某鲕状赤铁矿流化床燃煤还原焙烧-磁选研究

运用小型循环流化床锅炉,针对铁品位为49.20%、磷质量分数为1.16%的湖北某鲕状赤铁矿进行磁化焙烧-磁选试验研究.试验结果表明,将粒径为106～150 μm的鲕状赤铁矿在700 ℃下焙烧15 min,选取磨矿后粒径在74 μm以下的颗粒质量分数为85%的焙烧矿物,运用湿式磁选管在139.22 kA/m的磁场强度下对筛选后的焙烧矿物进行磁选抛尾,可以获得铁品位为55.12%、全铁回收率为70.11%、磷质量分数为0.67%的铁精矿.研究表明,运用循环流化床局部还原性气氛高速磁化焙烧铁矿石是可行的,运用该磁化焙烧-磁选工艺流程可以达到一定的提铁降磷效果.     

Application of multi-stage dynamic magnetizing roasting technology on the utilization of cryptocrystalline oolitic hematite: A review

A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size, high harmful impurity content and oolitic structure. To recover iron from oolitic hematite, we developed a novel multistage dynamic magnetizing roasting technology. Compared with traditional magnetizing roasting technologies, this novel technology has the following advantages: firstly, the oolitic hematite is dynamically reduced in a multi-stage roasting furnace, which shortens the reduction time and avoids ringing and over-reduction; secondly, the novel dynamic magnetizing roasting technology has strong raw material adaptability, and the size range of raw materials can be as wide as 0–15 mm; thirdly, the roasting furnace adopts a preheating-heating process, and the low-calorific value blast furnace gas can be used as the fuel and reductant, which greatly reduces the cost. The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore. The iron grade of the concentrate and iron recovery reached 65% and 90%, respectively.     

Effect of coal levels during direct reduction roasting of high phosphorus oolitic hematite ore in a tunnel kiln

The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorization agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grinding followed by magnetic separation. XRD and SEM–EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affecting the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94% to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.     

冷却方式对焙烧鲕状赤铁矿磨矿性能影响

鲕状赤铁矿有用矿物嵌布粒度细,磨矿成本高,属于典型难选铁矿石。磁化焙烧-磁选工艺是分选此类难选铁矿石的有效方法,研究了不同冷却方式对磁化焙烧矿的磨矿性能产生的影响.鲕状赤铁矿进行磁化焙烧后分别隔绝空气密闭冷却、水淬及空气中自然冷却,进行粒度筛析和磨矿试验.发现焙烧后矿石粒径变粗,从原矿的平均粒径为0.069 9mm至密闭冷却、水冷和自然冷却焙烧矿的0.088 2mm、0.084 3mm、0.087 0mm.相同磨矿条件下,原矿、密闭冷却焙烧矿、水冷焙烧矿和自然冷却焙烧矿-0.045mm含量分别为84.89%、83.89%、76.51%、77.14%.表明磁化焙烧使鲕状赤铁矿变得更为难磨,密闭冷却时磨矿效果最佳,自然冷却次之,水冷最差.     

助磨剂对鄂西高磷鲕状赤铁矿磨矿的影响

鄂西高磷鲕状赤铁矿在微细粒磨矿时黏度非常高,严重影响磨矿效率,导致磨矿能耗大幅上升。用助磨剂六偏磷酸钠和三聚磷酸钠对鄂西高磷鲕状赤铁矿进行降黏度磨矿试验。结果表明,添加两种助磨剂均可降低矿浆的黏度,助磨剂添加量为0.2%时降黏和助磨效果最佳;助磨剂使球磨机的生产能力得到显著提高,其相对增量最高可达144%,磨矿时间为5min时助磨效果最佳。添加助磨剂后磨矿产品中粒度小于38μm的颗粒含量明显增加,两种助磨剂都能有效降低磨矿的能耗,最大能耗降幅为57.14%。     

高磷铁矿碳热还原同步脱磷的实验研究

为探索高磷铁矿的有效利用途径,对高磷鲕状赤铁矿进行碳热还原同步脱磷实验研究,在含碳球团中添加CaO和Na2C O3作为脱磷剂,采用D T A-T G- M S综合热分析、X R D、SE M、E DS等方法分别对高磷鲕状赤铁矿的碳热还原过程以及还原产物进行分析. 结果表明,添加适量的CaO和Na2C O3可以显著提高脱磷率;在1 573 K、Na2C O3添加量为2 %、含碳球团碱度为1 .2的条件下,高磷鲕状赤铁矿能够被快速还原成含磷0 .09 %、含碳4 .6 %的碳饱和铁,脱磷率达到95 %;生铁中碳过饱和后以片状石墨的形态析出,生铁中的磷以夹杂物Ca3（P O4）2和Na2Ca4（P O4）2SiO4的形式存在     

