿更容易与黄药结合,六方(5C型)磁黄铁矿更容易被氧化,也更容易被Ca2+抑制;当pH>4时,单斜磁黄铁矿的可浮性优于六方磁黄铁矿,当pH值较低或较高时,单斜磁黄铁矿与六方磁黄铁矿的可浮性则会变差。(2)磁黄铁矿容易氧化生成Fe(OH)3和FeO(OH)等亲水层从而降低其可浮性,同时氧化过程会大量消耗矿浆中的溶解氧,恶化浮选环境,严重时会导致目的矿物不浮。谢泽政(2022)认为氧化剂对磁黄铁矿的氧化过程起着决定性作用,矿物自身晶体结构也会对氧化造成较大的影响。(3)在磁黄铁矿的影响下,方铅矿、闪锌矿和黄铜矿等矿物的可浮性均有不同程度的下降,而磁黄铁矿在这些矿物的影响下可浮性有较大幅度的提高。在磁黄铁矿中,Fe原子的亏损空位被S元素所取代,易被Cu2+活化,导致其可浮性大幅提升,增加了黄铜矿与磁黄铁矿浮选分离的难度(马先峰等,2012)。针对上述问题,可以从以下2个方面展开研究:一是研发对黄铜矿具有高选择性的高效捕收剂,二是开发能够有效抑制磁黄铁矿浮选的抑制剂。如:Zheng et al(2025a)发现NaIO4对磁黄铁矿具有较强的抑制作用,从而可以实现黄铜矿与磁黄铁矿的浮选分离。
磁黄铁矿的浮选回收率与其氧化程度有关,氧化程度越高,可浮性越差,因此许多学者对磁黄铁矿表面氧化机理开展了较深入的研究。磁黄铁矿的氧化需要氧气和水同时存在。在无氧的情况下,磁黄铁矿在水中不会被氧化,仅在表面产生羟基和化学吸附水(Knipe et al,1995;Zhao et al,2016)。在有氧的情况下,磁黄铁矿氧化时,其表面依次划分为3层,最外层为羟基氧化铁层,其次为富硫层,然后是磁黄铁矿本体(图2)。其形成机制为富硫层的S2-被O2氧化为S22-和S n2-;铁从内部扩散到表面,并与O2、OH-和H2O结合形成羟基氧化铁(徐洪辉等,2000;Qin et al,2005)。Buckley et al(1985)研究表明,在暴露于湿度为65%的空气中的最初几秒内,铁就已经从磁黄铁矿晶格中扩散至最外层,这个最初的氧化阶段可表示为
4Fe1-x S+3yO2+2yH2O→2yFe2O3·H2O+4Fe1-x-y S(y<1-x)
虽然铁从内部扩散到表层,但硫不会从磁黄铁矿本体迁移到富硫层;同时没有证据表明在磁黄铁矿的初始阶——氧化阶段,O2能够从羟基氧化物层扩散到富硫层中(Mycroft et al,1995)。最普遍认为的氧化机制是表面吸附氧通过从磁黄铁矿本体结构中的Fe2+和S2-获得电子从而还原为O2-,晶格中Fe2+与Fe3+之间的快速电子转移能够促进氧的还原;并且氧还原最活跃的位点被认为是Fe(III)-S键。同时,结构中的空位促进了铁从本体扩散到表面并形成羟基氧化铁或氧化物并留下缺铁、富硫层。富硫层的单硫化物最终被氧化成二硫化物和多硫化物(Multani et al,2018)。
1.2 磁黄铁矿表面氧化产物及其对浮选的影响
在磁黄铁矿氧化过程中,元素硫和硫酸盐是主要产物,其中硫酸盐在碱性溶液中生成量尤为显著。研究表明,在pH值为4.6、9.2和13的条件下,元素硫是磁黄铁矿氧化的主要产物之一,但同时会伴随大量硫酸盐的生成(Hamilton et al,1981;Buckley et al,1985)。此外,磁黄铁矿的进一步氧化反应会受到表面生成的Fe2O3强烈抑制。Linge(1995)进一步研究指出,在pH值为10的溶液中,当电极电位大于0.2 V时,磁黄铁矿表面氧化形成Fe(OH)3和SO42-,该反应的动力学机制随反应时间而变化,具体表现为:初期反应速率由本体溶液中的OH⁻向磁黄铁矿表面的扩散过程控制;随着反应的进行,Fe(OH)₃多孔产物层的形成使得OH⁻在该层中的扩散成为新的限速步骤,其反应过程可表示为
