Effect of sodium alginate on reverse flotation of hematite and its mechanism

Given the gradual increase in the chlorite content of hematite ores, pulp properties seriously deteriorate during flotation. The traditional anion reverse flotation of hematite cannot effectively eliminate the effects of chlorite, leading to a significant decrease in the total Fe(TFe) grade of the concentrate. In this work, the effect of sodium alginate on the reverse flotation of hematite was systematically investigated. Flotation tests of artificially mixed ores were conducted, and the results showed that sodium alginate can significantly improve the removal rates of quartz and chlorite. The adsorption measurements, infrared spectroscopy, and contact angle tests demonstrated that sodium alginate adsorbs on the quartz surface by chelating with calcium ions, thereby weakening the steric hindrance of oleate ions and increasing the adsorption capacity of sodium oleate to ultimately improve the removal rate of quartz. Furthermore, owing to its lower density and fine particle size, chlorite is easily entrained into the foam layer. Sodium alginate dramatically increases the liquid-to-gas ratio of the foam layer by increasing pulp viscosity, thereby increasing the entrainment rate of chlorite and finally improving its removal rate. The core content of this thesis bears significance in improving the Fe grade in the reverse flotation of chlorite-containing hematite.

Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate

To identify and establish beneficiation techniques for banded hematite quartzite （BHQ） iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.

Optimization of flotation variables for the recovery of hematite particles from BHQ ore

The technology for beneficiation of banded iron ores containing low iron value is a challenging task due to increasing demand of quality iron ore in India. A flotation process has been developed to treat one such ore, namely banded hematite quartzite （BHQ） containing 41.8wt% Fe and 41.5wt% SiO2,by using oleic acid, methyl isobutyl carbinol （MIBC）, and sodium silicate as the collector, frother, and dispersant, respectively. The relative effects of these variables have been evaluated in half-normal plots and Pareto charts using central composite rotatable design. A quadratic response model has been developed for both Fe grade and recovery and optimized within the experimental range. The optimum reagent dosages are found to be as follows： collector concentration of 243.58 g/t, dispersant concentration of 195.67 g/t, pH 8.69, and conditioning time of 4.8 min to achieve the maximum Fe grade of 64.25% with 67.33% recovery. The predictions of the model with regard to iron grade and recovery are in good agreement with the experimental results.

Effect and mechanism of siderite on reverse flotation of hematite

The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between siderite and quartz are the main reasons that siderite significantly influences the floatability. The interactions are attributed to dissolved siderite species and fine siderite particles. The interaction due to the dissolved species is, however, dominant. Derjaguin-Landau-Verwey-Overbeek（DLVO） theoretical calculations reveal that adhesion on quartz increases when the siderite particle size decreases and that fine particles partly influence quartz floatability. Chemical solution calculations indicate that the dissolved species of siderite might convert the surface of active quartz to CaCO_3 precipitates that can be depressed by starch. The theoretical calculations are in good agreement with the results of adsorption tests and FTIR spectroscopy and explain the reasons why siderite significantly influences reverse flotation of hematite.

Possibility of using strain F9(Serratia marcescens) as a bio-collector for hematite flotation

In this study, we characterized strain F9 and evaluated the interaction between strain F9 and hematite by scanning electron microscopy（SEM）, Fourier transform infrared spectrophotometry（FTIR）, zeta potential, flotation, and other methods. The results showed that strain F9 belongs to Serratia marcescens. This brevibacterium had CH2, CH3, and hydroxyl groups on its cell wall, which imparted a strong hydrophobic and negative charge. Adsorption of strain F9 reduced the zeta potential of the hematite surface and increased the hydrophobicity of the hematite surface, thereby generating hydrophobic hematite agglomerates. At least four groups on strain F9 interacted with the hematite surface, which contributed to chemical interactions of carboxylic groups and hydrophobic association among hydrophobic hematite particles. The possible use of strain F9 as a bio-collector for hematite flotation was proved.

Improved flotation performance of hematite fines using citric acid as a dispersant

In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy（SEM）, zeta-potential measurements, and X-ray photoelectron spectroscopy（XPS）. The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid（less than 300 g/t） favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.

Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

The effects of carbonate minerals（dolomite and siderite） on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared（FTIR） spectroscopic studies, and X-ray photoelectron spectroscopy（XPS） analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations（Ca^（2＋） and Mg^（2＋）） and CO_3^（2＋）ions dissolved from dolomite depressed hematite flotation, whereas only the 23CO-ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca^（2＋）, Mg^（2＋）, and CO_3^（2-）（HCO_3^-） could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.

Effect and mechanism of siderite on reverse anionic flotation of quartz from hematite

Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry(UV) and Fourier transform infrared spectroscopy(FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO^(2-)_3 from siderite dissolution and Ca^(2+) from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.

Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers

Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the reactions of chemical-looping gasification (CLG) of biomass with natural hematite (Fe2O3) as oxygen carrier were analyzed using commercial software of HSC Chemistry 5.1. The feasibility of the CLG of biomass with hematite was experimental verified in a lab-scale bubbling fluidized bed reactor using argon as fluidizing gas. It was indicated the experimental results were consistent with the theoretical analysis. The presence of oxygen carrier gave a significant effect on the biomass conversion and improved the synthesis gas yield obviously. It was observed that the gas content of CO and H2 was over 70% in CLG of biomass. The reduced hematite particles mainly existed in form of FeO. It was showed that the reduction of natural hematite with biomass proceeds in a stepwise manner from Fe2O3 →Fe3O4→ FeO. Reduction product of natural hematite can be restored the lattice oxygen by oxidation with air.

Adsorption mechanism of N-laurel-1,3-diaminopropane in a hematite-quartz flotation system

关于石英的 N-laurel-1,3-diaminopropane (ND13 ) 的强壮的收集表演鼓励了我们在实验室房间筹款测试学习它赤铁矿和石英混合物的分离。当肉 pH 是加 6.67 mg/L 镇静剂的 7.27 和 58.3 mg/L 收集者时，最好的分离结果的结果表演能被完成被加到混合。当到石英的赤铁矿的集体比率是 2:3， 1:1，和 3:2 时，有 58.45% ， 62.78% 和 63.72% 铁等级的产品能分别地被完成。石英表面上的 ND13 的吸附机制被希腊语的第六个字母潜力和 X 光检查光电子光谱学大小调查。结果揭示那静电并且氢结合吸附发生在之间 ND13 和石英表面，和那 ND13 主要在石英表面上与氧原子交往。

BEHAVIOUR OF α-NITROSO-β-NAPHTHOL IN HEMATITE FLOTATION

Based on theoretical calculation of electronegativity of groups of flotation reagent and method of infrared adsorption spectroscopy,the collection and adsorption of α-nitroso-β- naphthol in hematite flotation have been studied.The chemical adsorption seems to be predominant owing to formation of pentacyclic nitrosyl chelate compound by atoms of nitrosyl bond in α-nitroso-β-naphthol together with Fe(Ⅲ)on hematite surface.Mean- while,the nonuniform multilayer physical adsorption is also occurred.

FLOTATION MECHANISM OF FLUORITE AND HEMATITE WITH SODIUM NAPHTHENE SULFONATE

ＦＬＯＴＡＴＩＯＮＭＥＣＨＡＮＩＳＭＯＦＦＬＵＯＲＩＴＥＡＮＤＨＥＭＡＴＩＴＥＷＩＴＨＳＯＤＩＵＭＮＡＰＨＴＨＥＮＥＳＵＬＦＯＮＡＴＥ￥Ｇｅ，Ｙｉｎｇｙｏｎｇ；Ｑｕｅ，Ｘｕａｎｌａｎ（ＣｈａｎｇｓｈａＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＭｉｎｉｎｇ...

CARRIER FLOTATION OF ULTRAFINE PARTICLE WOLFRAMITE

ＣＡＲＲＩＥＲＦＬＯＴＡＴＩＯＮＯＦＵＬＴＲＡＦＩＮＥＰＡＲＴＩＣＬＥＷＯＬＦＲＡＭＩＴＥ￥Ｈｕ，Ｙｕｅｈｕａ；Ｑｉｕ，Ｇｕａｎｚｈｏｕ；Ｌｕｏ，Ｌｉｎ；Ｘｕ，Ｊｉｎ；Ｗａｎｇ，Ｄｉａｎｚｕｏ（ＭｉｎｅｒａｌＥｎｇｉｎｅｅｒｉｎｇＤｅｐａｒｔｍｅｎｔ...

