新型捕收剂N—十二烷基—1，3—丙二胺浮选铝硅酸盐类矿物的机理

以十二胺和丙烯腈为原料,常压下合成了阳离子捕收剂N-十二烷基-1,3-丙二胺(DN12),考察了其对高岭石、叶蜡石、伊利石的浮选行为.结果表明DN12的捕收性能优于十二胺;DN12的浓度为3×10-4mol@L-1时,对3种铝硅酸盐矿物的浮选回收率均超过80%,对3种铝硅酸盐矿物的捕收能力顺序为高岭石＞叶蜡石＞伊利石;浮选pH范围为5～8.动电位和红外光谱说明DN12与铝硅酸盐类矿物形成了氢键并产生静电吸附,且作用较强.     

十二烷基胍对铝硅矿物的浮选分离

采用含有胍基的长碳链季铵盐作捕收剂,研究-水硬铝石、高岭石、叶腊石和伊利石单矿物的浮选行为、铝硅人工混合矿样的浮选分离以及河南铝土矿的精选.结果表明:在捕收剂用量为2×10-4mol/L条件下,在广泛的pH范围内,十二烷基胍对硅酸盐矿物具有较好的捕收能力,平均浮选回收率可达80%;强碱性条件下,一水硬铝石的浮选回收率从80%急剧下降至20%,与高岭石、叶腊石和伊利石之间形成较大差异:以十二烷基胍为捕收剂可望实现铝硅矿物反浮选分离:实际铝土矿(原矿铝硅比为5.70)经过反浮选脱硅,精矿铝硅比达11.08,铝浮选回收率为75%;与传统的阳离子捕收剂十二胺相比,胍类阳离子捕收剂对硅酸盐矿物浮选能力强、受pH的影响小,是一种新型高效的铝硅矿物浮选分离捕收剂.     

新型季铵盐捕收剂对白钨矿和方解石的常温浮选分离

采用二辛基二甲基溴化铵(DDAB)作捕收剂,研究白钨矿、方解石单矿物的浮选行为和其人工混合矿的浮选分离以及柿竹园白钨矿的常温精选。结果表明:在单矿物和人工混合矿的浮选中,DDAB在对白钨矿的捕收能力和选择性上均显著优于油酸,其最佳的浮选pH值范围为8~10;在对柿竹园白钨矿的常温精选中,DDAB取得了开路最终浮选精矿WO3品位51.63%,回收率43.83%的良好指标。这些都证明DDAB是一种新型高效的白钨矿常温精选捕收剂。通过对白钨矿和方解石的表面动电位分析、DDAB的结构分析以及DDAB与白钨矿作用的红外光谱分析和量子化学分析,推断DDAB主要依靠静电力与白钨矿表面作用。     

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。     

捕收剂的分子设计与绿色合成

捕收剂是矿物浮选分离过程中必不可少的药剂,研究捕收剂的分子设计与绿色合成对于提高浮选技术水平具有重要意义。综述近年来中南大学钟宏教授课题组在捕收剂的分子设计、绿色合成与浮选机理研究方面的系列成果。研究开发溶剂法合成黄原酸盐等硫化矿捕收剂的绿色合成技术,提高合成效率,改善生产环境。设计并合成异丁基黄原酸苯甲酰基酯等多种新型硫化矿捕收剂、Gemini双季铵盐等多种新型非硫化矿捕收剂及N,N-二丁基二硫代氨基甲酸乙羟肟酸等硫化?氧化矿双功能捕收剂,此外还研究选矿药剂之间的组合用药。     

烷基羟肟酸对细粒锡石的浮选及其溶液化学性质(英文)

采用烷基羟肟酸作为捕收剂对细粒锡石进行浮选,并对其溶液化学性质进行研究。结果表明,3种烷基羟肟酸在碱性条件下对细粒锡石有较好的捕收能力,且适宜的浮选pH随着捕收剂碳链的加长而升高。金属离子对锡石浮选的影响主要由矿浆pH决定,金属离子浓度对锡石浮选也有影响。计算基团电负性得出烷基羟肟酸作为锡石捕收剂的适合烷基碳链长度大约为7。由溶液的组分浓度对数分布图(lgc—pH)分析可知,捕收剂以分子-离子共吸附模式作用于矿物表面。动电位测试及红外光谱分析表明,吸附反应中涉及到电荷作用力、氢键力和络合作用力,其最终产物可以表示为锡石的O,O-五元环结构的螯合物。     

