Strengthening pelletization of manganese ore fines containing high combined water by high pressure roll grinding and optimized temperature elevation system

Pelletization is one of useful processes for the agglomeration of iron ore or concentrates. However, manganese ore fines are mainly agglomerated by sintering due to its high combined water which adversely affects the roasting performance of pellets. In this work, high pressure roll grinding(HPRG) process and optimization of temperature elevation system were investigated to improve the strength of fired manganese ore pellets. It is shown that the manganese ore possesses good ballability after being pretreated by HPRG twice, and good green balls were produced under the conditions of blending 2.0% bentonite in the feed, balling for 7 min at 16.00% moisture. High quality roasted pellets with the compressive strength of 2711 N per pellet were manufactured through preheating at 1050 °C for 10 min and firing at 1335 °C for 15 min by controlling the cracks formation. The fired manganese pellets keep the strength by the solid interconnection of recrystallized pyrolusite grains and the binding of manganite liquid phase which filled the pores and clearance among minerals. The product pellets contain high Mn grade and low impurities, and can be used to smelt ferromanganese, which provides a possible way to use imported manganese ore fines containing high combined water to produce high value ferromanganese.

Mechanism of high pressure roll grinding on compression strength of oxidized hematite pellets

The mechanism of high pressure roll grinding on improvement of compression strength of oxidized hematite pellets was researched by considering their roasting properties. The results indicate that oxidized hematite pellets require higher preheating temperature and longer preheating time to attain required compression strength of pellets compared with the common magnetite oxidized pellets. It is found that when the hematite concentrates are pretreated by high pressure roll grinding （HPRG）, the compression strengths of preheated and roasted oxidized hematite pellets get improved even with lower preheating and roasting temperatures and shorter preheating and roasting time. The mechanism for HPRG to improve roasting properties of oxidized pellets were investigated and the cause mainly lies in the increase of micro-sized particles and the decrease of dispersion degree for hematite concentrates, which promotes the hematite concentrate particles to be compacted, the solid-phase crystallization, and finally the formation of Fe203 bonding bridges during subsequent high temperature roasting process.

Fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll

The fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll(HPGR) was studied based on the characteristics of comminuted products at different specific pressure levels. The major properties included the reduction ratio, liberation, specific surface energy, and specific surface area. The results showed that the fracture of low-grade hematite ore in HPGR was an interactive dynamic process in which the interaction between coarse particles of gangue minerals and fine particles of valuable minerals was alternately continuous with increased compactness and compacting strength of materials. Within a range of 2.8–4.4 N/mm^2, valuable minerals were crushed after preferentially absorbing energy, whereas gangue minerals were not completely crushed and only acted as an energy transfer medium. Within a range of 4.4–5.2 N/mm^2, gangue minerals were adequately crushed after absorbing the remaining energy, whereas preferentially crushed valuable minerals acted as an energy transfer medium. Within a range of 5.2–6.0 N/mm^2 range, the low-grade hematite ore was not further comminuted because of the "size effect" on the strength of materials, and the comminution effect of materials became stable.

3D Design and Analysis of Crushing Roller of High-pressure Grinding Roller

Crushing roller is one of the main parts of High-p re ssure Grinding Roller, which is a kind of high efficient ore crushing equipment. A kind of assembled roller, which is more convenient to renovate worn surface b y simply replacing segmented surface of the roller, was developed. The structura l models of assembled roller’s components were designed with SolidWorks softwar e based on feature modeling, these solid models of the roller were virtually ass embled. Through this work, not only was the assemble interference checked out so as to examine validity of the structure design, but also these solid models cou ld be recognized by COSMOS/Works software, through which the finite element an alysis can be done. Then the stress and displacement of the main shaft and sur face segment in two different working states were analyzed and detected quickly according to the analysis results with COSMOS/Works. In conclusion, the optimum clearance of 1.0～2.0 mm between concave-convex studded segments is determined to make the using life of assembled roller longer.

Effects of high pressure roller grinding on size distribution of vanadium-titanium magnetite concentrate particles and improvement of green pellet strength

The vanadium-titanium magnetite concentrate from Panxi region of China was pretreated by high pressure roller grinding（ HPRG） and then used in pelletization. Size distribution change of the vanadiumtitanium magnetite concentrate after HPRG and the improvement of its green pellet strength were investigated. The results indicated that,besides the increase of fine particles,the vanadium-titanium magnetite concentrate after HPRG had a smaller size ratio of fine particle to coarse particle of 0. 126,meaning a lower porosity,compared with the size ratio of raw material of 0. 157. The concentrate particles were more closely packed when there was a smaller size ratio of fine particle to coarse particle. The particle packing in the green pellets was closer after HPRG,which strengthened the green pellets with an average drop number of 5. 1（ drop height of 0. 5 m） and average compressive strength of 13. 1 N per pellet of 11 mm in diameter.