黄药类捕收剂与磁黄铁矿的作用是一个电化学过程,包含捕收剂在矿物表面的电化学吸附,进一步氧化形成二聚物的阳极反应,以及氧在矿物表面还原的阴极过程(Woods,1996;Zhang et al,2004)。Biegler et al(1975,1977)研究表明,O2在黄铁矿、磁黄铁矿和方铅矿等硫化矿表面的还原动力学显著影响捕收剂的吸附行为。除黄药类捕收剂之外,Fu et al(2026)通过乳液聚合合成了新型纳米颗粒捕收剂PS-Ⅵ,研究结果显示,在存在蛇纹石覆盖层的情况下,带正电的PS-Ⅵ纳米颗粒通过静电吸附与化学吸附相结合的机制,减少了蛇纹石的覆盖程度,并吸附在蛇纹石层的间隙中,且这种吸附行为有助于在磁黄铁矿表面形成三相接触线(TPCL),从而提高了受蛇纹石覆盖影响的磁黄铁矿的回收率,同时减少了蛇纹石的夹带。
Hodgson et al(1989)通过电化学研究发现,黄药在磁黄铁矿上的吸附过程遵循两步机制:首先黄原酸根阴离子(X-)通过静电作用吸附在Fe(Ⅲ)位点[式(3)和式(4)],随后在溶解氧作用下氧化成双黄药并吸附在矿物表面。Khan et al(2004)研究进一步证实了这一机制。Zhang et al(2022)采用原位AFM-拉曼联用技术直接观测到丁基黄药在磁黄铁矿表面的吸附过程,发现低pH值条件下主要形成单层物理吸附,而中性至弱碱性条件下则观察到明显的双黄药特征峰。
FeS+H2O=Fe(OH)[S]++H++2e
Fe(OH)[S]++X-=(Fe(OH)[S])X
Rao et al(1991)发现氮气气氛下黄药在磁黄铁矿表面的吸附量减少但未完全消失,表明产生黄药不依赖氧的吸附途径。而Wang et al(2023a)采用在线电化学质谱(OEMS)证实,氧的存在使双黄药产率提高了3~5倍,特别是在电位大于0.25 V时。基于现有研究,黄药在磁黄铁矿表面的吸附过程可划分为2个特征阶段:首先黄原酸根离子通过静电作用吸附于磁黄铁矿表面的活性位点;然后在氧分子参与下发生电化学反应,吸附态黄药被氧化为双黄药(杨家红等,1995;邱显扬等,2011)。
在浮选过程中,最常用的磁黄铁矿抑制剂为石灰(孙小俊等,2010),在矿浆中加入大量的石灰,在高碱度条件下可实现对磁黄铁矿的抑制(谢臻辉,2024)。同时也开发了一些有机抑制剂:da Costa Gonçalves et al(2023)以2种不同分子量的糊状淀粉作为研究对象,研究其对磁黄铁矿的抑制效果,认为高分子量糊状淀粉的强抑制作用与其水化水平有关,较高的水化水平会产生更强大的排斥水化力,不利于矿物颗粒与气泡的附着,进而削弱磁黄铁矿的可浮性;Zheng et al(2025b)探究了木质素磺酸钙(CL)作为选择性抑制剂在黄铜矿和磁黄铁矿浮选分离中的吸附性能及分子动力学模拟。试验结果表明,CL的羧基和羟基与磁黄铁矿表面的活性铁位点发生配位反应,从而形成以FeOH+为主的亲水物质,促进了磁黄铁矿固液界面水分子层的稳定性。因此,CL对磁黄铁矿表现出强烈的抑制作用,增强了水分子与磁黄铁矿之间的界面相互作用力,成功实现了黄铜矿与磁黄铁矿的浮选分离。Ma et al(2026)研究表明,新型捕收剂ML-8能够实现铜离子活化的铁闪锌矿与磁黄铁矿的有效浮选分离。ML-8对磁黄铁矿表面的铜位点亲和力较弱,且经Cu2+活化后,其吸附几乎没有变化,因此,在ML-8体系中,磁黄铁矿的可浮性较低。但ML-8增强了铁闪锌矿表面硫位点的氧化,提高了Cu(Ⅰ)的浓度,同时降低了磁黄铁矿表面Cu(Ⅰ)的浓度,从而选择性地改善了铁闪锌矿的可浮性。王嘉乐等(2024)研究表明,NaOH仅在强碱矿浆环境中才会对单斜磁黄铁矿具有抑制作用,而石灰对单斜磁黄铁矿具有更加显著的抑制作用,且在乙硫氮捕收体系中石灰的抑制效果强于丁铵黑药体系。李泽涛等(2026)研究成果表明,添加少量高锰酸钾即可在较宽的pH值范围内获得优于石灰高碱对单斜磁黄铁矿的抑制效果,使单斜磁黄铁矿浮选回收率低至6.23%。
