451 research outputs found
Enhanced Calcium Extraction From Steel Converter Slag Using Wet Extractive Grinding And Comparison
No full textDefence is held on 8.10.2021 12:00 – 15:30
Remotely via Zoom https://aalto.zoom.us/j/69652895150This thesis belongs to the field of process engineering. The goal of this research is to develop an effective recovery method for calcium from industrial waste streams to produce precipitated calcium carbonate, PCC. This would reduce our dependency on virgin raw material resources, reduce CO2 emissions and offer a pathway to circular economy by closing material loops in industrial processes. We focused on the utilization of steel converter slag as a source of calcium for the pH-swing process named as X2PCC (X refers to Ca-bearing materials). As the first process step, we extract calcium from steelmaking slag using aqueous ammonium chloride solvent and separate solids by filtering. In the second step, the Ca-rich solution is treated with CO2 gas to produce precipitated calcium carbonate (PCC).
The main scientific objective of this thesis is to experimentally analyze phenomena in Ca extraction step and develop process solutions for increasing the Ca dissolution rate and yield. As a part of the work, we developed the new wet extractive grinding (EG) method. Traditional mechanical mixing (MM) process is first briefly explained and then compared with the new wet extractive grinding process. The carbonation step was left out of the scope of this thesis. In this thesis, the effects of various process parameters on the performance of these two techniques are systematically and quantitatively investigated.
The first part (paper I) focuses on the experimental study on the traditional mechanical mixing with respect to particle size distribution and strength of the solvent. Aqueous ammonium chloride (NH4Cl) was used as an extracting solvent with concentrations of 0-2 mol/L. The slag to solvent ratio was constant 100 g/L for all experiments. The main objective of this part was to determine the optimal concentrations of solvent and particle size for leaching out the maximum amount of calcium from the slag. All the tests were conducted at ambient pressure and temperature. The extraction rate of different size fractions of the slag, 0–50 μm, 50–74 μm and 74–125 μm were studied. If was found that the smaller the particle size, and the higher the solvent molarity, the higher the yield of Ca. We found that Ca extraction is limited by the mass transfer and the availability of Ca within the large particles. We proposed a mechanism that the surface layer of the slag particles could be get blocked by reaction products, mainlySiO2, and this stops the reaction. This would explain the lower yield in the larger particles.
The second part (papers II and III) of the work focuses on the new wet extractive grinding method and optimizing it for the maximum extraction efficiency of calcium from steel slag. Extractive grinding was compared with our traditional mechanical mixing to give better understanding of the performance of our new extractive grinding method, and to study the effects of the different process parameters on the calcium extraction and dissolution of other trace elements such as V, Si and Mg. Physical and chemical characterization is performed for the analysis of particle morphology before and after the extraction. Here, we found that with our new method we can achieve up to 73 % Ca-extraction efficiency as compared to below 40 % in MM. EG process, that combines grinding and extraction stages, reduces the overall energy requirement of the process. There are two mechanism that makes this possible: the processing time reduces due to reaction surface grinding effects and the Ca yield also significantly increases.
The main scientific contribution of this thesis is in identifying the limiting factors in the Ca extraction stage and presenting and analyzing the new wet extractive grinding method. We were able to show that with the EG method, Ca yield increased from 35 to 73%, processing time decreased from earlier used 30 to 5 min. To obtain Ca yield higher than 70% via mechanical mixing, energy intensive fine grinding is required. With EG method, based on preliminary calculations, energy saving can be up to 56 % compared to fine grinding and mechanical mixing path. We also found that EG method does not significantly affect the particle size distribution, which means that there are fewer filtering issues expected, compared with the fine-grinded slag. We are presenting unique data on the effects of solvent molarity, slag to solvent ratio, particle size distribution, process time. These will be later used in the actual process design and feasibility analysis.
Finally, we studied also initially a concept for the integration of CO2-capture Ca-looping integrated with our X2PCC process. Initial results show that CO2 capture potential of the process could be significantly increased by this. This will be further studied in our future work and we will evaluate what would be the optimal use for the PCC produced in terms of circular economy and environment. Tämä väitöskirja kuuluu prosessitekniikan tutkimusalaan. Tutkimuksen laajempi tavoite on kehittää tehokas menetelmä kalsiumin talteen ottamiseksi teollisuuden sivu- ja jätevirroista ja valmistaa tästä saostettua kalsium karbonaattia (PCC). Tämä askel vähentäisi riippuvuuttamme neitseellisistä raaka-aineista, vähentäisi fossiilisia CO2 päästöjä ja veisi alan kehitystä kohti kiertotaloutta sulkemalla materiaalikiertoja. Työssä keskityttiin teräskuonaan X2PCC prosessimme raaka-aineena. X viittaa tässä materiaaleihin, jotka sisältävät runsaasti kalsiumia. X2PCC-prosessimme ensimmäisessä vaiheessa kalsium liuotetaan selektiivisesti ja kiintoaines suodatetaan pois. Puhtaaseen kalsiumliuokseen puhalletaan sen jälkeen CO2 kaasua, jolloin tuotteena syntyy saostettua kalsiumkarbonaattia, CaCO3.
