Selective Reduction of Southeast Sulawesi Nickel Laterite using Palm Kernel Shell Charcoal: Kinetic Studies with Addition of Na2SO4 and NaCl as Additives

The aim of the reduction process is to concentrate nickel at high temperatures with a certain carbonaceous material as a reducing agent. The use of chemicals like Na2SO4 and NaCl in the reduction process can increase the content and recovery of nickel in ferronickel concentrates. A selective reduction of laterite nickel was carried out in a non-isothermal and an isothermal using palm kernel shell charcoal as a reductant and with Na2SO4 and NaCl as additives. Firstly, the raw material is made into a pellet and dried in an oven at 100 °C for two hours. The pellets are weighed before and after the reduction process. The non-isothermal reduction process used the Thermal Gravimetric Analysis (TGA) method from a temperature of 100 to 1300 °C, with a heat rate of 10 °C per minute. The isothermal reduction at temperatures 500, 600, 700, 950, 1050, and 1150 °C occurred with a reduction time of 30, 60, and 90 minutes. The analysis is Inductively Coupled Plasma (ICP) to determine the content of nickel and iron from the reduction process, X-ray Diffraction (XRD) to see changes in the phases formed after the selective reduction process, and Scanning Electron Microscopy (SEM-EDX) for viewing the microstructure of the phase. The Differential Thermal Analyzer-Temperature Gravimetric Analysis (DTA-TGA) results show the endothermic at 256 °C, and the exothermic peak at 935 °C with a total mass loss of 42.15% at 1238 °C. The shrinking core model was used for the kinetic studies of the reduction process. The closest kinetic model to the experimental results is the Ginstling-Brounshtein model, with an activation energy value of 8.73 kcal/mol. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

SOLVENT EXTRACTION PROCESS FOR THE RECOVERY COBALT AND NICKEL FROM LOW-GRADE LATERITE USING BATCH RECYCLE SYSTEM

Low-grade laterite which contains nickel lower than 0.5 % is difficult to beprocessed using pyrometallurgy. One method which isable to solve this problem is solvent extraction. In thisstudy, a solvent extraction process using batch recycle methods has been successfully applied to separate nickel and cobalt from low-grade laterite. Sulphuric acid was used to leach laterite at atmospheric pressure. Meanwhile, cyanex in toluene was used as an organic solvent. Taguchi experimental design has been used to analyze and optimize the solvent extraction process using batch recycle methods. Taguchi analysis results show that the optimum conditions are at 7 of pH, 3 hours of time operation, 0.9 liter/minute of flow rate and 0.75 of organic/aqueous solutions ratio.

Studi Pengaruh Variabel Proses dan Kinetika Ekstraksi Nikel dari Bijih Nikel Laterit Menggunakan Larutan Asam Sulfat pada Tekanan Atmosferik

Leaching at atmospheric pressure is one of the leaching methods of concern because it has several advantages, namely that it can process low-level nickel ore, can operate at temperatures >100 ⁰C at atmospheric pressure, and can be used in saprolite and limonite ores. In this research, nickel extraction from nickel laterite ore was carried out using sulfuric acid solution (H2SO4) as a leaching agent. The variables that were varied in the leaching process were temperature (30, 60, and 90 ⁰C), sulfuric acid concentration (0.2, 0.5, and 0.8 molar) and leaching time (30, 60, and 90 minutes). In this study, a 3-factor analysis of variance (ANOVA) was used to see the significance of the variable effects and the order of the most influential variables. In addition, leaching kinetics was studied by shrinking core models to determine rate determining step. The results showed that the increase in temperature, sulfuric acid and leaching time produced a higher percentage of extracted nickel. Based on the 3-factor ANOVA, the order of the most influential variables was obtained, namely temperature, acid concentration and leaching time. The kinetics analysis showed that rate determining step of leaching ore nickel laterite with H2SO4 solution on atmospheric pressure is controlled by diffusion through solid layer product.Keywords: analysis of variance; leaching; saprolit; limonitA B S T R A KLeaching pada tekanan atmosfer adalah salah satu metode pelindian yang menjadi perhatian karena memiliki beberapa keuntungan yaitu dapat mengolah bijih nikel kadar rendah, dapat beroperasi pada temperatur >100 ⁰C pada tekanan atmosfer serta dapat digunakan pada bijih saprolit dan limonit. Dalam penelitian ini, dilakukan ekstraksi nikel dari bijih nikel laterit menggunakan larutan asam sulfat (H2SO4) sebagai agen pelindi. Variabel yang divariasikan dalam proses pelindian yaitu temperatur (30, 60, dan 90 ⁰C), konsentrasi asam sulfat (0,2; 0,5; dan 0,8 molar) dan waktu pelindian (30, 60, dan 90 menit). Dalam penelitian ini digunakan analysis of variance (ANOVA) 3 faktor untuk melihat signifikansi variabel dan urutan variabel yang paling berpengaruh. Selain itu, dilakukan studi kinetika pelindian menggunakan shrinking core model untuk mengetahui pengendali laju reaksi. Hasil penelitian menunjukkan bahwa peningkatan variabel temperatur, konsentrasi asam sulfat dan waktu pelindian menyebabkan meningkatnya persen ekstraksi nikel. Berdasarkan hasil ANOVA 3 faktor diperoleh urutan variabel yang paling berpengaruh yaitu temperatur, konsentrasi asam dan waktu pelindian. Hasil analisis kinetika menunjukkan bahwa pengendali laju reaksi pelindian bijih nikel laterit menggunakan larutan H2SO4 pada tekanan atmosfer yaitu difusi melalui lapisan produk padat.Kata kunci: analysis of variance; pelindian; limonit; saproli

