攀枝花钛石膏在水泥生产中的应用研究

钛石膏是采用硫酸法生产钛白粉时,加入石灰（或电石渣）以中和大量的酸性废水而产生的以二水石膏为主要成分的废渣。攀枝花钛白粉生产企业每年产生约40万吨钛石膏,堆放这些废渣需要占用大量的农田。     

钛石膏作为缓凝剂在水泥生产中的应用

钛石膏是采用硫酸法生产钛白粉时，为治理酸性废水减少环境污染，加入石灰（或电石渣）以中和大量的酸性废水而产生的，以CaSO4·2H2O为主要成分，并含有少量的废酸和硫酸铁，呈弱酸性。从废渣处理出来时先是灰褐色，暴露空气中Fe2+逐渐被氧化成Fe3+而变成红色偏黄，所以钛石膏又称红泥、红石膏或黄石膏。     

使用全工业废渣生产熟料配料方案的探讨

<正>我集团公司生产中产生的废渣主要有粉煤灰、炉渣、脱硫石膏、电石炉收尘灰、石灰渣、石灰石渣、净化灰、硫酸渣、煤矸石和电石渣等。为了完全处理这些废渣,集团成立了天能水泥有限公司,配套有1×3000t/d+1×2 500t/d生产线。1废渣特性1)电石渣是电石水解获取乙炔气后的以氢氧化钙为主要成分的废渣。我集团有两种形式的电石渣,干电石渣和湿电石渣。2)炉渣是高温水淬过的活性SiO2来源,其作用     

电石渣的处理及回收利用

在采用电石-乙炔工艺生产PVC树脂的过程中，如何处理所产生的大量电石渣是企业迫在眉睫的问题。文中简单介绍了电石渣浆的前期处理方法，包括自然沉降法和机械分离法；扼要阐述了电石渣浆的加工回用方法：废水可经过二次处理循环用于电石反应生产乙炔及中和酸性废水，而干电石渣可制成石灰作为电石的生产原料、与煤渣等煅烧生产电石渣水泥或用作普通建筑材料及防水涂料。     

电石灰作为石灰质原料在水泥生产中的应用

<正>我公司有两条2000t/d完全利用废渣生产水泥的生产线,主要处理的废渣有电石渣、粉煤灰、电石灰、硫酸渣、柠檬酸渣和石灰粉末等。本文谈电石灰在我公司的应用情况。1原料1.1电石灰的主要成分电石灰主要是电石粉末,含有少部分未燃烧完全的焦炭和石灰,主要成分是CaC2,以及Ca(OH)2和CaCO3。目前我公司根据生产工艺不同,产生的电石灰主要有三种,电石炉收尘灰、净化灰和除尘灰,其外观     

电石渣制水泥熟料形成热计算方法

大规模利用电石渣生产水泥熟料已成为处理电石渣污染的重要方法,电石渣与石灰石的物理及化学特性存在较大的差别,特别是关于电石渣制水泥的理论形成热和电石渣中的氢氧化钙的分解热存在争议,本文将给出电石渣制水泥的理论形成热和氢氧化钙的分解热计算方法,仅供参考。     

电石渣与石灰在氨碱和氯碱厂的综合利用小试

本文阐述了利用氨碱厂石灰窑生产的石灰用于氯碱厂制造电石,电石用于生产乙炔后的电石渣替代石灰制成灰乳用于氨碱蒸氨的小试情况,探讨了电石渣与石灰在氨碱和氯碱厂的综合利用的可能性及由此带来的经济效益和环保效应。     

浅谈电石法生产PVC工艺中废物的回收利用

介绍了电石法生产PVC工艺中电石渣和氯乙烯尾气的处理。电石渣用来代替石灰石生产水泥或直接生产石灰。用膜分离的方法循环利用氯乙烯尾气。     

浅谈电石法生产PVC工艺中废物的回收利用

介绍了电石法生产PVC工艺中电石渣和氯乙烯尾气的处理。电石渣用来代替石灰石生产水泥或直接生产石灰。用膜分离的方法循环利用氯乙烯尾气。     

钛白粉生产废水处理总磷影响因素分析控制

钛白粉为三大无机化工产品之一,号称“白色颜料之王”,是人工制品的色彩基石,生产方法主要有硫酸法和氯化法,目前国内主要以硫酸法为主,硫酸法钛白粉生产过程中产生大量的酸性废水,这些废水需要中和处理后才能排放,本文阐述了硫酸法钛白粉生产过程中废水环保指标总磷主要影响因素。     

