Recycling possibilities of fine-grained metallurgical wastes

Import 02/11/2016Předkládaná práce se zabývá výběrem a charakterizací pojiv, které by bylo možno využít pro průmyslovou přípravu briket s vhodnými mechanickými vlastnostmi. Současně sleduje vliv obsahu vybraných pojiv (škrob Unipret, portlandský cement) na redukci oxidů železa ve zkoumaných odpadních materiálech (vysokopecní a konvertorový kal) při tepelné úpravě v laboratorních podmínkách v závislosti na době výdrže při třech zvolených teplotách (900, 1000 a 1100 °C). V neposlední řadě je provedena studie vlivu pojiva na množství a složení odpadního plynu vznikajícího během tepelné úpravy a jeho možný dopad na životní prostředí. Získaná experimentální data byla zpracována mnohorozměrnou analýzou, aby byla prokázána jejich vzájemná souvislost. Provedené experimenty prokázaly vzájemnou souvislost mezi stupněm konverze oxidů železa na kovové železo a obsahem pojiva i teplotě výdrže. Přítomnost pojiva rovněž ovlivnila množství vznikajícího odpadního plynu. Faktorová analýza na smíšených datech (FAMD) dokázala, že zjištěné koncentrace uhlovodíků (methanu, ethanu, ethenu, propanu, propenu, butanu, isobutanu, isobutenu, buta 1,3-dienu) jsou mezi sebou ve vzájemném vztahu (mimo ethyn) a že koncentrace vyšších uhlovodíků a vodíku jsou v nejtěsnějším vztahu s použitými pojivy. Naopak sledované koncentrace ethynu, oxidu uhličitého a oxidu uhelnatého nejsou ve vztahu s použitým pojivem. FAMD neprokázala přímý vliv zvolené konečné teploty termické úpravy na množství vznikajících uhlovodíků, vodíku, oxidu uhličitého a oxidu uhelnatého. Rovněž byl prokázán vliv pojiva na obsah PAHs.Thesis deals with the topic of choice and characterization of applicable binders in the industrial manufacture of briquettes with suitable mechanical properties. At the same time, it is focused on the effect of the amount of the selected binders in the briquettes (Unipret starch, Portland cement) on the iron oxides reduction in the waste materials under study – blast furnace sludge and converter sludge – depending on retention time during the thermal treatment in laboratory (900, 1000, 1100 °C). Moreover, study was conducted on the effect of the binder on the volume and composition of the waste gas originating during the thermal treatment as well as the possible impact of this gas on the environment. In order to find the relationships in the data, the data were assessed using multivariate analyses. Conducted experiments proved relationship between the degree of iron oxide to metal iron conversion and the amount of the binder as well as the retention temperature. The presence of the binder influenced the amount of the produced waste gas as well. Factorial analysis on mixed data proved that the observed concentrations of the hydrocarbons (methane, ethane, ethene, propane, propene, butane, isobutane, isobutene, buta-1,3-diene) are positively correlated with each other (all apart from ethyne) and that the concentration of the hydrocarbons and hydrogen are in close association with the applied binder. On the other hand, observed concentrations of ethyne, carbon dioxide and carbon monoxide were not influenced by the binder used. FAMD did not prove any direct effect of the chosen final temperature of the thermal treatment on the amount of the produced hydrocarbons, hydrogen, carbon dioxide and carbon monoxide. The effect of the choice of the binder on the amount of PAHs was also observed.9360 - Centrum nanotechnologiívyhově

PhD students´day FMST 2023

The authors gave oral presentations of their work online as part of a Doctoral Students’ Day held on 15 June 2023, and they reflect the challenging work done by the students and their supervisors in the fields of metallurgy, materials engineering and management. There are 82 contributions in total, covering a range of areas – metallurgical technology, thermal engineering and fuels in industry, chemical metallurgy, nanotechnology, materials science and engineering, and industrial systems management. This represents a cross-section of the diverse topics investigated by doctoral students at the faculty, and it will provide a guide for Master’s graduates in these or similar disciplines who are interested in pursuing their scientific careers further, whether they are from the faculty here in Ostrava or engineering faculties elsewhere in the Czech Republic. The quality of the contributions varies: some are of average quality, but many reach a standard comparable with research articles published in established journals focusing on disciplines of materials technology. The diversity of topics, and in some cases the excellence of the contributions, with logical structure and clearly formulated conclusions, reflect the high standard of the doctoral programme at the faculty.Ostrav

