scholarly journals Reclaiming Ability of Spent Sands with Modified, Hydrated Sodium Silicate

2014 ◽  
Vol 14 (1) ◽  
pp. 41-44
Author(s):  
J. Kamińska ◽  
A. Kmita
Keyword(s):  
Sodium Silicate ◽  
Water Glass ◽  
Bending Strength ◽  
Colloidal Suspension ◽  
Strength Properties ◽  
Matrix Component ◽  
Na2o Content ◽  
Zinc Carbonate ◽  
Ignition Loss

Abstract The presented in the paper investigations were aimed at the determination of the reclaimed material (obtained in the dry mechanical reclamation process) addition influence on properties of moulding sands with hydrated sodium silicate modified by colloidal suspension of zinc oxide nanoparticles in propanol. Nanoparticles originated from the thermal decomposition of alkaline zinc carbonate, were used. The results of the reclamation of the spent moulding sand with hydrated sodium silicate performed in the AT-2 testing reclaimer are presented in the paper. Both, spent sands from the Floster S technology and from the technology with the modified water-glass were subjected to the reclamation processes. The following determinations of the reclaimed material were performed: pH reaction, acid demand, ignition loss and Na2O content. The obtained reclaim was used as a matrix component of moulding sands with water-glass in the Floster S technology, in which it constituted 60% and 50% of the sand matrix. The strength properties of the prepared moulding sands were determined (bending strength Rgu, tensile strength Rm u) after samples storing times: 1h, 2h, 4h and 24 hours.

scholarly journals Influence of Binding Rates on Strength Properties of Moulding Sands with the GEOPOL Binder

2014 ◽  
Vol 14 (1) ◽  
pp. 37-40 ◽  
Author(s):  
M. Holtzer ◽  
D. Drożyński ◽  
A. Bobrowski ◽  
W. Plaza
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Bending Strength ◽  
Strength Properties ◽  
Technological Properties ◽  
Inorganic Binder ◽  
Splitting Strength ◽  
Moulding Sand ◽  
Tensile And Bending Strength

Abstract The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these sands (bending strength, tensile strength, permeability and grindability). In addition, the final strength of moulding sands of the selected compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest hardener (SA 72) were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking to pieces the mould made of such moulding sand will be 1.5 - 2 hours.

Bending and Compression Properties of Malaysian Medium Hardwood in Orthotropic Directions Kelat (Syzygium spp.)

2013 ◽  
Vol 330 ◽  
pp. 938-941 ◽  
Author(s):  
Nur Hasmiza Abdul Hamid ◽  
Mansur Ahmad ◽  
Mohd Nazip Suratman
Keyword(s):  
Compression Strength ◽  
Bending Strength ◽  
Construction Material ◽  
Tangential Direction ◽  
Strength Properties ◽  
Compression Tests ◽  
Effective Utilization ◽  
Compression Properties ◽  
Commercial Medium

Wood behaves differently in three independent orthotropic directions, namely radial, tangential and longitudinal. Determination of mechanical properties of wood and the study on the orthotropic behavior could enhance effective utilization of wood as construction material. Kapur and Kelat are two commercial medium hardwoods that are found abundantly in the east-coast of Malaysia. The purpose of the study is to determine the variation of bending and compression strength properties of Kapur and Kelat in three different anatomical directions. Bending and compression tests on small clear specimens were carried out according to BS373:1987. The result shows that Kapur is higher in bending and compression strength compares to Kelat. Bending strength properties for Kapur and Kelat were found to be significantly higher on the radial direction compared to tangential direction. In compression, the strength properties are higher on the longitudinal directions that are parallel to the grain. This is followed by radial and tangential direction for both Kapur and Kelat. The result also shows that compression strength parallel to the grain for both wood species to be significantly different from those perpendiculars to the grain.

scholarly journals Density, hardness and strength properties of densified fir and aspen woods pretreated with water repellents

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hüseyin Pelit ◽  
Fatih Emiroglu
Keyword(s):  
Compression Ratio ◽  
Bending Strength ◽  
Linseed Oil ◽  
Vacuum Treatment ◽  
Strength Properties ◽  
Aspen Wood ◽  
Positive Effect ◽  
Water Repellents ◽  
Impregnated Wood ◽  
Compression Temperature

AbstractIn this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.

scholarly journals Silica extraction from bauxite reaction residue and synthesis water glass

2021 ◽  
Vol 10 (1) ◽  
pp. 268-283
Author(s):  
Yunlong Zhao ◽  
Yajie Zheng ◽  
Hanbing He ◽  
Zhaoming Sun ◽  
An Li
Keyword(s):  
Sodium Silicate ◽  
Water Glass ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Hydrated Calcium Silicate ◽  
Precipitated Silica ◽  
Alumina Gel ◽  
Silica Alumina ◽  
Element Removal ◽  
Hydrated Calcium

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

scholarly journals Chlorine-Functional Silsesquioxanes (POSS-Cl) as Effective Flame Retardants and Reinforcing Additives for Rigid Polyurethane Foams

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec
Keyword(s):  
Flame Retardants ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Reaction System ◽  
Fire Retardant ◽  
Polyurethane Foams ◽  
Polymerization Reaction ◽  
Three Point Bending ◽  
One Step

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.

Study on Particleboard made from Nipa palm (Nypa fruticans) stem wood and Rajkoroi (Albizia richardiana) wood

2018 ◽  
Vol 25 (1) ◽  
pp. 15-18
Author(s):  
Md. Mahabubur Rahaman ◽  
◽  
Khurshid Akhter ◽  
S. Hossain ◽  
Md. Rakibul Islam ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Dimensional Stability ◽  
Bending Strength ◽  
Strength Properties ◽  
Wood Chips ◽  
Standard Specification ◽  
Stem Wood ◽  
Nypa Fruticans ◽  
Albizia Richardiana ◽  
Nipa Palm

The study was conducted to find out the suitability of making particleboard using nipa palm (Nypa fruticans) stem wood and rajkoroi (Albizia richardiana) wood chips. Particleboards were fabricated at six different ratios of nipa palm stem and rajkoroi wood chips such as 100:0, 75:25, 50:50, 25:75, 10:90 and 0:100. Characteristics of particleboards such as modulus of rupture, internal bond strength, water absorption, thickness swelling and moisture content were measured. Results shows that particleboards made from 100% rajkoroi wood chips have the highest static bending properties and highest tensile strength properties of other particleboards but 100% nipa palm stem wood chips have the lowest static bending and lowest tensile strength properties of other particleboards. 10% nipa palm stem wood chips particleboard have the highest bending strength and tensile strength is better than 100% nipa palm stem wood chips and other mixing chips of particleboards. Mechanical, water resistance and dimensional stability properties were tested according to Indian standard specification. Tensile strength passed the British and German standard specification and nearest to Bureau of Indian Standard, bending strength was found nearest to Indian Standard but lower than German and British Standard specification. Strength property of rajkoroi wood chips particleboard is higher than nipa palm steam wood chips particleboard but dimensional stability is lower than nipa palm steam wood chips particleboard.

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