Weight Of Lime Research Articles

PERUBAHAN KADAR TSS ( Total Suspended Solid) DAN PHOSPHATE AIR LIMBAH LAUNDRY DENGAN METODE KOAGULASI DAN FLOKULASI

Community life is growing along with increasing population and technological advancements. One of them is the use of laundry services that increases directly proportional to the waste produced. Laundry waste containing phosphate derived from Sodium Trypoliphosphate and high TSS (Total Disolved Solid) levels can cause eutrophication and turbidity in water bodies. The purpose of this study was to examine the effect of lime and alum addition in reducing phosphate and TSS (Total Suspended Solid) levels. The research method used is the experimental method, covering the principles of chemical and physical precipitation through the addition of 0.01 lime coagulant; 0.015; 0.02; 0.025 and 0.03 g and alum 0.1; 0.5; and 1.0 g. From the experiments, the best dose of lime and alum was obtained in reducing phosphate and TSS (Total Disolved Solid) levels in laundry wastes in lime weight 0.025 g and 1,000 g alum with a 99.80% removal percentage. Whereas for TSS (Total Disolved Solid) levels with a removal percentage of 90.89%. The processing of laundry waste using the ANOVA test showed an effect of the addition of variations in lime weight and alum to the decrease in phosphate and TSS levels in laundry waste. The results of the Tukey method showed that phosphate and TSS levels from each weight variation had different averages.

Comparison of the Prediction of BOF End‐Point Phosphorus Content Among Machine Learning Models and Metallurgical Mechanism Model

The five machine learning models (MLM) of ridge regression, gradient boosting regression (GBR), support vector regression, random forest regression (RFR), convolutional neural network, and a metallurgical mechanism model (MMM) are compared in predicting the end‐point P content in the basic oxygen furnace steelmaking process. The prediction accuracy of MMM is much lower than those of five MLM. The GBR and RFR models have the best performance, with the correlation coefficient values of 0.599 and 0.608, respectively. The smallest mean absolute relative error value of 0.155 and the root mean square error value of 0.00319 are obtained with GBR and RFR, respectively. The values of correlation coefficient after data distribution optimization for all MLM are increased two times higher than before. The second blowing time, lime weight, and oxygen consumption amount are evaluated to have the greatest impacts on the end‐point P content. The end‐point P content decreases with decreasing the second blowing time and with increasing the lime weight and the oxygen consumption amount. The GBR and RFR models are optimized by removing the variables with little impacts on the end‐point P content. The highest prediction accuracy is obtained when 14 variables are remained.

Mathematical modelling and plant trial on slagging regime in a ladle furnace for high-efficiency desulphurization

ABSTRACT Intelligent iron/steel manufacturing has been drawing increasing attention in recent years. Slagging is of importance for clean steel production in the ladle furnace (LF) refining process. In this study, a calculation model of slag-making materials was established based on the actual LF refining conditions, the metallurgical mechanism model and the production data model of the sulphur distribution ratio. In order to test the slag-making model, the data of 50 heats from historical production were examined by using the model; as a result, 49 heats successfully reached the target sulphur content when the error of the lime weight is within the range of ±40 kg. Meanwhile, plant trials were carried out to validate the slag-making model; the results demonstrated that 45 out of 48 tested heats successfully reached the required level of desulphurization by adding slag-making materials at one time.

Optimization of Dephosphorization Parameter in Consteel Electric Arc Furnace Using Rule Set Model

The proper process parameter of dephosphorization is a key problem in actual steelmaking production. This article presents a rule set model combining a k‐means method and a decision tree model, which can extract the rule set from the actual production data to optimize the dephosphorization process. The industrial data from Consteel electric arc furnace are selected as the sample data, and then, the phosphorus partition ratio (Lp) is calculated based on the selected data. The k‐means method is used to divide the calculated Lp into two classes (high Lp and low Lp), and meanwhile, through the data statistic, the importance variables, including oxygen consumption, lime weight, dolomite weight, smelting temperature, and scrap ratio (ratio of scrap weight and hot metal weight), are extracted and merged with the classified Lp data into the new data set. Then, the decision tree is used to extract the valuable information to obtain the rule set from new data set. From the rule set, the optimum range of scrap ratio and oxygen consumption under different smelting conditions is obtained, which can guide the adjustment of process parameters in the actual production to enhance the dephosphorization effect.

