Table of contents

Preface

Mineral Processing and Technology International Conference (mineprocèt) 2018 was a scientific meeting that is technically organized by Research Unit for Mineral Technology in conjunction with Indonesian Science Expo (ISE) 2018 organized by Indonesian Institute of Sciences (LIPI). mineprocèt 2018 was held on November 1, 2018 at Indonesia Convention Exhibition (ICE), BSD City, Serpong, Tangerang, Indonesia.

This symposium aimed to bring together researchers, academicians, and scholars all around the world to share information and their research results. This event was also expected to become a beneficial media in exchanging their innovative ideas and build research collaborations in the future. The symposium covered all scientific and technical activities in mineral processing and technology – from basic to the advanced applications – to pitch ideas, insight and findings for optimal and sustainable use of sub-economic mineral resources especially those related to mineral beneficiation, extractive metallurgy (bio-hydrometallurgy, pyrometallurgy, electrometallurgy), separation and purification, physical metallurgy and foundry, powder and nano technology, mineral industry application, energy and coal technology, mineral economy and policy, phytoextraction and environmental remediation, control and modelling for mineral processing.

We specially invited 4 scientists as keynote speakers from various countries to share their knowledge to all participants. The total participants attending this symposium were 51 people. This symposium has successfully attracted 46 submitted papers. Papers that have been presented in the mineprocèt 2018 were eligible for publishing in IOP Journal of Material Science and Engineering: Conference Series. The editorial board has decided to accept 41 papers from Indonesia and Philiphines. The accepted papers have passed through strict reviewing process by scientific committee of this symposium. EDAS system has been used to facilitate the submission, reviewing, and revision processes.

List of Conference Organizers and Keynote Speakers are available in this PDF.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

In this present work, the selective reduction of nickel laterite was conducted by using 5 to 15 wt. % of sodium carbonate, sodium chloride and sodium sulfate as additives. The 5% wt. of palm shell charcoal was used as the reductant. The selective reduction process for nickel laterite was carried out at 1150°C for 60 minutes followed by wet magnetic separation using 500 Gausses permanent magnet. The characterization of reduced ore was performed by using X-ray Diffraction, optical microscope and Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy, while the chemical composition of concentrate or ferronickel was identified by X-ray Fluorescence. The results showed that the increase of nickel grade and recovery of nickel laterite was significantly more affected by the addition of sodium sulfate rather than sodium carbonate and sodium chloride. The ferronickel particle was agglomerated and growth with the increasing of reduction temperature and dosses of additives, thus it provided favorable conditions for the separation of ferronickel from impurities in the magnetic separation process.

Selective reduction process and magnetic separation of nickel lateritic ore wereconducted through the two-stage thermal upgrading processwith the addition of sodium sulphate and sodium chloride as the additives agent. Effect of the first thermal stage temperature has been investigated at various of temperature of 500, 600 and 700°C for 60 minutes and continued with the reduction process at temperature of 1050°C for 30 minutes. The mineralogical composition of the reduced samples was performed by XRD analysis. The optimum temperature was 500°C, which produced a concentrate withnickel grade of 2.98% and iron recovery of 40.17%. Effect of the first thermal stageretention time also has been investigated at temperature of 500°C for 30, 60, and 90 minutes, and continued with the reduction process at temperature of 1150°C for 60 minutes. The optimum temperature was 90 minutes, which produced a concentrate with 3.69% nickel grade, and 90.61% nickel recovery.

Increasing building in property sectors causes chain effects in many of its supporting fields. One of them is the fence construction. Fence nowadays is not only functions as separator between a main building and other open spaces but it also has prestige values for the owner of the building. Fence ornaments continue to develop over time from its form, raw material, to its making process. Fence makers start to gradually abandon cast iron for fence ornament raw material. The aluminum becomes an alternative raw material in the fence making process. A research on the technological and economy aspects of aluminum scrap processing into fence ornament was conducted. From the technological aspect, small and middle sized industries were suggested to use batch system (50 kg/batch) with solid-fuel-based crucible furnace. The furnace dimension was 390 mm diameter and 440 mm height. Furnace isolation used fire brick type SK 32 with 240 mm thickness and 700 mm of furnace height. The molding process used sand molds method and used local raw material. Ratio of scrap raw material to ornament product was 1.1-1.3, while ratio of solid fuel use was 1.5-2.1. It took 6 hour / batch for smelting process with temperature of 600-710°C. From economy aspect, it took investment cost of Rp. 210,000,000 to start aluminumscrap smelting business into fence ornament product. The financial analysis obtained net present value (NPV) of Rp. 176,699,790; net B/C (benefit/cost ratio) of 1.84; and internal rate of return (IRR) of 31.12%.

