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Search Results: 1 - 10 of 469 matches for " refractory "
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Development of Insulating Refractory Ramming Mass from Some Nigerian Refractory Raw Materials  [PDF]
O. A. Olasupo, J. O. Borode
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.89058
Abstract: Insulating refractory ramming mass was developed from suitable Nigerian refractory raw materials. Rammed samples from several ratios of clay, silica, mica, bentonite and calcium aluminate cement (Durax) were prepared using the American Foundrymen Society (AFS) standard rammer. They were thereafter tested for such properties as apparent porosity, volumetric firing shrinkage, cold compression strength, green compression strength, loss on ignition, thermal shock resistance and refractoriness. Results indicate that eight ramming cycles were just enough for the production of the ramming masses. Two optimal ratios obtained from the experiments have a refractoriness of 1500℃ , good compression strength and excellent thermal shock resistance. They are therefore recommended for lining of rotary furnaces and crucible furnaces for the melting of ferrous and non-ferrous alloys. It could be concluded that the ramming mass serve as a viable alternative to foreign ramming mass at the same temperature application.
Production of MgO-X Refractory Material with Cellular Matrix by Colloidal Processing  [PDF]
Wagner da Silveira, Guido Falk
Low Carbon Economy (LCE) , 2012, DOI: 10.4236/lce.2012.323012
Abstract: The production in the siderurgy and foundry industry has changed considerably in the past years. Despite the new technologies and process, the use of magnesia carbon refractory remains constant. Namely the magnesia carbon refractory is widely used due low-priced cost, high refractivity, excellent corrosion resistance, thermal shock resistance, low thermal expansion, high slag penetration resistance and low wettability. The main disadvantages of use magnesia carbon refractories are the high carbon oxidation susceptibility and the formation CO and CO2 gases. As a result, tonne of CO and CO2 are expelled to the atmosphere. The use of open cell carbon-foam magnesia composite for refractory application can offer a substitute for the traditional refractory material since the high carbon content can be minored and the low mechanical strength and poor oxidation resistance of these materials can be improved.
Evaluation of the Refractory Properties of Nigerian Ozanagogo Clay Deposit  [PDF]
Alexander Asanja Jock, Fatai Afolabi Ayeni, Abdulkarin Salawu Ahmed, Umar Adeiza Sullayman
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2013, DOI: 10.4236/jmmce.2013.16048
Abstract: In this paper, the refractory properties of clay from Ozanagogo had been studied for possible utilization in refractory production. The clay had a specific gravity of 2.57, linear firing shrinkage of 1.01%, 2.14 g/cm3 bulk density and porosity of 20.4%. A cold crushing strength of 17.48 MN/m2 was obtained with modulus of rupture of 8.28 MN/m2. The thermal shock resistance exceeded 30 cycles and the refractoriness was 1750℃. The sample was analysed for its chemical composition, and it was revealed that it contained 38.07% alumina (Al2O3), 46.00% silica (SiO2) and iron impurities (Fe2O3) of 0.78%. The results generally showed that Ozanagogo clay could be used as a refractory material.
Barbiturate Coma: Rebound and Refractory Hyperkalemia  [PDF]
Bonnie C. Greenwood, Christopher D. Adams, Zain I. Khalpey, Peter C. Hou
Case Reports in Clinical Medicine (CRCM) , 2014, DOI: 10.4236/crcm.2014.35067

Purpose: To describe a traumatic brain injury patient who experienced profound dyskalemia upon the initiation and cessation of a pentobarbital infusion and propose management options for future patients receiving this intervention. Methods: Case report. Results: Case report. Conclusions: Dyskalemia has become an anticipated side effect of high dose barbiturate infusions in the setting of elevated intracranial pressure. Hypokalemia during the administration of a barbiturate infusion has been identified within this patient population and was an expected adverse event during this intervention. However, in this case we observed a significant and complicated refractory hyperkalemia upon cessation of the barbiturate infusion which required aggressive management. An objective causality assessment suggests that this adverse event was possibly related to pentobarbital. What this case documents that other cases have not is that upon re-introduction of the pentobarbital infusion, serum potassium levels did not normalize. This questions whether severe rebound hyperkalemia is a pharmacodynamic or infusion-related reaction. More data is needed to identify the mechanism of this adverse event and recommend an appropriate treatment approach.

