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用铬渣、钡渣代替部分天然砂制作强度等级为C15的普通混凝土,混凝土的强度等级与钡渣、铬渣的加入量关系较大.用PO32.5标号水泥,铬、钡渣的质量代替砂子质量的50%时,混凝土的抗压强度达到18.9MPa,比普通混凝土设计的抗压强度提高26%,混凝土的收缩量为1/300,优于国家标准,对混凝土作浸出毒性试验,Cr6+和Ba2+都远小于国家规定的标准值. 相似文献
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铬渣的物相组成及其对铬渣解毒和综合利用的影响 总被引:7,自引:0,他引:7
本文系统地列举了铬渣的元素组成,物相组成和六价铬各种存在形式,讨论了含有六价铬的各组分还原解毒时发生的变化以及各种因素的影响,指出固溶体中的六价铬难以还原,是铬渣解毒和综合利用时必须解决的主要困难。评论了各种治理方案,认为做水泥混合材是综合利用铬渣的重要途径。 相似文献
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铬渣治理工作回顾及经验教训 总被引:9,自引:0,他引:9
介绍国内铬渣治理和综合利用的现状及其主要方法,其中铬渣干法解毒、作玻璃瓶着色剂、炼铁以及近年来研究成功的铬渣制铬铸铁等方法,可达到综合利用或安全排放的目的。在回顾过去治理工作的基础上,总结了经验教训。 相似文献
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用铬渣作熔剂的高炉法生产钙镁磷肥 总被引:4,自引:0,他引:4
本文介绍了用铬渣作熔剂的高炉法生产钙镁磷肥的工艺路线、铬渣在高炉中的解毒机理、除毒效果以及磷肥的肥效,指出了此法是一条技术上成熟、经济上合理、值得推广的铬渣综合利用途径。 相似文献
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太原第一热电厂简易湿法脱硫石膏品质及利用 总被引:3,自引:0,他引:3
通过对简易脱硫石膏理化性质及矿物组成的研究发现,虽然石膏外观差、颗粒细、含尘量及石灰石过剩率高,但所含CaSO3质量分数极小,而CaSO4·2H2O质量分数高于一般天然石膏。用它作水泥缓凝剂、水泥矿化剂和生产半水石膏的试验也充分证明:脱硫石膏可完全替代天然石膏。 相似文献
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《化工环保》1990,10(3):181-186
前言铬渣,是生产重铬酸钠(红矾钠)过程中产出的一种废渣。因渣内含有0.25%左右的水溶性六价铬离子,故具有毒性,是国家环境保护部门严格控制排放的“三废”之一。就我厂年产2500吨级生产规模计,年排放铬渣6000余吨,这对当地环境是一大危害,对我们本身的生存和发展也是一大威胁。因此,废渣治理是我们铬盐生产企业亟待解决的重要课题。全国有关单位对铬盐的处理和利用作了不少试验和研究工作。如用铬渣代替蛇纹石制钙镁磷肥,用铬渣烧制铸石,用马蹄窑烧制青砖等等。但均因种种原因未能达到理想要求。要想做到“消毒”彻底,又能大量吃渣,就目前情况看,我厂用旋风炉处理铬渣仍是一个切实可行的途径。 相似文献
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Increasing pulp industry production has generated additional solid waste (i.e. biological sludge, dregs, etc.) and therefore an increasing disposal problem. On the other hand, composting is emerging as an interesting alternative for the disposal of residues. The objective of this study was to evaluate the physical and chemical properties of sludge, dregs and bark and the effect on their initial conditioning stage prior to composting, using pine chips as bulking agent. After their characterization, these solid wastes were combined in different mixture proportions defined by a 32 experimental design based on the response surface methodology (RSM), in which 18 observations were required for the independent variables (dregs and bark) and the C: N ratio, moisture content and pH were the dependent variables. The characterization indicated that the dregs have alkaline properties with the presence of some essential plant nutrients, such as phosphorous (0.37%), potassium (0.76%), magnesium (1.4%) and calcium (27%). The combination of the macronutrients (phosphorous: 0.39%, potassium: 0.24%, calcium: 1.7%, magnesium: 0.44%) and micronutrients such as ferrous material (0.47%) and zinc (0.12%) found in the sludge suggest a promising alternative despite the potential problem due to the high pH of the dregs. The RSM design indicated a feasible region that satisfied the optimal dregs: bark ratio of 0.25 without exceeding the addition of 12.5% dregs, due to the alkaline properties of these inorganic wastes and the quadratic influence over the C:N ratio. The experimental results indicated that the composting process of dregs, bark and sludge is technically suitable, although the use of a rapidly available C source needs to be evaluated. 相似文献
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Pyrolysis characteristics of bean dregs and in situ visualization of pyrolysis transformation 总被引:2,自引:0,他引:2
Guangyong Zhu Xian Zhu Zuobing Xiao Rujun Zhou Fengping Yi 《Waste management (New York, N.Y.)》2012,32(12):2287-2293
Biomass is an important renewable and sustainable source of energy. Waste products from biomass are considered as attractive feedstocks for the production of fuel. This work deals with the pyrolysis of bean dregs, a biomass waste from soybean processing industry. A technique has been developed to study bean dregs pyrolysis by in situ visualization of bean dregs transformation in a quartz capillary under a microscope using a charge-coupled device (CCD) camera monitoring system. The technique enables us to observe directly the processes and temperatures of bean dregs transformation during pyrolysis. In situ visualization of reaction revealed that how oily liquids are generated and expulsed concurrently from bean dregs during pyrolysis. Pyrolysis characteristics were investigated under a highly purified N2 atmosphere using a thermogravimetric analyzer from room temperature to 800 °C at different heating rates of 10, 30 and 50 °C/min. The results showed that three stages appeared in this thermal degradation process. The initial decomposition temperature and the peak shifted towards higher temperature with an increase in heating rate. Kinetic parameters in terms of apparent activation energy and pre-exponential factor were determined. 相似文献