Heat Treatment of Centrifugally Cast High-Vanadium Alloy Steel for High-Pressure Grinding Roller

The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kind of roller material, the high-vanadium alloy steel （HVAS）, was investigated. The results showed that the as-cast microstructures of the HVAS roller contained martensite, residual austenite, and alloy carbides. The HVAS sample quenched at 1,080 ℃ had a high hardness, and it had much higher compressive strength and abrasive wear resistance after tempering at 560 ℃ for 30 rain. The mechanical properties of the HVAS are more sufficient than the existing roller materials, which are feasible for larger machine design.

南芬选矿厂北山矿石选矿工艺试验

为配合南芬铁矿绿色矿山选矿提效及高效利用北山原矿石,在工艺矿物学研究的基础上,对北山矿石进行了选矿工艺流程试验。试验结果表明:采用辊磨前干抛—高压辊磨—辊磨产品湿式抛尾—阶段磨矿—弱磁选工艺,干抛和湿抛可提前抛除合计产率23.26%的尾矿,大幅降低了后续入磨矿量,提升了入磨矿样铁品位,最终获得的铁精矿产率为30.77%,TFe和mFe含量分别为68.17%和60.22%,TFe和mFe回收率分别为66.63%和98.16%。

高压辊磨对某铜矿浮选指标影响的研究

为了研究高压辊磨破碎对国内某低品位铜矿石后续浮选指标的影响,采用单因素分析方法进行了高压辊磨破碎试验、浮选优化条件试验和浮选开路对比试验。结果表明,在磨矿细度-0.074 mm占65%,粗选氧化钙用量1000 g/t、MAC-12用量20 g/t、丁基黄药用量10 g/t,扫选MAC-12用量10 g/t、丁基黄药用量5 g/t条件下,经1粗1扫浮选流程,常规破碎产品浮选可获得铜、硫品位分别为4.31%和22.46%,铜、硫回收率分别为74.382%和79.053%的粗精矿;辊压产品浮选粗精矿铜、硫品位分别为4.76%和23.06%,铜、硫回收率分别为88.137%和87.082%。铜、硫品位分别提高0.45和0.60个百分点,铜、硫回收率分别提高13.755和8.029个百分点。由此可知,通过高压辊磨破碎作业,可提高该铜矿石浮选精矿的铜、硫品位和回收率。

高压辊磨机碎磨新工艺国内外研究及应用现状

高压辊磨机作为国内外选矿领域“多碎少磨”设备和选择性粉碎设备应用的主流,在选矿行业中的应用较为成熟,由于其具备单次处理矿石量大、粉碎效率高、且其粉碎产品粒度细的优点,因此被金属与非金属行业所广泛应用。对高压辊磨机的工作原理及粉碎过程进行了简要介绍,结合实际案例对高压辊磨机三种破碎工艺在矿山中的应用及优缺点进行了分析;对高压辊磨机在选矿行业的典型应用进行了介绍;对高压辊磨机新工艺在国内外的应用进行了重点阐述并就新工艺在选矿行业中的应用进行了展望,高压辊磨机联合搅拌磨/塔磨机工艺、高压辊磨机联合风力分级机工艺、两段高压辊磨机串联工艺、两高压辊磨并联工艺以及高压辊接双层振动筛节能降耗优势明显,有望为物料高效粉碎提供新的方案。

高压辊磨对超微细粒嵌布磁铁矿破碎和预选的影响

针对某超微细粒嵌布贫磁铁矿开发难度大、原矿入磨品位偏低、磨矿能源消耗高的问题,本文进行高压辊磨—预选工艺试验,通过对比两种破碎产品的粒度特征、相对可磨度、Bond球磨功指数、预选指标,并结合破碎产品的表面形貌和内部微裂纹,研究高压辊磨所产生的微裂纹对于磨矿和分选的影响。结果表明:相对于常规破碎,辊压产品中<0.074 mm粒级质量分数增加了14.69个百分点,>2 mm的粗粒级质量分数降低了8.59个百分点;在160 kA/m预选磁场强度下,辊压产品的铁品位为31.96%,提高了1.46个百分点;磁性铁的回收率高达99.45%,提高了1.17个百分点,抛尾率提高了5.03个百分点。相对可磨度试验结果表明,当磨矿细度达到<0.03 mm粒级质量分数为85%时,辊压产品的耗时相对于常规破碎缩短了42.13%。辊压产品的Bond球磨功指数(目标粒度<0.15 mm)降低了27.90%。偏光显微镜和SEM扫描电镜结果表明,辊压产品结构疏松多孔、微裂纹发育充分,能产生大量的晶界裂纹,解离更充分。

