Fine Hematite Research Articles

Flocculation/flotation of hematite fines with anionic temperature-responsive polymer acting as a selective flocculant and collector

A novel approach to the recovery of valuable fines is the use of temperature-responsive polymers such as poly (N-isopropyl acrylamide) (PNIPAM). These polymers act as dual-function flocculants and collectors to form hydrophobic aggregates improving particle–bubble collision and attachment. The aim of this study is to investigate the flotation performance of anionic PNIPAM for an iron ore sample containing fines compared to sodium oleate, an industrial collector for hematite. PNIPAM conditioned at room temperature (25°C, below the lower critical solution temperature (LCST)) and floated at 50°C (above the LCST) was found to provide improved hematite grade and recoveries for particles above 20μm, compared to sodium oleate. This was attributed to the increased selectivity and hydrophobicity of PNIPAM. Turbidity testing confirmed the flocculation of fines with PNIPAM, which deslimes the surface of the coarser particles. Below 20μm, the hematite fines were almost completely recovered with PNIPAM. However, this recovery was not selective, attributed to the entrapment of gangue in the hydrophobic aggregates. Furthermore, conditioning of the polymer above the LCST resulted in significant losses in grade and selectivity, as the polymer self-aggregates hydrophobically and precipitates unselectively onto the closest surface.

The Mössbauer study of atmospheric iron-containing aerosol in the coarse and PM2.5 fractions measured in rural site

The size-resolved iron-containing atmospheric aerosol was measured by Mössbauer spectroscopy. The particulate matter (PM) was size-segregated into aerosol <2.5μm in diameter (fine fraction, PM2.5) and aerosol >2.5μm (coarse fraction).The Mössbauer spectra at room temperature show components assigned to mono- and polymeric species which are products related to hydrolysis of ferric solutions in the atmosphere. In order to extract reliable information regarding the quadrupole splittings necessary for identification of iron-containing compounds, the histogram method was used for evaluation of the Mössbauer spectra. The value and distribution of quadrupole splitting (QS) parameters obtained by this method suggests that the ultra fine particles (<10nm) identified as a ferrihydrite, hematite and goethite were observed in the spectra both in fine and coarse fraction of the collected aerosol. However, the content of the individual chemical components was different for each fraction. The least crystalline form of ferrihydrite (QS≅0.85mm) was observed in PM2.5 fraction more frequently than in the coarse fraction. The content of the ultra fine hematite particles which presence was confirmed in low temperature measurements was also larger in PM2.5 fraction than in the coarse fraction. Superparamagnetic behavior of iron-containing atmospheric aerosol was observed in low temperature Mössbauer spectra.

Melting and Reduction Behaviour of Individual Fine Hematite Ore Particles

Melting and Reduction Behaviour of Individual Fine Hematite Ore Particles

Reduction Kinetics of Fine Hematite Ore Particles with a High Temperature Drop Tube Furnace

Reduction Kinetics of Fine Hematite Ore Particles with a High Temperature Drop Tube Furnace

Colour origin of Tortonian red mudstones within the Mersin area, southern Turkey

Fluvial red mudstones of Tortonian age (overbank deposits) are widespread in the Mersin area in southern Turkey. The XRD analysis reveals that the mudstones consist predominantly of smectite, containing 3.0 to 6.6wt.% Fe2O3, of which ≤1% is present as hematite. However this is evidently sufficient hematite to yield a red colour to the whole rock. SEM images show that very fine hematite crystals are disseminated in the mudstones as pore-filling cement between smectite flakes. After reddening, some of the clay and hematite were most likely leached and accumulated with smectite in the shrink–swell fractures as infill. Reddening in the mudstone took place in a terrestrial environment and the hematite pigment formed from intrastratal water by inorganic precipitation at the initial stage of diagenesis. The free Fe2+ was most likely released from the Fe-bearing minerals in an aqueous reducing environment, with hematite being precipitated as cement during the dry periods.

Separation analysis of dry high intensity induced roll magnetic separator for concentration of hematite fines

In this study, a three level Box–Behnken factorial design combined with response surface methodology was used for modeling and optimization of process parameters of induced roll dry high intensity magnetic separator. The influence of magnetic field intensity, roll speed and feed rate was analyzed for the separation of hematite minerals. Second-order response functions were produced for the grade and recovery of the hematite minerals in the magnetic fraction. Taking advantage of the quadratic programming, optimized levels of the process variables have been determined as optimum levels to achieve the maximum grade of 51.2% Fe, and maximum level of recovery was 97.8% Fe whereas minimum grade of 23.9% SiO2 in the magnetic product was predicted. Further optimization was carried out by targeting the Fe (%) content and recovery of the magnetic product of above 50%. The influence of the process variables of the induced roll high intensity magnetic separator on grade and recovery of the hematite mineral in the magnetic fraction were presented as 3D response surface graphs.

