Proses pembuatan waterglass dari pasir silika dengan pelebur natrium hidroksida

2018 ◽  
Vol 8 (2) ◽  
pp. 56 ◽  
Author(s):  
Sirin Fairus ◽  
H Haryono ◽  
Mas H. Sugita ◽  
Agus Sudrajat

Waterglass from silica sand production process with buster sodium hydroxideWaterglass may be prepared by the fusion process of silica sand using alkali. Waterglass component, which mainly contains SiO2 and Na2O, have various applications depending on their composition. Waterglass is usually used in the soap and detergent, paper, textile, and ceramic industries, in the cleaning of metals, the manufacture of silica gel, and others. This research was done to study the effect of silica sand particle size and the quantity of NaOH as fluxing agent on the yield and SiO2 content of waterglass produced by the alkali fusion process in a furnace. Silica sand particle size was varied at 35/40 and 50/60 mesh. The quantity of NaOH fluxing agent was varied at 1:1, 1.5:1, 2.4:1, 3.2:1, and 4:1 g/g to mass of the silica sand. Other fusion process variables, namely temperature, time, and silica sand quantity, were held constant at 500oC, 2 hours, and 10 gram, respectively. Research results indicated that decreasing silica sand particle size resulted in the increasing SiO2 and Na2O content. Increasing NaOH fluxing agent quantity increases the Na2O content of the waterglass. In this research, the highest SiO2 content of the waterglass of 34.6 %-mass SiO2, was obtained at an NaOH content of 2.4:1 g/g to mass of the silica sand, and silica sand particle size of 50/60 mesh.Keywords: silica sand, NaOH fluxing agent, particle size, waterglass AbstrakWaterglass dapat dibuat melalui proses peleburan pasir silika dengan alkali. Kandungan dalam waterglass, terutama berupa SiO2 dan Na2O mempunyai berbagai kegunaan tergantung pada komposisinya masing-masing. Biasanya waterglass digunakan pada industri sabun atau deterjen, kertas, tekstil, keramik, digunakan untuk pembersihan logam, pembuatan silika gel, dan lain sebagainya. Penelitian ini bertujuan untuk mempelajari pengaruh ukuran partikel pasir silika dan jumlah NaOH sebagai pelebur terhadap perolehan waterglass dan kadar SiO2 pada pembuatan waterglass dengan proses peleburan alkali di dalam furnace. Variabel berupa ukuran partikel pasir silika dipelajari pada ukuran 35/40 dan 50/60 mesh. Sedangkan banyaknya pelebur NaOH divariasikan sebanyak 1:1, 1,5:1,  2,4:1, 3,2:1, dan 4:1 g/g terhadap pasir silika. Kondisi peleburan lainnya berupa temperatur, waktu dan jumlah pasir silika, dilakukan pada nilai konstan, secara berturutan pada 500°C, 2 jam, dan 10 gram. Hasil penelitian menunjukkan bahwa pada penggunaan pasir silika dengan ukuran partikel yang makin kecil diperoleh waterglass dengan kadar SiO2 dan Na2O yang makin besar. Dan dengan makin banyaknya penggunaan pelebur NaOH, diperoleh kadar Na2O dalam waterglass juga makin tinggi. Pada penelitian ini waterglass dengan kadar SiO2 tertinggi diperoleh pada penggunaan pelebur NaOH sebanyak 2,4:1 g/g terhadap pasir silika dan ukuran pasir silika sebesar 50/60 mesh, yaitu sebesar 34,6 %-b SiO2.Kata kunci: pasir silika, pelebur NaOH, ukuran partikel, waterglass.

2021 ◽  
Vol 10 (1) ◽  
pp. 157-168
Author(s):  
Biwei Luo ◽  
Pengfei Li ◽  
Yan Li ◽  
Jun Ji ◽  
Dongsheng He ◽  
...  