Correlation of Nano Titanium Dioxide Synthesis and the Mineralogical Characterization of Ilmenite Ore as Raw Material

A study on mineral characterization and nano titanium dioxide synthesis from ilmenite ore of Bangka Island, Indonesia, has been carried out using a caustic fusion method and hydrochloric acid leaching. Comprehensive mineral characterization was conducted using X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) to depict each fractionated particle's elemental composition and mineralogy, i.e., +80, ?80+100, ?100+150, ?150+200, -200+325, and -325 mesh. Other analyses performed are VSM to measure the magnetic properties and SEM to determine the distribution of elements at each particle size. Based on the characteristics of the ilmenite ore, magnetic separation was applied for the initial stage and analyzed gravimetrically. Later processing was the synthesis of nano titanium dioxide, conducted sequentially, including roasting and leaching. Roasting was run at 900°C with and without caustic soda, and then hydrochloric acid was applied. In reference to the elemental analysis, titanium (Ti) concentration is higher in smaller particle sizes and vice versa for iron (Fe) concentration, so the synthesis of nano titanium dioxide was carried out using a -100+150 mesh particle size. The optimum condition for nano titanium dioxide synthesis was 2:1 of NaOH and ilmenite weight ratio, 20% HCl concentration, and 4 hours of leaching time. The nano titanium dioxide (TiO2) obtained was then characterized using XRF, XRD, particle size analyzer (PSA), and transmission electron microscopy (TEM). Roasting with caustic soda showed better nano titanium dioxide purity with 96.04% of TiO2 with particle size in the range of 50–80 nanometers

PENGAMBILAN LOGAM Ni DALAM LIMBAH ELEKTROPLATING DENGAN PROSES KOAGULASI FLOKULASI

Kegiatan industri elektroplating sering menimbulkan permasalahan lingkungan, karena banyak mempergunakan bahan-bahan kimia yang berbahaya. Salah satu diantaranya adalah Nikel (Ni) yang dipergunakan sebagai bahan baku pelapisan logam. Melihat dari permasalahn tersebut, perlu dikembangkan suatu teknik pengolahan limbah untuk mengurangi kadar salah satu unsur logam yang ada di dalam limbah. Penelitian ini bertujuan untuk mengambil logam Nikel dengan proses koagulasi flokulasi. Variabel proses penelitian ini bertujuan untuk mengetahui pH optimum, pengaruh konsentrasi koagulan, jenis koagulan yang efektif, dan kecepatan pengadukan dalam pengambilan logam nikel dari limbah elektroplating dengan proses koagulasi flokulasi. Limbah yang digunakan dalam penelitian ini adalah limbah elektroplating dengan konsentrasi awal 14,823 ppm. Variabel yang digunakan adalah pH koagulasi 6, 7, 8, 9, dan 10, konsentrasi koagulan 100 mg/l, 200 mg/l, 300 mg/l, 400 mg/l, dan 500 mg/l, jenis koagulan tawas, PAC, dan ferro sulfat, kecepatan pengadukan 100 rpm, 115 rpm, 160 rpm dan 200 rpm. Dari hasil penelitian diperoleh pH paling optimum untuk mengendapkan Ni yaitu pH 9, jenis koagulan yang paling efektif yaitu tawas, pengaruh variabel konsentrasi koagulan yaitu semakin banyak jumlah koagulan semakin banyak Ni terlarut yang dapat dikoagulasi dan mengendap, dan pengaruh variabel kecepatan pengadukan yaitu semakin cepat kecepatan pengadukan semakin banyak Ni terlarut yang dapat dikoagulasi dan mengendap

