浅谈矿料混合料的质量控制

针对沥青混合料的质量问题,对矿料原材料不合格和混合料级配不合格的产生原因进行了初步分析,并提出了一些质量控制方法,以保证矿料混合料的质量,从而保证沥青混合料的质量。

基于铅同位素比值的古代矿料混合模型分析法

为深入研究古代青铜器示踪矿料来源中矿料混合问题,通过铅同位素研究数据构建矿料混合模型,从理论上探讨满足条件的青铜器数据样本其矿料混合的情况。基于模型,通过对铅同位素数据的处理,不仅能够匹配相应的矿料混合模式,而且可为器物分类提供依据。此外,还可计算出相应的铜料中表观含铅量,为相关研究提供参考依据。

混合料矿槽模糊预估器的建立

混合料矿槽料位控制系统是一个大滞后、非线形、时变的控制系统。本文应用模糊预估器去实现混合料矿槽料位控制 ,通过近一年的运行 。

混合尾矿料的工程特性试验研究

根据室内试验,研究了一种尾矿料在掺入不同比例的粉煤灰后,其物理力学性质发生的变化情况,从而分析了粉煤灰掺量对这种尾矿料的工程特性的影响规律。由试验结果分析知,在掺入粉煤灰适量的情况下,其混合料仍然是一种良好的筑坝材料。这样,在满足筑坝材料物理力学性质的前提下,增加了筑坝材料的产量,满足了筑坝进度的需求。

细集料密度对沥青混合料矿料间隙率值的影响

研究了我国的VMA规定值和计算方法。指出了我国普遍使用的马歇尔设计方法,根据集料公称最大粒径规定的最小VMA值,与美国马歇尔设计方法给定的最小VMA及美国Superpave设计方法规定的最小VMA值,本质上是一致的,但计算方法却不同。采用现行计算VMA的4种方法,计算了25种工地沥青混合料的VMA值。我国的粗集料用毛体积相对密度,细集料用表观相对密度计算VMA的方法和美国的方法所用公式形式一样,但我国计算的VMA比美国方法计算的VMA均偏大。在实际使用时,建议按照细集料含量与细集料平均吸水率的乘积大小,修正我国计算公式,使之接近沥青混合料的真实VMA。

尾矿坝混合料特性及加高扩容稳定性研究

通过三轴固结排水剪切试验,分析尾矿料与粉煤灰不同配合比的力学特性及加高扩容后尾矿坝体的安全稳定性,确定合理的工程施工配比。结果表明:掺入适量的粉煤灰后,混合料具有较好的工程力学性质,能够满足坝体的抗滑稳定要求。

300m^2烧结机混合料矿槽内壁黏结料清除爆破

马钢第二炼铁总厂1#300 m2烧结机主要为1#2 500 m3高炉提供烧结矿。多年来,烧结机的关键设备之一混合料矿槽在生产过程中,内壁时常出现不同程度的黏结料,既影响了生产效率,又影响了设备的安全运行,人工或机械清理时间长,无法满足检修工期要求,并存在诸多安全隐患。经反复论证,采用爆破法清除,对爆破技术方案、爆破参数进行了详细分析,并对爆破施工方案进行了讨论,实践效果显著,可供类似工程借鉴。

260m^2烧结机混合料矿槽粘料原因分析与解决措施

介绍了红钢260m^2烧结机混合料矿槽投产以来出现的矿槽本体粘料、矿槽下料不均匀等问题,通过矿槽结构优化、粘贴陶瓷衬板、增加空气炮等措施彻底解决了混合料矿槽粘料的问题。

烧结生产中混合料矿槽料位的自动控制

本文针对烧结生产过程中的物料平衡问题，提出了用建立控制模型的方法，实现混合料矿槽料位的自动控制，并结合我厂计算机控制系统给出控制程序的实现方案。

路面混合料级配组成设计算法研究

路面混合料矿料级配组成设计是工程设计的重要组成部分,传统的试算法和图解法工作量大,易产生误差.针对这种情况,根据实际施工需要建立符合矿料级配设计实际情况的数学模型.此模型不仅以设计级配为目标,还考虑了混合料组成中关键筛孔尺寸的通过率.经过对模型算法1范数和2范数分析比较后,选择对应模型取1范数的算法———线性规划法为路面混合料级配组成设计的优化算法.经实例检验,该方法可用于各类路面混合料级配组成设计.

