scholarly journals Fabrication of Ceramic Moulds Using Recycled Shell Powder and Sand with Geopolymer Technology in Investment Casting

2020 ◽  
Vol 10 (13) ◽  
pp. 4577 ◽  
Author(s):  
Wei-Hao Lee ◽  
Yi-Fong Wu ◽  
Yung-Chin Ding ◽  
Ta-Wui Cheng
Keyword(s):  
Environmental Concern ◽  
Raw Materials ◽  
Setting Time ◽  
Mixing Ratio ◽  
Ceramic Shell ◽  
Precision Casting ◽  
Original Sculpture ◽  
Waste Shell ◽  
Shell Mould ◽  
Shell Powder

Lost-wax casting, also called precision casting, is the process of casting a duplicate metal sculpture cast an original sculpture. The ceramic shell mould used in lost-wax casting usually consists of several layers formed with fine zircon and granular mullite particles using silica gel as a binder. However, it is a complicated and time-consuming process. Large amounts of waste moulds that need to be disposed and recycled become an environmental concern. In this study, waste shell sand from the recycled mould and calcium carbonate/metakaolin were used as raw materials to prepare geopolymer slurry and coating. The influence of mixing ratio and the SiO2/K2O modulus of the alkali solution on the setting time and green/fired strength were evaluated. Ceramic shells with one to four layers of geopolymer slurry and waste sand sprinkling were fabricated and tested for their permeability and green/fired strength. It was found that geopolymer shells had higher green/fired strength and better permeability than the original zircon/mullite shell. For foundry practice, metal casts were fabricated using recycled ceramic shell moulds with one to four layers of geopolymer coating. All cast results have their dimensions all within tolerance limitation and up to 13 h can be saved for the preparation of shell moulds.

Micro Palm and Kenaf Fibers Reinforced PLA Composite: Effect of Volume Fraction on Tensile Strength

2011 ◽  
Vol 145 ◽  
pp. 1-5 ◽  
Author(s):  
K.W. Neoh ◽  
Kim Yeow Tshai ◽  
P.S. Khiew ◽  
Chin Hua Chia
Keyword(s):  
Tensile Strength ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Environmental Concern ◽  
Raw Materials ◽  
Kenaf Fiber ◽  
Composite Effect ◽  
Fiber Loading ◽  
Biodegradable Composite ◽  
Kenaf Fibers

Extensive environmental concern associated with the disposal of solid plastic wastes has stirred tremendous interest in the production and use of sustainable biodegradable polymers. Among the vast variety of available materials, Polylactic Acid (PLA) standout as the most commercially viable mass produced resin to date. However, its low thermal and mechanical stability, excessive brittleness, and relatively higher cost have led to numerous research efforts in producing biodegradable polymer composite filled with natural organic fibers. This paper describes the preparation and the mechanical characteristics of a compression molded biodegradable composite made entirely of renewable raw materials. The composites were reinforced with pulverized palm, kenaf and alkali (1M NaOH:fiber in ratio 2:1) treated kenaf fibers, at a fiber mass proportion of 20 to 60% blended PLA and processed in a custom-built compression mold. SEM microscan revealed that the kenaf fiber has a mean diameter of 40μm, length 1236.6μm, and aspect ratio of 31 while the measured values for palm fiber was 58.7μm, 1041.2μm, and 17.7, respectively. All resulting composites showed significant enhancement in tensile strength. At 20, 40 and 60% fiber loading, the palm/PLA composite recorded tensile strength increment of 46.9, 47.8 and 36.6%, respectively. For the kenaf/PLA composite, greatest improvement was achieved at 40% fiber loading with alkali treated kenaf, with approximately 54% higher than the neat PLA while only 12.6% was recorded for the non-treated kenaf/PLA composite, signifying that the surface modification greatly improved fiber-matrix adhesion. SEM observations on the fracture surface showed similar findings. Compared to commercially available palm/Polypropylene (palm/PP) composite at 50% fiber loading, our measured tensile strength for the PLA composite loaded with 40% alkali treated kenaf fiber was still about 20% lower. Further enhancement in the mechanical characteristic of the kenaf/PLA composite is required to push for its wider utilization in the polymer industry.