此外,控制溶解氧和磁黄铁矿的表面氧化程度也能够实现对磁黄铁矿的浮选与抑制(Legrand,2005;Miller et al,2005;Wang et al,2023b)。Rao et al(1991)研究认为,用氮气作为浮选气体能够有效抑制磁黄铁矿。由于矿浆中Fe2+的存在会导致磁黄铁矿的表面形成Fe(OH)+阳离子,促进了黄原酸根阴离子在矿物表面的吸附,同时矿浆中部分具有氧化性的阳离子会将吸附在表面的部分黄药氧化成双黄药,黄药与双黄药共同作用导致了磁黄铁矿的浮选。而用N2代替空气作为浮选气体则能够降低矿浆中氧的活性,从而阻碍Fe(OH)+位点的形成,减少了黄药在磁黄铁矿表面的吸附。此外,吸附了的黄药也无法被氧化成双黄药。因此用N2替代空气能够有效抑制磁黄铁矿的浮选。Legrand(2005)等则认为控制矿浆中O2浓度可以抑制磁黄铁矿。通过采用X射线光电子能谱方法研究了在pH值为9.3且加入戊黄药的情况下,磁黄铁矿和镍黄铁矿在不同溶液O2浓度下的氧化程度,发现2种矿物的表面氧化程度随O2浓度的增大而增大,但在O2的浓度为3×10-8时,磁黄铁矿表面氧化严重,但镍黄铁矿表面的氧化程度比未反应的样品还低。由于过度氧化会降低硫化矿物的可浮性,因此利用控制矿浆中O2浓度的方法来抑制磁黄铁矿,能够实现磁黄铁矿与镍黄铁矿的浮选分离。
被石灰抑制的磁黄铁矿则可以用硫酸、草酸和硫酸铜等活化后进行浮选。Liu et al(2018)研究了酸性活化剂对磁黄铁矿浮选的影响,结果表明磁黄铁矿表面氧化会生成Fe(OH)3或FeOOH,形成O-Fe3+亲水膜,从而导致其可浮性降低,而该亲水膜可在草酸和硫酸中溶解,因此草酸和硫酸可用做氧化磁黄铁矿的活化剂。相比硫酸,草酸不仅具有清洗作用,电离出的草酸根还具有很强的配位作用,与矿浆中的Ca2+反应,生成草酸钙络合物,进而阻止单斜磁黄铁矿表面CaSO4亲水层的生成,因此草酸作为pH值调整剂的效果优于硫酸(宋强,2024)。
纯矿物浮选试验结果显示:在自诱导浮选和捕收剂浮选体系中,单斜磁黄铁矿的浮选回收率高于六方磁黄铁矿,认为黄药在2种磁黄铁矿表面的吸附产物均为双黄药(洪秋阳,2011;张小普,2021)。Multani et al(2018)研究发现,在pH值为7.0、8.5和10.0的情况下,戊基黄药在单斜磁黄铁矿表面的吸收量显著高于六方磁黄铁矿,因此认为在单斜/六方磁黄铁矿表面均存在不同比例的Fe(OH)[S][X]和Fe(OH)[S][X2]。除黄药类捕收剂之外,其他类型捕收剂对磁黄铁矿超结构的选择性亦表现出显著差异。李文娟等(2010)通过单矿物浮选试验研究了单斜磁黄铁矿在丁铵黑药和乙硫氮2种捕收剂体系下的浮选行为。结果表明,与乙硫氮相比,丁铵黑药对单斜磁黄铁矿具有更好的捕收效果。刘之能等(2009)进一步研究表明,在丁铵黑药体系下,六方磁黄铁矿在中性pH值条件下可浮性最好,表面可能形成疏水性产物正二丁基二磷酸亚铁[Fe(DTP)₂],这一发现为超结构磁黄铁矿的差异化浮选提供了新依据。
电位调控研究表明,2种超结构磁黄铁矿均在特定电位范围内表现出最佳可浮性。He et al(2012)研究发现,在pH值为5的条件下,单斜磁黄铁矿浮选的最佳电位范围为125~580 mV,峰值出现在350 mV;六方磁黄铁矿浮选的最佳电位范围为200~580 mV,峰值出现在300 mV。
关于磁黄铁矿超结构的表面电性特征,研究显示其等电点明显受氧化状态的影响。洪秋阳(2011)和张小普(2021)采用动电位测试方法研究了2种磁黄铁矿超结构的表面电性差异,测试结果表明:单斜磁黄铁矿的等电点约为7.3,六方磁黄铁矿的等电点约为8.8。这些值接近于Fe(OH)3和Fe2O3的等电点。Multani et al(2018)研究结果表明:在没有氧气的情况下,新鲜的、未氧化的磁黄铁矿超结构在pH值为2~11范围内表现出相同的表面电位,并具有相同的等电点(pHIEP~3.5)。这一对比结果表明,氧化程度是造成磁黄铁矿超结构表面电性差异的关键因素。
