Arief Sudarsono
Jurusan Teknik Pertambangan, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132

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Study on the Making of Blended Cement by Mixing Granulated Blast Furnace Slag with Portland Cement Clinker Arief Sudarsono; Kris M. Kosasih
Journal of Mathematical and Fundamental Sciences Vol. 32 No. 2 (2000)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract. This paper presents the results of laboratory into the effect of slag fineness and slag composition added to portland cement clinker, to the compressive strength of the paste. The results showed that slag of 4260 cm2/gram fineness can be added up to 3O% to a portland cement clinker to increase compressive strength from 28 MPa to about 40 MPa. Scanning electron micrograph of the pastes showed that the inter granular voids between slag particles and sand particles were densely filled with line CaO-SiO2-H2O gel after 28 days observation, and in case clinker without slag, densification of CaO-SiO2-H2O gel still left pores even after 23 days of observation. The fineness of slag is more important than its composition in the blended cement. Studi Pembuatan Semen Campur (Blended Cement) dari Campuran Terak Tanur Tiup dan Klinker Semen PortlandSari. Paper ini menyajikan hasil percobaan laboratorium yang meneliti pengeruh kehalusan terak dan komposisi terak yang ditambahkan ke dalam klinker semen Portland. Hasil percobaan menunjukkan bahwa terak dengan kehalusan 4260 cm2/gram dapat ditambahkan ke dalam klinker sampai maksimum 30%, untuk meningkatkan kuat tekan dari semula 28 Mpa menjadi 40 Mpa. Foro SEM menunjukkan bahwa kekosongan antarbutir partikel terak dengan partikel pasir terisi dengan baik oleh pasta halus CaO-SiO2-H2O setelah pengamatan selama 28 hari. Untuk klinker tanpa terak, pasta masih mempunyai pori mesipun setelah 28 hari pengamatan. Kehalusan terak lebih penting daripada komposisinya di dalam semen campur.
Linear Potential Sweep Voltammetry in Conjunction with Small Amplitude Cyclic Voltammetry Study for Chalcopyrite-Xanthate Electrochemical Flotation System Arief Sudarsono
Journal of Mathematical and Fundamental Sciences Vol. 31 No. 3 (1999)
Publisher : Institute for Research and Community Services (LPPM) ITB

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Abstract. The present study was undertaken to investigate the electrochemical aspects of reactions on platinum, copper, and chalcopyrite aqueous xanthate solution interfaces by the small amplitude cyclic voltammetry (SACV) technique. In the technique, the potential of an electrode is swept linearly with time within very narrow potential limits. Typically a 10 to 20 mV peak-to-peak triangular potential excitation has been used. Characteristic parameters of the observed current-potential response loop, like apparent polarization resistance, was used to analyze the surface reaction mechanism in the flotation of chalcopyrite minerals. The analysis of the electrochemical interaction between platinum, copper and xanthate ions has also been carried out by using linear potential sweep voltammetry (LPSV) techniques in different xanthate concentrations. The voltammograms obtained on platinum appear due to the possibility of the formation of dixanthogen from the oxidation of xanthate ions, and the formation of copper-xanthate species from elecbochemical reactions between xanthate ions and copper. Studi Voltametri Penyapuan Potensial Linier Dikaitkan dengan Voltametri Siklus Amplitudo Kecil untuk Sistem Flotasi Elektrokimia Kalkopirit-xantatSari. Penelitian ini memberikan gambaran reaksi elektrokimia pada antarmuka elektroda platina, tembaga, dan kalkopirit di dalam larutan encer xantat. Penelitian dilakukan dengan metode SACV (Small Amplitude Cyclic Voltammetry), dengan rentang eksitasi potensial segitiga yang sangat kecil, yaitu 10 mV sampai 20 mV eksitasi dipakai untuk menganalisis mekanisme reaksi flotasi mineral kolkopirit. Untuk mempertegas hasil SACV penelitian dilanjutkan dengan metode LPSV (Linear Potential Sweep Voltammetry). Voltammogram yang diperoleh menggambarkan terbentuknya dixantogen di permukaan elektroda platina, dan terbentuknya senyawa tembaga-xantat karena adanya reaksi permukaan antara ion xantat dengan tembaga.