The Effect of Reagents on Ultrafine Iron Ore Vacuum Filtration

Continuous vacuum filters normally carry out the final removal of water from iron ore products. The objective of this investigation is to check the possibility of enhancing the industrial performance of a horizontal belt filter by adding one flocculant and two surfactants to the filtration feed slurry. The mineral sample came from the Iron Quadrangle (State of Minas Gerais, Brazil). X-ray diffraction showed a predominance of hematite and small amounts of quartz and goethite. The filtration tests were performed at laboratory scale using a modified Büchner funnel apparatus, which was connected to a scale/computer system. The results indicated: a) the best filtration condition was achieved near the zero charge condition; b) cake moisture, cake porosity, cake formation time and the specific cake resistance were pronouncedly influenced by the flocculant addition; and c) surfactants tested were not able to significantly reduce the cake moisture.     

The Effect of Flocculants and Surfactants on the Filtration Dewatering of Iron Ore Fines

Abstract

The filtration and separation characteristics of iron ore fines have been investigated. The experimental work included: characterization, evaluation of suitable flocculants to enhance settling and dewatering rate, determination of optimum dosages of flocculants, and influence of surfactants on nitration dewatering of both flocculated and unflocculated iron ore fines by vacuum filtration. The results showed that 1) the settling rate can be enhanced many-fold (from 2.52 to 90 m/h) by a suitable flocculant, 2) the residual filter cake moisture content can be reduced from 18.2% without reagents to 12.6% with suitable surfactant dewatering aids while the filtration rate can be enhanced from 4.8 to 97.2 L/h with suitable dewatering filter aids, and 3) the specific cake resistance to filtration can be brought down from 8.6 × 10⁹ to 1.0 × 10⁹ m/kg by using a surfactant sodium petroleum sulfonate at a concentration of 1.47 × 10^?3 kg/t. The economics of using flocculant filter aids and surfactant dewatering aids before thermal drying is described and discussed.     

Iron Behavior in the Ozonation and Filtration of Groundwater

In Finnish groundwater, the main substances that require treatment are iron and manganese. In addition to this, groundwaters are soft and acidic. Iron removal is usually relatively effective by oxidizing dissolved iron into an insoluble form, either by aeration or chemical oxidization and removing the formed precipitate by sand filtration. Sometimes, if the untreated water contains high amounts of organic matter, problems may arise for iron removal. In Finland, it is quite common that groundwater contains high levels of both iron and natural organic matter, mainly as humic substances. The groundwater of the Kukkala intake plant in Liminka has been found to be problematic, due to its high level of natural organic matter. This research studied the removal of iron from this water by means of oxidation with ozone and filtration. While the oxidation of iron by ozone was rapid, the precipitate particles formed were small, and thus could not be removed by sand and anthracite filtration, and the iron residue in the treated water was more than 2 mgL^?1. And while the filtration was able to remove iron well without the feed of ozone, the iron residue in the treated water was only 0.30 mgL^?1. In this case, iron was led to the filter in a bivalent dissolved form. So, the result of iron removal was the best when the sand/anthracite filter functioned largely as an adsorption filter.     

The Effect of Polymeric Flocculants on Settling and Filtration of Iron Ore Slimes

Abstract

During the wet processing of iron ores, a substantial amount of fine particles known as slimes are generated in downstream which need to be recovered effectively for their usage and beneficiation. Besides water from slime ponds overflow remains contaminated with very fine particles which are difficult to settle and cause environmental pollution when contaminated water is discharged to the downstream river. The settling behaviour in the slime pond gets affected in particular when ore contains hydrated oxides. The above problems necessiatate to study the settling and filtration behaviour of the slimes by means of effective flocculants. The flocculants namely, amylopectin-g-polyacrylamide (Ap-g-PAM), sodium alginate-g-polyacrylamide (SAG) were synthesized by graft copolymerization using redox initiated catalyst. The high molecular weight flocculants, namely, magnafloc (1011) superfloc (N 300) were used for comparative studies. The present paper reports the settling and filtration behaviour of iron ore slimes.

The experiments show that sedimentation rate increases with increasing flocculant dose upto a certain limiting value. The settling rate decreases with increasing the pulp density. The volume of filtrate increases with increasing flocculant dose. The filtration efficiency of synthesized polymer is comparable with the commercial one, i.e., magnafloc (1011) at natural pH.     

