Surface Of Diaspore Research Articles

Molecular dynamics study of the effect of temperature on the flotation behavior of sodium oleate on the surface of diaspore

The effect of temperature on the flotation behavior of sodium oleate on the surface of diaspore was investigated by using molecular dynamics (MD) simulations at three selected temperatures of 278.15 K, 303.15 K and 328.15 K. Conformational analysis, RDF analysis, hydrogen bonds statistics, SASA calculations and interaction energy analysis revealed that a certain range of temperature increase was beneficial for flotation, and the right temperature could yield better reagent dispersion and better mineral-reagent interactions. It was also noted that the enhanced molecular motion due to increased temperature may negatively affect the adsorption of the reagent on the mineral surface. The present study has theoretical implications for the effect of temperature on the flotation behavior of ionic surfactants on mineral surfaces.

Low-Temperature Flotation Separation of Diaspore from Kaolinite by Using a Mixed Collector

In this paper, the effect of a new mixed collector sodium oleate (NaOl)/tert dodecyl mercaptan (TDM) on the separation of diaspore and kaolinite at 283 K was investigated. The molar ratio of NaOl to TDM is 8:2. The properties of the mixed collector and its adsorption mechanism on diaspore and kaolinite were studied by surface tension measurements, Zeta potential determinations and XPS analysis. The flotation results show that the mixed collector NaOl/TDM has a good collection ability for diaspore and a good selectivity for kaolinite at low temperatures. Therefore, the mixed collector NaOl/TDM can effectively separate diaspore and kaolinite under alkaline conditions at 283 K. The results of surface tension measurements show that the molecular density, hydrophobic association ability and collection ability of the mixed collector NaOl/TDM are better than those of the single collector at 283 K. In addition, the formation of a micelle effect of the mixed collector NaOl/TDM has a synergistic effect, which improves the reagent activity at low temperatures with the flotation effect enhanced. The results of the Zeta potential determinations and XPS analysis show that the total adsorption capacity of the mixed collector NaOl/TDM on the surface of the diaspore at low temperatures is higher than that of NaOl, and the adsorption capacity on the surface of kaolinite is similar to that of NaOl. The mixed collector NaOl/TDM may be adsorbed on the surface of diaspore and kaolinite by a hydrogen bond at 283 K.

Effect and mechanism of quaternary ammonium salt ionic liquid as a collector on desulfurization and desilication from artificial mixed bauxite using flotation

An quaternary ammonium ionic liquid (1401) was synthesized through tetradecyl dimethyl benzyl ammonium chloride and sodium isobutyl xanthate. Firstly, it was used as a flotation collector for reverse flotation of silicates and sulfur from diaspore-type high-sulfur and high silicon bauxite. Results demonstrated that maximum Al2O3 recovery of 50.8% were achieved, the sulfur content and the ratio of A/S were 0.65% and 3.24. The results showed the 1401 has a stronger collecting ability and selectivity for diaspore compared with dodecyl trimethyl ammonium chloride and N-butyl xanthate. The adsorption mechanism of 1401 on the surface of diaspore, kaolinite and pyrite was studied by Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS) analysis. Results indicated that physical adsorption was occurred between the 1401 and the surface of diaspore, kaolinite, and the adsorption amount on the surface of kaolinite is much greater than that of diaspore. And the chemisorption between the 1401 and pyrite was occurred and suggested that 1401 was preferred to adsorb on the surface of diaspore and pyrite. These results indicate that the quaternary ammonium ionic liquid 1401 can be used as the collector for reverse flotation of diaspore, providing new ideas for the utilization of bauxite.

