Корозија топа 75/27, модел 1911. DEPORT из колекције Војног Музеја у Београду

This paper analyzes the state of the French Cannon 75/27 model 1911. Déport made of steel. The amount of non-corroded materials, the presence of cracks and other defects in the cannon were determined by the radiographic method. The composition of corrosion products were analyzed using diffraction of X-rays (XRD method). In addition to goethite α-FeO(OH), lepidocrocite γ-FeO(OH) and magnetite Fe3O4, the presence of akaganeite was observed in the corrosion products, β-Fe8O8(OH)8Cl1.35 which indicates the accelerated corrosion of the base metal. With the ion chromatography method, the content of chloride, sulphate and other ions in corrosion products were examined. On the basis of conducted experiments, it can be concluded that it is necessary to treat the cannon in appropriate solutions, as quickly as possible, to remove chloride and sulphate ions.У овом раду анализирано је стање француског топа 75/27 модел 1911 Déport израђеног од челика. За одређивање количине некородиралог материјала, присуства прслина и других дефеката у експонату коришћена је радиографска метода. Састав корозионих продуката је анализиран методом дифракције рендгенских зрака (XRD). Поред гетита, α-FeO(OH), лепидокрокита, γ-FeO(OH) и магнетита, Fe3O4, на експонатима је уочено присуство акаганита које указује на активну корозију основног метала. Методом јонске хроматографије је одређен садржај хлоридних и других анјона у корозионим продуктима. На основу изведених експеримената намеће се закључак о неопходности третмана топа у одговарајућим растворима што је могуће пре у циљу уклањања хлоридних и других корозионо активних јона

Corrosion of an archaeological find from the roman period in Serbia

The degree of preservation of iron artifacts depends on the type of underground environment and the type of corrosion products formed on their surface. This paper analyses the conditions of an archaeological find made of iron and originating from the Roman period and belonging to the collections of the Museum of Science and Technology in Belgrade. The radiographic method has been used to determine the quantity of non-corroded metal as well as to determine the presence of cracks and other defects in the artefact. The composition of the corrosion products has been analysed by the X-ray diffraction method (XRD). In addition to iron corrosion products (goethite α-FeO(OH) and magnetite Fe3O4), the presence of a significant quantity of akaganeite β-Fe8O8(OH)8Cl1.35, has been noticed on the artifact. The content of chloride, sulphate and other ions in the corrosion products has been determined by ion chromatography (IC). The analyses have pointed to the necessity of having artifacts treated in adequate solutions immediately after their excavation in order to eliminate chloride and sulphate anions. The aim of this paper is to determine the type of corrosion products and their influence on the corrosion behaviour ofr an archaeological artefact.Koroziona postojanost eksponata od gvožđa zavisi od tipa podzemne sredine i vrste korozionih produkata koji se formiraju na njegovoj površini. Ovaj rad analizira stanje arheološkog predmeta koji potiče iz rimskog perioda i koji pripada kolekciji Muzeja za nauku i tehniku u Beogradu. Radiografska metoda je korišćena za određivanje količine nekorodiralog metala, kao i prisustva prslina i drugih defekata u eksponatu. Sastav korozionih produkata je analiziran difrakcijom X-zraka (XRD). Pored korozionih produkata gvožđa (getita α-FeO(OH)I magnetita Fe3O4), uočena je značajna količina akagenita β-Fe8O8(OH)8Cl1.35 u sloju korozionih produkata. Metodom jonske hromatografije (IC) je određen sadržaj hloridnih, sulfatnih i drugih jona u korozionim produktima. Pomenute analize su ukazale na neophodnost tretmana arheološkog predmeta u odgovarajućem rastvoru za desalinaciju, neposredno posle iskopavanja, u cilju uklanjanja hloridnih i sulfatnih anjona. Cilj ovog rada je određivanje tipa korozionih produkata i njihovog uticaja na koroziono ponašanje arheološkog predmeta

Arsenic Removal from Water Using Industrial By-Products

In this study, removal of arsenic ions using two industrial by-products as adsorbents is represented. Removal of As(III) and As(V) from water was carried out with industrial by-products: residual from the groundwater treatment process, iron-manganese oxide coated sand (IMOCS), and blast furnace slag from steel production (BFS), both inexpensive and locally available. In addition, the BFS was modified in order to minimise its deteriorating impact on the initial water quality. Kinetic and equilibrium studies were carried out using batch and fixed-bed column adsorption techniques under the conditions that are likely to occur in real water treatment systems. To evaluate the application for real groundwater treatment, the capacities of the selected materials were further compared to those exhibited by commercial sorbents, which were examined under the same experimental conditions. IMOCS was found to be a good and inexpensive sorbent for arsenic, while BFS and modified slag showed the highest affinity towards arsenic. All examined waste materials exhibited better sorption performances for As(V). The maximum sorption capacity in the batch reactor was obtained for blast furnace slag, 4040 μgAs(V)/g

Analytical techniques for determination and control of silica content in the water in thermal power plants

Ultrapure water with minimum contents of impurities is used for the preparation of steam in thermal power plants. More recently it has been found that the corrosion process is also influenced by sodium ions, chloride ions, and all forms of silicon in water. At higher temperatures and under high pressure the less soluble compounds of silicon are extracted, which form deposits on the walls of the boiler, the piping system and the turbine blades. Silicon is found in water in the form of different types (species) which are characterized by specific physical and chemical properties. Distinctions can be made between highly reactive species of ionic (silicate anions) and molecular forms (silicic acid) and relatively inert types (suspended, colloidal, and polymerized silicon). The determination of various forms of silicon in water is a complex analytical task. This paper covers relevant research in the field of silicon specification analysis. Maintaining the unchanged, original composition of silicon species during various stages of analysis (sample collection, storage, and conservation) has been given special attention. A large number of methods and procedures have been developed for the analysis of species of silicon, including chromatographic, spectroscopic and electrochemical techniques and combinations thereof. The techniques used for determining both the total amount and individual forms of silicon have been singled out. There is also an overview of the coupled techniques used most frequently in practice by using the methodology which involves preliminary separation of species and then individual specification. The paper offers an overview of analytical properties, advantages and disadvantages of the most representative analytical methods developed specifically for the analysis of silicon species in ultrapure water. The most important studies focusing on the silicon species in water have been highlighted and presented in detail. The determination of silicon content in water is of great importance because of various effects of silicon species (corrodibility and toxicity) and the selection of methods for the efficient removal of silicon from water