3D Printing of Ceramic Shell Molds for Precision Casting of Turbine Blades

2021 ◽  
Author(s):  
Liubov Magerramova ◽  
Boris Kozlov ◽  
Eugene Kratt
Keyword(s):  
3D Printing ◽  
Turbine Blades ◽  
Shell Shape ◽  
Ceramic Shell ◽  
Labor Costs ◽  
Precision Casting ◽  
Design And Manufacturing ◽  
Refractory Ceramic ◽  
Internal Core ◽  
Ceramic Shell Mold

Abstract Traditionally, the technology used in the production of gas turbine blade castings characterized by a large number of technological conversions, high labor costs with a large amount of manual labor and the need to produce various types of complex and expensive equipment at different stages of production. This work aims to reduce the time and money spent on the manufacturing of ceramic shell shapes — a form suitable for the standard methods of precision casting by traditional heat-resistant nickel alloys. The proposed approached involves obtaining a shell shape with an internal core as a single, non-assembled product, without lengthy and time-consuming design and manufacturing processes involved in forming equipment for the production of castings based on smelted models. The proposed method is based on the use of 3D printing with refractory ceramic pastes. Using both uncooled and cooled blades as examples, models of casting molds were designed, technological processes were developed, and ceramic shell molds were manufactured. Experimental casting into a manufactured ceramic shell mold for an uncooled blade with a bandage shelf was performed and showed satisfactory results.

scholarly journals Characteristic of materials for the 3D printed building constructions by additive printing

2018 ◽  
Vol 222 ◽  
pp. 01013 ◽  
Author(s):  
Katarzyna Pacewicz ◽  
Anna Sobotka ◽  
Łukasz Gołek
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
New Technology ◽  
Setting Time ◽  
Three Dimensional ◽  
Construction Site ◽  
Printing Technology ◽  
Three Dimensional Printing ◽  
Materials Used ◽  
Dimensional Printing

Three dimensional printing is a promising new technology to erect construction objects. Around the world in every moment a new prototypes constructions are made by using this method. Three dimensional printing is taken into account as technology which can be used to print constructions in automated way on the Moon or Mars. The raw materials, which can be used with three dimensional printing have to fulfil basic requirements for those which are used in construction. That means that components of printing mortars are made from ingredients easily accessible in area nearby construction site and can be reusable. The cost of printing building objects due to that requirements is comparable to costs of traditional building, which are currently available. However additive techniques of printing needs a dedicated mortars for printer supplying. Characteristic for such mortars is: setting time, compressive strength, followability in the printing system, shape stability of every printed layer, controlling the hydration rate to ensure bonding with the subsequent layer, reusable capabilities, easily accessible raw materials, cost of such mixtures shouldn’t be too high in order to keep 3D printing competitive for traditional ways of building, mortar components should be recyclable and printing process should not influence negatively on an environment and people. All properties of printing mortars are determined by the device for additive application method. In this paper review of available materials used for three dimensional printing technology at construction site is presented. Presented materials were analysed in terms of requirements for building materials technology. Due to the lack of detailed information’s in available literature, regarding to the properties of raw materials, the results of this analysis may be used in the designing of new concrete mixtures for the use in three-dimensional printing technology for construction.