改善明胶生产废水污染的磷酸氢钙回收工艺

在考察明胶生产工艺、废水水质特性的基础上,提出一改进的磷酸氢钙清洁回收工艺。在浸灰工段后设一沉淀池,沉淀分离石灰沉渣,将上层饱和的氢氧化钙浸灰废液送至浸酸工序,处理浸酸废液,调pH至4.7左右,回收磷酸氢钙。而原工艺是用灰乳处理浸酸废液回收磷酸氢钙,大量饱和Ca(OH)_2浸灰废液外排,造成了难于治理的明胶生产废水高碱、高钙、高悬浮有机物污染。实验证明,该改进工艺能消耗大量的浸灰废液,有效降低明胶生产废水的高碱特性,对悬浮COD的去除效果与使用普通净水剂效果相当,且对磷钙复合肥的收率无重大影响,所排废液不再是饱和的氢氧化钙溶液,钙污染也得到一定控制,与原废水相比生化处理难度大大降低,具有显著的环境效益。     

电镀废水处理技术与实践

用次氯酸钠溶液和双氧水组合的方法处理含氰废水,效果好且成本低。可以用双氧水处理含镍废水中的氰化物,但不能使用次氯酸钠溶液,在碱性条件下Ni 2+被次氯酸钠氧化生成Ni(OH)3沉淀。设置两个中和池,在一级中和池中加入石灰处理掉约90%的废酸,同时在二级中和池中加入石灰处理剩余的废酸。在二级中和池中用pH自动控制系统控制石灰的加入量,保证排放水的浊度达到标准。     

Simultaneous CO2 capture and thermochemical heat storage by modified carbide slag in coupled calcium looping and CaO/Ca(OH)2 cycles

The simultaneous CO_2 capture and heat storage performances of the modified carbide slag with by-product of biodiesel were investigated in the process coupled calcium looping and CaO/Ca(OH)_2 thermochemical heat storage using air as the heat transfer fluid. The modified carbide slag with by-product of biodiesel exhibits superior CO_2 capture and heat storage capacities in the coupled calcium looping and heat storage cycles. The hydration conversion and heat storage density of the modified carbide slag after 30 heat storage cycles are 0.65 mol·mol~(-1) and 1.14 GJ·t~(-1), respectively, which are 1.6 times as high as those of calcined carbide slag. The negative effect of CO_2 in air as the heat storage fluid on the heat storage capacity of the modified carbide slag is overcome by introducing CO_2 capture cycles. In addition, the CO_2 capture reactivity of the modified carbide slag after the multiple calcium looping cycles is enhanced by the introduction of heat storage cycles. By introducing 10 heat storage cycles after the 10 th and 15 th CO_2 capture cycles, the CO_2 capture capacities of the modified carbide slag are subsequently improved by 32%and 43%, respectively. The porous and loose structure of modified carbide slag reduces the diffusion resistances of CO_2 and steam in the material in the coupled process. The formed CaCO_3 in the modified carbide slag as a result of air as the heat transfer fluid in heat storage cycles decomposes to regenerate CaO in calcium looping cycles, which improves heat storage capacity. Therefore, the modified carbide slag with by-product of biodiesel seems promising in the coupled calcium looping and CaO/Ca(OH)_2 heat storage cycles.     

电石渣在循环流化床烟气脱硫中的应用

干法烟气脱硫一般采用生石灰或者熟石灰作为脱硫剂,采用电石渣作为脱硫剂以废制废,有效降低了干法烟气脱硫的运行成本。文中在一台自主开发研制的75 t/h循环流化床烟气脱硫装置上,进行了用电石渣作为脱硫剂的干法烟气脱硫热态试验研究。试验发现,由于电石渣杂质较多、活性差,当电石渣浆液质量分数大于15%时,易造成喷嘴阻塞,影响了脱硫设备的稳定运行。为了兼顾运行成本和脱硫效率,进行了用电石渣和石灰粉混合使用作为脱硫剂的试验研究,当电石渣与石灰混合,其质量比为2∶1,Ca/S摩尔比为1.3时,脱硫效率可达到80%左右。     

电石渣/生石灰复合脱硫剂脱硫性能研究

为将电石渣有效地应用于半干法烟气脱硫中,对电石渣与生石灰进行不同比例的配比、均化后产生复合脱硫剂。通过对复合产物进行含水质量分数、比表面积的分析,得出摩尔比为1.4∶1—1.6∶1时具有较高的比表面积和3%—5%的含水质量分数。对比生石灰、电石渣与1.6∶1摩尔比产物的粒径分布和扫描电镜图,发现复合脱硫剂粒径分布均匀,结构整齐,无任何团聚现象,且从机理上分析了含水电石渣与生石灰的复合匀化过程。对电石渣、消石灰及各配比复合脱硫产物进行小型脱硫实验研究,结果证实,在1.6∶1的摩尔比下,复合脱硫剂的脱硫性能较好。     

电石渣动态煅烧及烧结过程的微观结构分析

利用管式电炉、X射线衍射仪、压汞仪和SEM扫描电镜研究了电石渣在1200℃高温下动态煅烧及烧结过程中的微观结构变化.发现电石渣主要由含量大于80%的Ca (OH)₂以及少量CaCO₃、α-SiO₂和α-Fe₂O₃晶相组成,高温煅烧后其主要晶相变成CaO.在1200℃下煅烧及烧结过程中,随时间增加电石渣的平均孔径逐渐增大,比表面积逐渐减少,总孔容积先增大后减少.高温长时间烧结后,电石渣表面由许多膨胀变形的类哑铃形CaO晶粒结构组成,且大小均匀、排列有序、边界明显.     