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Nowadays, the increasing amount of wastes is a concerning reality and the environmental aspects has become a major priority. Following this worry, the purpose of this experimental study was to investigate the possibility of using pulp and paper inorganic wastes, named dregs and grits, in bituminous mixtures as aggregate replacement to reduce environmental effects of these wastes disposal.First, the wastes were chemically and physically characterized and also tested primarily taking into account the requirements for aggregates in bituminous mixtures. Then, formulations were prepared replacing aggregates with wastes in different amounts. The mechanical properties of these mixtures containing wastes were compared with reference samples based on standard methods.According to the results it was possible to verify that grits had a good performance and it might be directly tested industrially as an aggregate in road construction. On the other hand, dregs need to be treated before incorporation to guarantee stable mixes in terms of water sensitivity. 相似文献
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Environmental contamination with ionic chromium has been identified as a problem at numerous Superfund and RCRA Corrective Action sites. In many cases, contamination of groundwater to levels above existing standards or criteria may be a potential problem both for direct consumption of groundwater and for transport of mobile forms of chromium to areas such as basements where it can becontacted. In the environment, chromium occurs in two forms: trivalent and hexavalent. The trivalent form is generally immobile and nontoxic; hexavalent chromium is generally mobile and toxic. This article first presents the extent of the chromium problem, reviews the environmental chemistry literature on chromium, and reviews existing treatment technology for chromium immobilization in the nontoxic trivalent state. Finally, we present a case study where immobilization of chromium occurred through natural processes allowing a modified no-action scenario for site remediation. 相似文献
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采用干式还原法处理铬渣。在多级还原焙烧炉中于高温条件下,将过量的煤粉和铬渣混合后与O2反应,经冷却、擦磨、磁分离后可得到铁精砂和处理后铬渣。介绍了干式还原法处理铬渣的机理和工艺参数。以3种铬渣试样进行应用试验,经多级还原焙烧—磁分离后,铬渣中的Cr(Ⅵ)质量浓度为0.05~0.18 mg/L,低于HJ/T301—2007标准中的要求(0.50 mg/L),可作为建材原料加以利用。磁分离得到的铁精砂产品中铁的质量分数大于50%,铁回收率大于70%。目前设计的多级还原焙烧炉单炉处理铬渣能力为150 kt/a,标煤消耗为35 kg/t,处理成本约为60元/t。 相似文献
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Maria J. Ferreira Manuel F. Almeida Sílvia C. Pinho Isabel C. Santos 《Waste management (New York, N.Y.)》2010,30(6):1091-1100
Due to the amounts of chromium in the leachate resulting from leather leaching tests, chromium sulfate tanned leather wastes are very often considered hazardous wastes. To overcome this problem, one option could be recovering the chromium and, consequently, lowering its content in the leather scrap. With this objective, chromium leather scrap was leached with sulfuric acid solutions at low temperature also aiming at maximizing chromium removal with minimum attack of the leather matrix. The effects of leather scrap dimension, sulfuric acid and sodium sulfate concentration in the solutions, as well as extraction time and temperature on chromium recovery were studied, and, additionally, organic matrix degradation was evaluated. The best conditions found for chromium recovery were leather scrap conditioning using 25 mL of concentrated H2SO4/L solution at 293 or 313 K during 3 or 6 days. Under such conditions, 30–60 ± 5% of chromium was recovered and as low as 3–6 ± 1% of the leather total organic carbon (TOC) was dissolved. Using such treatment, the leather scrap area and volume are reduced and the residue is a more brittle material showing enhanced anaerobic biodegradability. Although good recovery results were achieved, due to the fact that the amount of chromium in eluate exceeded the threshold value this waste was still hazardous. Thus, it needs to be methodically washed in order to remove all the chromium de-linked from collagen. 相似文献
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Konstantinos Kostarelos Daniela Reale Dimitris Dermatas Ennio Rao Deok Hyun Moon 《Water, Air, & Soil Pollution: Focus》2006,6(1-2):171-189
The presence of hexavalent chromium, Cr(VI), in soil is an environmental concern due to its effect on human health. The concern
arises from the leaching and the seepage of Cr(VI) from soil to groundwater. In this paper, a stabilization technology to
prevent this problem was simulated on an artificial soil contaminated with hexavalent chromium. The process is a physico-chemical
treatment in which the toxic pollutant is physically entrapped within a solid matrix formed by the pozzolanic reactions of
lime and fly ash to reduce its leachability and, therefore, its toxicity. This paper presents the optimum ratio of fly ash
and lime in order to stabilize artificial soils contaminated with 0.4 wt.% of Cr (VI) in a brief term process. The degree
of chromium released from the soil was evaluated using a modified Toxicity Characteristic Leaching Procedure (TCLP) by US
Environmental Protection Agency (EPA). Overall, experimental results showed reduced leachability of total and hexavalent chromium
from soils treated with both fly ash and quicklime, and that leachability reduction was more effective with increasing amount
of fly ash and quicklime. Stabilization percentages between 97.3% and 99.7% of the initial chromium content were achieved,
with Cr(VI) concentration in the TCLP leachates below the US EPA limit for chromium of 5 mg/l. Adequate treatment was obtained
after 1 day of curing with just 25% fly ash and 10% quicklime. 相似文献