Utilization of Coal Gangue and Copper Tailings as Clay for Cement Clinker Calcinations

In order to avoid environmental pollution from Coal gangue (CG) and copper tailings (CT), the utilization as cement clinker calcinations was experimentally investigated. Low-calcium limestone was also selected as another raw material. The clinker component and microstructure were analyzed by XRD and SEM. The experimental results showed that qualified cement clinker could be generated by substituting CG and CT compound for clay. While mixed with high-calcium limestone and low-calcium limestone, the calcinati...     

煤矸石代黏土煅烧水泥熟料配方优化试验研究

为获得煤矸石代黏土配料应用于水泥生产的煅烧热工条件和合理配方,选取不同煤矸石和不同品位的石灰石等原料配制6种水泥生料,在实验室熟料煅烧试验台中进行不同温度下煅烧水泥熟料的试验研究,对试验所得的熟料样品分别进行了游离CaO质量分数的测定和矿物组成的X射线衍射（XRD）分析.试验结果表明：煤矸石代黏土与中钙石灰石和高中钙石灰石配料,都能烧制出合格的水泥熟料,烧成温度比黏土配料的烧成温度降低50 ℃以上;而煤矸石与高钙石灰石的配方则在烧成温度上没有明显优势,说明煤矸石与中钙石灰石或高中钙石灰石配料更能烧制出高质量的水泥熟料.     

Composition Design for High C3S Cement Clinker and Its Mineral Formation

A new composition of Portland cement clinker was studied, in which KH, SM and IM was 0.98,2.4 and 2.4 respectively as well as its meal added 1%CuO （in mass）. Fired at 1 200℃,1 350℃,1 400℃ and 1 450℃ for 30 min, the resultant mineral phases component and mineral morphology were analyzed. The performances of the cement which was made of clinker burned at 1 450℃ and fly ash were determined. By means of QXRD, XRD and optical microscopy, it is shown that the clinker burnt at 1 450℃ has the larger size crystals and distinct crystal interface, in which the C3S content is 73.37% and the mineral phases is dominantly C3S, following by minor C2S, C3A and tetracalcium aluminoferrite. The results reveal that a new type of high C3S content clinker can completely be made by traditional temperature-time schedule. The performances of the cement produced from this clinker with addtion of 50% fly ash and 5% gupsum were in agreement with the 32.5 strength grade of Portland fly-ash cement. The results also show that the clinker has a significant effect of saving energy and utilizing waste slag.     

稀土尾矿对水泥熟料性能的影响

试验选用云南楚雄州某地稀土尾矿,以稀土尾矿部分取代黏土原料进行水泥熟料煅烧试验。试验结果表明:掺入稀土尾矿及铅锌矿烧成熟料中的f-CaO含量明显减少,生料的易烧性提高;其3 d、7 d和28 d抗压强度均有不同程度的提高;水泥熟料中的C3S、C3A和C4AF含量有所增加,对水泥熟料的烧成起到促进作用,有利于水泥熟料矿物的形成,尤其是熟料中的C3S增加明显。     

Comparison of temperature field distribution between cement preclinkering technology and cement precalcining technology

Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology,we studied the characteristics of temperature field distribution of cement preclinkering technology systems including cyclone preheater,preclinkering furnace,and rotary kiln.We used numericalsimulation method to obtain data of temperature field distribution.Some results are found by system study.The ratio of tailcoalof cement preclinkering technology is about 70%,and raw mealtemperature can reach 1070 ℃.Shorter L/D kiln type of preclinkering technology can obtain more stable calcining zone temperature.The highest solid temperature of cement preclinkering technology is higher than 80 ℃,and high temperature region(1450 ℃)length is 2 times,which is beneficialfor calcining clinker and higher clinker quality.So cement preclinkering technology can obtain more performance temperature filed,which improves both the solid-phase reaction and liquid-phase reaction.     

