scholarly journals Sustainable Development of Human Society in Terms of Natural Depleting Resources Preservation Using Natural Renewable Raw Materials in a Novel Ecological Material Production

2020 ◽  
Vol 12 (7) ◽  
pp. 2651 ◽  
Author(s):  
Cătălina Mihaela Grădinaru ◽  
Radu Muntean ◽  
Adrian Alexandru Șerbănoiu ◽  
Vasilică Ciocan ◽  
Andrei Burlacu

In the last few years, the building industry experienced a significant development as a response to the demographic growth of human society and to the increasing demand for housing. Their construction involves the traditional use of concrete as a material that provides added strength to the finished building. This is manufactured respecting standard recipes depending on the way of its use. Anyway, all concrete recipes involve the use of mineral aggregates extracted from the riverbed, as is happening in Romania, or rock blocks crushing, as reported in other countries. Under these conditions, the rationalization of the use of natural mineral resources and the identification of new possibilities to reduce their consumption through their replacement with vegetal waste has become an important research issue. In this study, two types of vegetal waste—namely, shredded corn cobs and sunflower stalks—were used to manufacture novel ecological concretes. The vegetal wastes, both in untreated and treated forms (with 20% and 40% of sodium silicate solution), were used to replace 50% of the river (mineral) aggregate volume. The obtained concretes were tested, and the values of some important parameters in the concrete characterization (such as bulk density, water adsorption capacity, compressive strength and splitting tensile strength) were compared with the concrete contains cement CEM II/A-LL 42.5R. The obtained results show that these vegetal wastes have the potential to be used in the manufacturing of new ecological concrete. In addition, this alternative material meets the requirements for the sustainable and healthy development of the environment, offering low-polluting solutions in the context of an increasing demand for constructions.

2010 ◽  
Vol 92 ◽  
pp. 183-187 ◽  
Author(s):  
X.K. Hu ◽  
Zhi Tang Song ◽  
H.B. Wang ◽  
W.L. Liu ◽  
F. Qin ◽  
...  

Chemical mechanical polishing technique is more frequently adopted for planarization in integrated circuit fabrication. The silica abrasives in colloidal state are fabricated with the sodium silicate solution as raw materials through the polymerization reaction among silicic acid molecules. By continuous injection of silicic acid into the preexisting silica solution, the diameter of silica nanoparticles increases. The different sized silica nanoparticles are imaged by scanning electron microscopy, and the dried silica are characterized by X-ray diffraction and thermal analysis. The polishing test on silicon wafer with as-fabricated silica abrasives shows that the surface flatness reaches 1.1 nm roughness, however, micro scratches are still present in the surface.


Author(s):  
V. Men'shikova

In modern conditions, clay raw materials of fine-grained structure are used for the production of building ceramics. The task of using coarse non-traditional non-plastic components in the compositions of ceramic masses and the choice of rational sizes of their grains is relevant. The exclusion of pre-grinding determines the reduction of energy costs and, as a result, the cost of finished products. The paper offers an optiom of using diopside concentrate of various grain sizes in compositions with minor additions of clay and sodium silicate solution. The problems of stress development at the interface of grain and ligament contact, which in case of a negative outcome do not make it possible to obtain a strong structure of a ceramic shard, are solved. The presence of an insignificant voltage formed as a result of the relationship between the diopside and the forming glass phase is revealed, this does not prevent the consideration of the probability of obtaining a ceramic material. The study of the behavior of ceramic samples containing diopside of different granulometric composition when adding a solution of sodium-silicate glass after molding and firing shows the effectiveness of using diopside concentrate in 100-150 microns. Contacts of this size of diopside are wrapped in liquid glass during molding. A glass phase is formed when fired. In this case, the diopside is partially melted, but it is preserved and exists as an independent unit. A smaller grain size during sintering requires more glass phase, which leads to structural stresses, and with a larger size, not enough glass phase is formed and the strength of the material is significantly reduced. When studying the influence of grain size on the properties of the sample, the results of water absorption indicators of 7 %, mechanical compressive strength – 36 MPa, bending strength-17 MPa are obtained. It is found that the dispersion of diopside in 100–150 microns allows to develop a technology for the use of coarse-grained raw materials in the ceramic mass


2019 ◽  
Vol 8 (3) ◽  
pp. 3151-3158

Today, developing nations are witnessing an unprecedented pace of urbanization in the wake of industrialization and globalization. This is giving rise to an ever increasing demand for housing and infrastructure to support the growing population and its activities. Embodied energy is the energy in total needed in manufacturing and extracting the raw materials, energy consumed for transportation and the external energy applied to raw materials in producing or assembling the final product. In this project, Energy accounted in different material used for construction of this building is calculated. All the material used for construction is accounted and Embodied energies of different materials has been worked out. The Embodied energy calculation arrived based on energy consumed for production and Transportation. With the estimated total quantity of all the materials and the energy, an analysis about the major contributors of embodied energy has been studied and comparisons have been made across different materials between the production and transportation energies. The values have been normalized and a tool has been made on a platform called Spyder to generate the embodied energy calculation for the provided inputs. Suitable alternative material, which consumes less Embodied energy is suggested.


2018 ◽  
Vol 777 ◽  
pp. 508-512 ◽  
Author(s):  
Van Quang Le ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
Vo Thi Ha Quyen Pham ◽  
Thu Ha Bui ◽  
...  