Influence of Lime and Volcanic Ash on the Properties of Dune Sand as Sustainable Construction Materials.

This study focused on evaluating dune sand stabilized with lime and volcanic ash as base course materials in engineering construction. Dune sands are found in Saudi Arabia in huge quantities. Due to the high demand for construction materials, this makes them highly suitable for construction. A testing program was designed to investigate the effect of adding different percentages by weight of lime (L: 0, 2, 4, and 6%) and volcanic ash (VA: 0, 1, 3, and 5%) on the engineering properties of the stabilized mixture. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted. In addition, Raman spectroscopy and laser-scanning microscopy (LSM) tests were performed to explore the chemical characteristic, packing, and structure of the mixture. The results showed that the UCS, CBR, and the Young’s modulus (Es) of the treated dune sand increased with the increase in percentage of both stabilizers. Furthermore, LSM images of mortar blended with intermediate L-to-VA blend ratio ≈0.55 (L: 6% and VA: 5%) exhibit compact packing of sand grains, indicating strong adhesion and higher cementing value. The results of the study are promising and encourage using the treated dune sand in engineering construction even with a low percentage use of lime (2%) and volcanic ash (1–3%) as stabilizers.

A convolutional neural network-based model for predicting lime utilization ratio in the KR desulfurization process

In the presented work, desulfurization process parameters and the lime utilization ratio were correlated by data-driven technique, and a convolutional neural network was applied to predict the lime utilization ratio in the Kambara Reactor (KR) desulfurization process. The results show that compared with the support vector regression model and random forest model, the convolutional neural network model achieves the best performance with correlation coefficient value of 0.9964, mean absolute relative error of 0.01229 and root mean squared error of 0.3392%. The sensitivity analysis was carried out to investigate the influence of process parameters on the lime utilization ratio, which shows that the lime weight and the initial sulfur content have the significant effect on the lime utilization ratio. By analyzing the influence of the lime weight on the lime utilization ratio under the current desulfurization process parameters, it can be concluded that decreasing the lime weight from 3256 kg to 2332 kg can increase the lime utilization ratio by about 5%.

Properties of mortars based on β-belite-metakaolinite-hydrated lime binder system

A novel β-belite cement was prepared, characterized (by chemical and phase composition, particle size distribution, bulk density, specific surface area) and incorporated into mortars based on a mixed binder β-belite-metakaolinite-hydrated lime with different contents of β-belite cement (0, 20, 40, 60, 80 and 100 wt.%). The metakaoline:hydrated lime weight ratio of 1:1 and binder:sand weight ratio of 1:3 were observed in all mortars. The effect of the β-belite cement fraction on the properties of fresh mortars (water:binder ratio needed to achieve the required mortars consistency and initial setting time), on the phase composition (X-Ray diffraction phase analysis and thermogravimetric analyses) and on the structural properties of mortars (compressive strength, flexural strength, bulk density, water absorption, water absorption coefficient, shrinkage) over 1 year of curing was investigated. Freeze and thaw resistance of the mortars after 1 year of curing was also evaluated. Partial replacement of metakaolinite-hydrated lime binder with β-belite cement affected all investigated mortar properties. Significant improvements in mechanical properties and resistance to freezing and thawing cycles were the main advantages.

A Straightforward Mathematical Model of Hot Metal Desulphurization

A straightforward kinetic model for the hot metal desulphurization process is presented. The model contains some of the most important parameters and variables that govern the process. The inputs, outputs and parameters of a desulphurization program employed at industry are discussed. The model is able to cope with different injection policies of desulphurizers such as mono- injection, co-injection or multi-injection. When compared to the rotary impeller method, results of this model shows that the weight of lime consumed in the lance injection method is lesser than that consumed in the rotary impeller method for the same conditions of the hot metal charge.

Ladle Desulfurization of Converter Low-Sulfur Pipe Steel

Three stages of metal desulfurization in a ladle during production of low-sulfur pipe steel grade DNV SAWL 485 FD in the PAO MMK oxygen converter workshop are analyzed: the first stage is the treatment of semiproduct during metal delivery from a converter with solid slag-forming mixture; the second stage is steel processing in a ladle-furnace unit under a “white” slag; the third stage is the injection of fluidized lime into steel in a ladle-furnace unit. The relative amount of sulfur removed at different stages of treatment is compared. The greatest amount of sulfur, i.e., approximately three quarters of the total amount, is removed in the ladle-furnace during the second and third stages in the ratio 1:1.33. Dependences are revealed for the degree of metal desulfurization on the ratio of the lump lime weight to fluorspar weight, the specific consumption of fluidized lime and the intensity of its injection in the argon stream, are revealed for the second and third stages. Rational values are recommended for parameters in order to improve metal ladle desulfurization efficiency.