QM/MM Molecular Dynamics Investigation of the Binding of Organic Phosphates to the 100 Diaspore Surface

The fate of phosphorus (P) in the eco-system is strongly affected by the interaction of phosphates with soil components and especially reactive soil mineral surfaces. As a consequence, P immobilization could occur which eventually leads to P inefficiency and thus unavailability to plants with strong implications on the global food system. A molecular level understanding of the mechanisms of the P binding to soil mineral surfaces could be a key for the development of novel strategies for more efficient P application. Much experimental work has been done to understand P binding to several reactive and abundant minerals especially goethite (a-FeOOH). On the other hand, atomistic modeling of the P-mineral molecular systems using molecular dynamics (MD) simulations is emerging as a new tool which provides more detailed information regarding the mechanisms, nature, and strength of these binding processes. The present study characterize the binding of the most abundant organic phosphates in forest soils, inositol hexaphosphate (IHP) and glycerolphosphate (GP), to the 100 diaspore (a-AlOOH) surface plane. Here, different molecular models have been introduced to simulate typical situations for the P-binding at the diaspore/water interface. For all models, quantum mechanics/molecular mechanics (QM/MM) based MD simulations have been performed to explore the diaspore–IHP/GP–water interactions. The results provide evidence for the formation of monodentate (M) and bidentate (B) motifs for GP and M and as well as two monodentate (2M) motifs for IHP with the surface. The calculated interaction energies suggest that GP and IHP prefer to form the B and 2M motif, respectively. Moreover, IHP exhibited stronger binding than GP with diaspore and water. Further, the role of water in controlling binding strengths via promoting of specific binding motifs, formation of H-bonds, adsorption and dissociation at the surface, as well as proton transfer processes is demonstrated. Finally, the P-binding at the 100 diaspore surface plane is weaker than that at the 010 plane highlighting the influential role of the coordination number of Al atoms at the top surface of diaspore.

The role of bulk micro-nanobubbles in reagent desorption and potential implication in flotation separation of highly hydrophobized minerals.

Micro-nanobubbles (MNBs) generated during hydrodynamic cavitation (HC) have been extensively studied in mineral processing field in the past two decades. Many researchers have claimed that MNBs can effectively promote the collection of fine particles in flotation, while studies on MNBs assisted mineral separation are rare. In this study, the role of bulk MNBs in desorbing flotation reagent was investigated, with the aim of illustrating the potential effects of MNBs on minerals separation. The results showed that bulk MNBs could efficiently remove the sodium oleate (NaOl) from diaspore surfaces, reducing the residual concentration of NaOl on solids, which was more significant when the amount of NaOl pre-adsorbed was relatively small. Furthermore, lower residual concentration of NaOl on solids caused by MNBs cleaning made the particles less hydrophobic and flocs more friable. Given that gangue entrapment in flocs was one of the main limits for high-selective flotation, the roles of MNBs in enhancing reagent desorption and associated flocs breakup and reorganization probably contribute to higher separation efficiency of different minerals, which was confirmed by the flotation results of diaspore/kaolinite mixture.

Effects of Fine Minerals on Pulp Rheology and the Flotation of Diaspore and Pyrite Mixed Ores

In this study, the effects of four fine minerals, which were fine diaspore (FDIA), kaolinite, illite, and pyrophyllite (D50 is about 4.55 μm, D80 is about 10.78 μm), on the pulp rheology of the diaspore and pyrite mixed ores (D50 is about 120.53 μm, D80 is about 187.36 μm) and the recovery of pyrite were investigated through flotation tests, pulp rheology measurements, and sedimentation tests. It was found that fine minerals could change the pulp rheology and affect the pyrite recovery. The apparent viscosity of the mixed ores slurry increased with the addition of FDIA, kaolinite, and illite and the pyrite recovery decreased in varying degrees. When the addition was 15 wt.%, the recovery of pyrite decreased from 92.3% to 60.8%, 81.4%, and 84.7%, respectively. The addition of pyrophyllite had a significant deteriorating effect on flotation. When the addition of pyrophyllite was 5 wt.%, the pyrite recovery was reduced to 49.2%, and when the addition was further increased to 15 wt.%, the pyrite recovery reduced to 28.5%. However, the effect of pyrophyllite addition on the pulp rheology of the mixed ore was not remarkable. Pyrophyllite affected pyrite recovery not only by affecting the rheological behavior of the pulp, but also because pyrophyllite was adsorbed on the surface of pyrite and diaspore, producing hetero-aggregation, which made it difficult for the pyrite particles to collide with the bubbles effectively. This was the main reason for the reduction of pyrite recovery. Generally, the order in which the reduction of pyrite recovery was affected by the additions of fine minerals was pyrophyllite > FDIA > kaolinite > illite.