生料辊压机终粉磨系统节能减碳实践中存在的问题与对策

因原材料水分大、系统烘干能力不足、设备阻力大、高效选粉机结构缺陷等原因造成生料辊压机终粉磨系统运行不稳定且循环负荷大、停机次数较多、系统阻力大、循环风机拉风过大、细度跑粗现象,导致生料工段电耗偏高、成品细度合格率低。对物料特性、工艺流程、设备选型及运行、成品细度进行热工诊断和研究分析,并实施相应的设备、工艺及系统操作优化措施。优化后,生料辊压机终粉磨系统工段电耗降低了2.2kWh/t,选粉效率提升,成品细度明显改善,实现提质增效,节能减碳的目的。

基于活塞压载试验预测高压辊磨机静压功指数的方法

以Bond第三粉碎理论为基础,提出将静压功指数作为评价矿石高压辊磨机料层粉碎比能耗的指标。研究活塞压载试验中不同施载压力对矿石粒度、比能耗和破碎比的影响,确定不同矿石活塞压载试验的适宜条件。通过试验测定3种矿石的高压辊磨机静压功指数,并将其与高压辊磨机生产实践中粉碎同种矿石的净输入功率进行对比。研究结果表明:在活塞压载条件试验中,随着压力的增加,金矿、磁铁矿和钒钛磁铁矿这3种矿石粉碎产品细粒级质量分数增高、粒度分布更加均匀,三者粉碎效果的差异逐渐减小;在加载压力为80 MPa、加载速度为0.2 mm/s的情况下,金矿、磁铁矿和钒钛磁铁矿这3种矿石的高压辊磨机静压功指数分别为1.36、1.44和1.42 kW·h/t,试验所得高压辊磨机静压功指数与工业生产实际中净比能耗的相对误差绝对值在5.26%以内。试验结果可为高压辊磨机静压功指数的预测及设备选型提供理论基础。

峨口铁矿石高压辊磨粉碎产品粒度特性研究

峨口铁矿为了提高磨矿作业效率,降低选厂生产成本,对峨口铁矿细碎产品开展了高压辊磨辊面压力、辊面速度和含水率3种影响因素的条件试验研究,并采用R-R粒度特征方程对高压辊磨机粉碎产品的粒度特征进行了系统分析。粒度特性研究结果表明:随着辊面压力、辊面速度和含水率的增加,3种影响因素不同条件下的辊压产品的均匀性系数n均呈先增大后降低的趋势;由均匀性系数可知,当辊面压力为5.5 MPa、辊面速度为0.524 m/s、含水率为1%时的辊压效果最佳,辊压产品均匀性系数最大,粒度分布较为集中。在3种影响因素最佳条件下进行闭路辊压试验,结果表明,辊压产品中-1 mm含量达到69.99%,此时单位通过量为25.10 t/h,比功耗为1.88(kW·h)/t,增加高压辊磨后,矿石变得更易磨,降低了后续磨矿的作业能耗。

高压辊磨技术在铜冶炼渣粉磨工艺中的应用研究

对铜冶炼渣进行了高压辊磨开路试验、边料循环试验、闭路粉磨试验以及与颚式破碎机产品的磨矿对比实验,并对各产品进行了粒度分析。结果表明,铜冶炼渣经高压辊磨处理后,产品中细粒级含量明显增加,可磨度提高约36个百分点,高压辊磨有利于提高铜冶炼渣的磨矿效率和选矿技术指标。

高压辊磨对细鳞片石墨解离的影响

为了研究高压辊磨对细鳞片石墨的粉碎特征,通过对比不同粉碎产物的粒度组成和浮选精矿的粒度组成,得出高压辊磨产物和球磨产物的分离和护片效果。通过浮选动力学实验研究了高压辊磨产物和球磨产物的浮选率。在此基础上,利用扫描电镜对球磨浮选精矿和高压辊磨产物的微观形貌进行了表征,揭示了细鳞片石墨的解离和保护机理。研究结果表明:基于石墨鳞片本身的韧性和高压辊磨粉碎过程的线接触,高压辊磨对石墨鳞片有明显的保护作用,促进石墨的解离。浮选动力学试验表明:高压辊磨产物在实际生产中显著提高了细鳞片石墨的浮选速率和浮选指标。扫描电镜分析结果表明:高压辊磨促进裂隙沿着石墨和脉石的共生界面产生,促进了石墨的解离和鳞片的保护。该研究为细鳞片石墨保护和高效解离提供了理论指导。