Zhao et al(2015)通过密度泛函理论计算,从电子结构层面揭示了不同晶系磁黄铁矿浮选行为的差异机制。研究显示,丁基黄药的最高占据分子轨道(EHOMO)与单斜磁黄铁矿最低未占据分子轨道(ELUMO)之间的值(0.22 eV)小于丁基黄药EHOMO与六方磁黄铁矿ELUMO之间的值(0.35 eV),因此,单斜磁黄铁矿比六方磁黄铁矿更容易与丁基黄药作用。六方磁黄铁矿HOMO中因Fe的贡献系数较大而有利于CaOH+在其表面吸附;单斜磁黄铁矿HOMO中虽然也有Fe原子的贡献,但Fe的系数与S非常接近,S的存在阻碍了CaOH+的吸附。因此,石灰对六方磁黄铁矿的浮选抑制作用强于单斜磁黄铁矿。Liu et al(2021)通过DFT计算表明,磁黄铁矿表面Fe空位的存在显著增强了黄药分子的吸附能(从-1.2 eV增至-1.8 eV),这为解释不同超结构磁黄铁矿的可浮性差异提供了理论依据。
生产实践表明,单斜磁黄铁矿和六方磁黄铁矿超结构在浮选行为上存在显著差异:由于六方磁黄铁矿氧化速率低于单斜磁黄铁矿,因此六方磁黄铁矿具有更好的可浮性,并且认为磁黄铁矿氧化对于磁黄铁矿抑制至关重要。Qi et al(2019)采用循环伏安法和XPS对Strathcona矿场的单斜磁黄铁矿和六方磁黄铁矿的浮选和抑制机制进行了研究。其研究结果表明单斜磁黄铁矿比六方磁黄铁矿具有更高的氧化速率,其表面能够更快地形成铁的氢氧化物层,因而可浮性比六方磁黄铁矿更差。Multani et al(2019)通过一系列浮选试验研究磁黄铁矿超结构对浮选的影响。其研究结果表明在减少浮选夹带的情况下,10~100 μm粒级的六方磁黄铁矿浮选回收率最高,而对于单斜磁黄铁矿则是小于10 μm粒级的浮选回收率最高,且六方磁黄铁矿难以抑制,而单斜磁黄铁矿容易抑制。造成不同超结构浮选反应具有显著差异的原因有:在碱性条件(pH>9)下,单斜结构更易氧化;活化离子(Cu2+和Ni2+)对超结构的选择作用、超结构对氧的反应性不同。研究表明:在较高的pH值(pH>9)条件下,单斜磁黄铁矿表面的氧化加速造成了浮选差异,且由于单斜磁黄铁矿在结构上比六方磁黄铁矿具有更高的空位比例和Fe(Ⅲ)-S键数,促进了电子向氧转移。
尽管部分学者已针对磁黄铁矿超结构氧化与浮选行为的差异开展了研究,并取得系列研究成果,但也出现了一些不一致的研究结论,如许多文献报道单斜磁黄铁矿更易浮选,但也有生产实践表明非磁性比磁性磁黄铁矿更易浮选(He et al,2012);同样地,针对磁黄铁矿超结构的氧化研究也呈现出不一致的结论。Multani et al(2018)认为不同研究得出的结论存在矛盾,其原因可能是用于研究的磁黄铁矿样品的超结构没有被准确地量化以及测试前的样品因处理不当被氧化。Multani et al(2018)在进行研究前对磁黄铁矿超结构进行了表征,并用超声处理方法去除磁黄铁矿表面的氧化产物。在研究中通过微泡浮选试验、正戊基黄药吸附和氧气吸附量对磁性和非磁性磁黄铁矿的浮选行为进行了研究。研究结果表明,当磁黄铁矿表面少量吸附氧气时表现出相似的超结构行为,即相同的等电点(pH=3.5)和相同的表面电位(pH=2~10);在表面氧化不可避免的情况下,超结构的浮选性将因其对氧的不同反应性而显著不同。超结构中的铁缺陷将会导致其周围的Fe2+转变为Fe3+,以保持电中性,而Fe3+的存在会使得磁黄铁矿表面氧化速率加快。对于磁性磁黄铁矿(Fe3+Fe2+S8),其Fe3+占铁的29%,而非磁性磁黄铁矿(Fe3+Fe2+S10)中的Fe3+占铁的22%,由此得出磁性磁黄铁矿更容易氧化。因此,在表面氧化不可避免的工业生产中,非磁性磁黄铁矿可能更易浮选。Qi et al (2019)也认为磁黄铁矿的氧化对于磁黄铁矿的抑制必不可少,由于六方磁黄铁矿比单斜磁黄铁矿具有更低的氧化速率,因此其表面更难形成铁的氢氧化物层,从而具有更高的可浮性。Multani et al(2019)认为单斜磁黄铁矿比六方磁黄铁矿具有更高的结构空位比例和Fe(Ⅲ)-S键数,促进了电子向氧转移,因此六方磁黄铁矿比单斜磁黄铁矿更易浮选。
5 磁黄铁矿对硫化矿物浮选分离的影响
5.1 磁黄铁矿氧化消耗矿浆中的溶解氧
