分级式冲击磨制备硫磺粉

针对硫磺粉的易燃易爆特性和粉碎要求,对现有分级式冲击磨的结构进行研究;对粉碎、分级和收集系统的操作参数、设备结构以及系统运行过程中出现的静电积聚、粉尘爆炸等问题进行分析探讨和优化改进,通过加工硫磺粉的工业试验,对改进后的分级式冲击磨进行测试。结果表明,控制粉碎主机转速为1 500 r/min,分级机转速分别调为450、600、750 r/min,袋式除尘器过滤风速为0.94 m/min,获得的成品硫磺粉的粒径d97分别为107.79、74.21、46.15μm,产率分别为3.650、2.802、2.205 t/h,单位能耗分别为31.929、43.012、58.095 k W·h/t。     

分级式冲击磨制备玉米秸秆粉体

为了得到生物质粉体并使其产量最大化,采用分级式冲击磨在干法状态下制备玉米秸秆粉体,考察锤头安装方式、进料方式、轨道与锤头间距和系统流量对粉体产量的影响。结果表明,磨盘上方安装锤头的情况下玉米秸秆粉体产量较高;上进料时粉体产量比下进料时提高15.89%;轨道间距为5⁷ mm时粉碎效率较间距为37 mm时粉碎效率较间距为3⁵ mm时高;在一定范围内,粉体产量随着系统流量的减小而提高;最佳条件下,平均粒径为30.13μm的玉米秸秆粉体产量高达103.4 kg/h。     

分级式锤式冲击磨加工石油焦粉

针对石油焦的特性与粉碎要求,对现有分级式锤式冲击磨的结构进行研究,主要对粉碎速率、锤头与轨道之间的距离、设备磨损、分级精度、收集系统稳定性及安全问题进行探讨、改进及优化,设计出LNI-660A型分级式冲击磨,通过实际加工石油焦粉的工业应用,证明了该设备锤头使用寿命高达2 400 h以上,当石油粉产品粒度d90<68.98μm时,产品达3.5 t/h以上,并且部件磨损较小,能有效地控制大颗粒,系统运行稳定。     

LNI-66A型分级式冲击磨磨损实验研究

采用LNI-66A型分级式冲击磨对粗碎后的水牛角粉进行粉碎,考察锤头数量、锤头高度对产量、锤头磨损量、磨盘磨损量的影响。结果表明:粉体产量随着锤头数量的增加而逐渐降低,随锤头高度的增加而先增大后减小,当锤头数量为4个,锤头高度为30 mm时,粉体产量最高;随着锤头数量的增多,锤头磨损量逐渐降低,随着锤头高度的增加,锤头磨损量先减小后增大,当锤头高度为30 mm时,锤头磨损量最低;磨盘磨损量随锤头数量、锤头高度的增加,无太大变化。     

冲击磨制备云母氧化铁及其重防腐涂料应用

为提高传统球磨法生产云母氧化铁的产品质量,设计并实验新的生产工艺,采用冲击磨对云母氧化铁原矿进行粉碎,用多转子分级机进行分级,用布袋除尘装置进行除尘;通过变换冲击磨的工作条件,得到不同粒度和粒度分布的云母氧化铁粉体产品;对产品进行粒度分析,测试其应用在涂料中的防腐蚀性能,并与球磨法制备的云母氧化铁产品进行对比。结果表明,冲击磨制备的云母氧化铁其粗粉产品和细粉产品均能符合云母氧化铁的国家或行业标准,其总产率在90%左右;经过冲击磨粉碎的云母氧化铁在保存片状结构的同时,在粒度和粒度分布上得到明显改善,应用于涂料中也表现出优越的防腐蚀性能。     

分级式冲击磨破碎废弃印刷电路板实验及功耗分析

针对废弃印刷电路板具有硬度高、韧性强的特点,采用具有冲击、剪切作用的分级式冲击磨对粗碎后的废弃印刷电路板物料进行细碎实验研究,根据实验数据,利用Rittinger面积学说对破碎功耗进行分析。结果表明:使用分级式冲击磨能够实现对废弃印刷电路板的充分破碎,并且当破碎粒径小于0.6 mm时,金属与非金属能够完全解离;分级式冲击磨破碎废弃印刷电路板过程中粒度分布规律符合Rosin-Rammler粒度特性方程式;随着破碎粒径的减小,破碎比表面功耗增大,当平均粒径小于0.312 mm时,比表面功耗急剧增加。     

