油酸在石英与长石表面的吸附

通过动电电位测定、吸附量测定、红外光谱分析及单矿物浮选等手段，研究了油酸在石英和长石表面的存在状态及吸附作用。结果表明，油酸以两种方式吸附：油酸根离子的静电吸附和油酸分子的物理吸附，在长石表面还存在油酸根离子与铝离子之间的化学吸附，因此，油酸在长石表面的吸附强度高于石英，试验还表明，在抑制剂的配合下，油酸钠可以活化阳离子胺类捕收剂对长石的捕收。     

石英长石矿物结晶化学特性与药剂作用机理

根据油酸钠和十二胺在长石、石英表面的吸附作用机理,分析了矿物晶体结构特性与药剂作用机理之间的关系。发现石英和长石在晶体结构和化学组成上的相似性,使其在荷电机理上相同,荷电量上亦接近,从而决定了以静电吸附为主的胺类捕收剂在浮选分离这两种矿物时是没有选择性的。两矿物在化学组成上的差异带来了油酸吸附性质上的差异,即油酸离子与长石表面上的 Al~(3+)存在化学吸附,这种吸附所占的比重虽不大,却为油酸钠选择性活化长石提供了可能。长石和石英在结晶化学上的特性差异是实现其浮选分离的基础。     

组合捕收剂浮选锂辉石的作用机理

通过浮选试验、表面张力测试、Zeta电位以及红外光谱分析,考察油酸钠(NaOL)、十二烷基琥珀酰胺(HZ)两种捕收剂及其组合捕收剂对锂辉石的浮选性能和作用机理。结果表明:单一捕收剂在一定浓度下都能较好地浮选锂辉石,其中HZ的捕收性能强于NaOL,组合捕收剂浮选效果明显优于任意单一捕收剂。在药剂用量为200mg/L、pH=9.0左右、组合捕收剂的混合摩尔比n(NaOL):n(HZ)为5:1的条件下,浮选效果最好,浮选回收率达88.48%。红外光谱分析表明NaOL在锂辉石表面以化学吸附为主,HZ则以物理吸附为主,两种捕收剂组合使用后的正协同作用是由于锂辉石矿物表面的不均匀性和表面的活性质点的差异使这两种不同药剂能选择性的吸附在矿物表面的不同位置,从而提高药剂捕收性能。     

乙酰丙酮对菱镁矿一步反浮选脱硅脱钙的影响及机理

在十二胺捕收剂浮选体系下,通过单矿物与人工混合矿浮选试验,考察了乙酰丙酮对菱镁矿一步反浮选脱硅脱钙的影响,并通过对药剂作用前后矿物表面Zeta电位及红外光谱的分析,探讨了乙酰丙酮对菱镁矿浮选脱硅脱钙的作用机理。结果表明：乙酰丙酮对菱镁矿具有一定的抑制作用,对白云石和石英作用不明显,乙酰丙酮对菱镁矿反浮选脱硅脱钙具有较好的分选效果;乙酰丙酮在菱镁矿表面形成较在白云石表面更多的含镁络合物,吸附量大且稳定,使其矿物表面正电性增强,不利于捕收剂十二胺在菱镁矿表面的吸附,从而对菱镁矿产生较强的抑制作用;乙酰丙酮在石英表面几乎不吸附,但不影响十二胺在石英表面的吸附。     

金属阳离子在锂辉石浮选中的活化行为及作用机理

在油酸浮选锂辉石体系中分别加入Ca^2+、Al^3+、Fe^3+离子,通过单矿物浮选试验、金属离子吸附量检测、金属离子水解组份浓度计算、矿物表面动电位测试、红外光谱检测以及量子化学模拟计算研究Ca^2+、Al^3+、Fe^3+离子对锂辉石浮选的活化行为和作用机理。结果表明:Ca^2+离子的最佳活化区间为pH大于12的强碱性条件,Al^3+离子的最佳活化pH为6.47,而Fe^3+离子的最佳活化pH为7.25;在这些pH区间内,锂辉石浮选回收率和金属离子吸附量均达到最大值。在锂辉石浮选过程中起活化作用的有效组份为它们分别对应的氢氧化物沉淀。Ca^2+、Al^3+、Fe^3+离子可使锂辉石表面动电位向正值方向显著偏移;Ca^2+离子在锂辉石表面双电层的外层发生静电吸附,Al^3+和Fe^3+离子在锂辉石表面双电层的内层发生特性吸附。钙原子与锂辉石矿物表面吸附后形成的Ca—O键的键强较小,以离子键为主;铁原子与矿物表面形成Fe—O化学键的键强较大,含有一定的共价键组份;而铝原子与矿物表面吸附后形成的Al—O键的键长、键强等参数介于钙、铁的参数之间。油酸在Ca^2+活化后的锂辉石表面发生了化学吸附和少量的物理吸附,而在Al^3+、Fe^3+活化后的锂辉石表面发生了较为强烈的化学吸附。     