直链烷基胺浮选铝硅矿物机理

研究了一水硬铝石和高岭石、叶蜡石及伊利石等几种含铝硅酸盐矿物在不同pH条件下的动电行为与浮选行为。一水硬铝石、高岭石、叶蜡石及伊利石的等电点（IEP）分别为pH6．2,4．3,2．0,3．4。在pH＞IEP时,烷基胺类阳离子捕收剂主要以静电作用吸附在一水硬铝石矿物表面,其浮选高岭石等3种铝硅酸盐矿物的可浮性大小顺序是叶蜡石＞高岭石＞伊利石。高岭石、叶蜡石和伊利石均是层状硅酸盐矿物,其破碎磨细时,将沿层间断裂,由于晶体结构的原因其层面荷负电荷。烷基胺类阳离子捕收剂以静电作用力吸附于铝硅酸盐矿物表面的层面使矿物疏水上浮。     

氯化钠对铝硅矿物浮选的影响及其作用机理

采用季铵盐DTAL作捕收剂,研究了氯化钠对一水硬铝石和叶蜡石浮选的影响及其作用机理.随着氯化钠浓度的增加,叶蜡石的浮选回收率显著提高,而一水硬铝石的可浮性受其影响很小.机理研究表明:氯化钠对一水硬铝石的zeta-电位没有影响,而能显著降低叶蜡石的zeta-电位,增强捕收剂与叶腊石的静电作用,促进捕收剂的吸附而活化其浮选;叶蜡石表面电位的降低是因为氯离子对叶蜡石存在选择性吸附作用并对其结构进行插层,使得叶蜡石的层间距从0.93 nm增大至1.40 nm.溶液化学计算表明:氯化钠改变溶液的离子强度,显著降低了季铵盐阳离子表面活性剂的临界胶束浓度,使得吸附了捕收剂的矿物表面更容易疏水上浮.     

1-羟基-2-甲基-2-烯辛基膦酸对锡石的浮选行为及吸附机理（英文）

采用纯矿物浮选实验、动电位测试、红外光谱检测以及密度泛函理论计算研究了1-羟基-2-甲基-2-烯辛基膦酸(HEPA)对锡石的浮选行为及吸附机理。浮选实验结果表明,相比苯乙烯膦酸(SPA),HEPA具有出更强的捕收性能。当HEPA浓度为50mg/L时,在pH2-9范围内锡石回收率都保持在90%以上。动电位测试和红外光谱检测结果表明,HEPA在锡石表面的吸附主要是通过HEPA单阴离子与锡石表面的锡原子形成化学吸附。密度泛函计算结果表明,HEPA单阴离子比SPA单阴离子具有更高的HOMO能量和对锡石更强的吸附力,这为浮选实验和动电位测试中HEPA的更强捕收力提供了有力证明。     

盐酸溶液中阳离子Gemini表面活性剂在碳钢表面的吸附与缓蚀性能研究

 合成并用元素分析和核磁共振(1H-NMR)表征了阳离子Gemini表面活性剂1,2-双亚甲基-双(十烷基二甲基溴化铵)和1,2-双亚甲基-双(十二烷基二甲基溴化铵)(分别简写为10-2-10和12-2-12)，并用失重法研究了1M盐酸溶液中该类表面活性剂在碳钢表面的吸附行为及其缓蚀性能.实验结果表明，其缓蚀机理为表面活性剂在钢铁表面的吸附形成单分子膜，从而阻碍了盐酸对钢铁的侵蚀，其缓蚀效率随着表面活性剂浓度的增加而增加，当表面活性剂浓度接近其临界胶束浓度时达到最大，理论计算表明，在研究的浓度范围内，盐酸溶液中该类Gemini表面活性剂在碳钢表面的吸附行为符合Langmuir吸附等温式.      

Comparative studies on flotation of illite, pyrophyllite and kaolinite with Gemini and conventional cationic surfactants

To search a novel class of effective silicate mineral collectors, the Gemini quaternary ammonium salt surfactant (butane-α, ω-bis(dimethyl dodeculammonium bromide), 12-4-12) and its corresponding conventional monomeric surfactant (dedecyl trimethyl ammonium bromide, DTAB) were adopted to comparatively study the flotation behaviors of illite, pyrophyllite and kaolinite. Three silicate minerals with the Gemini surfactant as collector reveal floatability far better than with the corresponding traditional one. At pH 6, the best recoveries of illite, pyrophyllite and kaolinite with 3.5×10-4 mol/L 12-4-12 are 99.2%, 91.7% and 99.6%, respectively. The fluorescence and contact angle measurement were also conducted for the further investigation of surfactants aggregation behavior and silicate mineral surface hydrophobic properties. FTIR spectra analysis and electrokinetic analysis show that the mechanism of adsorption of collector molecules on mineral surfaces is almost identical for the electronic attraction and hydrogen bonds effect. The superior collecting power of dimeric collector may be attributed primarily to its special structure and its essential properties.     