Refractory Oedema of Nephrotic Syndrome in a Resource Poor Setting: A Case Presentation  [PDF]
Nneka Chioma Okoronkwo, Chukwuemeka Ngozi Onyearugha, Ikechukwu Frank Ogbonna
Case Reports in Clinical Medicine (CRCM) , 2018, DOI: 10.4236/crcm.2018.71003
Abstract: Background: Oedema, a constant feature of childhood nephrotic syndrome can be severe, enough to cause respiratory embarrassment. It can also be refractory to diuretic monotherapy. In such cases, combination of salt poor albumin (SPA) infusion and diuretics has remained the best treatment option. However, the cost of SPA has made it practically unavailable in resource-poor settings. It becomes a therapeutic dilemma when nephrotic syndrome patients of financially-constrained caregivers present with refractory anasarca in a resource-poor settings. Case review: We present a seven-year-old boy with relapsed steroid sensitive nephrotic syndrome who presented to Abia State University Teaching Hospital Aba, in respiratory distress with anasarca and a weight of 58 kilograms. SPA could not be accessed due to financial constraints. A decision to use fresh whole blood in the place of SPA, in combination with frusemide, achieved a lifesaving diuresis and regression of the anasarca. Conclusion: Whole blood is a good alternative for the treatment of refractory oedema in children with nephrotic syndrome in resource poor settings.
Artigo revis?o: estabiliza??o de suspens?es aquosas contendo grafite
Oliveira, I. R. de;Studart, A. R.;Silva Júnior, F. A. e;Pandolfelli, V. C.;
Ceramica , 2000, DOI: 10.1590/S0366-69132000000400004
Abstract: the application of graphite-containing refractories has increased enormously over the latest ten years, especially in the case of refractory castables. graphite in such refractories contributes to the reduction of the material thermal expansion and improvement on its thermal shock resistance, fracture energy and slag resistance. however, the low wettability of graphite in water and organic liquids represents a barrier to its processing. therefore, a surface treatment of graphite particles is required to improve its wettability and enable its dispersion in aqueous suspensions. the main structural and surface characteristics responsible for the low wettability of graphite, as well as the most common surface treatment methods applied are discussed in the present review article. such surface treatment methods include the surface covering of graphite by hydrophilic species and the adsorption of active agents on the surface, such as surfactants and polyelectrolytes.
Bender del Busto,Juan E.;
Revista Habanera de Ciencias M??dicas , 2007,
Abstract: it's a revision of historical, epidemiological and clinical antecedents of refractory epilepsy and different aspects related to surgery as alternative treatment for other syndromes with could be solved surgically. the objectives of the surgery, pre-evaluation and results are described as well.
Elaboration and Characterization of Mullite Refractory Products from Moroccan Andalusite  [PDF]
Mostafa Sardy, Abdelhak Arib, Kacem El Abbassi, Moussa Gomina
New Journal of Glass and Ceramics (NJGC) , 2012, DOI: 10.4236/njgc.2012.23017
Abstract: Enrichment of schist mined in Morocco resulted in an extract essentially made of andalusite, quartz and muscovite, which was investigated with the aim to synthesize mullite refractory materials. X-ray diffraction analysis was used to assess phase transformations upon heating at different temperatures. Mullite formation starts as early as 1200℃ and seems almost total at 1450℃. This process correlates with a weak shrinkage (3.5% at 1450℃) and the formation of an important glass phase. Green compacts obtained by unidirectional pressing the extract powder were heated under air in the temperature range 1200℃ - 1600℃. Chemical and mechanical properties of these materials were investigated and correlated with their microstructure.
Production of Refractory Lining for Diesel Fired Rotary Furnace, from Locally Sourced Kaolin and Potter’s Clay  [PDF]
Fatai Olufemi Aramide, Saliu Ojo Seidu
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2013, DOI: 10.4236/jmmce.2013.13014
Abstract: This research was conducted to formulate a refractory lining recipe for lining diesel fired rotary furnace from locally sourced kaolin, using locally sourced potter’s clay as binder. Six samples (A-F) of kaolin clay mined locally from Apata II area, Ondo road, in Ile-Ife,Nigeria, were roasted at 1200oC held for 8 hours, mixed with different percentages of raw kaolin and appropriately made into briquettes using potter’s clay of good plasticity as binder. The samples were tested for various refractory properties. The result showed that sample mixes A (100% chamotte), B (80% chamotte, 20% rawkaolin) and C (60% chamotte, 40% raw kaolin) are considered to have good properties. However, the optimum material-mix for the refractory bricks lining, with particular reference to the highest thermal shock resistance was found to be 80% chamotte mixed with 20% raw kaolin.
Effect of Tin Tailings on Some Refractory Properties of Alumino-Silicates (Alkaleri) Clay  [PDF]
Victor Sunday Aigbodion, Clement Uche Atuanya, Chikaodi Cynthia Daniel Mkpume
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2013, DOI: 10.4236/jmmce.2013.12006

The possibilities of upgrading some refractory properties of Alkaleri Clay (Alumino-silicates), found in Alkaleri Village, Bauchi State, Nigeria, by blending with tin tailings for the production of fireclay refractory bricks were investigated. Refractory properties such as: linear shrinkage, apparent porosity, bulk density, cold crushing strength and thermal shock resistance were tested with percentage additions of tin tailings from 5 - 30 wt% in the blend. The test was conducted using the standard test techniques in each case. The results were compared with standard refractory properties for fire clay bricks. Cold crushing strength, bulk density, refractoriness and thermal shock resistance of the bricks made from the blend clay increased, as the percentages of tin tailings increased. The Linear shrinkage and apparent porosity decreased as the percentages of tin tailings addition increased. All the values obtained from the blends are within the recommended values for dense fireclay bricks. Hence, dense fireclay can be produced from this blended.

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