Influence of Nano Silica on the Geotechnical Properties of Clayey Soil Stabilized with Lime

The soil must be able to withstand the load and transfer it to ground within the range of allowable deformations, for which it must possess good physical and geotechnical properties. The conventional method of stabilization such as removal and replacement of ill – suited soils incur higher cost and is time consuming. A new method of stabilization, designated as chemical stabilization can be adopted. This method initiate chemical reactions such as cation exchange, pozzolanic activity etc., which consequently enhance the geotechnical properties of soil. In this study, the mechanical behavior of soil is improved by addition of nanoparticles i.e., nano silica along with cementitious material, lime. Considering economic issues of nano silica usage and results of this research in soil stabilization projects, in this study 0, 1, 3 and 5 % weight of nano silica is used as well as 0, 2 and 4 % weight of lime is used. The effect of these replacements is studied by Atterberg limits test, compaction test and unconfined compressive strength (UCS) test. The effect of curing time on samples at 3, 7 and 28 days of age has also been investigated. The optimum percentage replacement of nano silica in lime stabilized soil is determined. The microstructure of the stabilized soil is studied by Scanning electron microscopy (SEM) test. Thus the results proved that there is a significant improvement in the plasticity, compaction and strength properties with slight addition of nano silica in clayey soil mixed with lime.

Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w(CaO)/w(SiO2) ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al2O3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100:16.17:59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca2SiO4 and Ca12Al14O33, with small amounts of FeAl2O4, CaAl2O4, and Ca2Al2SiO7.

Trona Causes Foetal Loss in Pregnant Rat via an Oestrogen-dependent Mechanism

There is a claim in folklore medicine in Nigeria that trona (a sesquicarbonate or hydrated carbonate of sodium) causes fetal loss. However, this has not been substantiated or refuted by any scientific evidence. This study evaluates whether or not trona causes fetal loss in pregnant female Wistar rats. Pregnant Wistar rats of comparable weights were randomized into three groups. Group A (control) was given a single dose of 1.25 mL/kg body weight of lime while groups B and C were given 250 mg/kg and 500 mg/kg body weight of trona, respectively. There was no significant difference in the body weight gained across all the groups. The dose of 250 mg/kg body weight of trona decreased the number of live fetus, while 500 mg/kg body weight produced no live fetus; 250 mg/kg and 500 mg/kg body weight of trona led to fetal loss rate of 83.33% and 100%, respectively. Trona also reduced the concentrations of serum progesterone and cholesterol, and increased serum oestradiol. This study revealed that trona causes fetal loss. This is possibly via an oestrogen-dependent mechanism, and attributed to the chemical constituents of trona.

مدل سازی جرم و حجم لیمو ترش و بررسی روابط بین خصوصیات فیزیکی با استفاده از روش تحلیل مولفه اصلی (PCA)

مدل سازی ریاضی به منظور تخمین جرم لیموترش با استفاده از خصوصیات هندسی (ایعاد، حجم) و سطح تصویری صورت پذیرفت. مدل ها به صورت تک و چند پارامتری ایجاد شدند. همچنین خصوصیات فیزیکی لیموترش شامل ایعاد هندسی، جرم، حجم، دانسیته میوه و توده، ضریب اصطکاک و سطح تصویری میوه اندازه گیری شدند. سطح تصویری لیموترش با استفاده از تکنیک پردازش تصویر و در 3 بعد محاسبه گردید. در میان مدل های ساخته شده، مدلی بر مبنای3 بعد میوه، حجم محاسبه شده با استفاده از فرمول محاسبه حجم کره دوکی شکل و سطح سوم تصویری لیموترش با ضریب تبیین 909/.، 958/.، 942/. و خطای استاندارد تخمین 52/1، 19/1، 14/1 به ترتیب به عنوان مدلهایی مناسب جهت پیشگویی جرم لیموترش و مدلی بر مبنای 3 بعد میوه و سطح تصویری سوم لیمو ترش با ضریب تبیین 951/0 و 942/0 و خطای استاندارد 32/1 و 41/1 به ترتیب به عنوان مدلهای مناسب جهت تخمین حجم لیموترش پیشنهاد گردید. به منظور بررسی خصوصیات فیزیکی لیموترش و روابط بین آنها از روش تحلیل مولفه اصلی استفاده گردید. نتایج نشان دهنده وجود رابطه نزدیک میان سطوح اصطکاکی با یکدیگر و پارامتر های رنگی لیموترش می باشد.