Mineralogical control and characteristics of rare earth elements occurrence in Carboniferous bauxites from western Henan Province, north China: A XRD, SEM-EDS and LA-ICP-MS analysis

High concentrations of rare earth elements (REE) are found in the bauxite deposits in the Songqi area of Henan Province, North China. However, no studies have been carried out on the occurrences of REE in these bauxite ores. In this study we explored the REE occurrence and their possible enrichment mechanism in the Songqi bauxite deposits using petrographic observation, X-ray diffraction (XRD), scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), and LA-ICP-MS techniques. The major aluminum-rich ore mineral in the Songqi bauxite deposits is diaspore, and other coexisting minerals include clay mineral aggregates, with minor amounts of hematite, pyrite, anatase, and zircon. The bauxite ores are rich in REE and also some other critical metals (Li, Zr, Nb, and Ga). Most of the REE are adsorbed in the form of ions on the surface of clay minerals and diaspore, and some heavy rare earth elements (HREE) exist in the form of xenotime. The SEM-EDS and LA-ICP-MS analyses show that REE is closely related to the content of P and therefore it is possible that other dispersed and minor P-bearing rare earth minerals may occur in the bauxite deposits except for the possible co-adsorption of P and REE in the clays and diaspore.

Utilisation of propyl gallate as a novel selective collector for diaspore flotation

Propyl gallate (propyl 3, 4, 5-trihydroxybenzoate; PG) was introduced as a new type of collector for diasporic bauxite flotation. The flotation performance of PG for diaspore and kaolinite was evaluated by comparing PG with sodium oleate (NaOl) as a typical collector through micro flotation tests. The results indicated that PG had higher collection ability for diaspore than for kaolinite at 15 mg/L and pH 7–9. Compared with NaOl, PG also exhibited higher selectivity for diaspore against kaolinite. Analyses of zeta potentials, adsorption amount, Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectra (XPS) revealed that PG adsorbed onto diaspore surfaces through chemical adsorption and hydrogen bonding, whereas PG hardly adsorbed onto kaolinite surfaces. Specifically, PG chelated with Al atoms on the diaspore surfaces by forming five-member rings through its ortho oxygens. These findings indicated that PG could be adopted as a novel collector for diaspore flotation and the activated phenolic hydroxyl groups also offered new insights for the development of flotation collectors.

A novel surfactant 2-amino-6-decanamidohexanoic acid: Flotation performance and adsorption mechanism to diaspore

In this paper, a novel surfactant, 2-amino-6-decanamidohexanoic acid (AHA-10) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of AHA-10 onto diaspore was also evaluated by FTIR spectra, zeta potential, XPS and solution chemistry. The flotation results demonstrated that AHA-10 exhibited superior collecting power to diaspore and good selectivity against kaolinite and illite, and could effectively recover diaspore from bauxite ores contained aluminosilicate minerals at pH around 10. The analyses of FTIR spectra, zeta potential and solution chemistry inferred that at pH around 10, AHA-10 might chemisorb on diaspore surfaces by formation of AlO and AlN bonds. AHA-10’s unique properties, such as characteristic bond model to Al atoms on diaspore surfaces, double hydrophobic groups and intermolecular hydrogen bonds between neighboring AHA-10 molecules coated on diaspore surfaces, rendering a weakening surface energy and enhancing hydrophobicity of diaspore particles.