Research on Mixing Ratio of Waste Mud Brick

2013 ◽  
Vol 368-370 ◽  
pp. 1103-1106
Author(s):  
Hai Long Wu ◽  
Bing Zhang Huang ◽  
Bang Biao Huang ◽  
Ji Zhen Zhu ◽  
Xi Qiang Li ◽  
...  
Keyword(s):  
Building Materials ◽  
Heat Insulation ◽  
Raw Materials ◽  
Mineral Resources ◽  
Green Building ◽  
National Standards ◽  
Mixing Ratio ◽  
Waste Reuse ◽  
Green Building Materials ◽  
The Relationship

In order to achieve green building materials, energy conservation, waste reuse purposes. Use city sewage sludge as part of the raw materials for production of shale brick is studied by experiments adopted the different mixing ratio, find matching and the relationship between the compressive strength. Experimental results show that the shale powder to add quality percentage is 40% of dry sludge, formed a burning brick, brick of various performance accord with national standards, not only can save coal and mineral resources, improve the heat insulation brick, but also a lot of recycling of utilization of sludge.

Residue Characterization from Polishing Granite Submitted to the Hydrocycloning Process

2018 ◽  
Vol 930 ◽  
pp. 584-588
Author(s):  
André Luiz Araújo Caetano ◽  
Manoel da Cruz Barbosa Neto ◽  
Verônica Cavalcanti Marques ◽  
Daniel A. de Macedo ◽  
Heber Sivini Ferreira ◽  
...  
Keyword(s):  
Environmental Concern ◽  
Raw Materials ◽  
Industrial Processes ◽  
Technological Properties ◽  
Separation And Purification ◽  
Efficient Tool ◽  
Different Characteristics

The waste generated in granite processing has caused great social and environmental concern due to the release of its solid effluents into landfills and other places. The recycling and reuse of waste from different industrial processes as new raw materials has been the object of various researches. The use of hydrocyclone in the treatment of residues can represent a very efficient tool for separation and purification of the granite residue. This work aims to characterize and analyse the technological properties of the granite sawdust residues submitted to the hydrocyclone process in comparison with the same residue without going through the hydrocyclone process. The results indicate that the material resulting from this process presented different characteristics from the material without the process, mainly in terms of granulometric distribution and technological properties.

Setting Time and Compressive Strength of Mortar Containing Cockle Shell Powder as Partial Cement Replacement

2021 ◽  
Vol 879 ◽  
pp. 62-67
Author(s):  
Khairunisa Muthusamy ◽  
Rahimah Embong ◽  
Nabilla Mohamad ◽  
Nur Syahira Hanim Kamarul Bahrin ◽  
Fadzil Mat Yahaya
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Cement Replacement ◽  
Compressive Strength Test ◽  
Shell Waste ◽  
Suitable Combination ◽  
Time Test ◽  
Partial Cement Replacement ◽  
Shell Powder ◽  
Cockle Shell

Environmental degradation caused by deforestation activities for harvesting of limestone from the hills and its calcination process at cement factory along with disposal of cockle shell waste from fisheries industries is in need of resolution. In view of sustainable green environment, approach of utilizing cockle shell waste as partial cement replacement in cement production would reduce pollution caused by both industries. Thus, this research investigates the effect of cockle shell powder as partial cement replacement on setting time and compressive strength of mortar. A total of five types of mortar mixes consisting different percentage of cockle shell powder as partial cement replacement from 0%, 10%, 20%, 30%, and 40% by weight of cement were prepared. Setting time test were conducted on fresh paste. All specimens were subjected to water curing until the testing age. Compressive strength test were conducted on hardened mortar cubes at 3, 7 and 28 days. Finding shows that integration of cockle shell powder as partial cement replacement influences the setting time and compressive strength of mortar. Suitable combination of 10% cockle shell powder successfully enhances the compressive strength of mortar. Conclusively, success in transforming the cockle shell waste to be used as partial cement replacement in mortar production able to reduce cement consumption, save landfill usage for trash dumping and promote cleaner environment for healthier lifestyle of community nearby.

scholarly journals Preparation of Portland Cement with Gold Ore Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Wang ◽  
Geng Yao ◽  
Xiangnan Zhu ◽  
Junxiang Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Hydration Product ◽  
Difficult Problem ◽  
Initial Setting Time ◽  
Gold Ore ◽  
Curing Age

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.