Investigation of the compressive strength, time lags and decrement factors of AAC-lightweight concrete containing sugar sediment waste

Sugar sediment waste was incorporated into the raw material mix for the production of Autoclaved Aerated Concrete, and was demonstrated by extensive testing to provide greater compressive strength than conventional materials, and an extended time lag. In addition, the use of this otherwise waste material was demonstrated to be highly beneficial both economically and environmentally. Sugar sediment is a waste product of the sugar refining industry in Thailand, and is available in huge quantities.The optimum composition obtained had sugar sediment content of 30% by weight replacement of sand and 7.5% by weight of lime. The resultant product showed a maximum compressive strength of around 6.1N/mm2 and the highest proportion of tobermorite phase of 28.9%. The higher strength can be confirmed by a higher crystalline tobermorite phase. The surface of the Autoclaved Aerated Concrete is a finer needle-like crystalline morphology. The Autoclaved Aerated Concrete consisting of the optimum sugar sediment content also extended the time for the heat wave to propagate from the outer wall to the inner wall. This study also considered the environmental, economic and health impacts of removing a substantial quantity of the industrial waste product from landfill sites.

Behaviour of a starch as a viscosity modifier for aerial lime-based mortars

Different dosages of a commercialized potato starch were added to aerial lime-based mortars in order to check its efficiency as a rheological modifier. Several fresh state properties of the mortars were studied: consistency, density, air content, water retention capacity, setting time and evolution when applied on support. The effect of the starch on ζ-potential of the lime particle surface as well as the particle size distribution and viscosity changes in lime pastes were also assessed in order to elucidate the action mechanism of the polymer. The behaviour of this starch polymer was found to be strongly dosage-dependent: it acted as a thickener when the incorporated dosage was up to 0.30% of lime weight; conversely, above that dosage, it behaved as a plasticizer. The thickening effect took place because polymer molecules were adsorbed onto lime particles acting as a flocculant, as confirmed by zeta-potential and particle size distribution results. For large amounts of polymer, steric hindrance and electrostatic repulsive forces appeared, leading to a dispersion mechanism which explained the plasticizing effect as well as the fresh mortar behaviour.

Removal of ddye from water by coagulation using aluminium sulfate and lime

Wastewaters from textile industries represent a source of water contamination, and should be treated in some way so as to reduce the concentration of the polluting dyes, prior to discharge of the wastewater to the receiving environment. In this study the dye removal capacity of locally produced alum was investigated. The efficiency of the process was investigated in series of batch experiments using simulated textile dye solutions to assess the effects of various process parameters: contact time, alum -lime weight ratio, coagulant dosage, dye's initial concentration, pH and reaction kinetics of coagulation. The result of the study showed that an increase in both coagulant dosage and dye initial concentration increases the percentage of dye removal. In all cases the percentage of dye removal at optimized conditions is nearly or above 90%. Most of the reactions are completed in less than 20 minutes. The highest percentage of the dye removal was observed at pH around neutrality for all the dyes indicating that addition of lime is indispensable to maintain efficient floc formation. The reaction kinetics of Indantrene Brown and Imperon Orange was observed to obey pseudo first order kinetics, with rate constants k1 = 0.055 min-1 and k2 = 0.114 min-1 for Indantrene Brown and Imperon Orange, respectively. It was found that alum combined with lime is suitable material for removing dyes from wastewaters.