智利某铁矿干磨干选工艺研究

本文研究智利某铁矿的干磨干选工艺,主要是为了解决矿山在缺水等不利条件下无法开发的难题,通过利用干磨干选工艺,矿山实现了资源的有效利用,并创造了经济价值。首先,通过对矿石的矿物组成、化学性质、嵌布粒度等原矿性质的分析,初步确定该矿石可以通过干磨干选的工艺进行回收。其次,试验室小型试验通过两段破碎将矿石破碎至−1 mm,经过三段干式磁选作业,可以获得品位大于58%的合格铁精矿。最后,在工艺矿物学及小型选矿试验的支撑下,探索出适合的工业选矿流程。通过两段破碎-两段高压辊磨-三段干式磁选作业,选出品位大于58%、回收率为70%左右的合格产品,为矿山的开发利用提供了合理的解决方案。通过研究发现,在干旱缺水地区,采用本文所提到的干磨干选技术,可以有效地解决传统选矿工艺中需要大量工艺水的问题,在舍弃部分金属回收率的前提下,能够实现矿山效益的最大化,为此类矿山的开发提供了技术思路。

白云鄂博西矿含铁岩选矿工艺试验研究

为实现白云鄂博西矿TFe品位13%~16%铁素资源(含铁岩)的回收利用,本文以含铁岩为研究对象,通过采用化学分析、X射线衍射仪、光学显微镜等检测手段研究其矿石性质,并在此基础上进行系统的选矿试验。研究结果表明:该含铁岩中TFe品位13.14%,可回收的主要金属矿物为磁铁矿,占全铁比例为52.28%。含铁岩需破碎至−3 mm时才能获得TFe品位20%以上的预选粗精矿,且通过阶段破碎-分级预选流程试验可获得尾矿抛除产率56.01%、粗精矿TFe品位20.62%、磁性铁品位14.80%、TFe回收率69.19%、磁性铁回收率94.27%的技术指标,推荐采用三段破碎-两级预选-高压辊磨超细碎抛尾的原则流程作为预选技术改造方案。将预选粗精矿细磨至−0.045 mm含量85.80%时,经过两次弱磁选后最终获得TFe品位65.10%、TFe回收率50.25%、磁性铁回收率93.03%的合格铁精矿。该研究结果可为含铁岩的高效回收利用提供科学依据。

高压辊磨技术在铜冶炼渣选矿中的应用研究

介绍了高压辊磨技术的原理及其铜冶炼渣处理现状,为后续实验提供了理论基础;设计了高压辊磨机械结构,并分析了高压辊磨机械工作原理;分析了高压辊磨工艺参数,包括辊磨原理与磨削切入线与磨削宽度;仿真分析验证了工艺参数的有效性。结果表明:高压辊磨处理后的渣粒度分布更加均匀,颗粒尺寸更为细致,同时渣中有价金属的析出率显著提高。

抄浆靴压配对辊的加工研究

抄浆靴压配对辊为造纸设备的关键部件,主要由靴压配对辊轴头(传动侧)、靴压配对辊轴头(操作侧)、靴压配对辊辊壳构成。其两端轴头与中间辊壳采用过盈配合,装配后采用螺钉进行把合加固,因产品外形尺寸大,质量重,又属于过盈装配,保证装配间隙所需的加热方式、加热时间等极难控制,工件的起吊、把合孔的定位等装配难度也大。同时两端轴头及辊壳形位公差要求高,加工及制造难度大。介绍了抄浆靴压配对辊的加工方法。

微合金化与轧制工艺对Φ100 mm 80MnCr高碳磨球钢性能影响的研究

采用Ti和Al两种性价比高的细化晶粒元素进行微合金化以及粗轧大压下和轧后缓慢冷却的轧制工艺,研究了微合金化和轧制工艺对大规格轧球用高碳磨球钢80MnCr的内部质量和奥氏体晶粒度的影响作用。结果表明,增加粗轧阶段单道次压下量和优化轧后缓冷工艺对钢材低倍组织和超声波探伤合格率都有较好改进作用,特别是超声波探伤合格率,探伤合格率由90.5%提高到100%。在钛和铝微合金化作用下,结合粗轧阶段的大压下的轧制工艺,使得钢材的奥氏体晶粒度进一步细化,奥氏体晶粒度级别由6级细化为7级。