N-(6-(hydroxyamino)-6-oxohexyl) decanamide collector: Flotation performance and adsorption mechanism to diaspore

In this paper, a novel surfactant, N-(6-(hydroxyamino)-6-oxohexyl)decanamide (NHOD) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of NHOD onto diaspore was also investigated by FTIR spectra, zeta potential measurement and XPS. The flotation results demonstrated that NHOD exhibited superior collecting power to diaspore and selectivity against kaolinite and illite and could effectively realize flotation recovery of diaspore from bauxite ores contained aluminosilicate minerals under neutral conditions. The results of XPS, FTIR spectra and zeta potential illustrated that at around pH 7.0, NHOD might chemisorb on diaspore surfaces through AlO coordination bonds formed by binding its C(O)NHOH or C(O)NH chelate groups with aluminum atoms on diaspore surfaces. NHOD's unique properties, such as characteristic bond patterns onto diaspore surfaces, two hydrophobic groups, and intermolecular hydrogen bonds between neighboring NHOD molecules coated on diaspore surfaces, rendered it to be a superior flotation collector for diaspore.

Flotation mechanism of octylic hydroxamic acid on diaspore

Bauxite resources are widely spread in the earth. However, the effective utilization of this mineral is still under infant. The conventional collector for diaspore mineral is oleic acid. It has three main drawbacks which are highly insoluble, large dosages in bauxite flotation, and low selectivity, which hinder its application in industry. In this research, octylic hydroxamic acid was synthesized, and its collecting ability toward two major minerals in bauxite-diaspore and kaolinite was investigated. The collecting power of various reagents for diaspore are shown as follows: oleic acid<octylic hydroxamic acid; while the collecting power for kaolinite was like this: octylic hydroxamic acid<oleic acid. It is shown that octylic hydroxamic acid has the capability of high collectivity and good selectivity. The optimum pH was determined to be 8-9. Zeta potential test revealed that the anionic collectors-octylic hydroxamic acid and oleic acid had been adsorbed on the surface of diaspore and kaolinite, meanwhile the adsorption for diaspore was more remarkable. By the adsorptive capability and IR tests, the adsorption of octylic hydroxamic acid on diaspore was determined to be a process of chemical absorption, which was greater than that of oleic acid.