Työn tieteellinen tavoite oli tutkia kokeellisesti kalsiumin liuotusta ja siihen liittyviä ilmiöitä sekä kehittää menetelmää, joilla prosessia saataisiin tehostettua. Osana työtä kehitimme uuden märkäjauhatukseen perustuvan liuotusmenetelmän (EG). Perinteistä mekaanista sekoitusmenetelmää tutkittiin ensin ja sen jälkeen vertailtiin uuteen EG menetelmään. Karbonointivaihe rajattiin työn ulkopuolelle.Työn ensimmäinen osa (Julkaisu I) keskittyy mekaaniseen sekoitukseen ja kuonan kokojakauman ja liuottimen vahvuuden vaikutusten tutkimiseen. Vesiliukoista ammoniumkloridia (NH4Cl) käytettiin liuottimena vaihtelemalla sen molaarisuutta välillä 0-2 mol/L. Kuona-liuotinsuhde oli vakio 100 g/L kaikissa kokeissa. Tavoite oli löytää parametrit, joilla Ca-saanto kuonasta saadaan maksimoitua. Kokeet tehtiin ilmakehän paineessa ja huoneen lämpötilassa. Kuonajauhe seulottiin mekaanisesti kokoluokkiin 0–50 μm, 50–74 μm ja 74–125 μm. Havaittiin että mitä pienempi partikkelikoko ja mitä suurempi molaarisuus, sitä korkeampi Ca-saanto. Hypoteesimme on, että suurilla partikkeleilla Ca-saantoa rajoittaa aineensiirto ja kalsiumin saatavuus reaktioiden käyttöön. Ehdottamassamme reaktiota rajoittavassa mekanismissa reaktiotuotteet, pääasiassa SiO2, tukkii huokoset ja hidastaa reaktiota olennaisesti. Tämä ilmiö selittäisi suurempien partikkelien matalamman Ca-saannon.
Työn toinen osa (julkaisut II ja III) keskittyvät uuteen märkäjauhatusliuotukseen ja sen parametrien optimointiin teräskuonalla. Uutta menetelmään verrattiin mekaaniseen sekoitukseen, jotta saataisiin parempi käsitys uuden menetelmän eduista eri prosessiparametreillä. EG menetelmää karakterisoitiin kemiallisesti ja fysikaalisesti ja tutkittiin kuonan morfologian muutoksia prosessin aikana. Havaittiin, että uudella EG menetelmällä on mahdollista kasvattaa saantoa mekaanisen sekoituksen alle 40 % arvosta yli 70% tasolle. EG menetelmässä yhdistetään jauhatuksen teho sekä liuotusvaihe. Tällöin prosessin läpimenoaika pienenee huomattavasti ja saanto kasvaa. Tämän ansiosta energian kulutus myös pienenee huomattavasti.