水相环境中十二胺在石英及磁铁矿表面吸附的分子动力学模拟

采用分子动力学模拟方法,研究周期性水环境下十二胺在石英及磁铁矿界面上的吸附过程。考虑到十二胺的水解电离平衡以及矿物表面荷电机理,建立弱酸、中性以及强碱性3种条件下十二胺与石英及磁铁矿的吸附模型。采用微量热仪测量十二胺在石英及磁铁矿表面吸附过程中的吸附热。模拟结果表明:中性环境有利于十二胺在矿物表面的吸附;弱酸性条件下十二胺不能吸附于磁铁矿表面;强碱性环境下十二胺与石英及磁铁矿的相互作用很弱。十二胺与石英作用的吸附焓大于十二胺与磁铁矿的,十二胺更易于吸附在石英表面,且十二胺在矿物表面的吸附为物理吸附。分子动力学模拟与吸附热试验从分子力学及热力学层面上揭示了浮选过程中十二胺对石英及磁铁矿选择性的差异的原因。     

阴阳离子混合捕收剂对异极矿的浮选作用及机理

采用DDA(十二胺)和KAX(异戊基黄原酸钾)的阳阴离子混合药剂作为捕收剂,对异极矿进行单矿物浮选及检测,并与单独使用DDA或者KAX作为捕收剂进行比较。结果表明:采用DDA和KAX的摩尔比为1:3的混合捕收剂浮选异极矿时,比单独使用DDA或者KAX对异极矿的浮选效果要好,且在pH值为10左右时浮选效果最佳,回收率达86%;DDA和KAX混合后各自所带的阴、阳离子电性中和,降低了捕收剂分子之间的静电斥力,从而使混合捕收剂的临界胶束浓度值降低,在矿物表面吸附时形成半胶束吸附的浓度值降低,更易于在异极矿表面形成半胶束吸附,对矿物浮选捕收效果增强。     

超声预处理对锂辉石矿物浮选分离的影响

采用NaOH溶蚀与超声波耦合机械搅拌相结合的预处理技术对锂辉石、石英和长石进行浮选前预处理,以探究超声预处理对锂辉石矿物浮选分离的影响。通过开展单矿物浮选和人工混合矿浮选试验,比较超声波耦合机械搅拌与传统机械搅拌两种预处理技术的优缺点;为了探明预处理技术的作用机理,对经不同预处理后的矿样进行了SEM、吸附量测试和XPS分析。结果表明：超声预处理后,锂辉石与长石、石英之间的可浮性差异进一步增大,-0.074+0.038 mm粒级的锂辉石人工混合矿精矿浮选回收率最高可达48.23%,分选效率达到44.27%;相较于传统机械搅拌预处理,超声波耦合机械搅拌预处理的浮选效果进一步提高。介入超声波预处理后可进一步改变锂辉石矿物表面形貌,并促进更大范围的表面溶蚀,从而增加矿物表面药剂吸附,且超声波耦合机械搅拌预处理后的锂辉石比传统机械搅拌预处理后的锂辉石具有更强的NaOL吸附能力,可见超声预处理技术对锂辉石、石英和长石的浮选分离具有显著的促进作用。     

油酸钠作用下异极矿的浮选行为及作用机理

通过纯矿物试验研究油酸钠为捕收剂体系中异极矿的浮选行为。结果表明:当油酸钠用量为3×10~(-4)mol/L、p H值为4~8和11时,异极矿浮选回收率均在80%左右。Zeta电位及红外光谱测试结果表明:油酸钠在异极矿表面主要发生化学吸附,同时也可能存在物理吸附。根据油酸钠溶液和锌离子水解组分含量化学计算,当p H值为4~8时,油酸钠溶液的优势组分为RCOO~-和(RCOO)_2~(2-);而异极矿表面锌离子主要以Zn~(2+)和少量Zn OH~+形式存在。结合异极矿在油酸钠捕收剂体系中的浮选行为,油酸钠在异极矿表面的相互作用原理是异极矿表面Zn~(2+)和羟基络合物Zn(OH)~+成为浮选的活性质点,能与油酸钠作用形成油酸盐,从而使异极矿疏水上浮;RCOOH_(aq)分子和离子-分子缔合物RCOOH·RCOO~-的物理吸附也可能存在;而在p H为11时矿物可浮性较好,可能是油酸根离子与矿物表面的形成Zn(OH)_2发生离子交换。     