Cr-Al-BN powder was successfully applied as a coating agent on low carbon steel substrate by mechanical alloying method. The addition of BN as a doping material is considered as a feasible option because of excellent thermal and chemical stability presented by BN. In this paper, the compositions of Cr-Al-BN are varied Cr49.5-Al49.5-BN, Cr48.5-Al48.5-BN3, and Cr47.5-Al47.5-BN5. Each powder was milled by shaker mill for 2h in a stainless steel chamber with stainless steel balls to powder ratio 10:1. Subsequently, each powder compositions were mechanically alloyed onto substrate surface in air for 2h. The 2h heat treatment at temperature 800°C was conducted to each coated sample in vacuum furnace. In order to achieve the characteristics of phase composition and microstructure of the coating before and after heat treatment, XRD and Optical Microscope were performed, while the automatic microhardness tester was carried out to get the hardness of coating layer. The oxidation behaviour of coated substrates was also studied by heating treatment at 800°C for 8 cycles where each cycle is 20 h. The results show that the ball milling induces the formation of homogeneous Cr-Al-BN coating structure with a thickness of about 62.5 μm The optimum coating hardness and oxidation resistance was achieved by Cr47.5-Al47.5-BN5 coating composition. The addition of higher concentration ofBN increases the tendency onthe formation of intermediate phase of Cr₂B and Cr₂N. The detailed result of this study is shown in this paper.

Performance analysis of crucible that used in aluminum casting at Small and Medium Enterprises (SMEs) Foundry have been done by non-destructive test (NDT). A non-destructive testing method is a felicitous method because it does not interfere with the production process. The crucible analysis includes the Chemical composition analysis use X-Olympus XRF to know the crucible material, fluids flow analysis and design using finite element method with Autodesk Inventor Software and Autodesk Simulation CFD. Based on the results showed that the crucible consists of 97.17% Fe, 1.68% Si, 0.6% S, 0.22% Mn, 0.26% P, and 0.08% Cr. From fluids flow simulation founded a critical point in crucible area that appropriates with the leaks occur. In this critical point, the air velocity about 8.89 m/s and the velocity in the inlet and outlet drooped 266.7 m/s, increasingly severe with fixed support the crucible only on upper hatrack while at the bottom there is no support that caused the maximum stress in this section. Finite element method divided the displacement area by a mesh average of 0.08 in four colour variations, red colour at 48.94 mm max displacement, yellow colour on 29.36 mm – 39.15 mm displacement area, green colour at 19.58 mm – 29.36 mm displacement area, and blue colour at 0 mm – 19.58 mm displacement. The crack of crucible located between red and yellow colour about 39.15 mm displacement.

Aluminium beverage cans scrap recycling is expected to fulfil aluminium needs in Indonesia, reduce production cost, and pollution generated. Fluxing is one of the methods that can be used to reduce impurities in aluminium alloys such as magnesium, flux also can protect molten metal reacted with oxygen. In this research, aluminium beverage cans scrap used to consist of carbonated, isotonic, and refreshing beverage cans and NaCl+KCl as flux. The holding time of salt fluxing process was 60, 120, 180 and 240 minutes and 5, 10 and 15% variation of flux mass from total scrap mass. Ingot from the recycling process tested to know the percentages of Mg reduction and acquisition of Al using XRF analysis and metallographic. The result showed that the highest percentage of Mg reduction was 77.83% on the addition of the sample of 15% flux for holding time 120 minutes, but Al reached 97.49% for holding time 240 minutes on same flux. On the addition of 10%, flux for holding time 180 minutes was reached 98.82% for yield, 71.84% for recovery, and recycling efficiency 70.53%.

Nickel in the form of nickel laterite ore is one of the most prominent types of mining products in Southeast Sulawesi, Indonesia. One of the utilization of laterite nickel ore is as raw material for ferronickel and NPI production. In this research, the NPI was produced from laterite nickel ore originating from Sulawesi Island in electric arc furnace (EAF). This study aims to determine the effect of the amount of flux (limestone) and type of reducing agent (coal, coke, and shell charcoal) on the content of Ni and Fe in the NPI product and metal yield. Laterite nickel ore used in this study is a type of limonite from Pomaala (Sulawesi Island). The reducing agents used are coke, coal, and coconut shell charcoal. Limestone was used as a flux to adjust the basicity of material during the smelting process of lateritic nickel ore. Reduction and melting process of limonite nickel ore to produce NPI were conducted in small EAF with capacity of 30 kg/heat. The dried pellets are reduced and melted in the EAF with added reducing agents and limestone. Based on the results of the study it can be concluded that the results of the flux addition effect obtained that the optimum Ni and Fe values were obtained on basicity of 1. The results of the reductant type effect showed that coke was the greatest reductant in this study due to the highest Ni content produced when coke used as reductant. In addition, the XRD results showed that the FeNi phase has been formed.

The need of manganese to support human life has led to the exploitation of low-grade manganese ore. However, the appropriate technique has not been established and still under development. Having total amount of 120 thousand metric tons, Indonesia has huge potential of low grade manganese ore deposited in several areas such as Kulon Progo, Yogyakarta. In this study, leaching of low grade manganese ore was conducted using acetic acid which isenvironmentally friendly due to its ease to decompose naturally. Ore characterization was performed by X-Ray Diffraction (XRD), X-Ray fluorescence (XRF), and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) showing that 7.16 % is manganese while 32 % of the ore is dominated with calcite. Effects of leaching temperature and particle size on Kulon Progo low grade manganese ore were investigated. Particle sizes under study were less than 200 mesh and between 70 mesh and 100 mesh. The pH and temperature of experiment were varied on 0.7, 1.7, and 3; and 30 °C, 60 °C and 80 °C, subsequently. It was obtained that the ore particle size has no significant effect on Mn recovery. The manganese recovery of 76.08 % was obtained, containing lower recovery of calcium and iron which were 10%. The findings showed acetic acid is more selective towards manganese than to calcium and iron.