Effect of Minor Elements on Silicate Cement Clinker

The effect of rare-earth and HX addition agent on the burn-ability of silicate cement dinker was investigated by orthogonal experiment. The result shows, compared with blank sample, f CaO of the .samples added with rare-earth and HX agent drops by 84.95% , its 3 d and 28d compressive strength enhances by 24.40% and 16.90% , respectively. It was discovered by means of X-ray diffrnction and high temperature microscope analysis that sintering temperature of the sample added with rare-earth and HX addition agent is about 1320℃. At the same time, the tmrning temperature of triealeium silicate desends and its crystal growth forming- rate increases. Tricalcium silicate content in burning clinker is higher and its crystal is larger.     

镁渣配料煅烧水泥熟料的动力学研究

采用生料易烧性方法进行了实验,应用金斯特林格方程和阿累尼乌斯公式得出了熟料形成反应速率常数和熟料形成反应的表观活化能,利用XRD分析了镁渣的矿物组成。结果表明：镁渣可作为硅酸盐水泥熟料煅烧的原料使用,而且还可显著降低熟料形成反应的表观活化能,降低熟料的煅烧温度,加快熟料矿物的形成,缩短烧成时间。     

污泥制备水泥及其重金属释出的初步研究

城市污泥的最佳出路是无害化处理，资源化利用，产业化发展，将城市污泥作为生态水泥的生产配料是目前污泥资源化利用的新途径。该文将城市污泥作为配料分别按照6％和20％的比例与粘土混合制成水泥并养护7天后，测定水泥熟料的一些物理化学性质以及水泥固结体的重金属浸出含量。研究结果表明：与粘土相比，污泥有烧失量大、杂质含量高、A1203含量偏低的特点；以低比例污泥制备成的水泥熟料的化学成分、矿物组成和物理性能更接近于普通水泥熟料；水泥固结体中铅、镉、总铬、铜和锌可浸出含量未超出GB5085．3—1996浸出毒性标准，表明污泥中的重金属离子得到有效的束缚。     

磷渣基复合矿化剂对水泥熟料烧成的影响

研究了在水泥生料中掺入不同矿化剂对水泥生料的易烧性、硅酸盐水泥熟料矿物形成和岩相结构的影响：结果表明，与传统的萤石和磷渣矿化剂相比，磷渣与萤石复合的矿化剂可有效降低水泥熟料中游离氧化钙（f-CaO）的含量，改善生料的易烧性；在煅烧温度与时间增加的情况下，改善作用仍然明显；通过XRD、SEM与岩相结构分析表明，磷渣与萤石的复合矿化剂降低了液相的粘度，促进了A矿的生长，对矿物的结晶形态有改善作用，有利于晶体尺寸的生长发育。     

粉煤灰矿渣复合水泥试验研究及其应用

通过试验研究了粉磨方式、细度、复合组分比例及添加剂对粉煤灰、矿渣、石灰石与少量熟料组成的复合水泥性能的影响 .研究结果表明 :当以上三组分比例适当时 ,通过添加剂的有效作用 ,采取合理的粉磨工艺和制度 ,在熟料掺量 5 0 %时可以配制出 6 2 5R或 6 2 5复合水泥 ,熟料掺量 4 0 %可以配制出 6 2 5或 5 2 5R复合水泥 ,熟料掺量 30 %可以配制出 5 2 5或 4 2 5R复合水泥 .同时 ,对上述部分水泥配制的高性能混凝土进行了试验研究     

煤矸石代替黏土生产水泥可行性分析

为了研究煤矸石代黏土生产水泥的可行性,对10个省份28个矿点进行取样,开展煤矸石特性分析.分析结果表明,煤矸石具有高灰分、高硫分和低热值等特点,化学成分与黏土相近,还含有较丰富的微量元素和矿物组成.对煤矸石、中钙石灰石和硫酸渣等配料进行煅烧试验,试验表明,煤矸石在煅烧时,微量元素和矿物释放其储存的地质能量,加速促进硅氧键的断裂,比黏土配料更早生成硅酸三钙、硅酸二钙和铝酸三钙等水泥熟料矿物.煅烧过程中放出的二氧化硫与钙铝氧化物反应形成早强硫铝酸盐水泥熟料矿物,从而减少硫化物对环境的污染.     