氧是影响硫化矿浮选的重要因素,其对巯基捕收剂在硫化矿表面的吸附具有重要意义。然而磁黄铁矿易氧化,氧化过程大量消耗矿浆中的溶解氧,恶化浮选环境,严重时导致目的矿物不浮。Li et al(2023b)针对某高硫(37.62%)含磁黄铁矿难处理铜锌多金属硫化矿在高碱条件下进行浮选分离时发现,若在浮选前不对矿浆进行充气搅拌,锌粗精矿中锌品位仅为0.79%,锌回收率为1.83%;若在浮选前对矿浆进行充气搅拌,锌粗精矿中锌品位和回收率分别提升至37.01%和94.58%;同时对添加石灰后的矿浆进行拉曼光谱原位分析发现,强碱性矿浆中存在较高浓度的类似于多硫化钙CaS n (n=2~8)的多硫化物,在浮选前通过对矿浆进行充气搅拌,多硫化物被快速氧化,消除了其对浮选的不利影响(图3)。此外,通过对比不同矿石,确定矿浆中多硫化物的形成是磁黄铁矿的存在引起的。Wang et al(2023c)研究表明:磁黄铁矿比黄铜矿更容易氧化,因此磁黄铁矿的存在消耗了矿浆中大量的氧气,导致矿浆中残余氧含量不足以支持捕收剂的吸附;通过矿浆充气提供充足的氧气,冬瓜山铜矿铜的最大回收率从74.6%提高至86.3%。张福亚等(2022)针对含磁黄铁矿的硫化铜矿浮选研究也获得相似的结果。
5.2 磁黄铁矿与其他硫化矿物间的电化学相互作用
当磁黄铁矿与其他硫化矿物接触时,硫化物颗粒间的电化学相互作用不仅会影响磁黄铁矿的浮选与抑制,还会影响其他硫化矿物的浮选。六方磁黄铁矿促进了黄铜矿表面的氧化,伴随着大量铜离子的溶解并吸附在六方磁黄铁矿表面,使丁基黄酸盐在六方磁黄铁矿表面吸附量增加,浮选回收率提高5%~20%(Qiu et al,2023)。单斜磁黄铁矿则促进了黄铜矿表面O2的还原,导致黄铜矿表面生成Fe(OH)3,从而不利于捕收剂吸附,因此,浮选回收率降低了10%~16%(Yang et al,2021)。方铅矿和单斜磁黄铁矿发生电化学相互作用时,方铅矿表面生成亲水性物质PbS x O y 和Pb(OH)2,可浮性降低;单斜磁黄铁矿表面氧化受到抑制,硫的亲水性氧化产物SO和SO减少,而疏水性产物S0增加,使得单斜磁黄铁矿可浮性增加,增加了铅硫浮选分离的难度(杨柳,2023;Qiu et al,2024)。电化学相互作用降低了磁黄铁矿与其他硫化矿物的可浮性差异,显著增加了分离难度。
BieglerT,1975.Oxygen reduction on sulphide minerals part I.Kinetics and mechanism at rotated pyrite electrodes[J].Journal of Electroanalytical Chemistry,60(2):151-162.
[2]
BieglerT, RandD A J, WoodsR,1977.Oxygen reduction on sulphide minerals[M]//Trends in Electrochemistry.Boston,MA:Springer U S.
[3]
BuckleyA N, WoodsR,1985.X-ray photoelectron spectroscopy of oxidized pyrrhotite surfaces I.exposure to aire[J].Applications of Surface Science,22:280-287.
[4]
BunkholtI, KleivR A,2015.Pyrrhotite oxidation and its influence on alkaline amine flotation[J].Minerals Engineering,71:65-72.
[5]
da Costa GonçalvesC, BobickiE R, LiuQ X,2023.Insight on the mechanism of hexagonal pyrrhotite depression by starch during flotation[J].Minerals Engineering,203:108335.