Coagulation and Flocculation Study of Iron Ore Fines

ABSTRACT

A comparative study of the flocculation and coagulation response of an iron ore fines suspension has been carried out, and the extent of flocculation has been assessed by measurement of electrophoretic mobility, supernatant clarity, and settling rate. Of the several commercial flocculants and polyelectrolyte studied, the combination of medium molecular weight anionic flocculants Magnafloc 1011 and Rishfloc 258 (1:1), and coagulant aluminum nitrate was most effective in terms of enhancing settling rate and supernatant clarity.     

Filtration by falling particles

In one variation of deep-bed filtration the liquid is passed upwards through a fluidized bed of particles. In this variation, filtration efficiency is very much dependent on some type of attraction between the bed particles and the suspended particles, otherwise the suspended particles flow easily through the much larger voids in the fluidized bed, and filtration efficiency is low. When this inter-particle attraction exists, another variation in filtration procedure is possible. This is to pass the fluidized bed downwards, by gravity, through the liquid to be filtered. This variation is the subject of this paper. The ability of falling particles to induce a flow pattern in the body of the liquid makes it possible to devise a very large scale continuous filtration operation, to clarify volumes too large for other filtration techniques, especially when the suspended solids are at a very low concentration. In all of the above, the word gas can be substituted for the word liquid, and the whole spectra of gas cleaning by falling liquid or solid particles opens up. One of these — the cleaning of dust from the atmosphere by falling raindrops — is a familiar and interesting example of simultaneous filtration and flow inducement.     

Pneumatic Drying of Iron Ore Particles in a Vertical Tube

The drying and hydrodynamic characteristics of iron ore particles in a vertical pneumatic conveying dryer (0.078 m ID × 6.0 m high) have been determined. The pressure drop decreases along the height at the acceleration region, while it remains constant irrespective of the height in the fully developed region. The degree of particle drying in the dilute pneumatic region increases with increasing superficial inlet gas velocity at constant inlet gas temperature and solid injection rate. However, it decreases with increasing solid injection rates at identical superficial inlet gas velocity and inlet gas temperature. The degree of particle drying increases from 48.6 to 82.5% as the inlet gas temperature increases from 100 to 400 °C.     

硫铁矿渣湿法制备氧化铁红

以武汉天力集团的硫铁矿渣为原料,采用湿法工艺制备中间产品绿矾和最终产品氧化铁红。根据矿渣样品中杂质含量较大的特点,采取了多次过滤、加入除杂剂、重结晶等操作方法来提高产品纯度,使其达到国标规定要求,为其工业化提出了可行的建议。     

铁矿石中测铁实验方法比较与优化

采用不同方法测铁矿石中铁含量,即有汞法和无汞法,有汞法方法成熟,准确度高,但使用了氯化汞,环境不友好,对周围环境造成污染。无汞法则避免了汞对环境的污染,且无汞法有不同样品预处理方法。但是不同方法之间存在系统误差,准确度不能满足要求。用不同方法同时测定标样和试样,在对数据进行显著性检验,对不同实验方法进行比较和优化选择。寻找到最佳实验方法和测定条件,可在实验教学中推广采用。     

Pneumatic Drying of Iron Ore Particles in a Vertical Tube

Abstract

The drying and hydrodynamic characteristics of iron ore particles in a vertical pneumatic conveying dryer (0.078 m ID × 6.0 m high) have been determined. The pressure drop decreases along the height at the acceleration region, while it remains constant irrespective of the height in the fully developed region. The degree of particle drying in the dilute pneumatic region increases with increasing superficial inlet gas velocity at constant inlet gas temperature and solid injection rate. However, it decreases with increasing solid injection rates at identical superficial inlet gas velocity and inlet gas temperature. The degree of particle drying increases from 48.6 to 82.5% as the inlet gas temperature increases from 100 to 400 °C.     