石灰石矿粉在水泥混凝土中的应用

开发出了一种石灰石复合激发剂，应用该种激发剂可以用抗压强度52．5MPa的熟料稳定生产出石灰石混合材掺量为30％的42．5MPa水泥。同时该种复合激发剂对于大掺量石灰石粉的混凝土也具有良好的增强作用，并且石灰石矿粉可以有效改善混凝土的收缩性能。因此认为，石灰石作为一种新型改性材料在水泥混凝土中具有良好的应用前景。     

Determination of the apparent activation energy of concrete carbonation

Accelerated carbonation experiments about the development of carbonation rates of ordinary Portland cement concrete under different artificial climates were carried out. Six water cement ratios and six climate condition combinations of temperature and relative humidity were used. Results indicate that changes of concrete carbonation rate with environmental temperature agree the Arrhenius law well, which suggests concrete carbonation rate has obvious dependence on temperature. The higher the temperature is, the more quickly the concrete carbonates, and at the same time it is also affected by environmental relative humidity. Thereafter, the apparent activation energy E _a of concrete carbonation reaction was obtained, ranging from 16.8 to 20.6 kJ/mol corresponding 0.35–0.74 water cement ratio, and lower water cement ratio will cause the apparent activation energy increase. Concrete carbonation rates will increase 1.1–1.69 times as temperature increase every 10 °C at the temperature range of 10 to 60 °C.     

Numerical simulation of heat transfer process in cement grate cooler based on dynamic mesh technique

A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled heat transfer process between the cooling air and clinker in a grate cooler. In this study, we use the Fluent dynamic mesh technique and porous media model through which the transient temperature distribution with the clinker motion process and steady temperature and pressure distribution are obtained. We validate the numerical model with the operating data of the cooling air outlet temperature. Then, we discuss the amount of mid-temperature air outlet and average diameter of clinker particles, which affect the heat effective utilization and cooling air pressure drop in clinker layer. We found that after adding one more mid-temperature air outlet, the average temperature of the air flowing into the heat recovery boiler increases by 29.04°C and the ratio of heat effective utilization increases by 5.3%. This means heat recovery is more effective on adding one more mid-temperature air outlet. Further, the smaller the clinker particles, the more is the pressure drop in clinker layer; thus more power consumption is needed by the cooling fan.     

Influence of characteristics of alumina-silicate raw materials on the formation process of clinker

The traditional alumina-silicate raw materials, for example, clays, in the precalcining technique of cement production, have been replaced by low grade and high silica content sandstones, shales, and industrial waste residues, including fly ashes, slag, and others. The results are the change of compositions and characteristics of raw materials applied and a great effect on cement calcination process and clinker formation. In this work, the cement clinker formation process of different alumina-silicate raw materials to replace clay raw material was studied by chemical analysis, X-ray diffraction, differential thermal analysis, and high temperature microscope based on the characteristics of the alumina-silicate raw materials. The formation heat of the clinker was determined by the acid dissolution method. Influence of different alumina-silicate raw materials on the clinker burnability and formation process was studied. The results show that the changing of alumina- silicate raw materials, especially using industrial waste residues, can reduce the formation temperature of high temperature liquid phases, improve the burnability of raw materials, reduce the formation temperature and formation heat of clinker. And this study also observed the formation temperature and transformation of high temperature liquid phases in the heating process of raw materials by high temperature microscope.     