Technological and quality aspects of the use of innovative inorganic binders in the production of castings

The production of cores for the pre-casting of holes in castings places high demands on the quality of the molding mixtures used. For this reason, organic binders are still used to a large extent, which, although they meet the technological requirements, are a source of pollutant emissions during the production of castings. The current trend towards greening production is therefore looking for a suitable alternative in 'green' inorganic binders. Although for many decades standard inorganic binders could not be compared with organic resins in terms of technological properties, new inorganic binder systems are currently being developed that can largely eliminate these disadvantages, which include, in particular, significantly lower collapsibility and reclaimability, and lower mechanical strength values. Last but not least, the use of these binder systems may be limited by the technological parameter of shelf-life, which is the main focus of this study. The aim of this paper is to evaluate the influence of technological parameters of core production using a new generation of inorganic binder systems on their shelf-life. Shelf-life, defined as the change in mechanical strength and wear resistance as a function of exposure time in a given environment, is evaluated under different climatic conditions.Web of Science1111art. no. 177

Waste from health service

Import 06/06/2008Prezenční546 - Institut environmentálního inženýrstvíNeuveden

Incineration of Waste from Health-care Facilities

Import 29/09/2010Odpady ze zdravotnických zařízení představují pro lidské zdraví a životní prostředí velké nebezpečí. Především kvůli jejich nebezpečným vlastnostem a komplikovanosti složení.Nakládání se zdravotnickými odpady musí splňovat základní cíl a to je bezpečnost celého procesu likvidace. Nejčastějším odstraňováním odpadů ze zdravotnických zaříjení je v České republice spalování odpadů ve spalovnách nebezpečných odpadů. Spalovna nebezpečných odpadů Hoval Schiestel typ GG 14 v Nemocnici Znojmo je konstruována pro tento typ odpad. Odpadem spalovny Nemocnice Znojmo je popel a struska obsahující nebezpečné látky a upotřebené aktivní uhlí z čištění spalin. Tyto vzorky jsem podrobila bakteriálnímu loužení a následně analýzám v laboratořích Centra nanotechnologií Vysoké školy báňské – technické univerzity Ostrava.Waste from Health institutions represents a big danger for people and the environment. Mainly because of its infectivity, and complicated composition. Manipulation of medical waste has to fully fulfil one basic aim, which is the safty of all liquidation processes. The most common way of disposing of medical waste in the Czech Republic is to incinerate it. The Incinerator of hazardous waste, model Hoval Schiestel typ GG 14, in Znojmo hospital is designed for this type of waste. The waste from the incinerator, ashes and slag, contains dangerous substances and the used active carbon for cleaning flue gas. These samples were subjected to bacterial leaching and were analysed in laboratories in the Centre of nanotechnologies at the VSB – TUO university.Prezenční546 - Institut environmentálního inženýrstvívýborn

Den doktorandů 2022

Ostrav

Bioleaching of hazardous waste

Landfill represents the least environmentally-friendly method of waste disposal because of possible pollution to the environment. Dangerous wastes pose the greatest problems and are often disposed of by combustion. This process reduces their volume but entails the formation of new types of dangerous waste. The present study focuses on the possibilities of the removal of the hazardous properties of waste originating from hazardous waste incinerators (three types of bottom ash and charcoal from flue gas cleaning) by bioleaching. Toxic pollutants originating from waste could be removed by bioleaching with Acidithiobacillus ferrooxidans. The effectiveness of bioleaching was evaluated on the basis of the pollutant content in the aqueous leachates. For studying the relation between the efficiency of bioleaching and the binding of pollutants in the waste, Tessier’s sequential extraction was used. A comparison of bioleaching efficiency and the results of sequential extraction shows that bioleaching can be used to remove elements which are in an exchangeable form or are bound to carbonates, meaning that they are bound in bio-available forms. Bacterial activity was also shown to change the bonds of pollutants in wastes, leading to increased solubility of the pollutant.Web of Science6991201119