[6]
FuL W, JiaoF, WeiQ,et al,2026.Application of a novel nanoparticle collector in the flotation separation of serpentine-containing pyrrhotite[J].Minerals Engineering,235:109792.
[7]
HamiltonI C, WoodsR,1981.An investigation of surface oxidation of pyrite and pyrrhotite by linear potential sweep voltammetry[J].Journal of Electroanalytical Chemistry and Interfacial Electrochemistry,118:327-343.
[8]
HeM F, QinW Q, LiW Z,et al,2012.Flotation performances of polymorphic pyrrhotite[J].Journal of Central South University,19(1):238-243.
[9]
HodgsonM, AgarG E,1989.Eilectrochemical investigations into the flotation chemistry of pentlandite and pyrrhotite:process water and xanthate interactions[J].Canadian Metallurgical Quarterly,28(3):189-198.
[10]
KhanA, KelebekS,2004.Electrochemical aspects of pyrrhotite and pentlandite in relation to their flotation with xanthate.part-Ⅰ:cyclic voltammetry and rest potential measurements[J].Journal of Applied Electrochemistry,34(8):849-856.
[11]
KnipeS W, MycroftJ R, PrattA R,et al,1995.X-ray photoelectron spectroscopic study of water adsorption on iron sulphide minerals[J].Geochimica et Cosmochimica Acta,59(6):1079-1090.
[12]
LegrandD L,2005.Oxidation of pentlandite and pyrrhotite surfaces at pH 9.3:Part 2.Effect of xanthates and dissolved oxygen[J].American Mineralogist,90(7):1055-1061.
[13]
LiH D, QinW Q, TianZ Y,et al,2023a.A case study on marmatite- pyrite/pyrrhotite selective flotation with two-step pulp regulation[J].Journal of Environmental Chemical Engineering,11(5):110455.
[14]
LiH D, YangC R, QinW Q,et al,2023b. In situ Raman investigation of dissolved constituent and its evolution in pulp during Zn-S selective flotation with two-step pulp regulation[J].Minerals Engineering,192:107994.
[15]
LingeH G,1995.Anodic oxidation of pyrrhotite in simulated CIP liquors[J].Minerals Engineering,8(7):795-806.
[16]
LiuJ, LiE L, JiangK,et al,2018.Effect of acidic activators on the flotation of oxidized pyrrhotite[J].Minerals Engineering,120:75-79.
[17]
LiuM, ChenS, ZhangR,et al,2021. DFT study of xanthate adsorption on pyrrhotite surfaces with Fe vacancies:implications for flotation selectivity[J]. Applied Surface Science,563:150302.
[18]
MaY L, TongX, WangC T,et al,2026. Applying a novel collector ML-8 to achieve efficient flotation separation of marmatite from pyrrhotite[J].Minerals Engineering,235:109869.
[19]
MillerJ D, LiJ, DavidtzJ C,et al,2005.A review of pyrrhotite flotation chemistry in the processing of PGM ores[J].Minerals Engineering,18(8):855-865.
[20]
MultaniR S, WatersK E,2018.A review of the physicochemical properties and flotation of pyrrhotite superstructures(4C-Fe7S8/5C-Fe9S10) in Ni-Cu sulphide mineral processing[J].The Canadian Journal of Chemical Engineering,96(5):1185-1206.
[21]
MultaniR S, WatersK E,2019.Flotation recovery-by-size comparison of pyrrhotite superstructures with and without depressants[J].Minerals Engineering,130:92-100.
[22]
MultaniR S, WilliamsH, JohnsonB,et al,2018.The effect of superstructure on the zeta potential,xanthate adsorption,and flotation response of pyrrhotite[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,551:108-116.
[23]
MycroftJ R, NesbittH W, PrattA R,1995.X-ray photoelectron and Auger electron spectroscopy of air-oxidized pyrrhotite:Distribution of oxidized species with depth[J].Geochimica et Cosmochimica Acta,59(4):721-733.
[24]
NanthakumarB, KelebekS, KatsabanisP D,2007.Impact of oxidation on flotation of Ni-Cu sulphide ore with respect to grinding[J].Mineral Processing and Extractive Metallurgy,116(3):197-206.
[25]
QiC, LiuJ, MalaineyJ,et al,2019.The role of Cu ion activation and surface oxidation for polymorphic pyrrhotite flotation performance in Strathcona Mill[J].Minerals Engineering,134:87-96.
[26]
QinW Q, LiQ, QiuG Z,et al,2005.Electrochemical oxidation of pyrrhotute in aqueous solution[J].Transactions of Nonferrous Metals Society of China,15(4):922-925.
[27]
QiuT S, DingK W, YanH S,et al,2024.Electrochemistry and DFT study of galvanic interaction on the surface of monoclinic pyrrhotite(001) and galena(100)[J].International Journal of Mining Science and Technology,34(8):1151-1162.