Adsorbability of Mycobacterium phlei on hematite surface

The adsorption of microorganisms on the mineral surface is the base of microorganisms that are considered as mineral processing reagents. The principles of the use of a highly hydrophobic and negatively charged bacterium, Mycobacterium phlei, as a flocculating-flotating agent for finely divided hematite were investigated. The flocculating-floating recovery is strongly dependent on the pH and the dosage of the bacterium. Generally the pH should be controlled over the range of 5.5-7, and the dosage should be controlled about 16 mg/L. The infrared spectrometry analysis indicates that the six functional groups of M. phlei, substituted aromatic compound groups, -（CH2） n-groups, -CH2（-CH3） groups, carbonyl groups, aromatic hydrocarbon groups, and carboxyl groups, are on the hematite surface, among which the first five ones contribute physical adsorption and only the carboxyl groups provide chemisorption. Microscopic analysis reveals that the dimensions and tight aggregation degree of the flocs of hematite particles formed by M. phlei are also impacted by the pH and the content of M. phlei in flotation.

Biomass chemical looping gasification for syngas production using modified hematite as oxygen carriers

Syngas is a clean energy carrier and a major industrial feedstock. In this paper, syngas was produced via biomass chemical looping gasification(CLG) process. Hematite, the most common Fe-based oxygen carrier(OC), was modified with different metal oxides(CeO_(2), CaO and MgO) by the impregnation method. The hematite modified by CeO_(2), CaO and MgO was namely as CeO_(2)-hematite(CeO_(2)-H), CaO-hematite(CaO-H) and MgO-hematite(MgO-H), respectively. The introduction of CeO_(2), CaO and MgO enhanced the reactivity of lattice oxygen of hematite. The optimum condition for syngas production had been explored as the mass ratio of oxygen carrier to biomass(O/B) of 0.2, the mass ratio of steam to biomass(S/B) of0.75 and temperature of 800℃in the biomass CLG process. The CeO_(2)-H exhibited the most wonderful performance compared to that for CaO-H and MgO-H. The crystal composition of OC influenced greatly in the CLG process. CeFeO_(3)had a good oxygen mobility property and lattice oxygen releasing capacity due to the most oxygen vacancy distributed on the OC surface and the most active lattice oxygen, which is conducive to the biomass chemical looping gasification process for syngas production, leading to the highest gasification efficiency of 95.86% and gas yield of 1.20 m^(3)/kg of the three. Cyclic test proved that CeO_(2)-H had well sintering resistance and cyclic performance.

准东煤半焦赤铁矿载氧体化学链燃烧及碱(土)金属迁移特性

准东煤在常规燃烧利用过程中出现严重的积灰结渣和CO_(2)排放等问题,极大地限制了其低碳清洁高效利用。采用中低温热解低阶煤生产半焦、焦油和热解气是煤炭分质分级利用的龙头技术,准东高碱煤热解半焦气化活性高,采用化学链燃烧方式有利于实现其低碳清洁高效转化。以CO_(2)为气化介质,赤铁矿石为载氧体,在固定床上开展准东煤半焦原位气化化学链燃烧特性研究,并探究了准东煤半焦中碱(土)金属(AAEMs)的迁移转化规律。研究表明,赤铁矿载氧体能够显著提高固定床反应器出口烟气中CO_(2)体积分数,然而随着载氧体与半焦质量比(mOC/mC)不断增加,CO_(2)体积分数先急剧增加而后趋于不变,最佳的mOC/mC为50:1,而700℃热解制取的准东煤半焦经酸洗脱灰处理后固定床反应器出口相应烟气中CO_(2)的选择性降低了8.95%,这表明准东煤半焦中具有催化活性的AAEMs显著影响其化学链燃烧性能。赤铁矿载氧体对准东煤半焦表面AAEMs的分布也有显著影响,与未加入时相比,Na、K元素在半焦表面呈现较为明显的团簇富集,Ca、Mg元素在空间分布上呈更为明显的依赖关系。采用原位气化化学链燃烧方式后准东煤半焦中的AAEMs向赤铁矿载氧体中发生迁移与转化,并生成霞石(NaAlSiO_(4))、钾长石(KAlSi_(3)O_(8))、钙铝黄长石(Ca_(2)Al_(2)SiO_(7))、镁橄榄石(Mg_(2)SiO_(4))等高熔点矿物质,有效抑制了准东煤半焦中AAEMs向气相的挥发。