Flotation techniques for separation of diaspore from bauxite using Gemini collector and starch depressant

The floatability of diaspore and three kinds of silicate minerals,including kaolinite,illite and pyrophyllite,by a cationic Gemini surfactant as collector and starch as depressant was investigated as function of reagents concentration and pulp pH.Further studies of artificially mixed minerals and bauxite ore were also detailedly conducted.At last,the pre-desliming reverse flotation separation process was adopted.It can be concluded that the combinational use of a Gemini cationic collector and the starch dep...     

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.     

2,3-二羟基丙基二硫代碳酸钠对铜铅硫化矿可浮性的影响

在丁铵黑药浮选体系中,研究含有—OH和—CSS—的2,3-二羟基丙基二硫代碳酸钠（SGX）对黄铜矿和方铅矿的抑制效果,并通过动电位和吸附量的测试,探讨抑制剂SGX与矿物的相互作用机理。浮选试验研究结果表明：在整个p H范围内,抑制剂SGX对黄铜矿有活化作用,而对方铅矿有很强的抑制作用。随着抑制剂SGX用量的增加,方铅矿的回收率迅速下降,而黄铜矿的回收率有小幅度的升高。在矿浆p H为6的条件下,人工混合矿浮选得出的精矿中铜的品位和回收率分别为29.52%和82.15%。通过动电位和吸附量的测试结果可知,抑制剂SGX在方铅矿表面有较强的吸附,而在黄铜矿表面吸附很弱。     

H2S/CO2环境中Gemini表面活性剂对L360钢的缓蚀性能

采用静态失重法、动电位极化法和电化学阻抗法研究了三种Gemini表面活性剂12-2-12,16-2-16和18-2-18在H2S/CO2环境中对L360钢的缓蚀性能,并探讨了缓蚀机理.研究表明,在本试验条件下,三种表面活性剂均表现出一定的缓蚀性能,其中,12-2-12效果最优,16-2-16其次,18-2-18缓蚀效果...     

Swelling of clay minerals in ammonium leaching of weathered crust elution-deposited rare earth ores

The effect of hydrated radius, cation valence, pH and solution concentration on the zeta potential of clay minerals was investigated, and the relation between zeta potential of clay minerals and swelling was discussed in different leaching agents as well. The results show that the zeta potential of clay minerals decreases with the hydrated ionic radius increasing. It could be seen that the zeta potential of the clay minerals in AICl_3 solution is positive,whereas that in NH_4C1, KCl and MgCl_2 solution is negative. And the zeta potential of clay minerals increases with the cation valence increasing. Moreover, the zeta potential of clay minerals decreases with the solution pH increasing,whereas that increases with the solution concentration increasing in different ammonium solutions. In addition,the swelling of clay minerals decreases while the zeta potential of clay minerals increasing in different ammonium solutions. The ability of compound ammonium to inhibit the swelling of clay minerals is lower than that of single ammonium solution.     

Adsorption mechanism of styryl phosphonate ester as collector in ilmenite flotation

A styryl phosphonate ester (SPE) collector was used to improve the flotation performance of ilmenite, and the adsorption mechanism and model were revealed and established, respectively. Microflotation tests showed that SPE exhibited a stronger collecting ability for ilmenite than the traditional collector styrene phosphonic acid (SPA). Zeta potential measurements revealed that both SPE and SPA could negatively shift the zeta potential of ilmenite, while SPE had more effects than SPA, suggesting the stronger adsorption of SPE. The analysis of X-ray photoelectron spectroscopy confirmed the chemisorption of SPA and SPE onto the Fe/Ti sites of ilmenite. According to frontier orbital theory, the chemical activities of SPE are greater than those of SPA. The partial densities of states analysis indicated that the PO—H groups of the collectors could interact with the Ti/Fe atoms of the ilmenite surface to generate a stable four-membered ring. The bonding model of the collector and (104) ilmenite surface showed that the adsorption energy of SPE was higher than that of SPA. Overall, SPE presented a better collecting ability and interaction effect for ilmenite flotation than SPA, and had the potential to replace SPA in the industry.     

硅酸钠对5083铝合金点蚀性能的影响研究

通过循环阳极极化曲线、电化学阻抗谱的测试以及浸泡腐蚀试验,研究了硅酸钠对5083铝合金在3.5%氯化钠溶液中的点蚀性能的影响。极化曲线结果表明,硅酸钠的加入使得5083铝合金在3.5%氯化钠溶液中的点蚀电位正移。通过EIS试验和浸泡腐蚀试验可进一步得出:体系中硅酸钠水解使得溶液中OH-浓度增加,铝合金表面钝化膜和Al2(SiO3)3沉淀膜增厚,从而较好地抑制了铝合金表面的点蚀,基体得到保护。