黄土丘陵沟壑区80种植物繁殖体形态特征及其物种分布

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土丘陵沟壑区80种植物繁殖体形态特征及其物种分布 DOI: 10.5846/stxb201207231047 作者: 作者单位: 西北农林科技大学资源环境学院,陕西省榆林市府谷县林业局,中国科学院水利部水土保持研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院重要方向资助项目（KZCX2-EW-406）；国家自然科学基金重点资助项目（41030532） Research on diaspore morphology and species distribution of 80 plants in the hill-gully Loess Plateau Author: Affiliation: College of Resources and Environment, Northwest A,,Institute of Soil and Water Conservation, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物繁殖体的形态特征及其物种分布是植物长期适应环境的结果，对退化生态系统的更新与恢复具有重要的理论与实践指导意义。研究了80种植物的繁殖体形态特征及与其物种分布的关系，结果表明：1）繁殖体重量差别较大（0.020-357.428 mg），主要集中在1-9.999 mg（占52.5%）。2）繁殖体的形状指数FI变化范围较大（1.06-12.93），61.3%的植物繁殖体的形状近圆球形。3）33种植物繁殖体具有明显的附属物，包括毛、翅、芒和刺等。4）87.5%的植物繁殖体表面具有各种纹饰（棱、被毛、纹和颗粒状等）；繁殖体颜色以褐色和黑色为主，少数繁殖体颜色鲜艳；6种植物繁殖体具有吸水分泌粘液的特性。5）黄土丘陵沟壑区繁殖体重量小或形状近圆球形的植物分布数量多、范围广。6）繁殖体具有毛、翅和芒附属物或吸湿分泌粘液的植物在黄土丘陵沟壑区较繁殖体无附属物的植物能够分布更多、更广。繁殖体这些有利于物种分布的形态特征对于植物适应该区干旱与土壤侵蚀干扰具有重要的生态学意义，而且可用于指导该区人工补播促进植被恢复的物种选择。 Abstract:Soil erosion is a natural geomorphic process on slopes in semiarid region, which influences the soil water holding capacity, nutrients stored and the plant species distribution. The hill-gully Loess Plateau is located in the forest-steppe region and has a semiarid climate with severe soil erosion. Vegetation is identified as the essential and available approach to control soil erosion and to recover degraded ecosystem. Diaspore is the base of vegetation regeneration and recovery after disturbance. Unfortunately, in the degraded ecosystem, diaspore is always regarded as a limited factor of vegetation regeneration. Especially, in eroded environments, seed limitation is caused not only by seed production reducing due to the soil degradation, but also by other seed ecological process. Diaspore morphology is one of the most important functional characteristics of plant, which influences seed production, seed dispersal, seed longevity, seed germination, seedling establishment, then influences species distribution and community composition. Many ecologists have studied seed mass, seed shape, and the corresponding ecological function. However, there are few studies on diaspore morphology and ecological function carried out in the hill-gully Loess Plateau region. 80 species were chose to investigate their diaspore morphology and distribution characteristics, in order to better understand the influence of diversity and adaptation of diaspores on plant restoration. Diaspores of the 80 species were collected from three small watersheds of Xinzihe watershed. To determine species distribution (species density and frequency) on eroded slopes in the study area, 304 quadrats of 69 sample plots from 16 eroded slopes were investigated. The results showed the mean seed mass varied widely (0.020-357.428 mg), with the mean mass of the heaviest diaspore (Ziziphus jujuba) was 17870 times higher than the smallest diaspore (Artemisia scoparia). The mean diaspore mass of most plant species were varied from 1.000 to 9.999 mg, occupied 52.5% of the study species. The Flatness Index of diaspore ranged from a value of 1.06 for spherical shape to greater value of 12.93 for spindle shape, with most of diaspores had the approximate spherical shape (61.3%). Diaspores of 33 species had appendages, such as pappus, awn, wing, spine, etc. About 87.5% species had emblazonry on the surface of diaspore. The main colours of diaspores among these species were brown and black. The diaspores of six species had the ability to secrete mucilage in contact with water. The relationship between diaspore mass and species density and frequency were negative, as well as the relationship between diaspore shape (FI) and species density and frequency were negative. The species with small diaspore, or the approximate spherical diaspore, or with the appendages such as awn, wing and pappus on the diaspore, or with the diaspore that can secrete mucilage distribute widely in the study region. These morphological traits of the diaspore have important role in the distance dispersal, adhering to the soil and persisting in the eroded habitat. And then help the species to adapt the drought and erosion. Diaspore morphological characteristics of adapting the drought and erosion are useful to guide the species selection of revegetation by seed addition. 参考文献 相似文献 引证文献

Biosorption of &lt;i&gt;Bacillus Circulans&lt;/i&gt; and &lt;i&gt;Bacillus Mucilaginosus &lt;/i&gt;on the Surface of Diaspore , Kaolinite and Quartz

The effects of biosorption time and cell concentration on adsorption amount on the surface of diaspore, kaolinite and quartz were studied by using two kinds of silicate bacteria ____Bacillus circulans and Bacillus mucilaginosus, and three kinds of silicate minerals . the experimental results show that two kinds of silicate bacteria absorb more easily on the surface of diaspore than on that of kaolinite and quartz, and the adsorption amount of the strain of B•M is always higher than that of the strain of B•C on the surface of diaspore, kaolinite and quartz .The possible reason is that the pHPZC of diaspore is higher than that of kaolinite and quartz, and the strain of B•M probably produce more metabolites charged negatively than that of B•C in incubation process.