[28]
QiuT S, ZhangC, YangL,et al,2023. Effect of electrochemical interaction between chalcopyrite and hexagonal pyrrhotite on flotation separation [J]. Minerals,13(10):1303.
[29]
RaoS R, FinchJ A,1991.Adsorption of amyl xanthate at pyrrhotite in the presence of nitrogen and implications in flotation[J].Canadian Metallurgical Quarterly,30(1):1-6.
[30]
TangX Q, ChenY,2022.A review of flotation and selective separation of pyrrhotite:a perspective from crystal structures[J].International Journal of Mining Science and Technology,32(4):847-863.
[31]
WangC T, LiuR Q, ZhaiQ L,et al,2023a.Exploring the effect of pulp aeration and lime-aid grinding on pyrrhotite-rich type copper sulfide ore flotation separation[J].Separation and Purification Technology,311:123268.
[32]
WangC T, LiuR Q, ZhaiQ L,et al,2023b.Prospects of pulp aeration for the cleaner production of pyrrhotite-rich type copper sulfide ore:Mechanism and application[J].Journal of Cleaner Production,406:136921.
[33]
WangH, LiuX, ZhangT,et al,2023c. In situ monitoring of dixanthogen formation on pyrite surfaces by online electrochemical mass spectrometry: effect of dissolved oxygen[J]. Journal of Colloid and Interface Science,630(Pt A): 763-771.
[34]
WoodsR,1996.Chemisorption of thiols on metals and metal sulfides[M]//Reviews of Physiology,Biochemistry and Pharmacology,Volume 94.Berlin:Springer: 401-453.
[35]
YangL, ZhouX W, YanH S,et al,2021.Effects of galvanic interaction between chalcopyrite and monoclinic pyrrhotite on their flotation separation[J].Minerals,12(1):39.
[36]
ZhangQ, HuY H, GuG H,et al,2004.Electrochemical flotation of ethyl xanthate-pyrrhotite system[J].Transactions of Nonferrous Metals Society of China,14(6):1174-1179.
[37]
ZhangX, LiY, WangJ,et al,2022. In situ observation of butyl xanthate adsorption on pyrrhotite surface by AFM-Raman co-mapping[J]. Minerals Engineering,180:107430.
[38]
ZhaoC H, WuB Z, ChenJ H,2015.Electronic structure and flotation behavior of monoclinic and hexagonal pyrrhotite[J].Journal of Central South University,22(2):466-471.
[39]
ZhaoC H, ChenJ H, LiY Q,et al,2016.First-principle calculations of interaction of O2 with pyrite,marcasite and pyrrhotite surfaces[J].Transactions of Nonferrous Metals Society of China,26(2):519-526.
[40]
ZhengQ F, DongL Y, ShenP L,et al,2025a.A novel oxidation reagent scheme to realize efficient flotation separation of chalcopyrite and pyrrhotite[J].Applied Surface Science,693:162794.
[41]
ZhengQ F, ShenP L, SuC,et al,2025b.Selective depression mechanism:Surface chemistry and molecular dynamics study on the flotation separation of chalcopyrite and pyrrhotite[J].Journal of Environmental Chemical Engineering,13(6):119856.
[42]
ZhouJ, LuY P, MaoG Z,2018.Separation of oxidized pyrrhotite from fine fraction serpentine[J].Minerals,8(10): 472.
DongYingze, LuYiping, MaZhongxin,et al,2017.Effect of mixing intensity on surface components of pyrrhotite[J].Journal of Central South University (Science and Technology),48(2):277-281.
FengBo, FengQiming, LuYiping,2015.Mechanism of hetero-aggregation of chlorite and pyrite[J].Journal of Central South University (Science and Technology),46(1):14-19.
[51]
洪秋阳,2011.磁黄铁矿晶体化学和可浮性研究[D].长沙:中南大学. Hong Qiuyang,2011.Study on the crystal chemistry and floatability of pyrrhotite[D].Changsha:Central South University.
HuWenying, ZhouYongxiao, ZhongGuojian,et al,2018.The transform of improving quality and efficiency of copper mine processing in Dabaoshan minning Co.,Ltd. of Guangdong[J].Multipurpose Utilization of Mineral Resources,39(4):121-125.
LiPeiyuan, YangLingling, WuHongqiang,et al,2021.Experimental research on the copper-bearing pyrrhotite ore of Dongguashan copper mine[J].Modern Mining,37(10):124-126,129.