阴离子捕收剂与DTAC浮选分离赤铁矿和石英研究

以赤铁矿和石英两种纯矿物为研究对象,研究了阴离子捕收剂与十二烷基三甲基氯化铵(DTAC)组合使用对浮选分离赤铁矿和石英的影响,其中阴离子捕收剂分别为十二烷基磺酸钠(SDS)、十二烷基苯磺酸钠(SDBS)、油酸钠(NaOL)和十二烷基硫酸钠(SLS)。结果表明,与单一DTAC捕收剂相比,SDS或SLS与DTAC组合使用时,精矿Fe品位和Fe回收率明显提高,但捕收剂总用量较大。与单一DTAC相比,当SDBS与DTAC组合使用(质量比1∶2)时,在相同的浮选条件下,即捕收剂用量为20 mg/L,pH值为7,淀粉用量为20 mg/L,获得的精矿Fe品位相近,Fe回收率由81.44%提至85.96%。这为赤铁矿反浮选提供了一定的参考价值。

阴阳离子组合捕收剂对微细粒赤铁矿与石英浮选分离的研究

考察了十二烷基磺酸钠(SDS)、十二烷基硫酸钠(SLS)、十二烷基苯磺酸钠(SDBS)以及油酸钠(NaOL)四种阴离子捕收剂分别与阳离子捕收剂十二胺(DDA)组合对浮选分离微细粒(-18μm)赤铁矿和石英的影响。单矿物实验表明,与单一DDA相比,四种阴离子捕收剂分别与DDA组合使用能够降低赤铁矿的浮选回收率,有利于减少赤铁矿的抑制剂用量。十二胺与阴离子捕收剂组合使用时,四种阴离子捕收剂对微细粒赤铁矿和石英分离效果为:SDS>NaOL>SLS/SDBS。其中,DDA+SDS组合捕收剂在一定质量比例条件下组合使用的效果最优,在最佳浮选条件下(pH=7,捕收剂用量为20 mg/L,m(DDA)∶m(SDS)=2∶1,抑制剂用量为20 mg/L),泡沫产品中石英回收率达到91.05%,赤铁矿回收率仅为6.7%,有利于赤铁矿反浮选。人工混合矿物浮选实验结果表明,使用DDA+SDS组合捕收剂(m(DDA)∶m(SDS)=2∶1)获得精矿Fe品位为45.7%、回收率为87.0%,与单一DDA相比,分别提高了1.7、18.6百分点,有利于提高赤铁矿和石英的分离效果,DDA+SDS可作为微细粒赤铁矿和石英浮选分离的优良阴阳离子捕收剂。

某铁选厂尾矿中赤铁矿回收试验研究

为了回收利用某铁选厂尾矿中的赤铁矿资源,针对该尾矿特点,在详细的矿石性质研究的基础上,进行了不同选矿工艺的对比试验,试验确定强磁选—再磨—强磁选—浮选流程为最佳选铁工艺。试验结果表明:铁品位12.62%的矿样在最佳试验条件下,最终获得了铁品位60.01%、铁回收率23.62%的满意铁精矿指标,实现了对铁选厂尾矿中赤铁矿的有效回收。

江西某微细粒选钨尾砂回收铜资源试验研究

钨矿开采导致选钨尾砂长期堆存会产生社会安全和生态环境问题,开展选钨尾砂资源回收利用具有重要现实意义。江西某钨选厂开采钨矿预计产生选钨尾砂超9万t,对选厂现场尾砂和堆存尾砂采用一粗一扫两精浮选流程回收铜资源,针对选钨尾砂,进行了酯类药剂用量、捕收剂种类、捕收剂用量等条件试验,在此基础上进行了闭路试验。结果表明,现场尾砂可获得铜品位为21.145%、回收率为65.970%的铜精矿,堆存尾砂仅获得铜品位为12.512%、回收率为12.099%的铜精矿;以现场尾砂作为载体介质,对堆存尾砂进行载体浮选试验研究,最终获得铜品位13.520%、回收率49.123%的铜精矿。该工艺流程简单可行,选矿指标良好,可为选厂解决选钨尾砂长期堆存的问题,提高选厂经济效益。