Determination of heavy metal elements concentration in soils and tailing sediments from lateritic nickel post-mining areas in Motui District, Southeast Sulawesi

Heavy metal elements concentration study has been determined from soils and tailing sediments in laterite nickel post-mining area in Motui District Southeast Sulawesi. This study aimed to determine the concentration of some heavy metal elements, especially Fe, Co, Mn and Cr, from surface soils sediments in waste dump sites and tailing sediments in settling ponds from lateritic nickel post-mining areas. A total of 20 samples consisting of 18 soil samples and 2 tailing sediments samples were systematically collected for the study. The soil samples from the waste dump site profile were collected from 3 layers which were divided based on the colour of the soils from top to bottom, namely Layer C, Layer D and Layer E. Six soil samples were taken from each layer with space between each sample in one layer was about 50 – 60 cm. The samples were sent to the laboratory and analysed using Atomic Absorption Spectrometer (AAS) method to determine the concentration of heavy elements. Metal-bearing minerals detected from the bedrock consists of chromite, manganese, magnetite and limonite which are responsible for the Cr, Mn and Co, and Fe content, respectively. The result showed that Fe content is significantly higher in soil samples from Layer C and tailing sediments with dark red to brown in colour, suggesting the strong relation between Fe content and colour index. The general element mobility trend showed that Mn and Co are positively correlated in soil sampling from all layers and tailing samples, whereas Fe and Cr show a negative correlation trend in Layer C, D and tailing sediments but positively correlated in Layer E.

Preliminary Study of Scandium Enrichment in Lateritic Profile from Weathered Ultramafic Rock in Lapaopao Area Kolaka Regency of Southeast Sulawesi

Scandium is one of the rare earth elements which is currently widely used for various needs such as the aerospace industry, solid oxide fuel cells, electronics industry and in metallurgical applications. Generally, Scandium appears in small amounts so its structural role in the host minerals cannot be readily identified. Some studies reported the scandium extraction from lateritic nickel deposit where may contain considerable amount of scandium in addition to nickel and cobalt. Preliminary research of scandium enrichment has been investigated from the ultramafik rock indicates that an enrichment of scandium concentration was found in the red limonite. The aim of this study was to investigate the potentially enrichment of scandium mineral from nickel laterite in Lapaopao Area. There are a total of 38 samples from 1 (one) diamond drill holes which represent the limonite, saprolite and bedrock profiles have been collected and studied to investigate the distribution pattern of Sc grades within the lateritic profile. These samples are being analized by XRF for major and minor element and ICP-OES method for rare earth element assaying. The study has confirmed that scandium is enriched in limonite layer of weathered ultramafic laterite profile. The scandium content from the ultramafic bedrock is 15 ppm and has enriched until 81 ppm of scandium in the limonite layer.

Studi Literatur Potensi Pemanfaatan Terak Nikel (Slag Nikel) sebagai Agregat pada Mortar dan Beton

The increasing of infrastructure development has an impact on increasing demand for construction materials. Generally, construction materials come from nature and still being exploited, which could lead to environmental degradation. Visually, nickel slag resembles gravel and sand which can be used as an alternative material. Therefore, this literature study aims to determine the characteristics and potential utilization of nickel slag gathered from Indonesian lateritic nickel ore and its application as an aggregate in mortar and concrete. The method used in this study is a review of several literatures from a reputable digital publication database with the keywords "terak nikel" and "nickel slag". In addition, several criteria are also used as filters in order to get the more focused literatures. Although the fluctuations in its mechanical properties was reported, it can still be overcome by using slag nickel slag as coarse and fine aggregate simultaneously. The results also show that nickel slag can be used as fine or coarse aggregate in concrete up to 100% content as well and as fine aggregate in asphalt application mortars up to 50% content.

Data Analytics Approach for Understanding the Relationship Between the Thermal and Energy Performance in Ferronickel Large Industrial Rotary Kilns

The ferronickel production process closely resembles that of cement and steel. Published studies typically take the developments of the latter and adapt them to ferronickel. However, few open publications allow for a proper understanding of the calcination and reduction of lateritic nickel minerals. This research analyzes the operation of a rotary kiln calciner of 135 m length, a diameter of 6 m, and a mass flow rate between 170 and 180 t/h of partially dry mineral. The calciner uses coal as a reducing agent and natural gas as a thermal energy source. Principal component analysis (PCA) was used in a large industrial dataset to determine the variables with a greater influence on the process performance. Also, k-means clustering is used to locate operation points favorable to calcined mineral production. Results show that the most relevant variables are mineral and gas temperatures and the mass flow rates of air, mineral, natural gas, and coal.