油酸钠浮选锂辉石的表面晶体化学及各向异性

基于锂辉石与绿柱石和长石等铝硅酸盐矿物的表面皆含有活性Al原子,表面晶体化学特性是产生选择性浮选分离的决定性因素,通过不同粒级单矿物浮选实验、Zeta电位测试、红外光谱分析、密度泛函理论计算及分子动力学模拟等方法系统研究油酸钠浮选锂辉石的表面晶体化学及各向异性。结果表明:锂辉石浮选回收率随pH增大先增加而后减小,当pH=8.5左右,浮选回收率达到最大值;在一定粒度范围内,粒度越粗,锂辉石浮选回收率越高;锂辉石表面Al质点与油酸钠发生化学吸附作用;锂辉石晶面单位面积的断裂键数以及与油酸钠的相互作用能由大到小依次为(110)、(001),其是导致不同粒级锂辉石浮选行为差异性的根本原因。     

Flotation evaluation and adsorption mechanism of medialan collector to wolframite

Medialan has preferable flotation performance to wolframite,under the conditions of the best flotation pH value 7.0 and low dosage,wolframite recovery is up to80%.Medialan shows poor flotation performance to quartz,but better to fluorite and calcite.However,fluorite and calcite are inhibited in a certain degree by adding medialan mixed with sodium silicate.Adsorption mechanism of medialan collector on wolfram surface was also studied by using infrared(IR)radiation spectrum,adsorption volume,and zeta potential.The results show that medialan can adsorb on wolfram surface in the form of chemistry adsorption,and as medialan collector dosage changes,change law of adsorption volume is similar with that of wolfram pure mineral flotation.Zeta potential results prove that zeta potential of wolfram surface moves negatively after adsorbing medialan collector.     

A new collector used for flotation of oxide minerals

A surfactant containing a mixed aliphatic structure, with a hydrocarbon chain and a diamine group, has proven to be collector for the flotation of quartz, calamine and calcite. And research about its collecting capability was carried out in laboratory. The test results show that the flotation recovery ascends sharply with increasing the concentration of collector. When the concentration of collector reaches 1.83×10⁻⁴ mol/L, the flotation recoveries of quartz, calamine and calcite get their maximum of 97.64%, 91.04% and 95.99%, respectively. The flotation recoveries of quartz, calamine and calcite rise sharply with the rise of pH. And in a wide range of pH, their flotation recoveries all exceed 90%. And in the whole flotation experiment, the flotation recovery of hematite rises with the increase of collector concentration and pH, while the maximal recovery is not more than 55%. Compared with dodecylamine, the N-dodecylethylenediamine has strong capability to quartz and calamine, while the flotation recoveries of calcite are closely. Hydrogen binding adsorption and electrostatic adsorption occur between the collector and the surface of quartz.     

Flotation separation of quartz from magnesite using carboxymethyl cellulose as depressant

Carboxymethyl cellulose (CMC) was introduced as a depressant in reverse flotation separation of quartz from magnesite. The flotation behavior and surface properties of magnesite and quartz exposed to CMC were studied by zeta potential tests, atomic force microscopy imaging and contact angle measurements. The addition of CMC as the depressant in reverse flotation using dodecylamine (DDA) as the collector exhibited a selectively depressive performance towards magnesite and achieved an improved recovery of magnesite. The study of surface properties demonstrated that CMC and DDA exhibited different adsorption strengths on the surface of magnesite and quartz. It was found that the adsorption of CMC on magnesite surface was stronger than that of DDA, which hindered the subsequent adsorption of DDA on magnesite surface. On the contrary, the quartz surface was strongly adsorbed by DDA instead of CMC, which proved that the addition of CMC did not influence the flotation of quartz.     