Flotation and adsorption of quaternary ammonium cationic collectors on diaspore and kaolinite

The flotation and adsorption behaviors of dodecyltrimethylammonium chloride(DTAC) and cetyltrimethylammonium chloride(CTAC) on diaspore and kaolinite were studied. Solution depletion methods were used to determine adsorption isotherms. Fluorescence probe test along with Zeta potential measurement was also conducted for further investigation into the adsorption of quaternary amines at the mineral-water interface. The results show that the flotation recovery of kaolinite decreases with an increase in pH when DTAC and CTAC are used as collectors, while diaspore is on the contrary. As the carbon chain length of the collectors increases, the flotation recoveries of minerals increase. However, the increment rate of kaolinite is significantly lower than that of diaspore. In the low surfactant concentration range, the cationic surfactants adsorb readily on diaspore surfaces just due to electrostatic interactions. As for kaolinite surfaces, ion exchange process also exists. With a further increase in surfactant concentration, the adsorption was ascribed to the hydrophobic association of chain-chain interactions. Micro-polarity of mineral surfaces study shows that CTAC has a better hydrophobic characteristic than DTAC. Larger aggregates are formed with CTAC on diaspore than on kaolinite in the same solution concentration. The results also indicate that the chain length of cationic surfactants has a greater influence on the adsorption of diaspore than on kaolinite, which is consistent with the flotation result.

Preparation and performance of 4-alkyl-4,4-bis(hydroxycarbamoyl) carboxylic acid for flotation separation of diaspore against aluminosilicates

The existed collector for the flotation of diasporic bauxite in China is poor in selectivity. To look for a collector with high selectivity and strong collecting capacity on the diaspore flotation, novel 4-alkyl-4,4-bis(hydroxycarbamoyl) carboxylic acids (ABHC) including 4,4-bis(hydroxycarbamoyl) dodecanoic acid (HCDA), 4,4-bis(hydroxycarbamoyl) tetradecanoic acid (HCTA), and 4,4-bis(hydroxycarbamoyl) hexadecanoic acid (HCHA) were designed and synthesized for the beneficiation of diasporic bauxite by selective flotation. The results of flotation experiments for the single minerals showed that by using these compounds as collectors, the pulp pH value has significant influence on their collecting performance as the floatability of diaspore varies sharply with its change. The appropriate pH value for the flotation of diaspore gets close to neutral condition at which diaspore presents good floatability while kaolinite and illite exhibit poor floatabilities. HCDA, HCTA, and HCHA, especially HCDA, show good selectivity for the flotation between diaspore and aluminosilicate around pH 7. A satisfactory mass ratio of Al 2O 3 to SiO 2 (A/S) and recovery of Al 2O 3 were obtained from the flotation separation of artificially mixed minerals and the flotation desilication of diasporic bauxite by using HCDA as a collector, proving that the selectivity of HCDA is better than that of the traditional collector oleate. Moreover, adsorption amount, zeta-potential, DFT calculation, XPS, and FTIR were performed to study the mechanisms. The results indicated that the adsorption of HCDA on the surface of diaspore is dominantly chemisorption in the form of three chelate rings. The oxygen atoms contained in carboxyl and hydroxycarbamoyl of the polar group have the highly negative charges and stereo conditions to form five- to eight-membered ring, resulting in the coordination of carboxyl and hydroxycarbamoyl to the metal aluminum atoms to form chelate rings. By contrast, the adsorption of HCDA on the surface of kaolinite or illite is mainly physical adsorption.

Flotation behavior of four dodecyl tertiary amines as collectors of diaspore and kaolinite

The flotation of diaspore and kaolinite by one of a series of tertiary amines (DRN, DEN, DPN and DBN) was investigated. The tertiary amines show better floating recovery for kaolinite compared to diaspore. The maximum recovery D-value is 45% over a pH range from 3 to 8. FT-IR spectra confirm the presence of hydroxyl groups on the surface of kaolinite and diaspore. Zeta potential measurements show that the mineral surfaces are negatively charged over a wide pH range. Ionization of hydroxyl groups mainly accounts for the surface charging mechanism. The adsorption of tertiary amines onto the mineral surface is due mainly to electrostatic effects and the difference in electrostatic effect between a collector and the two minerals can explain the flotation separation. Inductive electronic and steric effects from the substituent groups result in different collecting powers for the four tertiary amines.