铁矿石中少量CaO、MgO的测定引起波动的原因分析

铁矿石中钙、镁的含量较低,大部分在2%以下,从抽查中,钙、镁的合格率较低,结果波动较大,我们就分离方法、蒸馏水及试剂空白等方面作了一些实验,供大家参考、讨论。     

在矿浆过滤预处理中表面活性剂的应用

针对钼矿的基本物性,筛选合适的表面活性剂,进行钼矿浆过滤条件的试验研究。结果表明,钼矿浆中加入合适的表面活性剂后,增加了滤饼厚度,降低了滤饼湿含量,提高了对矿浆的处理能力。     

测定铁矿石中全铁含量方法的改进

在测定铁矿石中全铁含量时,首先要将Ｆｅ（Ⅲ）还原为Ｆｅ（Ⅱ）,然后再用重铬酸钾滴定Ｆｅ（Ⅱ）。采取在较深的ＨＣｌ介质中,加入氟化氨后,氯化亚锡可以直接还原钨酸钠的方法,不需使用氯化汞、三氯化钛,可用于测定铁矿石中铁含量,结果满意。     

Feasibility of Producing Pellet Grade Concentrate by Beneficiation of Iron Ore Slime in India

Abstract

Beneficiation of low grade iron ore slime from Chitradurga, India was studied with a view to produce pellet grade fines. The slime sample had a feed grade of 49.86% total Fe, 7.93% Al₂O₃, and 10.19% SiO₂. Kaolinite and quartz was found to be the main gangue minerals and they formed porous and friable oxide and hydroxide of iron. Over 54% of the materials in the slime were less than 20 micron and this size fraction contained higher percentage of gangue minerals. Liberation of free gangue minerals was observed to be substantial in all size classes. Beneficiation studies indicated that excellent rejection of silica and alumina could be obtained through physical separation. The low grade slime could be enriched to 66.36% Fe with 1.75% silica, and 1.44% alumina.     

多功能真空装置在恒压过滤实验中的应用

介绍一种化工原理实验所需的,可用于恒压过滤参数测定以及旋转蒸发实验的减压真空控制装置。该真空控制装置适用于旋转蒸发实验,尤其在真空运行状态下收集高沸点的回收液,并能保证实验的连续性。该装置利用率高,体积小,节省实验室空间,而且维修方便、节省财力,适用于教学、科研等领域。当前已在化工原理实验教学改革中得到应用。     

离子色谱法测定铁矿石中水溶性氯化物

文章研究了离子色谱法测定铁矿石样品中水溶性氯化物。试样经超声波提取后,采用阴离子分离柱SUPP4-250和MSM（Metrohm Suppressor Module）抑制器,以电导检测器检测,用1．8mmol／LNa2C03和1．7mmol／LNaHCO3混合液作淋洗液,以标准曲线法为定量方法,测定其中的水溶性氯化物。方法检出限为1．7×10^-3mg／L,氯化物含量为0．2569％时,方法的相对标准偏差为0．77％,样品的加标回收率为95．6％～100．1％。该方法操作简单,快速高效,灵敏度高,结果准确、可靠。     

ICP-AES测定铁矿石中多元素的研究

提出了用ICP AES法同时测定铁矿石中Al,Ti,V,Mn,Cu,As元素的分析方法。各元素选用最佳光谱线和光谱仪合适的工作条件,测定数据的精密度和样品加标回收率结果令人满意,方法快速、简便。     

真空碳热还原氧化锌矿动力学

在真空条件下,对煤还原氧化锌矿的动力学进行了研究. 实验结果显示,增大C/Zn总摩尔比或提高反应温度,锌还原率增大;增大氧化锌矿的粒度或升高系统压强,锌还原率降低;在1073~1223 K范围内,碳气化和界面反应对氧化锌还原影响较小,Zn蒸汽和CO气体的扩散对氧化锌还原影响大,其活化能为177.72~191.31 kJ/mol,为整个还原过程的控制步骤.     

电感耦合等离子体原子发射光谱法测定铁矿中全铁

用四硼酸钠-碳酸钠混合熔剂熔融铁矿,用稀盐酸浸出.选择较高稳定性且无光谱干扰的Fe 248.327nm为分析线,加入钇为内标元素,Y 371.030nm为内标线,检测铁矿中的总铁。分析的相对标准偏差(RSD,n=7)为0.29%～0.39%,有证标准物质分析结果同证书值相对误差值均在0.3%以内。