scholarly journals Stabilization treatment of arsenic-alkali residue (AAR): Effect of the coexisting soluble carbonate on arsenic stabilization

2020 ◽  
Vol 135 ◽  
pp. 105406 ◽  
Author(s):  
Xin Wang ◽  
Jiaqi Ding ◽  
Linling Wang ◽  
Shuyuan Zhang ◽  
Huijie Hou ◽  
...  
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.


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

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.


Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 915-931 ◽  
Author(s):  
Alf Lindroos ◽  
Lior Regev ◽  
Markku Oinonen ◽  
Åsa Ringbom ◽  
Jan Heinemeier

This study focuses on radiocarbon dating of mortars that have withstood city fires and display visible fire damage effects. Some fire-damaged and undamaged original Medieval mortars from the same site have also been tested. The mortars were heated at different temperatures and then analyzed using the same preparation procedures as in 14C dating of mortars to see what kind of changes the heating would introduce to the mineralogy, chemistry, and the carbon and oxygen isotope ratios. We found that decarbonation during heating starts at ∼600 ° and recarbonation starts as soon as the temperature drops. Already after a few days, most of the lost CO2 has been replaced with atmospheric CO2. The renewed carbonates are readily soluble in the acid hydrolysis process and their carbon and oxygen isotopes have a light signature. Fire-damaged historical mortars display the same features. If a long time has elapsed between hardening of the original mortar and the fire, the new carbonates have 14C concentrations that point to the fire event rather than to the building event. In several cases, the fire-damaged mortars have an easily soluble carbonate fraction with a 14C age that could be related to a major fire event, but still most of the soluble carbonate yields a 14C age that seems like a reasonable age for the original construction.


2009 ◽  
Vol 22 (2) ◽  
pp. 168-175 ◽  
Author(s):  
O. Ozdemir ◽  
C. Karaguzel ◽  
A.V. Nguyen ◽  
M.S. Celik ◽  
J.D. Miller

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