Väitöskirjan tieteellinen kontrobuutio on, että pystytiin identifioimaan Ca-liuotuksen kontrolloivia mekanismeja sekä kehitettiin uusi märkäjauhatusliuotus menetelmä. Pystyimme näyttämään, että EG menetelmällä Ca-saanto nousi 35 % arvosta 73% tasolle, prosessiaika lyheni 30 minuutista 5 min tasolle. Jotta vastaava saanto saataisiin aikaiseksi mekaanisella sekoituksella, täytyisi kuona jauhaa erittäin pieneksi (<50 μm), vaatien paljon aikaa ja energiaa. Alustavien laskelmien mukaan energian kulutus voisi olla 50-60% alhaisempi uudella menetelmällä. Havaitsimme myös, että EG menetelmä ei juuri vaikuta partikkelikokojakaumaan, joka tarkoittaa sitä, että hienoksi jauhetun kuonan tapauksessa esiintyviä suodatukseen liittyviä ongelmia on huomattavasti vähemmän. Työssä on myös esitetty suuri määrä täysin uusia mittaustuloksia molaarisuuden, partikkelikoon, kuona-liuotinsuhteen ja prosessiajan vaikutuksista prosessin käyttäytymiseen, joita voidaan käyttää tulevaisuudessa teollisen kokoluokan prosessin suunnittelussa, optimoinnissa ja taloudellisen kannattavuuden arvioinnissa. Työn lopuksi teimme vielä alustavia laskelmia CO2 talteenottopotentiaalin kasvatusmahdollisuuksista. Alustavien tulosten mukaan, jos X2PCC prosessi yhdistettäisiin Ca-looping CO2 talteenottomenetelmään ja käyttämällä valmistamaamme CaCO3:a talteenottoprosessin sorbenttina, hiilidioksidin talteenottopotentiaalia voitaisiin kasvattaa merkittävästi. Tätä tutkitaan tulevaisuudessa laajemmin ja arvioidaan PCC tuotteemme parasta käyttökohdetta kiertotalouden ja ympäristön kannalta
Productivity Improvement in the Denim Industry by DMAIC Methodology
No full textProductivity Improvement in the Denim Industry by DMAIC Methodology Muhammad Owais Raza Siddiquia, Imran Noorb, Muhammad Dawood Husainc, Muhammad Usama Nooranid, Allah Dade, Waqar Iqbalf, Danmei Sung, a,b,c,dNED University of Engineering & Technology, Department of Textile Engineering, University Road, 75270, Karachi, Pakistan. a,gHeriot-Watt University, School of Textiles & Design, TD1 3HF, Galashiels, UK. ePakistan Institute of Fashion and Design, Lahore, Pakistan. fTiangong University, School of Textile Science and Engineering, Tianjin, China, Email: [email protected] The aim of this paper is to boost productivity improvement by reducing the rejection rate and finding ways to improve the quality of the textile (denim) industry. The methodology used here is based on Six Sigma, which aids as a catalyst for lowering the rejection rate in the denim industry. Six Sigma in this paper serves as a systematic tool for continuous quality process improvement and for achieving desired targets and quality. The DMAIC model provides a framework that ultimately decreases the variation in the process, and executes a central plain that would be readily accepted by the organisation and which encourages people to adapt it. In the defining phase, the root causes of the problem and faults were recognised. As a result, a broken end was found to be the main cause of the rejection of defective products. The root causes were analysed using a cause and effect diagram. In the improvement phase, the design of the experiment (DOE) was implemented, and key parameters of the process were set up. This revealed that high concentrations of acid and hydrogen peroxide are the core origin of the diminishing yarn strength in the back process. A factorial design, with two replications, was performed. Hydrogen peroxide and acid were used in the dyeing department as chemical oxidation for indigo dye. After the implementation of Six Sigma, the productivity of the company improved and the rejection rate was reduced
Yolo-pest: an optimized YoloV8x for detection of small insect pests using smart traps
No full textAbstract Fruit flies and fall-armyworm are one of the major insect pest that adversely affect fruit and crops, whereas fall-armyworm is also a highly destructive pest in maize crop but also damage other economically important field crops and vegetables. Adults of both pests can fly, making it hard to monitor them in the field. This study focuses on fine-tuning the YoloV8x model for automated monitoring and identifying insect pests, like fruit flies and fall-armyworms, in open fields and closed environments using IoT-based Smart Traps. The conventional techniques for monitoring of these insect pests involve pheromone attractants and sticky traps that require regular farm visits. We developed an IoT-based device, called Smart Trap, that attracts insect pests with pheromones and captures real-time images using cameras and IoT sensors. Its main objective is automated pest monitoring in fields or indoor grain storage houses. Images captured by smart traps are transmitted to the server, where Yolo-pest, a fine-tuned YoloV8x model with customized hyperparameters performs in real time for object detection. The performance of the smart trap was evaluated in a mango orchard (Fruit Flies) and maize field (fall Armyworm) in an arid climate, achieving a 94% average detection accuracy. The validation process on grayscale and coloured images further confirmed the model’s consistent accuracy in identifying insect pests in maze crop and mango orchards. The mobile application also enhances the practical utility as having a user-friendly interface for real time identification of insect pest. Farmers can easily acces the information and data remotely that empowering them for efficient pest maangment
Productivity Improvement in the Denim Industry by DMAIC Methodology