Abstract The feasibility of industrial waste fly ash as an alternative fluxing agent for silica in carbothermal reduction of medium-low-grade phosphate ore was studied in this paper. With a series of single-factor experiments, the reduction rate of phosphate rock under different reaction temperature, reaction time, particle size, carbon excess coefficient, and silicon–calcium molar ratio was investigated with silica and fly ash as fluxing agents. Higher reduction rates were obtained with fly ash fluxing instead of silica. The optimal conditions were derived as: reaction temperature 1,300°C, reaction time 75 min, particle size 48–75 µm, carbon excess coefficient 1.2, and silicon–calcium molar ratio 1.2. The optimized process condition was verified with other two different phosphate rocks and it was proved universally. The apparent kinetics analyses demonstrated that the activation energy of fly ash fluxing is reduced by 31.57 kJ/mol as compared with that of silica. The mechanism of better fluxing effect by fly ash may be ascribed to the fact that the products formed within fly ash increase the amount of liquid phase in the reaction system and promote reduction reaction. Preliminary feasibility about the recycling of industrial waste fly ash in thermal phosphoric acid industry was elucidated in the paper.


1990 ◽  
Vol 189 ◽  
Author(s):  
Arindam Dé ◽  
Iftikhar Ahmad ◽  
E. Dow Whitney ◽  
David E. Clark

ABSTRACTThe concept of 'hybrid heating with microwave (MW) energy at 2.45 GHZ.'for ultra rapid sintering of alumina is being introduced. This technique is a combination of MW - materual interaction as well as conventional radiant/conduction mechanisms, and facilitates the attainment of perhaps, the highest possible heating rates in a multimode MW cavity at 2.45 GJZz. (1500ºC in 120 sees.). Rapid sintering of pure.undoped alumina with this novel techniQue culminates in uniform, homogeneous microstructures and mechanical property enhancements vis-a-vis conventional fast firing.The role of green microstructure (particle size) on MW(hybrid) heating and processing variables (temperature, time) on the MW (hybrid) heating phenomena vs. conventional fast firing were investigated. Hybrid heated samples showed accelerated densification with comparable grain sizes when compared with the conventionally fast fired samples. The effectof particle size on the microwave (hybrid) heating phenomena was found to be analogous to conventional sintering.


2016 ◽  
Vol 16 (3) ◽  
pp. 157-161 ◽  
Author(s):  
M. Hrubovčáková ◽  
I. Vasková ◽  
M. Benková ◽  
M. Conev

Abstract The main bulk density representation in the molding material is opening material, refractory granular material with a particle size of 0.02 mm. It forms a shell molds and cores, and therefore in addition to activating the surface of the grain is one of the most important features angularity and particle size of grains. These last two features specify the porosity and therefore the permeability of the mixture, and thermal dilatation of tension from braking dilation, the thermal conductivity of the mixture and even largely affect the strength of molds and cores, and thus the surface quality of castings. [1] Today foundries, which use the cast iron for produce of casts, are struggling with surface defects on the casts. One of these defects are veining. They can be eliminated in several ways. Veining are foundry defects, which arise as a result of tensions generated at the interface of the mold and metal. This tension also arises due to abrupt thermal expansion of silica sand and is therefore in the development of veining on the surface of casts deal primarily influences and characteristics of the filler material – opening material in the production of iron castings.


Author(s):  
Risa Okita ◽  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Edmund F. Rybicki

Zhang et al (2006) utilized CFD to examine the validity of erosion models that have been implemented into CFD codes to predict solid particle erosion in air and water for Inconel 625. This work is an extension of Zhang’s work and is presented as a step toward obtaining a better understanding of the effects of fluid viscosity and sand particle size on measured and calculated erosion rates. The erosion rates of Aluminum 6061-T6 were measured for direct impingement conditions of a submerged jet. Fluid viscosities of 1, 10, 25, and 50 cP and sand particle sizes of 20, 150, and 300 μm were tested. The average fluid speed of the jet was maintained at 10 m/s. Erosion data show that erosion rates for the 20 and 150 μm particles are reduced as the viscosity is increased, while surprisingly the erosion rates for the 300 μm particles do not seem to change much for the higher viscosities. For all viscosities considered, larger particles produced higher erosion rates, for the same mass of sand, than smaller particles. Concurrently, an erosion equation has been generated based on erosion testing of the same material in air. The new erosion model has been compared to available models and has been implemented into a commercially available CFD code to predict erosion rates for a variety of flow conditions, flow geometries, and particle sizes. Since particle speed and impact angle greatly influence erosion rates of the material, calculated particle speeds were compared with measurements. Comparisons reveal that, as the particles penetrate the near wall shear layer, particles in the higher viscosity liquids tend to slow down more rapidly than particles in the lower viscosity liquids. In addition, CFD predictions and particle speed measurements are used to explain why the erosion data for larger particles is less sensitive to the increased viscosities.