浅析沥青拌和楼调试及混合料质量控制要点

沥青路面因具有表面平整、无接缝、耐磨、噪音低、行车舒适、施工期短、养护维修简便且适宜分期修建等优点,在高等级公路路面结构中得到了广泛的应用。为了满足现代公路交通运输需要,充分发挥沥青路面坚实、平整、抗滑、耐久的品质,施工过程中涉及到原材料的确定、配合比设计、施工机具组合、施工方法及技术性能检测等各个环节。现就间歇式拌和设备在拌和过程中影响拌和质量的几个因素进行分析与总结。

Comparative study on chalcopyrite bioleaching with assistance of different carbon materials by mixed moderate thermophiles

The catalysis of four carbon materials including artificial graphite(AG), carbon black(CB), activated carbon(AC) and carbon nanotube(CN) on chalcopyrite bioleaching by mixed moderate thermophiles was comparatively investigated. In AC and AG added bioleaching groups, low solution pH and suitable redox potential values, high total iron and ferric iron concentrations, and large number of adsorbed bacteria were obtained, resulting in high copper extractions. CB and CN inhibited the growth of bioleaching bacteria and led to the low bioleaching efficiency.X-ray diffraction analysis showed that jarosite and sulfur film were the main components of passivation layer with the addition of AG and AC,but did not hinder the dissolution of chalcopyrite. Microbial community structures of free and attached cells in AC and AG added groups changed dramatically compared with mixed moderate thermophiles. The sulfur-oxidizing bacteria of A. caldus S1 strain dominated the microbial community(93%-98%) at the end of bioleaching.The iron-oxidizing bacteria of L.ferriphilum YSK only accounted for low percentage(1%-2%).

Optimum blending of iron ore from Choghart stockpiles by using goal programming

Iron and steel industry is an important sector of Iran's economy.Choghart iron ore mine is an important iron ore producer of Iran steel industry.Phosphorous contained in the iron ore concentrates of Choghart mine has a detrimental effect on the steel making process,whereby this causes cracks to form in the refractory lining of blast furnaces.In the past,about 1.43 Mt of low-grade and 4.53 Mt of high-phosphorous materials had been transported to low grade and high phosphorous stockpiles,respectively,for future beneficiation.As a result of the progressive depletion of high-grade ore and establishment of beneficiation plant in Choghart,exploitation of these two stockpiles in this mine became an important issue.In this work,a linear goal programming(GP) model was developed in order to determine the optimum iron ore blend in terms of quality from low grade and high phosphorous stockpiles of Choghart mine.The model was solved by the SOLVER V.9 program.Results show that feeding with acceptable quality(w(Fe)≥50% and w(P)≤1.2%,mass fraction) materials can be blended from stockpiles that satisfy the needs of the Choghart processing line.

Portable mixed abrasive water jet equipment for rescue in high gas mine shaft

In order to rescue a trapped miner and clean out roadways quickly in a high gas mine shaft after a mining mishap, a special portable cold-cutting equipment is needed, the main technology parameters were calculated according to the advanced cold-cutting technology of high pressure abrasive water jet and the portable mixed abrasive water jet equipment （PAWE） was designed to meet the needs of emergency rescue in high gas mine shafts. Tested the PAWE in a high gas environment, and the result shows that the maximum cutting depth of solid iron pipe is 18 mm and the recoilforce of the sprayer is 28.9 N under the conditions that actual cutting pressure is 29 MPa, starting target distance is 10 ram, cutting speed is 180 mm/min and concentration of abrasive is 32%. The course of the experiment in the high gas environment was smooth and continuous, without any explosion. The PAWE is easy to move and operate, but the nozzle which was worn badly in the sprayer should be changed every 8 minutes.