搅拌磨制备超细粉体粉磨工艺的研究

通过模型实验 ,系统地研究了矿浆浓度、搅拌器转速、球料比、研磨介质种类及尺寸等主要操作参数对搅拌磨粉磨效果的影响规律 ,并分析了产生这种影响的原因     

分级式冲击磨及其分级机阻力损失的研究

为了研究分级式冲击磨以及分级机的阻力特性,对LNI-610-30型分级式冲击磨进行了阻力损失的现场测试与研究。结果表明:在相同流量下,单独开启冲击磨或分级机,其各自的工作阻力损失随各自传动转速的增大而增大;同时开启时(两者转向相反),由于各自形成的涡流场的相互影响,其总体阻力损失小于二者在同转速下分别开启时的阻力损失之和,其差值随着两者转速的增大而增大。     

扁平式气流磨制备超细粉料的研究

对I0型扁平式气流磨粉碎性能进行了研究 ,以α Al2 O3 为粉碎物料 ,探讨了加料速度、工质压强对粉碎效果的影响 ,并优化了气流磨的工艺操作条件 ,在最优工况下确定极限粒径     

半导体制造业用微纳米碳化硅粉体制备工艺研究

采用水流分级和高能纳米冲击磨对原始SiC粉料进行微纳米粉体加工。研究结果表明:水流分级得到纯度98.42%、中位粒径0.404μm的SiC粉体,比表面积由0.8879m2/g提高到8.0321m2/g;高能冲击磨得到纯度95.5%、中位粒径0.257μm的SiC粉体,比表面积由0.8879m2/g提高到8.2773m2/g,SiC的粒径及比表面积达到半导体制造业用微纳米碳化硅粉体的技术标准。纯度分析表明碳化硅粉体的水流分级未引入杂质,化学成分基本不变;SiC粉体冲击磨加工纯度下降,其他杂质含量偏高。粉体形貌分析表明原始SiC粉料形貌为非球形,粒度分布不均匀,水流分级和冲击磨加工碳化硅粉体形貌为非球形,粒度分布较加工前更均匀。     

球磨仪研磨硫磺粉的静电作用

采用高频振动球磨仪研磨硫磺,对研磨过程中硫磺粉的起电特性进行测试和分析。结果表明:控制研磨转速分别为1 200、1 500、1 800 r/min时,薄片状硫磺带静电量到达饱和值的时间为40、60、100 s,荷质比增大速率为0.269、0.470、0.700 nC/(g·s),粉状硫磺所带静电量到达饱和值的时间分别为30、40、70 s,荷质比增大速率为0.416、0.701、0.979 nC/(g·s);采用碳化钨材质的研磨体,研磨后的硫磺粉所带静电量最小,不锈钢研磨材质的是碳化钨的1.39倍,氧化锆研磨材质的是碳化钨的3.82倍;增大硫磺粉的湿基含水量能够有效减小研磨过程中硫磺粉所带的静电量,当湿基含水量为0.8%时,研磨硫磺粉的饱和静电量几乎减小为0。     

Preparation of waste glass powder by different grinding methods and its utilization in cement-based materials

Waste glass, as a hard-to-grind material, was often grinded into powder by ball-mill in order to be used as a supplementary cementitious material in concrete. In this study, three different glass powders (GP) referred to as GPd, GPw and GPe were fabricated by different methods (i.e. dry condition, water condition and ethyl alcohol condition), and the effect of GP on the properties of cement-based materials was systematically evaluated. The results showed that the milling efficiency of GP was significantly affected by grinding condition. Ultrafine GP can be obtained as additional water or ethyl alcohol was added during the grinding process. GP showed low pozzolanic reactivity in the early age, even when the particle size was decreased to about 300 nm. GPd with large particle size and non-absorbent feature could increase effective water-to-cement ratio and thus improved the workability and early strength of specimens containing GPd, while the later strength was lower than that of reference ones due to low pozzolanic reactivity of GPd. In contrast, specimens containing GPw and GPe exhibited higher early mechanical strength than reference specimen due to the filling and acceleration effects of GP. An encouraging result indicated that GPe presented high pozzolanic reactivity at 28 d, which was seldom reported in the literature.     