2018 ◽  
Vol 66 (6) ◽  
pp. 356 ◽  
Author(s):  
Taylor A. Stewart ◽  
David T. Booth ◽  
Mohd Uzair Rusli

The nest microenvironment affects hatching and emergence success, sex ratios, morphology, and locomotion performance of hatchling sea turtles. Sand grain size is hypothesised to influence the nest microenvironment, but the influence of sand grain size on incubation of sea turtle eggs has rarely been experimentally tested. At the Chagar Hutang Turtle Sanctuary, Redang Island, Malaysia, green turtle (Chelonia mydas) nests were relocated to sands with different sand grain sizes on a natural beach to assess whether grain size affects nest temperature, oxygen partial pressure inside the nest, incubation success, hatchling morphology and hatchling locomotion performance. Green turtle nests in coarse sand were cooler; however, hatching success, nest emergence success, oxygen partial pressure, incubation length and hatchling size were not influenced by sand particle size. Nests in medium-grained sands were warmest, and hatchlings from these nests were better self-righters but poorer crawlers and swimmers. Hatchling self-righting ability was not correlated with crawling speed or swimming speed, but crawling speed was correlated with swimming speed, with hatchlings typically swimming 1.5–2 times faster than they crawled. Hence, we found that sand particle size had minimal influence on the nest microenvironment and hatchling outcomes.


2007 ◽  
Vol 19 (4) ◽  
pp. 427-436 ◽  
Author(s):  
H.W. Hunt ◽  
A.M. Treonis ◽  
D.H. Wall ◽  
R.A. Virginia

AbstractEquations were developed to predict soil matric potential as a function of soil water content, texture and bulk density in sandy soils. The equations were based on the additivity hypothesis - that water-retention of a whole soil depends on the proportions of several particle size fractions, each with fixed water-retention characteristics. The new model is an advancement over previously published models in that it embodies three basic properties of water-retention curves: a) matric potential is zero at saturation water content, b) matric potential approaches -∞ as water content approaches zero, and c) volumetric water content in dry soil is proportional to bulk density. Values of model parameters were taken from the literature, or estimated by fitting model predictions to data for sandy soils with low organic matter content. Most of the variation in water-release curves in the calibration data was explained by texture, with negligible effects of bulk density and sand particle size. The model predicted that variation in clay content among soils within the sand and loamy sand textural classes had substantial effects on water-retention curves. An understanding of how variation in texture among sandy soils contributes to matric potential is necessary for interpreting biological activity in arid environments.


2016 ◽  
Vol 852 ◽  
pp. 459-465 ◽  
Author(s):  
Vikas Kannojiya ◽  
Satish Kumar ◽  
Mani Kanwar ◽  
S.K. Mohapatra

Erosion is a serious problem faced in many industries that includes the transport of sand and water slurry in slurry pipe line. This paper emphasizes on the investigation of erosion on a mild steel straight pipe at different parameters including fluid velocity, particle size and concentration. The fluid velocity is selected in the range of 2.5-10 m/s using computational fluid dynamics code ANSYS-CFX. Sand particle within the size range of 100-400 µm size and concentration 5%-15% are used in this study. An Euler-Lagrange approach is used to solve the multiphase flow phenomenon. A horizontal pipe of diameter 100 mm and length 1 m (10 times of diameter) is considered for the study. The stochastic model of Sommerfeld will be used to account the wall roughness of pipe. It is also observed that the erosion wear in the pipeline strongly depends on fluid velocity, particle size and concentration.


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