The leaching kinetic ore from Pomalaa (Southeast Sulawesi, Indonesia) using hydrochloric acid solution was investigated in a batch reactor. Variables studied were temperature, pH and particle size. To evaluate the kinetic parameters, the experimental data were fitted with a shrinking core model of a constant particle size. The experimental data fit very well with the proposed model and the overall rate is controlled by dissolution rate of nickel through product layer. The activation energy (E_De) for the dissolution of nickel is 22.5 kJ/mol. The maximum nickel recovery is 41.5% at pH 1, reaction temperature of 90°C, particle size of -200 mesh, solid to liquid ratio at 0.2 (w/w) and stirring speed of 400 rpm for 240 minutes.

A cyclic voltammetry study is one of electro analytical chemistry methods which able to study the corrosion of material. In this research, the cyclic voltammetry has been carried out in order to determine the voltage range that contributes to the initiation of the corrosion on the surface of stainless steel in the acidic thiourea solution. In this study, the knowledge of corrosion on stainless steel is useful in the optimisation process for gold recovery from electronic waste based on electrodeposition technique. Since stainless steel material has been used as both anode and cathode in the experimental setup, under certain applied voltage, corrosion might occur and hinder the gold recovery process by damaging the electrodes. With the aid of cyclic voltammetry study, the suitable applied voltage for electrodeposition process has been investigated and found to be approximately 1.4 V for two-electrode setup for a system with sulfuric acid concentration of 0.1 M in the presence of 0.1 M thiourea. The data obtained can be used as a basis to determine a suitable pre-set applied voltage in the electrodeposition process such that corrosion on the electrodes can be avoided.

Lithium Manganese is an important ingredient in the process of making lithium battery cathode materials. The purpose of this study was to observe the presence of lithium ions in the manganese hydroxide deposition process in mixing MnSO₄, LiCl, and NH₄OH. The expected result is that the adsorbed lithium ion reacts with manganese hydroxide and settles when sintered at high temperatures. In this experiment, the addition of MnSO₄ varied by 5, 10, 15, 20, 25 grams in 200 ml of LiCl solution with a concentration of 10 g / l and ammonia 25% by volume was added. The resulting solids were calcined at 800 °C for 24 hours. The results showed that the best adsorption of lithium ions on the addition of manganese sulfate was 15 g and 25 g. Characterization results obtained by solids have a 3.3% LiMn₂O₄ phase and 96.7% Li₂Mn₂O₄ at the addition of 15 g manganese sulfate. On the addition of 25 g of manganese sulfate, 36.6% of LiMn₂O₄ and 63.4% of Li₂Mn₂O₄ were obtained. The success of this study will make it easier for us to synthesize the manufacture of lithium battery cathode materials such as lithium manganese phosphate.

Titanium is very important metal which commonly used in industrial process, automotive, electronic devices and other application. Titanium is not pure element in nature but mixed with other elements such as in irons sands. Hence, it is required to do research to gain high concentration titanium and also eliminate its impurities. One of method which able to overcome this problem is the flotation method. On this research, titanium recovery process is done from natural iron sands of Lampung using oleic acid as a collector in the flotation process. The iron sands which used for each variation are 10, 15 and 20 wt% with a size of 60, 100 and 150 mesh. Those iron sands were mixed into 0,10; 0,20; 0,30 lb/tons of collector by varying pH condition of 6, 8 and 10. After that, each variation product was characterized by XRF characterization and then calculated based on Taguchi method. From the research that had been done, it is known that the optimum values are at the content: oleic acid = 0,1 lbs/ton, ore 20 wt%, pH 8, the Particle size of 150 mesh.

Pomalaa limonite nickel ore has nickel content of 1.29% and it has not been processed in Indonesia until now. In addition, The Minister of Energy and Mineral Resources Regulation No.5/2017 on adding the value of minerals. Therefore, the limonite nickel ore should be processed to produce nickel metal with the content 99.93%. The limonite nickel ore generally has low nickel content (less than 1.5%) therefore hydrometallurgy such as leaching is the suitable process. In this research is done 2 series of leaching. First, determination of leaching controlling rate by varying the temperature and time of leaching. Second, determination the optimum condition of the leaching variables (concentration of leaching agent, agitation and temperature) based on the leaching controlling rate. The amount of activation energy obtained from this research is 16.23 and 38.47 kcal/mol then it could be said that the reaction control of leaching limonite nickel ore from Pomalaa is a chemical reaction. In addition, a maximum extraction of 88.9% was achieved at 400 rpm, 6M hydrochloric acid concentration and a temperature of leaching about 90 °C.