Pre-Concentration of Ultrafine Crushed Hematite Ores

In this study, a lean hematite ore was crushed to produce ultrafine particles using a high pressure grinding roll and then pre-concentrated using a high gradient magnetic separator with a steel rod matrix to reduce the ore tonnage for milling and grinding energy consumption. Pilot test results showed that the primary concentrate grade was increased by 6.98 percentage points from the crude ore with 18.34% Fe at an optimum pre-concentration condition obtained using a matrix with a rod diameter and a rod gap that both measure 4 mm. The concentrate recovery reached a maximum of 86.13% with a tailings yield of 37.61%. Primary concentrates were separated further, and clean concentrates with a grade of 67.15% were obtained.In a magnetic field around a matrix rod, the magnetic capturing force on coarse hematite particles was increased, but such force on fine hematite particles was decreased as the matrix rod diameter increased at the same background magnetic field intensity. Considering gravity and viscous resistance of locked particles, the matrix with large diameter rods (e.g., 4 mm) could effectively and completely recover these particles. By contrast, the matrix with small diameter rods (e.g., 1 mm) could efficiently recover fine particles but not coarse particles such as lean-locked particles.

Selective flocculation of hematite in quartz–hematite–ferric ion–polyacrylic acid system. Part 2. Effect of grinding and a hydrofluoric treatment on selectivity of flocculation

A variety of materials and particle preparation methods were investigated to delineate their effect on the selective flocculation of quartz and hematite suspensions with polyacrylic acid (PAA) as flocculant. Synthetic hematite particles were effectively separated by selective flocculation with PAA in the 3 to 8 pH range from a mixture of quartz that had been ground in a quartz mill. However, grinding the quartz in a porcelain mill or co-grinding it with the hematite fines in a quartz mill resulted in non-selective flocculation due to cross-contamination of the quartz particles by coating of impurities from the porcelain or from hematite. Treatment of the ground product with hydrofluoric acid restored the purity of the quartz particles, thereby restoring selectivity in the flocculation step. Effective selective flocculation of Tilden hematitic taconite ore was achieved by hydrofluoric acid treatment of the minus 37μm fraction of the crushed ore.

Slice matrix analysis for combinatorial optimization of rod matrix in PHGMS

Rod matrix is effectively applied in pulsating high gradient magnetic separation (PHGMS), due to its reliable operation, simple combination and resistance to mechanical entrainment. The matrix is made of huge numbers of rod elements and as a whole its configuration presents a decisive role in the operation of PHGMS, due to the fact that it has an inherent determination on the distribution of magnetic field in the matrix and on the collision efficiency of particles with the matrix, thus producing a dominant control on the dynamics of magnetic particles in the matrix and on the separation performance of PHGMS. An experimental approach entitled Slice Matrix Analysis (SMA) method is developed and attempted to optimize the configuration of rod matrix, with a cyclic pilot-scale PHGMS separator in concentrating fine hematite. It was found that the configuration has a significant effect on the separation performance of PHGMS, and the SMA method provides an effective way for the optimization of rod matrix.

Applied Research Development of Flotation Column in Micro-Fine Hematite Flotation

Flotation column was originated from foreign countries, firstly it was mainly used in coal classification, then it has been used in nonferrous metal classification, due to the hematite iron ore resources tend to be poor, fine and complex, flotation column has the congenital advantage of micro fine minerals, therefore, this paper is according to the beneficiation technology of fine hematite ore in domestic and foreign ,through the characteristic of flotation column which is applicable to the processing of fine mineral, have good separation effect, and high enrichment ratio , flotation column are introduced in fine particle hematite beneficiation in some applications, Flotation column has a wide range of application prospects in our country fine mineral separation.

Selective Flocculation of Fine Grain Oolitic Hematite Behavior Research

The fine oolitic hematite ore (&lt;20µm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent dosage. In this paper, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

Research on the Selective Flocculant of Soluble Starch and Acrylamide Graft Copolymer for Fine Hematite Particle

This paper, a comprehensive analysis of selective flocculation am fine hematite selected based on the combination of soluble starch and the characteristics of acrylamide was prepared soluble starch - grafting of acrylamide polymer flocculant. We can see through selective testing, the preparation of starch - acrylamide graft polymer of pure quartz and pure hematite were produced on the surface adsorption, through the measured absorbance and then converted to the concentration of ways we can see remnants of the graft material in the quartz very small amount of surface adsorption, while in hematite adsorption volumes. By hematite flocculation test we can see, with flocculants prepared by flocculation, its ability to better than selective flocculation modified maize starch and polyacrylamide.