Novel Condensed Ring Carboxylic Hydroxamic Acid Studied in the Flotation Behavior of Diaspore and Aluminosilicates

Flotation reagents are the critical technique in the flotation separation process for desilication. Aimed at the highly selective reagent for direct flotation of diasporic bauxite, a novel compound, dibenzo-1-(7-carboxyl-4-hydroxyl bicycle [2.2.2] octan-7,8-diyl) carboxamic acid (DBCA) with two functional groups carboxyl and hydroxamate in the same molecule, was synthesized through Diels-Alder reaction followed by oximation reaction. Subsequently, the floatability of diaspore, kaolinite, and illite was measured by using DBCA as a collector, the interaction mechanism between minerals and DBCA was investigated through zeta potential measurements and FT-IR spectrum, and the structure and property relationship of the collector were also discussed. The flotation experimental results showed that DBCA had a very strong collecting ability for diaspore, while poor activity was observed for kaolinite and illite. The interaction of DBCA on diaspore surfaces may be mainly dominated by chemical bonding as the formation of three chelation rings; however, those on the surfaces of kaolinite and illite are mainly hydrogen bonding or physical adsorption. Consequently, it is possible to separate diaspore from such aluminosilicates as kaolinte and illite employing DBCA as a collector.

Selective depression of diaspore with waxy maize starch

Highly branched waxy maize starch (WMS) was used to separate diaspore from artificial mixtures of diaspore and kaolinite by microflotation using dodecylamine (DDA) as collector. It was found that WMS depressed the diaspore flotation while activated the kaolinite flotation more or less. The adsorption of WMS on diaspore was examined through adsorption test, zeta potential measurement, infrared spectroscopy, and atomic force microscopy. It is suggested that both chemical interaction and intermolecular hydrogen bonding by hydroxyl groups of starch with surface Al–OH moieties occurred in the adsorption. Results obtained from the adsorption of DDA and WMS on diaspore showed that starch virtually enhanced the DDA adsorption. The depressant action of WMS can be rationalized primarily by the formation of hydrophilic adsorption layer enveloping the surface of diaspore and covering the collector.

Synthesis and collecting properties of novel carboxyl hydroxamic acids for diaspore and aluminosilicate minerals

Novel carboxyl hydroxamic acids compounds, including 2-carboxyl-6-methylcyclohexane carboxamic acid (CMCA), 2-carboxymethyl-decylen-4-yl hydroxamic acid (CDHA), and 2-carboxymethyl-tetradecen-4-yl hydroxamic acid (CTHA) were synthesized, and the flotation behaviors of diaspore, kaolinite and illite were investigated by using these compounds as collectors. The adsorption mechanism of CTHA on the surface of diaspore, kaolinite and illite was conducted by zeta-potential, adsorption amount and FTIR spectra measurement. The interaction of CTHA on the diaspore surface may be mainly dominated by the chemical adsorption; however, the adsorption of CTHA on kaolinite or illite is mainly dominated by the physical one.

Utilization of soluble starch as a depressant for the reverse flotation of diaspore from kaolinite

The utilization of a non-toxic natural polysaccharide, soluble starch, in the flotation of diaspore and kaolinite with emphasis on depression of diaspore in the reverse flotation of bauxite ores by using a Gemini cationic collector, is reported in this work. Firstly, the depressant effect of soluble starch was studied by pure mineral micro-flotation of diaspore and kaolinite as functions of the depressant dosage and pulp pH. The results show that soluble starch depresses diaspore much better than kaolinite. When pH is over 10, a satisfactory separation of the alumina and the silicate minerals can be approached. Moreover, micro-flotation tests of artificial mixed minerals and bench scale reverse flotation of the diasporic bauxite ore was complementing conducted. The non-charged starch is highly proved to be an effective and selective depressant for the reverse flotation of diaspore from the gangue minerals like kaolinite. By zeta potential measurement, adsorption studies and D-IR spectra analysis, the mechanism of interaction between starch and the diaspore surfaces is established, which is the formation of a five membered ring complexes on mineral substrates. The number of broken Al–O bonds of diaspore is much more than that of kaolinite, so the selectivity separation of diaspore from kaolinite in this system is feasible.