Manganese ores from Waykanan region (WK ore) contain pyrolusite (MnO₂) as major minerals, whereas the main minerals in manganese ore from Tanggamus region (TG ore) are. The effects on manganese extraction of leaching reagents without reductant, leaching temperatur of non-reducing leaching, and reducing agents of sulfuric acid leaching were determined to investigate the leaching performances of the two manganese ores. Manganese leaching efficiency from WK ore is always higher than that from TG ore under the same leaching conditions. The mineral contents of the ores significantly affected the leaching performances and mineral dissolution behaviors of the samples.

A study has been conducted on the process of leaching of zinc dust using oxalic acid by hydrometallurgical method. The sample preparation process starts from the dust zinc washing. The leaching process was started by mixing the sample with solution of 5 M oxalic acid. There were three variations; the ratio of mole, temperature and leaching time to know the optimum condition. From the variation of leaching process that has been done, an optimum condition was obtained where the ratio of zinc mole dust to 5 M oxalic acid solution is 1:10 with temperature 90°C and leaching time for 150 minutes. The leaching filtrate was precipitated to obtain zinc oxalate with a solution of sodium hydroxide up to pH 7. The FTIR and XRD analysis showed that the leaching products confirmed as hydrozincite (Zn₅(CO₃)₂(OH)₆) and sodium bicarbonate (NaHCO₃). The carbonate compound may be caused by decarboxylation during the leaching process. The calcination of leaching products to convert hydrozincite turn out zinc oxide was done at 600 °C. The results of the XRD analysis show that there were zinc oxide and still found zinc carbonate and sodium carbonate.

Laterite with low-grade nickel (< 0.5%) was very difficult to process using pyrometallurgy technique. One method which able to process this laterite is solvent extraction process. This process also able to separate cobalt from nickel solutions. The aqueous phase of solvent extraction process which has a high nickel content able to collect using electrowinning methods. Electrometal-electrowinning (EMEW) method is one of the electrowinning methods which has better performance to collect metal from solution. In this work, laterite was leached using H₂SO₄ then was extracted using Cyanex 272 in toluene as an organic solvent. In this research, the effect of a voltage, a duration time of operation, a concentration of boric acid and a temperature on EMEW process were studied and were optimized using Taguchi method.

Rare earth elements (REE) 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 REE 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 one of REE (i.e. lanthanum) in various acid concentrations and leaching temperatures. 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 independent variables used in the research show significant effect on the response, especially the acid’s concentration. A second order polynomial equation was used to correlate response and independent variables. The coefficient of determination (R²) shows a satisfactory result of 86.53% and the normal probability plot ensure the model’s adequacy.

The present paper reports thecharacterization of gold ore from Tanggamus mine Lampung Province bychemical and geological analysis. The presence high content of Fe and S indicated that the ore issulfides which is form as pyrite crystal confirmed by XRD and SEM analysis. Auas trace element detected by fire assay and wet analysis comprises of 4 ppm in an amount. It is not yet clear that the existence of Au with minor of amount, merelythe possibility Au associated with pyrite or quartz matricesas micro inclusion. The gold ore is classified as refractories ore.

Titanium dioxide (TiO₂) contained in the Ilmenite Bangka mineral was synthesized by varying the calcination temperature to obtain characteristics that can improve the photocatalic ability. It can be a solution to handling of waste in the textile industry. Synthesis starts from a caustic fusion process using NaOH to decompose of ilmenite into the titanate compound were more soluble in acid, so that can reduce acid consumption in the leaching process. The leaching process uses 8 M H₂SO₄ in 5% solid to produce TiOSO₄ as a filtrate. Then the filtrate was hydrolyzed to obtain the precipitate TiO₂-Fe₂O₃. Calcination with variation of temperature was came after leached the precipitate with the water until neutral pH is obtained. The temperature used is: 350 °C (TiO₂ T₁), 450 °C (TiO₂ T₂), 550 °C (TiO₂ T₃), 650 °C (TiO₂ T₄), and 750 °C (TiO₂ T₅). The results of photocatalytic activity test using a solution of Rhodamin B (RhB) and Methylene Blue (MB) revealing that the highest photocatalyst efficiency was achieved by TiO₂ which calcined at a temperature of 650 °C, with 69.33% (RhB) and 83.41% (MB).Where in this temperature, rutile phase began to form about 15.38%, the band gap energy on 2.4 eV, and the growth of crystalite size become 53.41 nm which affected the increase in photocatalytic activity.

An inefficient gold leaching in the cyanidation process from refractory gold tailings was caused by gold particle locked in specific minerals. The aim of this study was to harness the ability of a sulfur-oxidizing bacterium to oxidize iron and sulfur and its behaviour on ferrous sulfate heptahydrate (FeSO₄.7H₂O) and pyrite (FeS₂) as the medium in the biooxidation process for gold and silver extraction. The results showed that the gold extracted in ferrous sulfate medium was 20.48%, while that in pyrite medium tended to reduce from direct cyanidation to 14%. The silver extraction increased from 80.96% to 99.26% in ferrous sulfate medium and 91.30% in pyrite medium. This result indicated that ferrous sulfate heptahydrate was more suitable than pyrite, which resulted in the higher extraction of gold.