Study on the Anti-Static Desulphurization Gypsum Fiberboard

2013 ◽  
Vol 772 ◽  
pp. 156-160
Author(s):  
Yan Long Liu ◽  
Chao Fa Tang ◽  
Wen Hao Shen ◽  
Ji Wen Han ◽  
Hong Shuang Du
Keyword(s):  
Raw Materials ◽  
Setting Time ◽  
Market Demand ◽  
Initial Setting Time ◽  
Application Range ◽  
Dry Process ◽  
Biomass Resources ◽  
Initial Setting ◽  
Forestry Industry ◽  
Positive Effect

The fiber of the agriculture and forestry biomass resources and the processing residues is main raw materials as a reinforcing material, the calcinated calcium sulfate hemihydrates by industrial flue gas desulfurization waste is a binder, adding efficient composite retarder to increase the initial setting time of gypsum and meet the production process requirements, adding conductive carbon black to reduce system resistance gypsum fiber to produce and meet the requirements of antistatic products. By semi-dry process, we produced the retardant, waterproof, environmental friendly and anti-static desulfurization gypsum fiberboard. Desulfurization gypsum antistatic fiberboard can meet the market demand for functional products used widely in antistatic floor, antistatic wall panel etc. The production of anti-static desulfhurization gypsum fiberboard expands the application range of desulfhurization gypsum, at the same time, which changes the structure of the forestry industry and has a positive effect on improving the forestry economic operation quality, efficiency and international competitiveness.

Effect of the Alkali-Activation on the Mechanical Property of Geopolymer Composite

2014 ◽  
Vol 804 ◽  
pp. 15-18
Author(s):  
Yeong Geum Son ◽  
Woo Keun Lee
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Calcium Ions ◽  
Raw Materials ◽  
Bottom Ash ◽  
Physical Property ◽  
Alkali Activation ◽  
Mixing Ratio ◽  
Mswi Bottom Ash ◽  
Silica Alumina

In this work, pastes were prepared from slag and MSWI bottom ash by geopolymer technique. And its physical property was evaluated with mixing ratio of sodium silicate and potassium silicate. The amounts of leaching products, such as silica, alumina and calcium ions were changed for mixing ratio of raw materials. The compressive strength was increased with the increment of leaching amount of silica, alumina and calcium ions.

Preparation of Calcium Phosphate Cement Utilizing Dicalcium Phosphate Dihydrate and Calcium Carbonate

2014 ◽  
Vol 608 ◽  
pp. 280-286
Author(s):  
Nudthakarn Kosachan ◽  
Angkhana Jaroenworaluck ◽  
Sirithan Jiemsirilers ◽  
Supatra Jinawath ◽  
Ron Stevens
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Cement Pastes ◽  
Setting Times ◽  
Phosphate Dihydrate

Calcium phosphate cement has been widely used as a bone substitute because of its chemical similarity to natural bone. In this study, calcium phosphate cement was prepared using dicalcium phosphate dihydrate (CaHPO4.2H2O) and calcium carbonate (CaCO3) as starting raw materials. The cement pastes were mixed and the chemistry adjusted with two different aqueous solutions of sodium hydroxide (NaOH) and disodium hydrogen phosphate (Na2HPO4). Concentrations of the solution were varied in the range 0.5 to 5.0 mol/L with the ratio of solid/liquid = 2 g/ml. The cement paste was then poured into a silicone mold having a diameter of 10 mm and a height 15 mm. Setting times for the cement were measured using a Vicat apparatus. XRD, FT-IR, and SEM techniques were used to characterize properties and microstructure of the cement. From the experimental results, it is clear that different concentrations of Na2HPO4 and NaOH have affected the setting times of the cement. The relationship between concentration of NaOH and Na2HPO4 and setting time, including final properties of the cement, is discussed.

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