Ekstraksi limonit dengan metode dua tahap reduksi selektif dan magnetic separation dengan variasi waktu tahan dan suhu rendah

The use of limonite and saprolite nickel ore with low Ni content as raw material for the manufacture of FeNi metal with a content of> 5% Ni has not been widely used. This is because to process limonite and saprolite ore into high levels of FeNi concentrate, it requires greater energy. The purpose of this study was to see the beneficiation process of low grade laterite nickel ore (limonite type, with 1-2% Ni content) at low temperature and holding time with graphite reducing agents and adding additives to iron nickel concentrate and nickel iron concentrates with nickel content above 5%. The method used in this research is to provide services with temperature variations of 250°C, 300°C, and 350°C with a holding time of 60 minutes and 90 minutes in the heat process stage 1 and continued in the heat process stage 2, namely at a temperature of 1150°C with a holding time of 60 minutes. The concentrates and tailings resulted from magnetic separation were then subjected to XRF testing and optical microscopy. With the erasing process and the holding time, the nickel content was quite high, namely 5-6%. With this, it can be neglected that the beneficiation process with this method is very effective and optimal. The levels of Fe in the concentrate obtained from several tests have increased and decreased with the addition of temperature and holding time.

Recovery of waste heat process through the various thermodynamic cycles: A critical review

This review study aimed at short description on most recent research available with regards to waste heat recovery (WHR) area which could be obtained with the help of various power as well as refrigeration cycles. From the literature, it is understood that WHR not only help us to reduce emission effects but even useful in energy saving that can further positively effect to the thermal performance or can be used for different purposes with the help of WHR cycles. Therefore, present study mainly discusses the literature with regard to application of various thermodynamic cycles widely employed these days for the WHR processes.

Quality Testing of Solid Soap with Mango Leaf Extract (Mangifera indica L.) Produced by Hot and Cold Processes

Mango leaves (Mangifera indica L.) contain alkaloids, flavonoids, stereoid compounds, polyphenols, tannins and saponins. The saponin content in mango leaves is able to act as a natural foaming agent. Mango leaf extract can be added in the manufacture of solid soap to produce natural soap. Making solid soap can be done through heating (heat process) and without heating (cold process). This study aims to determine the process of making solid soap in a hot and cold process, comparing the best quality soap analysis based on quality including organoleptic testing and pH balance. The results showed the average quality of the best soap through the heat process with the results of organoleptic tested.

Optimization of the Heating Phase for the Bi-frequency Heat Treat Process of a Gear

In this contribution, we attempt to optimize the heat process of a gear. The goal is to evaluate the best use of two frequencies to complete the heating phase in the least amount of time achieving a uniform distribution of temperature in the treated area of the gear. Assuming the application of the appropriate cooling, this temperature distribution will lead to the appropriate hardness along and between the teeth of the gear. A 3D model of part of the gear wheel is modelled in a multiphysics magneto-thermal analysis. The two frequencies used for the heating are first evaluated. In the optimization process, the duration of the application for each frequency is a parameter. Temperatures are evaluated through the heating process at selected locations as constraints of the optimization process.

Energy efficiency improvement in the system for drying baker`s yeast

Drying processes are one of the main consumers of heat energy in production. Any decreases in heat consumption during the drying process will considerably decrease production costs. This study analyzes the high consumption of heat in the drying of baker`s yeast. The main task is to minimize the energy demand and lower the price of the final products with partial heat recovery. These changes will require system modifications. One of the most popular and effective methods that can be used in this case is heat process integration with Pinch Technology. In this study, a reference system was simulated with a mathematical model and analyzed for waste heat streams.This paper suggests the redesigning of a drying system for production of active dry yeast. Selected streams that satisfy conditions for heat process integration were involved in the evaluation for a better solution. Two different scenarios were proposed as possible solutions. The suggested solutions are retrofit designs of Heat Exchanger Networks. These Heat Exchanger Networks include already installed heat exchangers as well as new heat transfer units. The selection of better design was made with economic analysis of investment. The proposed scenarios of the analyzed sub-system give improvement in heat energy recovery. The best determined solution reduces the cost and thus has the highest profitability, but not the highest heat energy recovery.