Biobeneficiation is considered to be a clean coal technology as an alternative method to reduce sulfur and ash content present in coal by using microbes, in particular bacteria. Recent studies have demonstrated that bacteria can oxidize iron and reduced sulfur compounds present in coal because they promote the oxidative conversion of the reduced forms of sulfur to soluble, easily washed-out compounds. Moreover, the use of bacteria in coal beneficiation has the following advantages, such as simple operation, extensive installation, performed under the mild condition without harmful product, low energy consumption and eco-friendly method. Hence, this study dealt with the investigation of the bacteria capable of oxidizing iron and sulfur compounds and also reducing ash content present in coal. Nine bacteria isolated from mercury-contaminated gold mine sites in Bandung, West Java Province, Indonesia were screened for their ability to oxidize iron and sulfur compounds and reduce ash content. Of the nine bacteria studied, two bacteria (i.e., Pseudomonas plecoglossicida and Pseudomonas hibiscicola) were able to oxidize iron and sulfur compounds and reduce ash content at pH of ~4. The findings of this study provide evidence that both bacteria could be employed as an oxidizing agent that will be applicable for the beneficiation of coal.

Mn determination in samples with high Fe content using derivative spectrophotometric method was proposed in this paper, which formaldoxime was used as chromogenic reagent. The derivative method is useful to manipulate spectra data in order to eliminate the noise spectra i.e. Fe and isolate the spectra of elements of interest (Mn). Formaldoxime was chosen since the reagent reacted both to Mn and Fe at the same pH condition. In this paper, the accuracy in Mn determination in the presence of Fe using proposed method would be assessed and discussed. Mn and Fe could be simultaneously determined Mn using zero crossing point of first derivative Fe-formaldoximate spectra at 530 nm for Mn determination, while Fe could be predicted using zero crossing point of second derivative Mn-formaldoximate spectra at 469 nm. Maximum concentration which obeyed the linearity of calibration curve is 2 and 20 mg/L for Mn and Fe, respectively. The error in Mn and Fe prediction depends on ratio of both elements.

Coal is one of the important energy sources in the world. It has been part of the important roles for centuries, not only for generating electricity but also the main fuel for steel and cement production as well as other industrial activities. However, the quality of the coal is generally too low for the practical, economical utilization. High sulfur and ash contents come up as one of the barriers in the productive usage of indigenous coal. Clean coal technology such as coal biobeneficiation can appear as a panacea for upgrading the coal reserves with high sulfur and ash contents. In the current study, the removal potential of the sulfur and ash content from coal of Kalimantan, Indonesia was investigated by using the bacterium Pseudomonas moraviensis. It was reported for the first time that the bacterium had the capability to remove about 17.37% of total sulfur and ash content from the coal. The results revealed that the bacterium Pseudomonas moraviensis used in this study could remove sulfur and ash content from the coal and could thus be used in the pre-combustion operation with appropriate arrangement.

The availability of lithium resources in the world is important along with the development of electronic technology and electrical transportation, especially lithium batteries. In Indonesia, lithium is found in brine associated with hot spring, clay associated with a geothermal activity, and spodumene minerals. The Bledug Kuwu’s Mud contained a Li-Montmorillonite phase with lithium content that was 0.0029%. For lithium recovery, Li-Montmorillonite was leached with distilled water on the S / L ratio was 1: 2 for 3 hours. In this experiment, the leaching temperature was varied as follows: 25°C, 30°C, 35°C, and 45°C. Experimental results showed that lithium recovery from Li-Montmorillonite was successfully carried out by water leaching at atmospheric pressure. This result was supported by XRD analysis on residues. It indicated that there was no Li-Montmorillonite phase at the residues. The highest percentage of lithium recoveries in this research obtained at leaching temperature of 25°C was 87.2% (15.78 ppm).

The biomass waste of rice husk and coconut shell in Indonesia reaches more than 15.8 million tons/year. In addition, the utilization of biomass waste has not been performed optimally. Rice husk and coconut shell are the biomass that can be processed as briquette material. This research aims to find the maximum temperature of hot briquette to generate the maximum coke strength from blending. First, the biomass waste was performed by a carbonization process at 400°C with a coal composition of biomass 95:5 wt%. The production of coke briquette used molasses binder 15 wt%. The hot briquette temperature variation was at 100 and 150°C with a briquette pressure of 200 kg/cm². Coke briquette then was carbonized at 1100°C for 4 hours and followed by water quenching. The result indicates that hot briquette temperature depends on the type of biomass used. Coke briquette with a rice husk blend at 100°C and 150°C hot briquette temperature, respectively produced coke strength of 11.5 and 20.9 kg/cm². Meanwhile, coke briquettes with coconut shell charcoal blend at 100°C and 150°C hot briquette temperature respectively produced coke strength of 15.8 and 10.8 kg/cm².

