scholarly journals ROCTECtm STABILIZATION TREATMENT OF WERF ASH

1998 ◽  
Author(s):  
Paul A. Lessing ◽  
William J. Quapp ◽  
Gary Renlund ◽  
Bob Clark ◽  
Colin Hundley ◽  
...  
Author(s):  
А.В. Селюков

Сообщается о новой комплексной технологии кондиционирования холодных маломинерализованных подземных вод. Технология разрабатывалась для целей хозяйственно-питьевого водоснабжения нефтегазоносных районов Тюменского Севера. При благополучном соотношении ресурсов пресной воды и фактического объема водопотребления в этом регионе России вопрос питьевого водоснабжения из подземных горизонтов остается острым из-за проблемного качества воды и низкой эффективности очистных сооружений. Технология предназначена для очистки от железа, марганца, сероводорода и обеспечивает стабилизационную обработку воды. Основные работы, включавшие лабораторные исследования и пилотные испытания, выполнены в период 2001–2020 годов. На основе разработанных технологических решений построены и успешно эксплуатируются водопроводные очистные сооружения в городах Ноябрьске (75 тыс. м3/сут, 2006 г.) и Новом Уренгое (65 тыс. м3/сут, 2007 г.). Дополнительные испытания технологии, проведенные в Ханты-Мансийске и Комсомольске-на-Амуре, подтвердили ее эффективность. Технология предусматривает применение в качестве основных реагентов пероксида водорода и перманганата калия для окисления примесей воды, а также щелочного реагента для корректировки рН и стабилизационной обработки. Для обеспечения требований стандарта ВОЗ по содержанию железа и марганца дополнительно может использоваться флокулянт. Обобщены данные по составу подземных вод, использованных для испытаний, и на их основе определена рекомендуемая область применения разработанной технологии. Приведена принципиальная технологическая схема кондиционирования холодных маломинерализованных подземных вод, учитывающая 15-летний опыт эксплуатации построенных станций, а также современные решения по дозированию и смешению реагентов. Указано, что данная технология обеспечивает также частичное снижение содержания кремния в очищенной воде (до 30%). Разработанная технология позволяет получать стабильную питьевую воду при нормативном остаточном содержании железа, марганца и сероводорода. An advanced integrated technology for conditioning low-mineralized cold groundwater is presented. The technology was developed for the purpose of supplying drinking water to the oil and gas-bearing regions of the Tyumen North. With a favorable ratio of fresh water resources and the actual volume of water consumption in this region of Russia, the issue of drinking water supply from underground aquifers remains acute due to the problematic water quality and low efficiency of the treatment facilities. The technology is intended for removing iron, manganese, hydrogen sulfide and providing for the stabilization treatment of water. The main work including laboratory studies and pilot tests was carried out in the period 2001–2020. On the basis of the developed process solutions, water treatment facilities have been built and successfully operated in the cities of Noyabrsk (75 thousand m3/day, 2006) and Novy Urengoy (65 thousand m3/day, 2007). Additional tests of the technology carried out in Khanty-Mansiisk and Komsomolsk-on-Amur confirmed its effectiveness. The technology involves using hydrogen peroxide and potassium permanganate as the basic chemicals for the oxidation of water pollutants, as well as using an alkaline chemical for pH adjustment and stabilization treatment. To meet the requirements of the WHO standard for the concentrations of iron and manganese, an additional flocculant can be used. The data on the composition of groundwater used for testing are summarized, and on their basis the recommended area of ​​application of the developed technology is determined. The basic process flow scheme of conditioning low-mineralized cold groundwater in view of 15 years of experience in operating the existing facilities, and of advanced solutions for dosing and mixing of chemicals, is presented. It is indicated that the technology also provides for a partial reduction in the silicon concentration in purified water (up to 30%). The developed technology ensures stable drinking water with a standard residual concentration of iron, manganese and hydrogen sulfide.