Silica from Geothermal Waste as Reinforcing Filler in Artificial Leather

The main components of artificial leather were polymer, plasticizer, stabilizer, and filler. Silica is one of the commons reinforcing filler for many composites. Meanwhile, amorphous silica is usually precipitate in geothermal power plants and become solid waste in large amounts. The aim of this study is to evaluate the mechanical properties of PVC-based artificial leather by utilizing geothermal silica as reinforcing filler. The plastisol was prepared by mixing the PVC, plasticizer, co-plasticizer, stabilizer, and filler with the amount of 100, 60, 3, 0.5 and 25 phr respectively. Commercial-calcium carbonate and geothermal-silica were used as filler for each sample formulation, then the non-filler plastisol also prepared as a reference. Artificial leather made by coating the release paper using the plastisol then heated at 190oC. The mechanical properties were investigated using a universal testing machine for the elongation, tensile strength and separation force. The surface morphology of each sample were analyzed using SEM. The results show us that the geothermal silica filled artificial leather has better elongation, tensile strength, and separation force compared to the calcium carbonate since there are stronger filler-polymer bonds formed. Therefore geothermal silica has high potential as filler for artificial leather, thus gives an alternative solution for the solid waste problem in geothermal power plant and also provide low-cost source of reinforcing fillers for artificial leather industries

PENGARUH VARIASI WAKTU DAN REDUKTOR PADA PELEBURAN TITANIUM DARI TERAK TIMAH MENGGUNAKAN TUNGKU BUSUR LISTRIK

Pengolahan bijih timah menjadi logam timah akan menghasilkan limbah berupa terak. Metode pirometalurgi biasanya dipilih dalam mengolah bijih timah tersebut karena mempunyai kelebihan, yaitu prosesnya lebih singkat dan dapat menghasilkan logam lebih murni. Salah satu proses pirometalurgi adalah menggunakan alat tungku busur listrik. Tungku busur listrik merupakan salah satu alat yang berperan dalam proses reduksi dan peleburan mineral llogam. Tungku busur listrik satu fasa memiliki beberapa kelebihan dalam penggunaannya, di antaranya konsumsi penggunaan elektroda dan konsumsi energi yang rendah. Pada penelitian ini dilakukan ekstraksi titanium menggunakan tungku busur listrik dengan variasi waktu proses dan rasio reduktor untuk mereduksi dan melebur terak timah. Waktu proses yang digunakan 20, 30, 40, 50 dan 60 menit serta variasi reduktor yaitu 1:5, 1:7 1:10, 1:13, dan 1:15 dengan temperatur peleburan yang sama yaitu 1600°C. Kadar titanium tertinggi diperoleh pada waktu proses 30 menit yaitu sebesar 23,11% pada rasio reduktor 1:15 dengan persen ekstraksi titanium sebesar 79,21 %

Studi Pendahuluan Pengendapan Cerium, Lanthanum, dan Neodymium dari Larutan Klorida Menggunakan Sodium Karbonat pada Pengolahan Monasit Bangka

ABSTRAK Mineral monasit sebagai mineral ikutan penambangan timah di Kepulauan Bangka Belitung mengandung unsur tanah jarang ringan, diantaranya Cerium (Ce), Lanthanum (La), dan Neodymium (Nd). Tujuan penelitian ini adalah untuk memperoleh konsentrat unsur tanah jarang karbonat melalui proses pengendapan dengan sodium karbonat (Na2CO3), serta menentukan pengaruh konsentrasi dan volume Na2CO3 terhadap recovery pengendapan Ce, La, dan Nd. Persiapan umpan dilakukan dengan mengikuti rute proses pengolahan monasit menggunakan metode basa meliputi tahapan dekomposisi, pelarutan, dan pengendapan unsur radioaktif. Recovery pengendapan tertinggi untuk Ce, La, dan Nd yaitu sebesar 10,84%, 7,81%, dan 2,68% pada penggunaan Na2CO3 dengankonsentrasi 30% wt dan volume 55 mL.ABSTRACT Monazite mineral as associated mineral of tin mining in Bangka Belitung Islands contains light rare earth elements like Cerium (Ce), Lanthanum (La), and Neodymium (Nd). The objective of this study is to obtain the concentrates of rare earth carbonate through the precipitation process with sodium carbonate (Na2CO3) and determine the effect of concentration and volume of Na2CO3 on the precipitation recovery of Ce, La, and Nd. The preparation of the feed solution was carried out by following the monazite processing route using the alkali method includes the stages of decomposition, dissolution, and precipitation of radioactive elements. The highest precipitation recovery for Ce, La, and Nd are 10.84%, 7.81%, and 2.68% respectively in the use of Na2CO3 with a concentration of 30% wt and a volume of 55 mL.