Recovery of Rare Earth Elements (REE) from waste is an important alternative to solve global REE crisis. Therefore, coal fly ash containing REE becomes a potential candidate as an alternative source of REE. Indonesia has a large potential of coal resources, however unlike other type of coals which is rich in SiO₂ and Al₂O₃, Indonesian coal contains significant amount of Fe₂O₃. As a consequence, fly ash resulted from burning Indonesia coal is also rich in iron oxides. The presence of high concentration of iron oxides will however reduce effectiveness of REE recovery from coal ash through hydrometallurgy process. Therefore, iron oxides in the coal fly ash needs, firstly, to separate preceding further REE separation. This study determined the optimal process conditions in the iron recovery process from coal fly ash. The variables studied were fly ash grain size, magnetic field strength and separation techniques. The iron recovery was determined by mean of the ratio of iron concentration after and before magnetic separation. Experimental results showed that increasing magnetic field strength and decreasing coal fly ash grain size in a wet separation will increase the recovery of magnetic iron component. Magnetic field strength of 4300 Gauss and grain size of -400 mesh were the optimal values in this study with iron recovery of 25.89%.

One of the technologies used to utilize low quality coal is by making bio-coal briquettes. Bio-coal briquettes are briquettes made of a mixture of coal and biomass. In this study, bagasse biomass is used as a mixture material of the briquettes. The objective of this study is to disclose the effects of the duration of carbonization on the characteristics of the briquettes. The process of carbonization is conducted to reduce water content and the level of volatile substances and increase the calorific value of the raw materials, so that the resulting briquettes will be of higher quality. This study uses the variations of carbonization duration of 30, 60, 90, 120, and 150 minutes. The result of the study reveals that the best duration of carbonization of raw materials in making bio-coal briquettes is 150 minutes. The bio-coal briquettes made with the duration of carbonization of 150 minutes has moisture content of 10.25%, ash content of 12.91%, volatile substance content of 31.88%, fixed carbon content of 44.96%, calorific value of 5,897 cal / gram, initial ignition time of 6.85 minutes, duration of combustionof 20.26 minutes, CO gas emission of 395 mg / Nm³, and NO gas emission of 5.6 mg / Nm³.

Dry gravity separation is widely used in industries due to its low operational cost. Furthermore, it does not require water to perform its separation process. Commonly used gravity separator is cyclone separator. Unfortunately, this type of separator is unable to yield various purities for its products. A modified gravity separator as an alternative relies on terminal velocity difference for different diameter and density is evaluated in this paper. The separated particles are coal fly ash and cenosphere which are the results of coal combustion where the content of cenosphere is generally 0.1% of total mass. Separated cenospehere can be used for various applications in the field of materials. In this simulation we use a particle model with a ratio of fly-ash to cenosphere mass of 1:1. Particles behavior in this gravity separator is affected by terminal velocity, linear speed, as well as rheology. Modeling with CFD (Computational Fluid Dynamics) using the Discrete Phase Model can take into account the behavior of particles that are affected by these factors. This model assumes that the simulated particles are perfectly round in shape. It uses the Euler-Lagrange framework in which the perfectly rounded particles (discrete phases, Lagrange frames) interact with air (continuous phase, Euler framework) and performed with ANSYS Fluent software. This study evaluates the effect of speed variation on Newton efficiency (NE) on a given geometry. Simulations were performed with variations of inlet velocity: 0.1 m/s; 0.25 m/s; 0.5 m/s; 1 m/s; 2 m/s; and 3 m/s. It was found that the lower the speed, the higher the NE and the optimum NE of 0.41 is obtained with 0.25 m/s inlet velocity.

Aluminum is one of the materials used for automotive, almost 90% of aluminum scrap from automotive cars can be recycled. The properties of aluminum are light and have a high ductility. The addition of SiC as reinforcement to aluminum based composite materials by multi-axial forging (MAF) is one of the newly developed SPD processes. Addition of SiC is to increase strength greater than the base material. The purpose of this research is to know the micro structure especially spread of distribution of precipitate evenly in matrix and change of mechanical properties after MAF process. Therefore, variation of weight fraction of SiC and pre-heating temperature were conducted. Kind of aluminum type AA1100 shaped plate as matrix added SiC as reinforcement, using variation 0.2%:0.4% and 0.6% wt. As for pre-heating temperature variation of 350°C, 450°C and 550°C then done MAF process with every change of pass rotate 90°. The results obtained from aluminum-based composite study by MAF, that with the addition of SiC on microstructure observation there is a change of grain boundary shape from equaxial to lamellar, there are grains of precipitate on the matrix that spread evenly and tensile test results and microhardness test increased along with the addition SiC fraction at a temperature of 350°C while for temperatures of 450°C and 550°C there is a decrease in hardness value, tensile strength value on Al/SiC.