[56]
李文娟,宋永胜,周桂英,等,2010.单斜磁黄铁矿浮选行为研究[J].金属矿山,(8):82-85. Li Wenjuan,Song Yongsheng,Zhou Guiying,et al,2010.Study on electrochemical flotation behavior of monoclinic pyrrhotite[J].Metal Mine,(8):82-85.
ChenJie, TangHonghu,et al,2026. The influence mechanism of potassium permanganate oxidation on the flotation behavior of monoclinic pyrrhotite[J/OL]. Nonferrous Metals Science and Engineering,1-14[2026-01-28].
LiuZhineng, QinWenqing, ZhangJianwen,et al,2009.Flotation and adsorption mechanism of hexa-pyrrhotite[J].Mining and Metallurgy,18(2):5-8,12.
[61]
马先峰,邱显扬,何晓娟,等,2012.黄铜矿与磁黄铁矿选别性质差异研究[J].有色金属(选矿部分),(6):35-38. Ma Xianfeng,Qiu Xianyang,He Xiaojuan,et al,2012.Investigation on separative properties of chalcopyrite and pyrrhotite[J].Nonferrous Metals (Mineral Processing Section),(6):35-38.
QiuXianyang, MaXianfeng, HeXiaojuan,et al,2011.Research progress in flotation separation of pyrrhotite from chalcopyrite[J].Mining Engineering,9(6):29-32.
ShenHongtao, LuoLiqun, ChenJingwen,2022.Mineralogical characteristics and separating behavior of different polytypes of pyrrhotite[J].Metal Mine,51(6):107-114.
[66]
宋强,2024.单斜磁黄铁矿的解抑与活化机理及产业化研究[D].昆明:昆明理工大学. Song Qiang,2024.Study on the mechanism of inhibition and activation and industrialization of monoclinic pyrrhotite[D].Kunming:Kunming University of Science and Technology.
SunXiaojun, GuGuohua, LiJianhua,et al,2010.Influences of collector CSU31 on chalcopyrite and pyrite flotation[J].Journal of Central South University (Science and Technology),41(2):406-410.
QinWenqing, QiuGuanzhou, WuBozeng),et al,1999.The stability of dixanthogen adsorbed on the surface of pyrrhotite and its effect on flotation[J].China Mining Magazine,8(4):47-50.
WangJiale, YanHuashan, XieZezheng,2024.Flotation behavior of monoclinic pyrrhotite on different collector systems[J].Jiangxi Metallurgy,44(5):361-366.
[73]
谢泽政,2022.表面氧化对磁黄铁矿浮选行为的影响机理研究[D].赣州:江西理工大学. Xie Zezheng,2022.Influence mechanism of surface oxidation on pyrrhotite flotation behavior[D].Ganzhou:Jiangxi University of Science and Technology.
[74]
谢臻辉,2024.黑药浮选分离不同铁含量闪锌矿和磁黄铁矿的基础研究[D].长沙:中南大学. Xie Zhenhui,2024. Basic research on the flotation separation of sphalerite with different iron contents and pyrrhotite by black catching agents [D].Changsha:Central South University.
YangJiahong, ChenWanxiong,1995.Oxidation kinetics of xanthate at the surface of pyrite and arsenopyrite[J]. Journal of Central South University(Science and Technology),26(5):600-604.
[79]
杨柳,2023.方铅矿与磁黄铁矿间的电偶腐蚀作用及其对浮选分离的影响机理[D].赣州:江西理工大学. Yang Liu,2023.Galvanic corrosion between galena and pyrrhotite and its effect on flotation separation[D].Ganzhou:Jiangxi University of Science and Technology.
ZhangFuya, ZhangJianhui,2022.Effect of aerated stirring pretreatment on the flotation separation of chalcopyrite and pyrrhotite[J].Multipurpose Utilization of Mineral Resources,43(5):164-167.
ZhangQin, HuYuehua, GuGuohua,et al,2004.Selective flotation separation of jamesonite from pyrrhotite by potassuim cyanide[J].Journal of Central South University (Science and Technology),35(3):372-375.
[84]
张小普,2021.不同晶系磁黄铁矿的矿物学特征和可浮性研究[D].赣州:江西理工大学. Zhang Xiaopu,2021.Study on the mineralogical properties and floatability of different crystal systems of pyrrhotite[D].Ganzhou:Jiangxi University of Science and Technology.
ZhengWenjun,2019.Experimental study on cyanide-free separation of lead and zinc from No.105 orebody in Dachang[J].Mining Engineering,17(5):23-28.
[87]
周利华,2017.黄铜矿与磁黄铁矿浮选分离的机理研究及技术应用[D].赣州:江西理工大学. Zhou Lihua,2017.The separation of chalcopyrite and pyrhotite flotation mechanism research and technology application[D].Ganzhou:Jiangxi University of Science and Technology.