Geopolymer is an inorganic polymer material formed from alumino-silicate structures. Geopolymer has many outstanding functions in comparison with ordinary materials such as high mechanical strength, high heat and chemical resistance, and lightweight property. The engineering properties of geopolymer-based materials depend on raw materials and synthesized conditions. In which, the aluminosilicate materials having high activity and consisting of many alkaline activators have the possibility of increasing pH in geopolymer paste. In the solution of paste, aluminosilicate compounds are solubilized and then react with alkali-activated ions to form geopolymeric networks. The geopolymer can be synthesized in many different conditions depending on factors of temperature, pressure, and curing conditions. In this study, red mud (RM) was used as the main alumino resource for geopolymerization process. RM is a solid waste residue being left from the mining process of bauxite ores with caustic soda for alumina production. Its disposal remains a global issue in terms of environmental concerns. Formation of RM-based geopolymer was affected by many factors, in which, the alkaline activators are the most important factor. This research was conducted with sodium hydroxide and sodium silicate solutions to elucidate the effect of alkaline activator ratio to the engineering properties of RM-based geopolymers. The results showed that the RM-based geopolymer used sodium silicate solution has more outstanding properties than RM-based geopolymer using sodium hydroxide solution.


2019 ◽  
Vol 956 ◽  
pp. 342-351
Author(s):  
Jian Wang ◽  
Yi Qiang Wu ◽  
Jun Hua Xiao ◽  
Ming Liu ◽  
Xin Li Zhang ◽  
...  

Magnesia inorganic lightweight material was prepared by using magnesium cementitious materials as raw materials, sodium silicate solution as modifier, hydrogen peroxide solution as foaming agent, manganese dioxide as activator, calcium stearate as stabilizer and polyacrylamide as thickener in this paper. The effects of sodium silicate addition on the apparent density, mechanical strength, pore structure, crystalline phase and water resistance of magnesia inorganic lightweight material were discussed. The results show that when the content of sodium silicate is 7.5‰, the pore structure presents better morphology and the crystallization contains more 5·1·8 phases (strength phase). At this moment, the compressive strength and bending strength of the composite reached 10.35 MPa and 2.22 MPa, respectively. When the addition of sodium silicate exceeded 7.5‰, SEM and EDS presented that a large amount of sodium silicate and perforation appeared in the pores, meanwhile large number of perforations occurred between pores. XRD showed that the 5·1·8 phases and 3·1·8 phases in the materials changed into Mg (OH)2 crystals. These results in a significant decrease in material properties. Keywords: Magnesium cementitious material; Sodium silicate; Inorganic light materials; Pore structure


2021 ◽  
Vol 328 ◽  
pp. 01015
Author(s):  
Srie Muljani ◽  
Heru Setyawan ◽  
Fryski Indra Irianto ◽  
Sylvanus Pridia Fransisco

The use of solid adsorbents such as amine-modified silica aerogels to capture CO2 has been commonly used but poses several obstacles, including expensive raw materials, production complexity, and considerations for adsorbent regeneration. This research develops sodium silicate solution as a carbon scrubber in a packed column. Besides being able to capture CO2, the amorphous silica which has economic value can also be produced. The packing size and CO2 flow rate were studied to prevent the deposition of silica inside of the packed column. The precipitated product analysis using XRF, XRD, FTIR, and SEM Image observed that CO2 was well absorbed by sodium silicate solution. The amorphous silica precipitated concentration reaches 98.6%.


2021 ◽  
Vol 309 ◽  
pp. 01195
Author(s):  
G.V.V. Satyanarayana ◽  
Kaparaboina Greeshma

The utilization of cement in concrete was an ancient method as well the utilization of cementitious materials in concrete not only improves mechanical properties but also improves workability and durability etc., Today urbanization expands in many folds, so that the usage of cement became more due to this the production of cement increases. The production of cement on one hand affects the environment in form of Carbon dioxide gases on other hand depreciation of raw materials like lime stone and sand etc. Globally many construction industry and researches focussed in reduction of cement content in concrete by production of new alternatives like Geo polymer concrete etc. In this investigation Alkali-Activated Fly Ash slag concrete (AAFSC) is introduced as an alternative for ordinary Portland cement concrete (OPCC). Researchers developed AAFSC with NaOH and Na2SiO3 as activators. In this study AAFSC produced is with neutral grade sodium silicate solution with silica modulus 2.9 (Ms).For production of AAFSC the quantity of binder content is 500kg/m3 by varying binders proportions like Fly Ash and GGBS along with solution/binder ratios varying from 0.6 to 0.7. During this experimental investigation the workability and compressive strength of AAFSC is tested.


1969 ◽  
Vol 31 ◽  
pp. 95-98
Author(s):  
Per Kalvig ◽  
Rune J. Clausen ◽  
Niels Fold ◽  
Karen Hanghøj

Mineral resources are building blocks of modern society and essential for progress and prosperity. Mankind has always depended on access to mineral raw materials, which have been a key factor for wealth, culture and development. Modern societies are characterised by a rapidly increasing demand for specialised mineral raw materials, determined by their stage of technological development, the number of consumers, and their standard of living. Generally, the availability of mineral raw materials has not, until recently, been considered an issue by the average consumer or by companies in the downstream end of the value chains, and mineral resources have not been part of the political agenda. In this context China’s control over rare-earth elements (REE) has been an eye opener to both industry and politicians worldwide, and has subsequently led to discussions about the possible exhaustion of finite resources and potential threats to the availability of raw materials caused by geopolitical tension and market restrictions.


Author(s):  
A. L. Dergachev ◽  
V. I. Starostin

Important trends in development of world's mineral complex at the beginning of the 21st century are increase of supply and demand for mineral materials differentiated for various metals and nonmetallic mineral resources, regions and countries; concentration of production of mineral commodities in small number of countries; falling availability of economic reserves of raw materials for world economy even at current level of material extraction. The tendencies should be taken into account when working out strategy of development of Russian mineral base.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2811
Author(s):  
Okpin Na ◽  
Kangmin Kim ◽  
Hyunjoo Lee ◽  
Hyunseung Lee

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.


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