Natural zeolite can be modified by single or combined treatment of heating and chemical modification using acids, bases, and inorganic salts. In this study, the Philippine natural zeolite (PNZ) was modified with alkali and acidic solution. The alkali-treatment and acid treatment used sodium hydroxide (NaOH) and acetic acid (CH₃COOH) as chemical modifier respectively. Various concentration of the solution (1M and 2M) and temperature (25°C and 50°C) was used during modification of the PNZ. The XRD of Na-PNZ and Ac-PNZ shows mineralogy of clinoptilolite and mordenite phases of the natural zeolite. The SEM images shows porous and plate-like morphologies of both modified materials. These property shows surfaces for adsorption of metals from wastewater solutions. The Na-PNZ and Ac-PNZ was used as adsorbents for the treatment of synthesized copper solution. The copper uptake of Na-PNZ from an aqueous solution is higher compared to the Ac-PNZ at 99.58%. The adsorption capacity sequence of the modified materials are as follows, 1M Na-PNZ > 2M Na-PNZ > 1M Ac-PNZ > 2M Ac-PNZ. The temperature used in the modification appears to have a significant effect on the adsorption capacity of the modified PNZ samples, the increase in temperatures resulted to a decrease in the uptake of copper.

Austenitic Stainless Steel Grade 304 which is used for power plants boiler pipes often occurs creep phenomenon that caused a decrease in performance due to work at elevated temperatures. Surface coating of SUS 304 with Metal Matrix Composites Coating feedstock material 60%NiCr + 40%Cr₃C₂ is deposited using high-velocity oxygen fuel (HVOF) technique. The post-annealing process at 600°C at an argon atmosphere, holding time for 3 hours, and cooling in the furnace. Creep resistance test was carried out at a temperature of 550°C with a load of 54 kg for 10080 hours on three specimens, i.e non-spray, as-spray, as-annealed, then followed by microstructure hardness testing and porosity observation. As-annealed specimens were assessed that the lowest creep resistance value, increased hardness in the coating and substrate and decreased the percentage of porosity in the coating.

Microstructure evolution and pitting corrosion behavior in repeated TIG welding cycles of UNS32760 super duplex stainless steel were studied. The microstructural evolution was observed through optical electron microscope. Meanwhile, pitting corrosion was investigated by means of potentiodynamic polarization and gravimetric test. The specimens were evaluated to simulate repeated welding cycles of original weld, Repair-1 (R1), Repair-2 (R2) and Repair-3 (R3) respectively. The result show that the chromium nitride precipitates starts appear in heat-affected zone R-2 welding cycles which followed by the growth of metastable pits.

This paper presents a failure analysis of reducer weld-joint leakage for liquid outlet of slug catcher. The leak point was found on the area of weld joint with position relative to clock position from 9 to 3 o’clock. In order to determine morphology and mechanisms of crack were observed through laboratory tests including chemical composition test, weld macro analysis, microstructure analysis, and corrosion product analysis. Failure analysis result was found that corrosion process consumed the root weld material and cause leakage. The corrosion is occurred due to combination effect of galvanic cell, root weld microstructure, turbulence and corrosive fluids. Scaling was found based on scale analysis. Therefore the pH was indicated high enough and showed the small chance for corrosion due to carbon dioxide (CO₂). Detailed investigation also revealed that the inconsistent of weld root which resulting excessive root penetration over 3 mm. An excessive weld root about 5.6 mm is observed which was as result of improper instant repair. This profile of weld root will disrupt the flow and cause the weld root to be more anodic and vulnerable to corrosion.

Hydrogen is one of the future energy because it is enviromentally friendly. However, there still some problem in the storage method of hydrogen. In its development, there are many candidates that are still in research as a hydrogen storage medium. Also in several studies, it was found that Silicon based material is a promosing candidate. In this study we conduct the effect of various pressure to the adsorption of hydrogen on Silica with molecular dynamics simulation using Lennard-Jones potential. The simulations indicate that Silica has a good hydrogen storage capability where pressure and time affect the amount of hydrogen adsorbed.

Technology of Severe Plastic Deformation (SPD) has emerged as a widely known procedure for the fabrication of ultrafine grained metals and alloys. Equal Channel Angular Pressing (ECAP) are one of methods of SPD has been developed for many applications; military devices, aerospace and automotive components. This paper examines recent developments related to the use powder of Aluminum alloys processed by consolidation-ECAP, for grain refinement; Al-5Mg, were compared by another type of Aluminum, which has also been researched. Characterization by mechanical, physical and microstructured. In the current study powder of material wrapped in copper capsule to be compressed and heated at a temperature of 400°C in hot press under the pressure of 450-500 MPa. Afterward the powder in solid condition was cooled in the air. The sample results of Aluminum by ECAP process then followed heat treatment with type Annealed, for heating at a temperature of 346°C for 1,5 continuing 415°C during 2 hours followed by heating at a temperature of 205-230°C for 4 hours. This paper describes the effect of heat treatment on the characteristics of the powder material on Al-5Mg are based on changes in the mechanical properties and microstructures.

God lavishes the country with abundant mineral resources, so we proudly say “what do we not have?”. But on the other hand, there are still many residents of this country who are still far below the poverty line. Of course, a follow-up question “what’s wrong?”. The research method used is qualitative method used through descriptive explorative approach. Explorative descriptive approach is done by document study. After the research concludes that there has been a “mismanagement” of mineral resources management, every mineral resource management policy should be based on the principles of good governance which are the principles of good governance, namely: 1) Participation, 2) Rule of law, 3) Transparency, 4) Responsive, 5) Consensus Orientation, 6) Equity, 7) Effectiveness and efficiency, 8) Accountability, 9) Strategic vision.