Preparation of copper powder by glycerol process

A simple, least energy intensive, efficient, low temperature chemical process for the production of copper powder of narrow size distribution is described. It involves reduction of copper salts by glycerol under atmospheric conditions at a temperature below 240°C. The powders produced by this process have been characterized by X-ray diffraction, chemical composition, BET surface area analysis and scanning electron microscopy. The powder is well crystalline and contains oxygen, carbon, and hydrogen as impurity elements. The purity of the powder produced by the process depends on the starting compound of copper. The glycerol process using copper acetate as starting compound yields copper powder having a purity of 99.7%.     

Mechanism and kinetics of grinding of zirconium dioxide powder

A model of grinding for dispersed powders of brittle substances is proposed within the framework of a phenomenological approach. The mechanism is established and the kinetics of grinding of a ZrO₂ powder is described. Scientific Research Institute of the Problems of Powder Technology and Coatings, Perm'. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 69, No. 1, pp. 3–8, January 1996.     

Preparation of nitinol by non-conventional powder metallurgy techniques

The aim of the present paper was to compare the evolution of Ni–Ti intermetallics in two non-conventional production techniques for the synthesis of NiTi shape memory alloy. Short term ultrahigh energy mechanical alloying is proposed to be able to describe the early stages of the milling process, which was not described in the literature previously, and to obtain intermetallics in shorter process durations. The reactive sintering using high heating rate (>300°C?min^??1) is a process designed to suppress the formation of secondary intermetallics and to reduce the porosity of the product. The same phases' formation sequence was determined for both processes. The detrimental Ti₂Ni phase forms preferentially, and therefore, its presence cannot be avoided in any of the investigated techniques.     

Preparation of extrapure Ga2S3 by reacting GaI3 with sulfur

This paper describes a process for the preparation of extrapure gallium(III) sulfide by reacting gallium(III) iodide with sulfur in an evacuated two-zone quartz glass reactor. The maximum synthesis temperature was 350°C. The residual iodine was removed by calcining the powders at temperatures from 500 to 650°C. The gallium(III) sulfide yield was 93–96% of theoretical yield. The samples were characterized by X-ray microanalysis, X-ray diffraction, and laser mass spectrometry and were shown to contain the following impurities (ppm): silicon, 20–28; iron and calcium, 0.5–0.6; potassium, 0.3–0.7; chromium, 0.2; chlorine, 70–100; aluminum, 0.05–0.1; and phosphorus, 0.1–2. The iodine content varied from 0.04 to 1.8 at %, depending on calcination temperature and time.     

Preparation of metal alloy powder by semi-solid processing

A laboratory study was carried out, using Pb–15 wt.% Sn alloy on self-made apparatus, to determine the solidification behavior of the semi-solid slurry with the solid fraction beyond 0.6. It is found that the solid–liquid separation is obvious in the samples with the solid fraction beyond 0.6. According to this character of semi-solid processing, a kind of single-crystal powder coated with Pb–Sn eutectic was made during continuous stirring and cooling processes. The analysis and discussion indicated that this approach can reduce the content of oxide and impurity in the powder.     

Predicting the flowability of alumina powder during batch grinding through the establishment of a grinding kinetic model

Grinding is one of the main unit operation in industrial processes handling powders. The particle size reduction that takes place during grinding tests, usually results in a significant change in the flow behavior of the ground powder. Up to now, a model predicting the evolution of powder flowability with grinding time, according to the operating conditions is still missing. In this paper, a methodology combining a grinding kinetic model and a flowability model involving the population-dependent granular Bond number is developed. The methodology has been applied to an alumina powder, ground in a batch ball mill. The flow function coefficient of the ground samples is measured after various grinding times in a powder shear tester. The comparison between model predictions and experimental data shows that this method allows an accurate prediction of the powder flow behavior over the first sixteen minutes of grinding.     

反相胶束法制备纳米ZrO2粉体

利用NA/煤油-n-C6-OH/NH3@H2O反胶束体系,制备了纳米ZrO2粉体.采用TG-DTA、TEM、XRD等手段对粉体及前驱体进行表征粉体粒度分布均匀,无硬团聚,平均粒度为20～40nm.并且研究了反相胶束中的溶水量对ZrO2粒径的影响以及pH值对ZrO2晶型的影响.并推测20～40nmZrO2的单斜晶(m)与四方晶(t)可能的相转变温度为723℃,比相应的体相材料降低了近450℃.