Chloride ion penetration into concrete under hydraulic pressure

The lining concrete of subsea tunnel services under combined hydraulic pressure, mechanical and environmental loads. The chloride ion and water penetrations into concrete under hydraulic pressure were investigated. The experimental results indicate that the water penetration depth, chloride ion transportation depth, and the concentration of chloride ion ingression into concrete increase with raised hydraulic pressure and hold press period. But the chloride ion transportation velocity is only 53% of that of water when concrete specimens are under hydraulic pressure. The chloride transportation coefficient of concrete decreases with hold press period as power function. And that would increase 500% 600% in chloride transportation coefficient when the hydraulic pressure increases from 0 to 1.2 MPa. The hydraulic pressure also decreases the bound chloride ion of concrete to about zero. Besides, the low water-cementitions materials and suitable content of mineral admixture(including fly ash and slag) improve the resistance capacity of chloride penetration, and binding capacity of concrete under hydraulic pressure.

Biological Protection against Fungal Diseases of Winter Wheat under Different Soil Tillage Technologies

The effect of biopreparations, homogenized with the seed （seed treatment before sowing as a dressing）, and used as a mixture with mineral fertilizer ANL （ammonium nitrate with limestone）, upon both grain production and the health state of the winter wheat were evaluated during 2006-2009. Besides conventional soil cultivation, reduced tillage with incorporated chopped straw, and direct drilling into untilled soil covered with mulch, were also used. The following biopreparations were applied： Supresivit （Trichoderma harzianum）, Polyversum （Pythium oligandrum）, and Trianum P （a different strain ofTrichoderma harzianum）. Attention was focused on the foliar fungi pathogens Drechslera tritici-repentis, Septoria tritici, and Alternaria triticina, as well as on the soil-borne pathogenic fungi of the genus Fusarium.

On carbonation behavior of recycled aggregate concrete

This study tries to reveal the carbonation behavior when recycled coarse aggregates(RCAs) are used to mix new concrete.Six series of tests including 22 groups of recycled aggregate concrete(RAC) specimens were carried out,in which the effects of the water/binder(w/b) ratios,the binder content,the types of mineral admixture,the quality of RCAs,the RCAs replacement and the loading levels on the carbonation behavior of RAC were evaluated,respectively.The results showed that the carbonation behavior of RAC was not only influenced by the quality of new mortar but also by the properties of RCAs.The admixture of mineral admixture influenced the carbonation,and the loading stress level might have a significant impact on the evolution of the carbonation.

Deterioration of dynamic mechanical property of concrete with mineral admixtures under fatigue loading

The dynamic mechanical property of concrete is one of the key parameters,which greatly influences durability of infrastructures subjected to continuous heavy loading,such as girder and track slab of high-speed railway foundation structure.This paper reports serials of experiments designed to investigate the deterioration of dynamic mechanical properties of different concretes under fatigue loading condition.Four parameters including relative dynamic elastic modulus(RDEM),relative dynamic shear modulus(RDSM),relative compressive strength(RCS)and water absorption(WA)of concrete were evaluated to assess the dynamic properties and microstructures of concretes.Results show that the fatigue stress levels and fatigue cycle durations significantly influence the dynamic mechanical properties of concrete including dynamic elastic modulus and dynamic shear modulus.Addition of proper mineral admixture can improve the dynamic mechanical characteristics of concrete and increase its resistance against the fatigue loading effect.Keeping the amount of mineral admixture in concrete constant,its dynamic mechanical property with fly ash is lower than that with fly ash and silica fume.The water absorption in concrete,which is an indirect parameter reflecting capillary porosity,increases evidently after bearing fatigue-loading.There is a close correlation between the deterioration of dynamic mechanical property and the increasing of water absorption of concrete.This indicates that the damage of microstructure of concrete subjected to fatigue loading is the indispensable reason for the decay of its dynamic mechanical performance.