Despite of the ability of cow bone and coconut shell to be able to be processed into a charcoal, so far these have been only used as fuel or left aside becoming waste, in order to improve the economy value of cow bone and coconut shell waste, it requires processing into a charcoal. The cow bone and coconut shell can be obtained from copra farmers and cow slaughtering house farmers. In this research cow bone and coconut shell charcoal were used as carbon sources to improve low carbon steel hardness. The objective of this research was to find out the influences of temperature and charcoal composition to low carbon steel hardness. A process to use in this research was pack carburizing by using cow bone and coconut shell charcoal and applied temperatures of 900°C, 950°C, and 1000°C during 3 hours of retention. After pack carburizing, the %C content was improved between 0.710% and 1.20%. This improvement was followed by hardness value up to 64.04 kgf/mm² at 900° C, 64.20 kgf/mm² at 950°C, and 64.30 kgf/mm² at 1000°C.

The use of clay minerals as the main raw material for pottery and sand additives has many weaknesses, among others, easy to crack, have high water absorption and low compressive strength. Therefore it is necessary to develop a better method of making traditional ceramics by providing additional materials such as mineral feldspar. Mineral feldspart can be used as a ceramic raw material because it is functional as filler and glass forming phases. Clay and mineral feldspart raw materials were analyzed using XRF method, followed by mixing with the composition of clay soil mixture as much as 65% compared to feldspart by 35%, printed with the shape of cube size 50x50x50mm. Drying in oven with temperature 110°C for 8 hours. Combustion in muflle furnace at temperature variation is 800°C, 900°C, 950°C and 1000°C and holding time is 2 hours, 3 hours, 4 hours and 5 hours. Test of compressive strength and porosity is done to see the physical properties of pottery ceramics and characterization by using XRF and XRD. The result of compressive strength test shows the temperature of 1000°C with 3 hours reaches the optimum value of compressive strength which is 9.52 Mpa, while the porosity value reaches the optimum point at heating temperature 1000°C with time of 5 hours that is equal to 16,19%. Characterization of XRF shows that ceramic pottery contains SiO₂ of 64.074%, and Al₂O₃ of 25.287% according to XRD characterization indicates the dominant phase formed by mineral quartz or silica oxside (SiO₂).

This study investigates the effect of surface modification on the surface charge of the natural zeolites (PNZ) from SAILE Industries in the Philippines by utilizing the zeta-potential technique. The SM-PNZ is prepared to be utilized in the adsorption of anionic aqueous solutions like gold cyanide [Au(CN)^2-] solutions from gold extractive companies. The experiment was designed by converting natural zeolites into its Na-form and modified using cetyl trimethylammonium bromide (CTAB), a micelles-forming surfactant, with dosages equal to 100% and 200% of ECEC (external cationic exchange capacity) of the PNZ. Further characterization of the adsorbents by SEM shows a plate-like morphology. The zeta-potential of the SM-PNZ material shows a decreased negative surface compared with the unmodified PNZ. The percentage recovery of gold cyanide to the PNZ, SM-PNZ (100) and SM-PNZ (200) was 22%, 45% and 40% respectively. Surface modification has shown to improve the adsorption of the PNZ by decreasing the negative potential of the PNZ and increasing the affinity of the SM-PNZ to anionic solutions.

This study was conducted to determine the effect of andesite stone substitution on compressive strength paving block. The percentage of andesite substitution of cement by 10, 20, 30, 40, and 50% by weight of cement. Andesite rock after calcination was characterized using XRD (X-Ray Diffraction). The results of XRD analysis after calcination at the calcination temperature of 900°C have formed muscovite, hedenbergite, and microcline phases. The highest compressive strength of the paving block is found in the substitution of andesite stone of 10% of age 28 days and the lowest compressive strength is in the substitution of andesite 50% of 7 days. This decrease is due to the excessive SiO₂ content will bind to the free CaO contained in the cement and form Ca(OH)₂. Ca(OH)₂ causes reduced paving block density due to the formation of air cavities. Besides the high FAS factor and the gradation of sand size also affect the decrease of compressive strength of paving block.

The existence of geometric complexity in the longitudinal direction makes 3D Limit Equilibrium Method (LEM) able to depict conditions in the field well and obtain Safety Factor (SF) that is more representative than the 2D limit equilibrium method. Safety factor calculations are not only influenced by the Direction of Sliding (DoS), but also by the location of the slip surface. Therefore, determining the location of the slip surface is important in the 3D limit equilibrium method. In this study, the method used for generating slip surfaces is a grid search where variations are made on the number of grid points and the radius increments to determine the effect of these two variables on the determination of safety factor and estimated sliding volume. Based on the results of the study, it can be stated that the greater the number of grid points and the radius increments, the estimated sliding volume will be more precise, while the calculation of safety factor is only affected by the number of grid points where the greater the number of grid points, the search of critical slip surface will be more accurate.