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All Journal Jurnal Sosio Ekonomika Bisnis Microbiology Indonesia Seminar Nasional Teknik Kimia Kejuangan Jurnal Zeolit Indonesia Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) Neo Teknika: Jurnal Ilmiah Teknologi Journal of Data Science and Its Applications Jurnal SUBLIMAPSI CENDEKIA: Jurnal Ilmiah Pendidikan Jurnal Psikologi Terapan (JPT) Aceh International Journal of Science and Technology Jurnal Kendali Akuntansi Metalurgi

Widi Astuti

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Author-ID : 415342

Religion Agriculture, Biological Sciences & Forestry Arts Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Engineering Environmental Science Health Professions Immunology & microbiology Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Nursing Public Health Social Sciences Other

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KARAKTERISTIK STRUKTUR MIKRO DAN SIFAT MEKANIK BESI TUANG PUTIH PADUAN KROM TINGGI HASIL THERMAL HARDENING UNTUK APLIKASI GRINDING BALL[Microstructure Characteristic and Mechanical Properties of Thermal Hardened of High Chromium White Cast Iron for Grinding Ball Application] Achmad Sofi; Widi Astuti; Fajar Nurjaman
Metalurgi Vol 28, No 3 (2013): Metalurgi Vol.28 No.3 Desember 2013
Publisher : National Research and Innovation Agency (BRIN)

Pembuatan Refraktori Dari Refraktori Bekas Pakai Kiln Dan Flyash Batubara Dengan Variasi Tekanan Greenbody [Recycling of Used Refractory of Kiln and Coal Fly Ash by Various of Greenbody Presure] Ayu Septriana; Azhar Azhar; Widi Astuti
Metalurgi Vol 32, No 3 (2017): Metalurgi Vol. 32 No. 3 Desember 2017
Publisher : National Research and Innovation Agency (BRIN)

Refractory is one type of ceramic material which is thermostable (high temperature resistant) and has the ability to maintain a good physical and chemical condition at high temperature. Manufacture of refractory in this study using used kiln refractory from cement industry and 15% coal fly ash as additional. This research analyzed the effect of green body pressure produced by physical properties of refractory which made from mixture of used refractory and coal fly ash. Used refractory crushed into large aggregate size -40 +80 mesh and small aggregate size -80 mesh, while fly ash -100 mesh. Then, the two of material mixed. Raw material pressed by press hydrauliuc, with a cube-shaped mold in 5 x 5 x 5 cm size. The pressure of green body varied in 8, 9, 10, 12, and 13 tons. The product tested by archimedes methode to getting apparent porosity and bulk density, and guarded hot plate methode standard use ASTM (C 177-04) to getting the cold crushing strengh and thermal conductivity. Higher pressure molding green body product was obtained with higher compressive strength and bulk density, with lower value of the apparent thermal conductivity and porosity. The highest value for the compressive strength and bulk density was 4.48 MPa; 1.119 g / cm3; the lowest value of thermal conductivity and apparent porosity is 11.60 W / m.K; 22.034%. Those values obtained from green pressure body 13 tons.AbstrakRefraktori merupakan salah satu jenis bahan keramik yang tahan terhadap panas (temperatur tinggi) dan memiliki kemampuan untuk mempertahankan kondisinya baik secara fisik maupun kimia pada temperatur tinggi tersebut. Pembuatan refraktori pada penelitian ini menggunakan bahan baku refraktori bekas pakai kiln pabrik semen dengan tambahan fly ash batubara. Penelitian ini menganalisis pengaruh tekanan green body dari campuran refraktori bekas pakai dan fly ash batubara yang dihasilkan terhadap sifat fisik refraktori tersebut.Bahan baku refraktori bekas pakai dihaluskan dengan distribusi ukuran agregat besar -40+80 mesh dan ukuran agregat kecil -80 mesh, sedangkan fly ash batubara berukuran -100 mesh. Setelah itu kedua bahan dicampur. Pemadatanbahan baku dilakukan dengan menggunakan alat press hydraulic, dengan cetakan berbentuk kubus dengan ukuran 5x5x5 cm. Dilakukan variasi tekanan campuran green body sebesar 8 ton, 9 ton, 10 ton, 11 ton, 12 ton, dan 13 ton. Pengujian produk dilakukan dengan uji apparent porosity (porositas) dan bulk density (densitas) dengan metode archimedes, cold crushing strenght (kuat tekan), dan uji konduktivitas termal bahan dilakukan dengan metode guarded hot plate menggunakan standar ASTM (C 177-04). Pengaruh tekanan green body dari campuran fly ash batubara dan refraktori bekas pakai kiln terhadap sifat fisik refraktori adalah semakin tinggi tekanan pencetakan green body, maka semakin tinggi nilai kuat tekan dan bulk density nya, sedangkan nilai konduktivitas termal dan apparent porosity akan semakin rendah. Nilai tertinggi untuk kuat tekan dan bulk density adalah 4,48 Mpa; 1,119 gr/cm3; nilai terendah konduktivitas termal dan apparent porosity adalah 11,60 W/m.K; 22,034 %. Nilai-nilai tersebut didapatkan dari tekanan green body 13 ton.