利用污水厂污泥配料煅烧水泥熟料研究

通过生料易烧性试验、水泥熟料矿物岩相分析、XRD、SEM、水泥胶砂强度试验等，对利用污水厂污泥代替部分粘土配料煅烧硅酸盐水泥熟料的过程，并对制备熟料的微观特征进行了研究。结果表明：污水厂污泥代替部分粘土烧制的水泥熟料，其矿物结构与常规的硅酸盐水泥熟料完全相同，且由污泥配料煅烧的熟料烧成温度有降低的趋势；其水泥水化和凝结、硬化过程与常规硅酸盐水泥完全相同；其水化产物结构与常规硅酸盐水泥完全相同；水泥胶砂强度达到50．0MPa。     

Preparation of Super Composite Cement with a Lower Clinker Content and a Larger Amount of Industrial Wastes

The effects of the grinling mode ,finencess,gypsum kinds and dosage,mix proportions on properties of the composite composite cements consisting of slag ,fly ash ,limestone and a lowr content clinker were investigated,respectively ,The results show that when thre proportions among slag ,fly ash and limestone are appropriate ,the grinding technology and system are reasonable ,the optinized gypsums and addities are effective,the 52.5R grade cement (52.5R grade cement menas a higher strength than 52.5 at ealy age) can be prepared by clinker dosage of 50% in weight,the 42.5R or 42.5 ,32.5 grade composite cement containing 40% and 30% clinker also may be made ,respectively ,Moreover,the high perfomance concrete preparde from the abover composite cements was studied experimentally.     

Effect of Curing Regime on Degree of Al3＋ Substituting for Si4＋ in C-S-H Gels of Hardened Portland Cement Pastes

The effect of curing regime on degree of Al3+ substituting for Si4+(Al/Si ratio) in C-S-H gels of hardened Portland cement pastes was investigated by 29Si magic angel spinning(MAS) nuclear magnetic resonance(NMR) with deconvolution technique. The curing regimes included the constant temperature(20, 40, 60 and 80 ℃) and variable temperature(simulated internal temperature of mass concrete with 60 ℃ peak). The results indicate that constant temperature of 20 ℃ is benefi cial to substitution of Al3+ for Si4+, and Al/Si ratio changes to be steady after 180 d. The increase of Al/Si ratio at 40 ℃ is less than that at 20 ℃ for 28 d. The other three regimes of high temperature increase Al/Si ratio only before 3 d, on the contrary to that from 3 to 28 d. However, the 20 ℃ curing stage from 28 to 180 d at variable temperature regime, is benefi cial to the increase of Al/Si ratio which is still lower than that at constant temperature regime of 20 ℃ for the same age. A nonlinear relation exists between the Al/Si ratio and temperature variation or mean chain length(MCL) of C-S-H gels, furthermore, the amount of Al3+ which can occupy the bridging tetrahedra sites in C-S-H structure is insuffi cient in hardened Portland cement pastes.     

Effects of Thaumasite Formation on the Performance of Portland-limestone Concrete Stored in Magnesium Sulfate Solution

The influence of theaumasite formation on the performance of Portland-limestone cement concrete stored in magnesium sulfate solution was studied.The experimental results show that the deterioration of Portlandlimestone cement concrete is higher than that of Portland cement concrete.The more the content of limestone,the more serious the deterioration of concrete,and also the lower the temperature,the earlier the deterioration of concrete.Thaumasite was detected to form in the Portland-limestone pastes when stored in 10wt% MgSO4 solution at 3-10℃ and is was easy to form at lower temperatures.     

Influence of CG With High Content of Metallic Particles as a Cement Admixture on Cement Strength

1　IntroductionCopperresidueisanindustrialby productdis chargedbycopperrefineries ,butitusuallycontainssomeusefulmetals .Forexamplecopperresiduecontains 4 %to5 %copper ,1.0 1g tgold ,2 4g tsilverand 4 2 %magne tite ,alltheseexceedthecontentforacomprehensiveutili zation .Inordertoextracttheseusefulmetals ,thecoolingtechnologyofremovingresidueisintroducedbyslowlycooling (4 8h)sothatsomemetallicionsgrow .Afteronemoreflotationforcopperandmagneticbyextractionofiron ,thedischargedresidueiscalledcopp…