2021 ◽  
Vol 303 ◽  
pp. 01048
Author(s):  
Elena Murko ◽  
Vasily Murko ◽  
Jurgen Kretchmann

Technologically contaminated water, formed during processing of coal slurries, finds its application in modern technological cycles of coal enrichment. Limitation of use of untreated recycled water of coal concentration plants is caused by a high degree of its mineralization by various salts, presence of insoluble solid particles and presence of flotation reagents, coagulants and flocculants. Part of technical water purified from mineral and organic contaminants can be used in heating systems and heat exchange equipment of industrial enterprises, including the coal industry. For this purpose, it is necessary to reduce the scale-forming ability of service water (to reduce the content of soluble calcium and magnesium salts in water). One of the most effective and advanced methods is the stabilization treatment of water with an electric field. In addition, this method is environmentally safe, low-cost and simple. The article gives the foundation of the method of stabilization treatment of recycled water of concentrating plants by an electric field, a description of the methodology of the laboratory experiment for scaling reduction, and the analysis of the results.


1984 ◽  
Vol 107 ◽  
pp. 245-250 ◽  
Author(s):  
A. Macías ◽  
R. Mendizabal ◽  
F. Pelayo ◽  
A. Riera ◽  
M. Yáñez

Author(s):  
Andrea Gruttadauria ◽  
Silvia Barella ◽  
Claudia Fiocchi

Abstract The Ni–Fe–Cr system is the basis of a series of commercial alloys featuring chemical–physical characteristics that allow them to be used in a variety of fields where excellent resistance to aggressive environments is required. In this scenario, the CU5MCuC alloy, the foundry counterpart of Alloy 825, is proving successful in the petrochemical field thanks to its good corrosion resistance in acidic and highly oxidizing environments. Intergranular corrosion resistance, critical for this material, is ensured by the stabilization treatment that allows precipitation of Nb carbides. Strengthening of this alloy takes place only via a solid solution. Therefore, its mechanical properties depend on the solution annealing treatment: often this treatment alone does not make it possible to reach the UTS imposed by the ASTM-A494 standard. In this work, the possibility of using stabilization treatment to increase mechanical strength as well was considered. Treatments, with different combinations of time and temperature, were carried out in order to modify the material’s microstructure. After the thermal treatments, microstructural analyses, mechanical tests and (pitting and intergranular) corrosion and resistance tests were carried out to identify optimal treatment parameters in order to promote the evolution of microstructural constituents capable of improving mechanical strength without decreasing corrosion resistance. The treatment that achieves the best compromise between mechanical properties and corrosion resistance is stabilization at 970 °C for 4 h.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 706 ◽  
Author(s):  
Davide Mombelli ◽  
Andrea Gruttadauria ◽  
Silvia Barella ◽  
Carlo Mapelli

Studies conducted over the past 10 years have demonstrated the technical suitability of the electric arc furnace slag as an alternative to natural stone in several applications. Steel slag can be profitably used as a road surface layer, for foundations and embankments, or for concrete aggregates. However, a strong limitation to their use is due to the presence of toxic metals (Ba, Cr, V, Mo, etc.) that can be released into the environment in particular conditions, especially for unbound products in which the slag can come into contact with water. Recent studies have investigated the role of chemical composition and microstructure of slag on toxic metal leaching, allowing for the design of suitable stabilization treatments for hindering such leaching. In this work, four batches of electric arc furnace carbon steel slag underwent a stabilization treatment and the obtained results were compared. In two batches, the stabilizer was added directly in the slag pot and the slag was cooled down in the same pot. The other two batches were stabilized during the downfall from slag door to slag pit. Several slag samples were collected before and after the stabilization treatment and were characterized by means of ED-XRF, XRD, and SEM analysis. Leaching tests were carried out in agreement with EN 12457-2 standard on 4 mm granulated slag, and the leachate concentration was compared with the current Italian limits listed in D.M. 3 August 2005 N. 201 and D.M. 5 April 2006 N. 186. The results clearly indicated that the cooling in the slag pot improved the efficiency of the stabilization treatment, leading to a complete transformation of the microstructure by a full development of homogeneous gehlenite matrix and a coarsening of Cr-spinels, assuring better toxic metal retention behavior. On the contrary, stabilization in the slag-pit was rapid and reduced the interaction between slag and stabilizer, leading only to partial transformation of larnite into gehlenite, and also reducing the coarsening of Cr-spinel. In addition, a layering effect was observed, resulting in an inhomogeneous product from top to bottom in terms of chemical composition, microstructure, and leaching behavior.


2020 ◽  
Vol 161 ◽  
pp. 110143 ◽  
Author(s):  
Yusheng Ding ◽  
Xiaolan Wu ◽  
Kunyuan Gao ◽  
Cheng Huang ◽  
Xiangyuan Xiong ◽  
...  

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