No full textProductivity Improvement in the Denim Industry by DMAIC Methodology Muhammad Owais Raza Siddiquia, Imran Noorb, Muhammad Dawood Husainc, Muhammad Usama Nooranid, Allah Dade, Waqar Iqbalf, Danmei Sung, a,b,c,dNED University of Engineering & Technology, Department of Textile Engineering, University Road, 75270, Karachi, Pakistan. a,gHeriot-Watt University, School of Textiles & Design, TD1 3HF, Galashiels, UK. ePakistan Institute of Fashion and Design, Lahore, Pakistan. fTiangong University, School of Textile Science and Engineering, Tianjin, China, Email: [email protected] The aim of this paper is to boost productivity improvement by reducing the rejection rate and finding ways to improve the quality of the textile (denim) industry. The methodology used here is based on Six Sigma, which aids as a catalyst for lowering the rejection rate in the denim industry. Six Sigma in this paper serves as a systematic tool for continuous quality process improvement and for achieving desired targets and quality. The DMAIC model provides a framework that ultimately decreases the variation in the process, and executes a central plain that would be readily accepted by the organisation and which encourages people to adapt it. In the defining phase, the root causes of the problem and faults were recognised. As a result, a broken end was found to be the main cause of the rejection of defective products. The root causes were analysed using a cause and effect diagram. In the improvement phase, the design of the experiment (DOE) was implemented, and key parameters of the process were set up. This revealed that high concentrations of acid and hydrogen peroxide are the core origin of the diminishing yarn strength in the back process. A factorial design, with two replications, was performed. Hydrogen peroxide and acid were used in the dyeing department as chemical oxidation for indigo dye. After the implementation of Six Sigma, the productivity of the company improved and the rejection rate was reduced
ڈاکٹرسیّدنظیر حسنین زیدی بہ طورمترجم
No full textTranslation is the conversion of the text of a language into an other language. Who converts the text of a language into an other language, is called a translater. Dr.Syed Nazeer Hasnain Zaidi has translated “Sachchon ki Batain” and “Hazrat Owais Qarani”which were translated from Persian language into Urdu language.
“Sachchon ki Batain”was written by Shaheed Murtaza Mutahiri.In this translation, the writer narrated 75 personalities of the world.
“Hazrat Owais Qarani” was written by Muhammad Muhammadi. In which, writer narrated the life achievements of “Hazrat Owais Qarani”
We care Sdn. Bhd. / Owais Qarni Qusham …[et al.]
No full textWe Care Sdn. Bhd. is a company that concern about the demand and needs of Malaysians especially to old folks and disable person. Therefore, we provide an easier medical transportation for them to use it everywhere they want. Besides that, we would make sure that the quality of the product will reach the expectation of the society with the good quality. Furthermore, we will make some upgrading in our product and others. We are not just looking for profits but we want to help people especially help our own country. With our product, we will provide the facility and also service to people. Our upgrade product will give better satisfaction to customers. It also can increase our country income by the tax that we pay and can also be an attractive to tourist with our service product. Moreover, we will create another job to citizen in Malaysia. We had decided to start our business at No. 10 Jalan Tun Teja 35/15, Alam Impian, 40470 Shah Alam, Selangor. The reasons we chose this location because the location was near the private and public hospitals, pharmacies and also residential area such as apartments and houses. So we think that this area is suitable for our product to invent in market
Slag2PCC-prosessin karbonointivaiheen automatisointi
No full textSignificant amounts of steelmaking slags are produced as a by-product of the steel industry. Steel manufacturing also accounts for approximately 5 % of all global carbon dioxide emissions. The Slag2PCC process offers a method to utilize steelmaking slags and simultaneously sequestrate CO2 to produce precipitated calcium carbonate using mineral carbonation phenomena. The main steps of the Slag2PCC process are grinding of the steel making slag, extraction of calcium from the slag using a liquid solvent and the precipitation of the calcium as CaCO3. The produced PCC is a valuable product and an important raw material to many industries making the Slag2PCC process also economically very attractive.
In this work, carbonation experiments were performed to investigate the relation between CO2 input flow rate, total CO2 consumption and the yield of PCC. The amount of CO2 consumed by the carbonated Ca2+ rich solution as a fraction of the amount of CO2 required for complete carbonation of all calcium and the flow rate of CO2 were varied between carbonation cycles to determine to optimal CO2 input regime.
With the lower CO2 input flow rate of 0.5 L/min, significantly higher PCC yields were obtained, and the carbonation process proceeded more intensively. There was no clear link between end pH and PCC yield. However, end pH value of 7.0 might be optimal and a slight peak in the yield was obtained approximately at that value with the lower flow rate. The phase of rapid pH decline begins at pH value 7.7 after which careful control of CO2 flow rate is required in order to reach a desired end pH..