Evaluation of collapsibility of selected core systems

There are mainly two different ways of producing sand cores in the industry. The most used is the shooting moulding process. A mixture of sand and binder is injected by compressed air into a cavity (core), where it is then thermally or chemically cured. Another relatively new method of manufacturing cores is the use of 3D printing. The principle is based on the method of local curing of the sand bed. The ability to destroy sand cores after casting can be evaluated by means of tests that are carried out directly on the test core. In most cases, the core is thermally degraded and the mechanical properties before and after thermal exposure are measured. Another possible way to determine the collapsibility of core mixtures can be performed on test castings, where a specific casting is designed for different binder systems. The residual strength is measured by subsequent shake-out or knock-out tests. In this paper, attention will be paid to the collapsibility of core mixtures in aluminium castings.Web of Science221524

Influence of microwave treatment on Ghassoul stability

Moroccan clay with a significant portion of stevensite, locally known as Ghassoul, is a very good sorbent. For the facilitation of the sorbent separation, it is convenient to use its magnetically modified form. Recently, the composites of FexOy/Ghassoul have been prepared using simple microwave assisted synthesis and the effect of method preparation on composite composition has been proven. The aim of the presented work was to evaluate the effect of the microwave radiation on the structure and stability of native Ghassoul. Water extracts were prepared by batch method using deionized water. The leachate was prepared for 1, 6 and 24 hours in 1:1000 ratio of solid and liquid phase from the original material and the material after interaction with microwave radiation. In the filtrate, pH was determined as well as concentrations of Al, Ca, K, Mg, Na and Si using Atomic emission spectrometry with inductively coupled plasma. The results imply that microwave treatment of the material changes the pH of the leachates to more acidic compared to the original material in which the pH increases. Even the microwave treatment of Ghassoul did not cause changes in Al, in contrast with Si which was leached considerably more in the case of the microwave-treated sample. Opposite result was observed in the case of Na and Mg. Leached amounts of Ca were comparable in both the treatments, leached amounts K were not affected by the treatment and leaching time.Web of Science19294093

Experimental verification of regenerable magnetically modified montmorillonite and its application for heavy metals removal from metallurgical waste leachates

Using magnetic sorbents to pollutants eliminations seem to be an efficient, easy to apply and low-cost technique. However, the majority of studies focus on the study of sorption properties using model solutions and research on actual wastewater is largely missing. Therefore, this study aims to assess the application of magnetically modified montmorillonite (MMt) to eliminate Zn(II), Cd(II) and Pb(II) cations from metallurgical waste leachates. First, model solutions were prepared to describe the properties of MMt, sorption kinetic and isotherm models. The determined elimination efficiency was higher than 98 %. The q(max) values were - in model solutions - determined to be 34.3, 2.84 and 7.25 mg/g for Zn(II), Cd(II) and Pb(II), respectively. Then, the MMt was applied in order to eliminate of Zn(II), Cd(II) and Pb(II) ions from actual metallurgical waste leachates. The experimental data obtained from the metallurgical waste leachates corresponded with the data obtained from the model solutions. The equilibrium metal uptake capacities obtained by heavy metals adsorption from model solution and metallurgical waste leachates followed the order: Zn(II) > Pb(II) > Cd(II) for dust leachates and Zn(II) > Cd(II) > Pb (II) for converter sludge leachates, which directly corresponds with the heavy metal ions concentration in the leachates. Moreover, the elimination of Zn(II), Cd(II) and Pb(II) by MMt was higher than 98 % even in the fifth recycling experiment cycle. After the sorption, the sorbent was still magnetically active, facilitating its removal from the solution. MMt proved to be an efficient and regenerable sorbent, applicable for wastewater treatment.Web of Science39art. no. 10169