Mechanical,flammability, and thermal properties of polyvinyl chloride‐wood composites with carbide slag

Carbide slag, an industrial waste produced by calcium carbide hydrolysis to prepare C₂H₂ gas, was successfully used as inorganic filler in the production of polyvinyl chloride (PVC)‐wood composites. carbide slag had an average diameter of 8.1 μm which thermally decomposed at about 450°C, and its main component was Ca(OH)₂. Incorporating carbide slag into PVC‐wood composites substantially decreased the flexural, tensile, and impact strength of the composites as a result of the poor interfacial adhesion between carbide slag and PVC matrix, which could be evidently observed from the scanning electron microscopy (SEM) study. To give carbide slag better use, silane coupling agent KH570 were chose to modify carbide slag. The results indicated that adding carbide slag modified by KH570 (MCS) into PVC‐wood composites could significantly improve its notched impact strength and flexural modulus. The thermogravimetric analysis (TGA) data showed that with the addition of MCS, composite had better thermal stability. It also turned out that with the addition of MCS, its smoke suppression property and flammability were enhanced effectively. To ensure sufficient properties of PVC‐wood composites, the optimal adding content of MCS was 20 phr and it leaded to remarkable performance (its flexural modulus was 3.4 GPa, notched impact strength was 3.87 KJ/m², limiting oxygen index value was 41.5% and smoke density ranting was 55.1%), all of which endowed PVC‐wood composites better utilization. All the results indicated that the preparation of PVC‐wood composites with carbide slag could resolve environmental pollution, reuse carbide slag in different fields, and provide a new method for resource utilization of carbide slag. POLYM. COMPOS., 38:2898–2906, 2017. © 2015 Society of Plastics Engineers     

Pilot plant investigation on petrochemical wastewater treatmentfor the removal of copper and chromium with the objective of reuse

There has been great demand for development of technologies that remove toxic heavy metal ions from wastewater. Chemical precipitation operation is known to remove heavy metal ions from water. In this study applicability of alkaline reagents such as Ca(OH)₂ (lime) and NaOH (caustic soda) in removing copper and chromium ions were evaluated. Separation of heavy metals such as chromium compounds from petrochemical industries' cooling water wastes was achieved by conversion of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). Maximum conversion occurred in the pH range of 2.0 and 2.3, adjusted by ferrous sulfate and sulfuric acid. Maximum precipitation of Cr(III) occurred at pH 8.7 with addition of Ca(OH)₂, followed by mixing and 2-h sedimentation. At the end, the concentration of chromate was reduced from 30 ppm to 0.01 ppm. In the case of copper, which is found in the form of cupro-ammonia in ammonia plant wastes, it was observed that the presence of ammonia in wastewater prevents effective chemical precipitation. Therefore, the quantity of ammonia was reduced by aeration. The optimum aeration rate was determined to be 70 L/min, and it was found that ammonia concentration reached equilibrium after 5.0 h o f aeration. Furthermore, hydroxide and carbonate methods were evaluated with respect to precipitation of heavy metals at bench scale, and the former was selected as the method of choice. The results obtained in the Jar test were then applied to pilot scale, and it was determined that the optimum pH for maximum copper precipitation was about 12.0 for both lime and caustic soda used in the hydroxide precipitation method. Lime was preferred due to economics and its high speed of precipitation. Finally, using established methods described here, the concentration of copper followed by coagulation with lime, mixing, 2-h sedimentation and filtration through Whatman 0.45 Am filters was reduced from 48.51 mg/L to 0.694 mg/L, which is below the environmental standards for water resources.     

水泥–矿渣复合胶凝材料中矿渣的水化特性

通过对不同矿渣掺量时水泥–矿渣复合胶凝材料中矿渣的反应程度、硬化浆体中Ca（OH）2含量以及水化硅酸钙（C–S–H）凝胶的Ca/Si比（Ca和Si的摩尔比）的测定,研究复合胶凝材料体系中矿渣的水化特性。结果表明：在水泥–矿渣复合胶凝材料中,矿渣掺量越大,矿渣反应程度越低,但矿渣掺量≤70%时,对矿渣的反应程度影响不大。高温养护可提高早期矿渣的反应程度,但阻碍其后期的进一步水化。矿渣早期水化生成外部水化产物时消耗一定的Ca（OH）2,使硬化浆体中Ca（OH）2含量降低,矿渣水化吸收Ca（OH）2中的Ca2＋,使生成的C–S–H凝胶的Ca/Si比降低较少;在水化后期,矿渣生成内部水化产物不再消耗较多的Ca（OH）2,使C–S–H凝胶的Ca/Si比降低相对较多,硬化浆体中Ca（OH）2含量有增加的趋势,保证硬化浆体的长期稳定性。