Pengambilan Lantanum dan Nikel dari Katalis Bekas Menggunakan Asam Sitrat: Peninjauan Performa secara Kuantitatif Menggunakan Response Surface Method (Lantanum and Nickel Recovery from Spent Catalyst Using Citric Acid : Quantitative Performance......) Himawan Tri Bayu Murti Petrus; Ardyanto Wijaya; Yusuf Iskandar; Danu Bratakusuma; Hendrik Setiawan; Wiratni Wiratni; Widi Astuti
Metalurgi Vol 33, No 2 (2018): Metalurgi Vol. 33 No. 2 Agustus 2018
Publisher : National Research and Innovation Agency (BRIN)

Heavy metals and Rare earth elements (REEs) are nowadays being used widely in many industries from electronics to petroleum industries as catalysts. However, their disposal caused serious problems to the environment. With the sharp growth in its usage, there is a better way to use and utilize valuable metals from secondary sources such as their disposal rather than using new raw materials. The aim of this work is to study the potential of citric acid as a leaching agent to extract lanthanum and nickel in various acid concentration and leaching temperature. The raw material used in this work is spent catalyst from Pertamina Refinery Unit VI, Balongan, Indonesia. The spent catalyst is decarbonized with a heat treatment at 725°C for 10 minutes before the leaching process. The leaching process used 0.1; 1; and 2 M of citric acid with a varied temperature of 30, 60, and 80°C. The lanthanum recovery was calculated by comparing the mass percentage of lanthanum before leaching process and after leaching process using Energy Dispersive X-Ray Spectroscopy (EDX). The results were analyzed by response surface methodology (RSM) and are proved to be a reliable method to depict and analyze the leaching characteristics. The molarity of the citric acid is the most significant independent variables used in the research for lanthanum recovery response. However, based on the Pareto analysis result there are no significant variables that affect the recovery of nickel. The second order polynomial fitting model is also proved to be compatible with the response of lanthanum recovery but is less compatible with nickel recovery. AbstrakPengambilan logam tanah jarang dan logam berat dari sumber sekunder (katalis bekas, limbah padat industri, dan abu terbang) menjadi alternatif karena pertimbangan lingkungan dan ketersediaan bijih di alam yang semakin sedikit. Pertimbangan tersebut yang mendasari studi tentang pengambilan lantanum dan nikel dari katalis bekas dengan menggunakan asam asetat. Bahan untuk penelitian ini adalah katalis bekas dari Penyulingan Pertamina Unit VI, Balongan. Sebelum pelindian dilakukan, katalis bekas didekarbonasi dengan perlakuan panas pada 725 °C selama 10 menit. Proses pelindian dilakukan dengan memvariasikan suhu dan konsentrasi asam asetat. Hasil eksperimen ditinjau menggunakanRSM (response surface methodology) dan terbukti sebagai metode yang dapat diandalkan untuk menggambarkan dan menganalisis karakter proses pelindian. Molaritas asam merupakan variabel independen yang secara signifikan mempengaruhi respon dalam pengambilan lantanum. Walaupun begitu, berdasarkan hasil analisis Pareto, tidak ada variabel yang secara signifikan mempengaruhi pengambilan nikel. Model fitting polinomial orde dua juga terbukti cocok dengan respon proses pengambilan lantanum daripada nikel. Hasil RSM menunjukkan bahwa kondisi optimum dari ekstraksilantanum dan nikel adalah pada pH 2 dan suhu 45 оC dimana lantanum dapat 100% terambil dan nikel sebanyak 60%.

Co-Authors Achmad Sofi Adil Jamali Adiwijaya Agus Hidayatullah Agustien Zulaidah Agustin, Niyar Candra Alvianda Ricky Lukman anggi solihah Anief Rufiyanto Aprimal Aprimal Apriyanti, Eny Aprolita Aprolita Ardyanto Wijaya Arsyad Lubis Ayu Septriana Azhar Azhar Baswindro Baswindro Cahya Novita Danu Bratakusuma Dinda Tri Novira Edy Sanwani Eko Wahyuni Fajar Nurjaman Fika Rofiek Mufakhir Ghina Khoerunnisa Halimatul Husni Hendrik Setiawan Himawan Tri Bayu Murti Petrus Ika Amalia Imam Prasetyo January Jefry Prasetya Jondri Kasman Kasman Laksono Trisnantoro Lukman Nulhakim Luluk Siti Zulaechah Monna Rozana Muhammad Amin Mujiono Mujiono Nuslia Bayangkara Lamandhi Rahmia Dewi Rini Julistia Riska Chairunisa Siska Siska SITI KHODIJAH CHAERUN Soehartono Soehartono Stefanus Lian Kristian Sukaryo Sukaryo Wiratni Wiratni Yara Andita Anastasya Yuliyana Yuliana Yustika Kusumawardani Yustika Kusumawardani Yustika Kusumawardani

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