超声波对At.f菌脱除鲕状赤铁矿中磷的影响

利用广西某温泉水样分离At.f菌并进行纯化,采用超声波诱变研究对鄂西鲕状赤铁矿磁选精矿脱磷技术。结果表明:1)超声波诱变可以提高At.f菌的活性,当超声波频率为59kHz、诱变时间为20min时,体系中Fe2+完全氧化所需时间为20min;2)超声波诱变20min后的At.f菌接种比为15%～20%时,30d铁矿的脱磷效果为85%以上;3)培养基中ρ(Fe2+)≥9g/L时,诱变后的菌株对于鲕状赤铁矿磁选精矿的脱磷率为80%以上。     

Extraction of valuable metals from low-grade nickeliferous laterite ore by reduction roasting-ammonia leaching method

Nickel and cobalt were extracted from low-grade nickeliferous laterite ore using a reduction roasting-ammonia leaching method. The reduction roasting-ammonia leaching experimental tests were chiefly introduced, by which fine coal was used as a reductant. The results show that the optimum process conditions are confirmed as follows: in reduction roasting process, the mass fraction of reductant in the ore is 10%, roasting time is 120 min, roasting temperature is 1 023–1 073 K; in ammonia leaching process, the liquid-to-solid ratio is 4:1(mL/g), leaching temperature is 313 K, leaching time is 120 min, and concentration ratio of NH₃ to CO₂ is 90 g/L:60 g/L. Under the optimum conditions, leaching efficiencies of nickel and cobalt are 86.25% and 60.84%, respectively. Therefore, nickel and cobalt can be effectively reclaimed, and the leaching agent can be also recycled at room temperature and normal pressure.     

Thermodynamics of chromite ore oxidative roasting process

To explicate the thermodynamics of the chromite ore lime-free roasting process,the thermodynamics of reactions involved in this process was calculated and the phrases of sinter with different roasting times were studied.The thermodynamics calculation shows that all the standard Gibbs free energy changes of the reactions to form Na2CrO4,Na2O·Fe2O3,Na2O·Al2O3 and Na2O·SiO2 via chromite ore and Na2CO3 are negative,and the standard Gibbs free energy changes of the reactions between MgO,Fe2O3 and SiO2 released f...     

阎地拉图红铁矿选矿工艺研究

对阎地拉图红铁矿进行了焙烧磁选、强磁选、重选及重选－强磁选四种选矿工艺的试验研究，结果表明，用螺旋溜槽选别＋０．０７４ｍｍ粒级，用强磁选别－０．０７４ｍｍ粒级的重选－强磁选方案可得到品位为５１．００％、回收率为７２．３０％的综合铁精矿。该方案投资少，生产成本低，适合现厂的实际。     

Two-step flotation recovery of iron concentrate from Donganshan carbonaceous iron ore

The flotation of pure and natural carbonaceous iron ore samples in the oleate flotation system was investigated. Starch can depress hematite effectively in a wide pH range, but cannot depress siderite efficiently in neutral conditions. The flotation recovery of pure hematite, siderite, and quartz in the oleate-starch-CaCl₂ system is significantly different when the slurry pH varies from 4 to 12. A novel two-step flotation process was developed for the separation of iron concentrate from Donganshan carbonaceous iron ore through which the siderite concentrate is first recovered and the high quality hematite concentrates with relative high iron recovery can be obtained in the second step flotation. The siderite concentrate may be utilized directly or undergo further concentration steps to increase iron grade.     

溶磷微生物的选育及除磷研究

从土壤中选育分离出8株溶磷微生物,研究了不同溶磷微生物对磷酸钙的溶解能力,其中菌株XH2对磷酸钙的溶解量最高可达415.69 mg/L。将溶磷微生物应用到高磷鲕状赤铁矿的除磷试验中,结果表明,菌株XH3的除磷最高达到79.58%的理想效果,为高磷铁矿石的脱磷技术提供了新的选择。     

一种风化低品位铁矿石的可选性试验

随着铁矿资源的日益贫乏,对低品位矿石的开发利用成为选矿的发展趋势。山东省某矿业公司矿石属于风化程度较高的低品位铁矿石,样品粒度为10～0mm,含水量1％～2％。根据试样的性质和风化矿分选的经验,采用干式磁选抛尾、干选粗精矿再磨再选的试验流程,获得品位为66％的精矿产品,对低品位铁矿石的开发利用具有一定的借鉴意义。     

Effect of bastnaesite as reductant on hematite reduction during in-situ suspension magnetization roasting of refractory iron ore under neutral atmosphere

The iron tailings of Bayan Obo mines are solid waste, which occupies land area and also causes environmental pollution; however, this waste can be recycled. In this study, based on the characteristics of iron minerals and fluorocarbonate contained in Bayan Obo iron tailings, clean magnetization roasting of iron minerals by bastnaesite from iron tailings during in-situ suspension magnetization roasting in a neutral atmosphere was explored. The results show that for iron tailings with a mass of 12 g, a N₂ gas flow rate of 600 mL/min, and roasting for 5 min at 800 °C, iron concentrate with a 60.44% iron grade at an iron recovery of 76.04% could be obtained. X-ray diffraction analysis showed that the weak magnetic hematite was reduced to strong magnetic magnetite in the neutral atmosphere, without additional reductant. The kinetics of the magnetization roasting of mineral mixtures (bastnaesite and hematite) in a neutral atmosphere showed that the optimal reaction mechanism function was the three-dimensional diffusion model with activation energy of 161.8838 kJ·mol^?1; this indicates that the reaction was a heterogeneous, diffusion-controlled solid-state reaction.     