With the higher flow rate of 0.8 L/min, less CO2 participated in the carbonation reaction and more was arguably absorbed by the solution. However, a clear link was observed between the end pH and the PCC yield. The yield increased steadily as the amount of used CO2 was increased and the end pH values decreased down to 7.79 as a result.
Further experiments with the higher flow rate aiming at end pH values at approximately 6.5–7.0 are recommended to verify the results obtained with the lower flow rate and if the optimal pH value lies around 7.0.Teräksenvalmistuksessa syntyy sivutuotteena suuria määriä teräskuonaa. Lisäksi terästeollisuus tuottaa noin 5 % kaikista globaaleista hiilidioksidipäästöistä. Niin kutsuttu Slag2PCC-prosessi voi mahdollistaa teräskuonan hyötykäytön saostetun kalsiumkarbonaatin (PCC, Precipitated Calcium Carboante) tuotantoon. Prosessin päävaiheet ovat kuonan jauhatus hienommaksi, kalsiumin uutto jauhetusta teräskuonasta sekä uutossa syntyneen kalsiumliuoksen karbonointi hiilidioksidilla. Lopputuotteena syntyvä PCC on arvokas tuote, jota tarvitaan raaka-aineena monilla teollisuuden aloilla. Siksi myös Slag2PCC-teknologian taloudellinen potentiaali on suuri.
Osana tätä diplomityötä suoritettiin karbonointikokeita, joissa pyrittiin selvittämään hiilidioksidin syöttönopeuden, käytetyn hiilidioksidin kokonaismäärän ja PCC:n saannon välistä yhteyttä. Käytetyn hiilidioksidin määrää verrattiin stoikiometriseen määrään, joka vaadittaisiin kaiken karbonoitavassa liuoksessa olevan kalsiumin karbonointiin. Tätä käytetyn ja stoikiometrisen määrien suhdetta sekä hiilidioksidin syöttönopeutta vaihdeltiinkarbonointisyklien välillä.
Pienemmällä hiilidioksidin syöttönopeudella saatiin tuotettua enemmän PCC:tä, ja karbonointiprosessi eteni tehokkaammin. PCC:n saanto ei kuitenkaan selvästi riippunut pH:n loppuarvosta. Karbointiprosessissa tapahtuva nopean pH-laskun vaihe todettiin kuitenkin yleisesti alkavan pH-arvossa 7.7, jonka jälkeen hiilidioksidin syöttövirtaa on säädettävä tarkasti, mikäli halutaan saavuttaa tietty tarkka pH:n loppuarvo.
Suuremmalla syöttönopeudella pienempi osa hiilidioksidista osallistui karbonointireaktioon ja suurempi osa ilmeisesti absorboitui liuokseen. PCC:n saanto riippui kuitenkin selvästi pH:n loppuarvosta. Saanto kasvoi tasaisesti, kun syötetyn hiilidioksidin kokonaismäärää kasvatettiin ja pH:n loppuarvot laskivat aina 7.79:än.
Kokeiden jatkamista suuremmalla tilavuusvirralla tähdäten 6.5–7.0 pH-loppuarvoihin suositellaan, jotta pienemmällä tilavuusvirralla saadut havainnot voitaisiin varmistaa sekä tutkia tarkemmin, onko 7.0 optimaalinen pH:n loppuarvo
دعوتِ حق کے اصول و آداب: Principles and manners of daa’vat-e-haq
No full textFundamentally, the literally meaning of preaching is to call people for good. The prime purpose of the Allah’s prophets on earth was preaching in order to place people on the right path. The teaching of prophethood is based on the principles of preaching. The Holy Quran calls the word of preaching as the worship of Almighty, in the way God, for the sake of good. In the book of Allah, the glorious word of preaching is explained in different ways. Importantly, there is a dire need to follow and accept these proposed traits of preaching. If someone does not follow these suggestive principles, he/she will not be considered as a true believer. Basically, the preaching has two distinguish things: the wisdom and the advice. Those who are in doubt are continuously arguing in the process of preaching. In such condition the Holy Quran gives the lesson of argumentation and discussion with productive consequences. Any discussion without robust arguing power has no place in the womb of Deen (Sharia)
Experimental work for enhanced Ca-extraction efficiency from steel converter slag with ammonium chloride for production of PCC
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