Relative performance of lime stabilized amended clay liners in different pore fluids

Successful design of soil liner and covers for landfills and waste impoundments involves selection of liner material and assessment of chemical compatibility of the liner material. In this work locally available materials with different mineralogy have been evaluated from the viewpoint of liner application. Many local soils may not meet the requirements of liner material; often it is necessary to amend these soils with commercially available processed bentonite. Clay liners may be attacked by chemical waste or leachate, concentrated organic chemicals can attack compacted clay effectively destroying the characteristics of liner material. Thus the main aim of this work has been to assess the suitability of different types of locally available materials for their potential use as liners for waste containment facilities. The materials studied are kaolinitic red earth, illite and fly ash. Based on literature survey and experimental work in this laboratory, 20% by weight of bentonite has been chosen for amending selected materials. Addition of 20% bentonite to selected liner material improved the hydraulic conductivity and adsorption capacity of the amended mixture but, reduced the volume stability. To improve the volume stability of the amended material and to have better resistance towards chemicals attack, stabilizing the amended mixture with 1% by weight of lime has been considered. The relative advantages and disadvantages of four materials namely; red earth with 20% bentonite, illite with 20% bentonite, fly ash with 20% bentonite and illite alone, stabilized with 1% by weight of lime were brought out. The chemical compatibility of the materials to electrolyte solution (0.5 N NaCl), alkaline solution (0.5 N NaOH), acid (0.5 N HCl) and organic fluid (CCl4) has been studied. The relative efficiency of the selected materials with selected pore fluids was compared.

Chemical Compatibility of Lime Stabilized Indian Red Earth as Liner Material

Geotechnical liners are widely used to contain leachate generated within landfills and minimize the risk of sub-surface and underground water contamination. In this study, an attempt has been made to utilize locally available soil red earth as liner material. The collected red earth contains mostly quartz and kaolinitic minerals. Studies have shown that bentonite content higher than 20% by weight is not usually required. This study aims to assess the red earth with 20% by weight of bentonite as liner material. Further, the studies are being carried out to improve the amended material by stabilizing the mixture with 1% by weight of lime. The relative merits of these materials under different physico-chemical environments are studied. The assessment of the liner material is based on their basic and geotechnical properties. The studies reveal that the geotechnical properties of red earth with 20% by weight bentonite stabilized with 1% by weight of lime enhanced, particularly after curing for sufficient period. The pore fluids such as HCl and CCl 4 increased volume change. The hydraulic conductivity of soils, which increased on treating with lime initially, decreased with curing. However, the hydraulic conductivity of stabilized soil increased in the presence of HCl and CCl 4 . The strength of stabilized soil is affected with the fluids NaCl and HCl solutions.

Geotechnical properties of stabilised Indian red earth

Locally available soils amended with sufficient bentonite are generally used for construction of liners for water and waste retention facilities. The amount of bentonite required to keep the hydraulic conductivity low varies with the nature of the local soil. Many studies have shown that bentonite content higher than 20% by weight is not usually required. This is also the case with Indian red earth containing predominantly quartz and kaolinite minerals. Incorporating bentonite, though keeps the hydraulic conductivity of soil low, increases the swelling and shrinkage potential; increases the loss of strength due to reduction in cohesion. This paper aims to improve the geotechnical properties of red earth and bentonite mixture with lime or cement. The studies reveal that the geotechnical properties of red earth with 20% by weight bentonite stabilised with 1% by weight of lime or cement are greatly enhanced, particularly after curing for 28 days. it has been shown that the early gain in strength is better with cement whereas its long-term strength gain is better with lime.

Water vapour in a closed anaesthesia circuit reduces degradation/adsorption of halothane by dried soda lime

Dry lime causes a loss of volatile anaesthetics by degrading and adsorbing them. Degradation produces toxic substances and heat. Rehydration of lime stops degradation. If humidified breathing gases rehydrate lime, closed anaesthesia-circuits may reduce the loss of anaesthetics. To test this hypothesis we ventilated a reservoir bag with PhysioFlex-devices using fresh (F) and dried (D) soda lime both in the presence (+H) and absence (-H) of halothane. We measured halothane delivery, humidity, temperature, and lime weight. Halothane was lost for 13 min in D + H. Humidity increased steeper with fresh lime, whereas absorbent weight increased more with dried lime; halothane increased both variables (F + H: 99%, 8 g; F - H: 93%, 6 g; D + H: 58%, 17 g; D - H: 24%, 15 g). Surprisingly, temperature remained constant, probably because of the high gas flow (70 litres min-1) generated inside the Physioflex. These findings indicate rehydration of dried lime by humid gases and a rapid cessation of the loss of halothane in the PhysioFlex.