-
Studies on Acidic Leaching of Waste Mobile Phones
Fatma Arslan,
Kudret Tahsin Perek,
Cuneyt Arslan,
Ilyas Emir Cuhadar,
Armagan Altun
Issue:
Volume 7, Issue 2, June 2022
Pages:
36-42
Received:
14 March 2022
Accepted:
1 April 2022
Published:
14 April 2022
Abstract: The consumption of mobile phones is increasing day by day and the replacement speed is also accelerating. Thus, a lot of old mobile phones and their parts need to be processed. Mobile phones contain more than 40 elements and/or materials. This experimental study aims to establish the possibilities of recovering valuable metals from waste mobile phones by using acidic leaching. The process steps include dismantling of waste mobile phones, pre-processing to liberate the materials, and directing them to final treatment processes. Prior to leaching tests, the PCBs of waste mobile phone sample are chemically analyzed and its metal contents are found as 33.22% Cu, 9.42% Fe, 1.86% Zn, 2.77% Ni, 1.63% Al, 0.4% Pb, 0.02% Co, 0.14% Ag, and 251.2 ppm Au. In the leaching experiments, sulfuric, nitric, and hydrochloric acids are used. In the sulfuric acid leaching experiments, effects of acid concentration, temperature, hydrogen peroxide addition, and leaching periods on metal dissolution efficiencies are investigated. Results are compared and discussed in relation to the types of acids. XRD analyses of feed material and leach residues are also carried out. As a result of this experimental study, 97.9% Fe leaching in 8 M H2SO4 solutions, 89% Pb, 100% Ni, 90.4% Co, and 4.1% Cu leaching in 1M HNO3 solutions, 100% Pb, and 100% Al leaching in 4 M HCl solutions in one hour are found. In conclusion, sequential leaching with different acids is recommended for the effective leaching of all metals.
Abstract: The consumption of mobile phones is increasing day by day and the replacement speed is also accelerating. Thus, a lot of old mobile phones and their parts need to be processed. Mobile phones contain more than 40 elements and/or materials. This experimental study aims to establish the possibilities of recovering valuable metals from waste mobile pho...
Show More
-
Design of Air Table Equipment for the Separation of Metal Minerals by Gravity Concentration with Wind Media
Taufik Arief,
Hasjim Machmud,
Eva Oktinasari
Issue:
Volume 7, Issue 2, June 2022
Pages:
43-49
Received:
23 April 2022
Accepted:
14 May 2022
Published:
24 May 2022
Abstract: This research is an air table device design and laboratory scale experimentation. Air table is a tool to separate valuable minerals from mineral impurities of tin ore based on differences in specific gravity, shape and size using air/wind media. The design of the tool starts from the design and manufacture of the table as well as the manufacture of other main components, including; feed hopper, ventilation and tertoron cloth. Then the next stage is the calculation and selection of a table driving motor in the form of an electric motor with a pulley system and the last is the calculation and selection of a blower machine as a machine that functions to blow pressure into the table. The installation of the air table was carried out at the Materials Processing Laboratory, Faculty of Engineering, Sriwijaya University. To determine the success rate of designing and evaluating the performance of the air table, experiments were carried out using several combinations of variables, including table slope, feed weight (grams), and processing time (minutes).). The experimental process of the tool was tested using tin ore samples from the remaining tin ore washing (SHP) from the Toboali Washing Plant, PT Timah, Tbk. The experimental results show that the performance of the tool shows good but not optimal performance where the lowest concentrate gain is achieved at 50.20% and the highest is 79.14% at a deck slope of 5.8°, feed weight is 600 grams and processing time is 15 minutes. The results of the evaluation show that the air table device functions relatively well, but needs to be improved and adjusted for more varied variables as well as representative samples and quantities of tin ore, so as to produce maximum concentrate and grade.
Abstract: This research is an air table device design and laboratory scale experimentation. Air table is a tool to separate valuable minerals from mineral impurities of tin ore based on differences in specific gravity, shape and size using air/wind media. The design of the tool starts from the design and manufacture of the table as well as the manufacture of...
Show More
-
Mineralogical and Chemical Quantification of Waelz Slag
Peter Onuk,
Frank Melcher
Issue:
Volume 7, Issue 2, June 2022
Pages:
50-60
Received:
20 April 2022
Accepted:
18 May 2022
Published:
9 June 2022
Abstract: Globally, roughly 1.75 million tons of waelz slag per year are produced from 35 waelz kilns. The increasing costs for landfilling, changing environmental concerns and a focus on sustainable production foster an investigation of this by-product to investigate if at least parts of it can be used as a raw material. Waelz slags are highly variable in the shape of the phases within the different samples, ranging from euhedral to spherical habitus. The variation in phase chemistry within the different samples is marginal. The main phases of `normal` waelz slag are ferrite solid solutions with different endmembers in the Zn-Mn-Mg-Ca system, followed by belite (C2S), wustite and metallic iron. Zn-sulphide, chromium spinel, alite (C3S), aluminate and zinc oxide can be considered as minor or accessory phases. The differences in the feed material (stainless steel filter dust) correlate with the increased amount of Ni (up to 3 m/m%) in metallic iron phases. Waelz slag that was treated with compressed oxygen and subsequently cooled in air shows differences in phase habitus (mostly euhedral) and phase chemistry (absence of wustite and metallic iron). The characterization of waelz slags involves several analytical steps. Among these, reflected light microscopy and SEM phase identification are regarded as obligatory.
Abstract: Globally, roughly 1.75 million tons of waelz slag per year are produced from 35 waelz kilns. The increasing costs for landfilling, changing environmental concerns and a focus on sustainable production foster an investigation of this by-product to investigate if at least parts of it can be used as a raw material. Waelz slags are highly variable in t...
Show More
-
Research Progress of Fusion Welding Techniques for TiNi Alloy to Steel
Zhijin Guo,
Yan Zhang,
Jianping Zhou,
Daqian Sun,
Hongmei Li
Issue:
Volume 7, Issue 2, June 2022
Pages:
61-64
Received:
31 March 2022
Accepted:
16 April 2022
Published:
21 June 2022
Abstract: This review aimed to provide a comprehensive overview of the recent progress in fusion welding of steel and heterogeneous metals and to introduce current research and application. Amongst numerous metals, TiNi shape memory alloys and steel have been most heavily investigated for producing excellent joints. However, the base materials on both sides of the traditional fusion welding must melt and the large melting point difference between the two seriously affects the weld formation. The metal compounds formed by the base materials on both sides also hinder the improvement of the mechanical properties of the joint. This review focused on the fundamental understanding of the microstructural characteristics, processing and property relationships in the welding and joining of heterogeneous joints. The primary problem finding intermediate metals with enhanced plasticity and toughness to improve the formation of joints. Welding of light metals and high specific strength metals has a wide range of applications in the aerospace industry, it is committed to reducing the quality of flight equipment.
Abstract: This review aimed to provide a comprehensive overview of the recent progress in fusion welding of steel and heterogeneous metals and to introduce current research and application. Amongst numerous metals, TiNi shape memory alloys and steel have been most heavily investigated for producing excellent joints. However, the base materials on both sides ...
Show More
