Thermal analysis of Indonesian copper sulphide

The development of extracting hydrometallurgical process for copper sulphide mineral becomes one of the promising fields, not only for the copper production but also for the production of metal by-products. The advantage of the thermal analysis is to get the phase form of the minerals on a certain temperature. With this result, the chosen metal can be selectively extracted. The goal of this study is to understand the thermal reaction of the copper sulphide as the basic data to develop a process flowsheet of extracting copper and other important metals from the copper concentrates by using an alternative new hydrometallurgy process to increase the value of the minerals. The thermal behaviour was investigated by simultaneous thermal analysis consisting of differential scanning calorimetry (DSC) in combination with thermo gravimetry (TG) and fourier transform infrared (FTIR) spectroscopy. Samples were pre-treated by roasting at the several temperature transitions and subsequently characterized by XRD and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS).

Development of a Pre-Verified EPD Tool with Process Simulation Capabilities for the Aggregates Industry

This paper has two aims: to describe the current status and challenges of aggregates producers regarding the analysis and communication of environmental information of their products and to present a layout of a pre-verified tool with simulation capabilities that could assist aggregates producers with their environmental goals. Semi-structured interviews were conducted with three Swedish aggregates producers, an aggregates customer, and an expert agency. Additionally, published Environmental Product Declarations (EPDs) for aggregates and the EN 15804:2012 + A2:2019 were studied to reveal current practices and upcoming changes due to the updated standard. The synergies with process simulations were explored as a step towards using the EPD framework for continuous improvement of aggregates production. The interviews indicated that the main challenge for aggregates producers is the lack of easily available plant data for environmental calculations and clearly defined environmental goals at each plant. The proposed tool uses a common process flowsheet for both EPDs and simulations and has a pre-defined LCA module. The use of such a tool is expected to raise the environmental interest at aggregates plants and improve collaboration with LCA experts. Since the analysis is based on the Swedish aggregates market, the interview results are not directly generalizable to the European context.

Membrane-Assisted Methanol Synthesis Processes and the Required Permselectivity

Water-selective membrane reactors are proposed in the literature to improve methanol yield for a standalone reactor. However, the methanol productivity is not a precise metric to show the system improvement since, with this approach, we do not consider the amount of energy loss through the undesirable co-permeation of H2, which could otherwise remain on the reaction side at high pressure. In other words, the effectiveness of this new technology should be evaluated at a process flowsheet level to assess its advantages and disadvantages on the overall system performance and, more importantly, to identify the minimum required properties of the membrane. Therefore, an equation-based model for a membrane reactor, developed in Aspen Custom Modeler, was incorporated within the process flowsheet of the methanol plant to develop an integrated process framework to conduct the investigation. We determined the upper limit of the power-saving at 32% by exploring the favorable conditions wherein a conceptual water selective membrane reactor proves more effective. Using these suboptimal conditions, we realized that the minimum required H2O/H2 selectivity is 190 and 970 based on the exergy analysis and overall power requirement, respectively. According to our results, the permselectivity of membranes synthesized for this application in the literature, showing improvements in the one-pass conversion, is well below the minimum requirement when the overall methanol synthesis process flowsheet comes into consideration.

THERMAL INTEGRATION OF COMPRESSION REFRIGERATION UNITS IN DAIRY FACILITIES

The heat integration of an ammonia compression refrigeration unit, that is used in different dairy facilities, was carried out by the pinch analysis methods. The schematic diagram of such unit with a cooling capacity of 1000 kW was taken as a basis. The main cycle temperatures, refrigerant consumption and its specific heat capacity were calculated for a given refrigerating capacity. Based on these data, a stream table was formed, that included a hot stream of a refrigerant – ammonia – and also two cold streams: water for chemical water treatment and water for technology. The hot stream of ammonia was divided into three streams: cooling of ammonia vapors, condensation and subcooling. Heat capacities flowrates and heat loads (stream enthalpy change) of the streams were determined. The minimum temperature difference in heat exchangers DTmin = 8°С was determined on the basis of technical and economic calculations for this process. The composite curves were plotted for the minimum temperature difference. The pinch temperatures were determined by the problem table algorithm for the hot and cold streams. The minimum values of hot and cold utilities load (QHmin and QСmin) were determined. The heat recovery capacity was determined, which was 701.8 kW. A grid diagram was built and heat exchangers are arranged in accordance with CP and N rules. The retrofit of process flowsheet is proposed on the basis of the grid diagram that includes the installation of three heat exchangers, one cooler and two heaters to achieve the target temperatures and flow rates. The use of Alfa Laval plate heat exchangers is proposed as heat exchange equipment. The payback period of the design is about two years.

Extraction of Non-ferrous Metals from Underspoil Waters

he focus of the study was the acidic underspoil waters of Safyanovskaya copper JSC containing 0.17 g/l of copper and 1.8 g/l of zinc (pH 2.8–2.9). The purpose of the work was research and development of water purification technology from impurities (copper, zinc, aluminum, iron, manganese), suggesting the possibility of copper and zinc extraction in the form of commercial products. The process of copper extraction by cementation with metallic iron was studied. It was shown that this method could allow to extract 94–95 % copper into a concentrate. The zinc extraction from solution after copper removal was studied by precipitation with NaHS, Na2CO3, NaOH and CaO. For economic reasons it is recommended to make zinc precipitation in two stages with CaO in order to produce cake containing 15–21 % Zn with extraction 80–87 %. This cake can be utilized at zinc processing plant. A process flowsheet for acidic underspoil waters, including copper cementation and the precipitation of zinc cake, has been developed. According to this scheme, mother liquor from zinc precipitation should be treated with lime until pH reaches 10–10.5, followed by pulp settling. As a result, purified water of the following composition is obtained, mg/l: zinc – 0.05, copper – 0.01, aluminum – 0.02, iron – 0.02, manganese – 0.05. Keywords: underspoil water, copper, zinc, iron, cementation, calcium oxide, concentrate, precipitation

Economic and Socio-Environmental Benefits of Dry Beneficiation of Magnetite Ores

In our previous studies, we demonstrated the performance of novel superfine crusher and pneumatic planar magnetic separator as energy-efficient technologies for dry processing of magnetite ores. The present study investigates the economic and socio-environmental benefits of applying these technologies in conceptual dry magnetite ore processing flowsheet. The outcome of the study is compared with that of a conceptual wet processing flowsheet for the same ore. The cost estimations used are based on the Brook Hunt C1 methodology whilst revenue estimations are based on the Platts Iron Ore Index specification. The demonstrated economic and socio-environmental benefits show that dry processing flowsheet offers significant energy and cost savings and improved revenue generation compared with the wet process flowsheet. These findings are vital to the magnetite industry, particularly in water- and energy-scarce regions as a benchmark for future studies aimed at deepening and expanding the knowledge base of dry beneficiation of magnetite ores.