The Research of the Preparation and Characterization of Selective Flocculant Suitable for Fine Hematite

This paper, a comprehensive analysis of selective flocculation am fine hematite selected based on the combination of soluble starch and the characteristics of acrylamide was prepared soluble starch - grafting of acrylamide polymer flocculant. Conditions of single-factor experiment studied the conditions on the starch - the impact of acrylamide polymerization and to the level of starch graft ratio to measure the various conditions on the polymerization to determine the optimal conditions of each are as follows: initiator using cerium nitrate Ammonium; initiator concentration 0.001moL / L; AM / soluble starch mass ratio of 2:1; reaction time of 2h; the reaction temperature is 60 °C. In terms of single-factor test, designed a four factors and three levels of the orthogonal test, the optimum conditions are: starch and monomer mass ratio of 1:2; initiator concentration of 0.001 mol / L; the reaction temperature is 65 °C; reaction time was 1.5h. Under these conditions, starch and the grafting rate of 153.24. By scanning electron microscopy and infrared spectrum we can see, the namely, the resulting polymer soluble starch and acrylamide graft copolymer. By hematite flocculation test we can see, with flocculants prepared by flocculation, its ability to better than selective flocculation.

Xperimental Research on Grinding Medium and Influence Factors of SiJiaYing's Fine Grain Hematite

SiJiaYing's iron ore is fine grain hematite and gangue mineral is quartz,chlorite,black mica and parts of clay mineral.Grinding process is tend to argillation,which seriously impact the subsequent strong magnetic and flotation thick operation.This paper mainly conduct ball mill sphere diameter,ball ratio and the grinding effect factor test,which including medium filling ratio,grinding concentration and so on.By compared experiments optimize,grinding process and improve the grinding effect.

Study on Adsorption Reaction Dynamics of Fine Hematite

In this article, the equation of the starch and fine hematite particle has been put forward combining with the collision theory. After analyzing the equation and test data, the reaction order of the starch and fen hematite particle can be obtained by integration method and half-life method, which is first degree. It lays the foundation about adsorbed rate equation of the starch and fen hematite particle.

Recovery Improvement of Fine Magnetic Particles by Floc Magnetic Separation

The performance of floc magnetic separation (FMS) has been compared with wet high-intensity magnetic separator (WHIMS). This study was performed on low-grade iron ore slime contained 59.58% Fe with 4.57% silica and 3.78% alumina. Detailed characterization data indicated that a substantial amount of the slime was below 20 µm in size. Beneficiation studies indicated that the FMS process is effective to recover fine hematite and goethite particles, compared with the conventional magnetic separation. In conventional magnetic separation, the extent of the fluid drag force exceeds the magnetic force exerted on ultrafine particles. Thus, ultrafine magnetic particles were usually not recovered effectively by magnetic separators, resulting in the loss of valuable ultrafine slime particles. The FMS process significantly increases the magnetic force on the ultrafine iron ore in the form of hydrophobic flocs in a magnetic field, thus the ultrafine particles can be picked up effectively as magnetic concentrates. The FMS process improved the Fe recovery from 37.35% to 79.60%.

Selective Flocculation of Banded Hematite Quartzite (BHQ) Ores

The recovery of fine hematite particles from banded hematite quartzite (BHQ) ore with potato starch has been investigated using selective flocculation. Microscopic features, coupled with x-ray diffraction (XRD), and Fourier trans- forms infrared (FTIR) spectroscopic data provide evidences for adsorption of starch molecules on hematite surface. The starch molecules show good selectivity for hematite particles in the pH range of 8.5-9.5 and in the reagent concentration range of 20-40 mg/l. The Scanning electron microscope (SEM) studies show that flocs of hematite particles are larger and appear to be denser than that of quartz. Initial results with 1:1 hematite-quartz mixture indicated that it is possible to achieve an iron concentrate of 64.5% Fe with 92.0% of iron recovery from a feed of 34% Fe. However under optical conditions of pH and reagent concentration, the BHQ ore could be upgraded from an initial grade of 38.9% Fe to 57.2% Fe with 71% recovery. The overall results indicate that separation of very fine grained hematite present in the BHQ iron ore is feasible by selective flocculation.

Study on Dispersion Behaviors of Oolitic Hematite Ultrafine Particles in Water

The fine oolitic hematite ore (＜20μm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent use level. In this article, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

Study on Dispersion Character of Fine Oolitic Hematite Ore Particle

The fine oolitic hematite ore (＜20μm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent use level. In this article, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

Experimental Study of Hematite Melting Reduction under High Temperature

For low-grade and fine disseminated grain size hematite, there is no good effect through traditional mineral separation. In this study, hematite will be smelted directly to separate quartz and hematite.The optimal technological condition is as: reduction time is 60 min, reduction temperature is 1550°C and alkalinity of slag should be controlled between 0.3~0.5 in order to get better slag to form glass ceramics.