Selective flotation of smithsonite,quartz and calcite using alkyl diamine ether as collector

The flotation separation of smithsonite from calcite and quartz using a alkyl diamine ether (GE-609) as the collector was investigated through micro-flotation experiments and the real ore flotation experiments. The results show that GE-609 exhibits good collecting capability to three minerals without selectivity. The presence of sodium sulfide enhances the flotation of smithsonite and calcite while inhibits quartz. Moreover, both sodium silicate and sodium hexametaphosphate exhibit good selective inhibition to calcite. The real ore test results show that a zinc concentrate containing 23.51% Zn with the recovery of 71.02% is obtained in the closed-circuit test. To understand the adsorption of GE-609 on smithsonite surface, zeta potential measurement and FTIR analysis were carried out, and the results indicate that the collector GE-609 can adsorb on smithsonite surface through both electrostatic adsorption and chemical adsorption, and the presence of sodium sulfide enhances the adsorption of GE-609.     

Reverse flotation separation on diaspore and kaolinite in the presence of cationic polyacrylamide polymers

1　INTRODUCTIONChinaisrichindiasporebauxiteresources[1,2 ]whichpossessspecialpropertiessuchashighgradeofbothAl2 O3andSiO2 andlowFecontent,buttheAl/Si(massratioofAl2 O3toSiO2 )valueislow .Inordertotreatthediasporebauxite ,unitedmethodsandsin teringmethods[3] arestillappliedalthoughsufferingfromdisadvantagesincludingcomplextechnologyflowchart,highenergyconsumption ,highproduc tioncost ,andrestrainingfurtherdevelopmentofalu minaindustry .However ,byimprovingbauxiteAl/Si>10 ,wecanchoosem…     

Effects of sodium carbonate and calcium chloride on calcite depression in cationic flotation of pyrolusite

In the cationic flotation of pyrolusite using dodecyl ammine (DDA), the depressive effect of sodium carbonate and calcium chloride on the calcite mineral was investigated systematically through flotation experiments, FTIR analysis, contact angle measurements and zeta potential tests. The microflotation experiments showed that both depressant agents decrease the flotation recovery of calcite significantly. In addition, sodium carbonate acts as activator agent for pyrolusite, and increases its floatability. The flotation experiments and contact angle measurements indicated that the selective depression effect of sodium carbonate on the calcite mineral is more than that of calcium chloride. As evidenced by zeta potential and FT-IR analysis, sodium carbonate decreases the negative charges on the surface of calcite mineral and subsequently reduces the adsorption of DDA collector through electrostatic forces. At a pH of 7.5, using 2000 g/t DDA and 1500 g/t sodium carbonate, a pyrolusite concentrate containing almost 40% MnO with 71.5% recovery is achieved by carrying out the ore flotation experiments on the tabling pre-concentrate.     

六偏磷酸钠在硫化铜镍矿浮选中的分散机理

通过浮选实验、沉降实验、Zeta电位测试、红外光谱测试和显微镜下观测考察六偏磷酸钠在硫化铜镍矿浮选中的作用,研究六偏磷酸钠的分散作用机理。人工混合矿实验结果表明:镍黄铁矿易与蛇纹石发生异相凝聚,降低镍黄铁矿的浮选回收率;六偏磷酸钠能提高人工混合矿的分散性,实现镍黄铁矿与蛇纹石的浮选分离。硫化铜镍矿实际矿石浮选结果表明:六偏磷酸钠能较好地分散矿浆,当原矿镍品位为0.33%时,通过两次粗选就能得到合格的镍精矿产品,镍总回收率为80.27%。作用机理研究表明:六偏磷酸钠通过化学吸附以及溶出蛇纹石表面的镁离子两种方式调整蛇纹石的表面电性,进而分散镍黄铁矿与蛇纹石。     

Adsorption effect mechanism of sodium oleate on feldspar and quartz

ＡＤＳＯＲＰＴＩＯＮＥＦＦＥＣＴＭＥＣＨＡＮＩＳＭＯＦＳＯＤＩＵＭＯＬＥＡＴＥＯＮＦＥＬＤＳＰＡＲＡＮＤＱＵＡＲＴＺＬｉｕ，Ｙａｃｈｕａｎ；Ｇｏｎｇ，Ｈｕａｎｇａｏ（ＭｉｎｅｒａｌＥｎｇｉｎｅｅｒｉｎｇＤｅｐａｒｔｍｅｎｔ，ＮｏｒｔｈｅａｓｔｅｎＵｎ...