Mechanism for suspension magnetization roasting of iron ore using straw-type biomass reductant

As an alternative reductant for fossil fuel in the future, straw-type biomass contributes to emission reduction and green utilization in the suspension roasting process. In this study, the influences of the roasting time, roasting temperature and dose of straw-type biomass after suspension magnetization roasting (SMR) and separation were investigated. The optimal conditions were determined to be a roasting time of 7.5 min with a straw-type biomass dose of 20 wt% and a roasting temperature of 800 ℃, in which an iron grade of 71.07% and recovery of 94.17% were obtained for the iron concentrate. The maximum saturation magnetization under optimal conditions was 35.05 A·m²·g⁻¹, and the gaseous regulation of the biomass revealed that cumulative reducing gas volume was 293.93 mL at the optimal roasting time of 450 s. The transformation of hematite to magnetite was detected by X-ray diffraction (XRD). During microstructure evolution, the outer layer consisting of fissures and tiny holes continuously deepened toward the core.     

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 par...     

磷矿堆场多目标优化配矿模型

以磷矿浮选场堆场配矿过程为研究对象,选取人选原矿品质指标及低品质矿石利用量为主要目标,增加资源量约束及决策变量非负约束,构建了堆场多目标优化配矿模型.同时应用Matlab优化工具箱中多目标规划解算函数,对算例及实际配矿模型求解验证,并与现场混配结果进行比较,配矿效果明显.研究结果表明:磷矿多目标优化配矿模型实现了磷矿堆场配矿工艺及过程的简单、直观、较完整描述,Matlab优化工具箱多目标规划相关函数,对求解磷矿堆场多目标优化配矿模型是简便、有效的.     

低品位铁矿石流化焙烧-磁选提质试验研究

针对我国低品位铁矿石嵌布粒度极细,成分复杂,难提难选的现况,运用循环流化床和磁选管进行劣质铁矿石的流化焙烧 磁选试验研究,试验采用CO、N2的混合气体营造还原性气氛（其中CO体积分数为10%）,将粒径为1 mm以下的新疆某低品位铁矿石（原矿铁品位为9.63%）于850 ℃焙烧10 min,得到强磁性的磁铁矿,将焙烧产物破碎细磨（磨至200 目以下占75%）,利用湿式磁选管在71.66 kA/m的磁场强度下进行弱磁选抛尾,可以得到铁精矿品位为46.25%,全铁回收率为25.52%的选矿指标.研究表明,运用循环流化床焙烧-弱磁选的方法提质铁矿石,可以有效地减少焙烧时间,在保证选矿达标的基础上,有效地降低生产周期.     

Flotation technology of refractory low-grade molybdenum ore

Because of the low grade, high oxidation rate and the accumulation of little associated metal sulfide ore in the molybdenum concentrate during flotation, the Qingyang molybdenum ore is difficult to beneficiate. The experimental studies of grinding fineness, the amount of roughing modifier, depressant and collector were completed. In the cleaning process, the contrast experiments of one regrinding, the regrinding and scrubbing, two-stage regrinding was carried. The result shows that the grade of molybdenum ore concentrate is 45.31%, the recovery is 65.98% and the rich ore ratio reaches 20.59% by the regrinding and scrubbing seven cleaning, the regrinding of concentrations from middling of molybdenum-sulfur separation. The regularly-concentrated material from the apparatus was as the middling products. Hence, ideal beneficiation index can be obtained with a rational mineral processing, which offers new beneficiating technology for the refractory low-grade molybdenum ore in China.     

华南磷块岩地质构造及其力学性能的对比研究

为掌握不同地域的磷块岩蕴藏地层的构造特点、高品位富矿分布、脉石结构以及力学性质之间的相互作用机理. 文章对我国中南湖北磷矿和西南贵州磷矿进行对比研究. 根据两矿区的地勘资料,同时结合电镜扫描、声波透射试验、破碎筛分等检测途径,从磷块岩的地层分布、构造类型、矿石结构、完整性及破碎后的颗粒级配等方面逐一分析,结果显示:首先西南片区磷块岩的震旦纪临海地理位置导致该区域矿体P₂O₅平均含量高,富矿储量大且共生矿物种类多,但岩体更为破碎. 其次宏观上岩体内部裂隙等弱面控制着磷块岩岩体的稳定性,而在细观层面,晶间结合力是矿石力学性质的控制因素.