Study on the adsorption of heavy metal ions Pb2+, Zn2+, Co2+, Ni2+from the aqueous solution of the copolymer prepared by gamma induced radiationpolymerization

Copolymer hydrogel (PVA-g-AA) having varied PVA (Polyvinyl alcohol) and AA (Acrylic acid) content is prepared by gamma induced radiation polymerization. The parameters affecting the gel fraction yield have been studied. The gel fraction and the swelling property are found to be 92.39 and 905% respectively at an absorbed dose of 20 kGy. Structural and property characteristics were determined by Fourier Transform Infrared (FTIR) spectrometer and Differential Scanning Calorimetry (DSC). The surface morphology of PVA and copolymer has been studied with Scanning Electron Microscope (SEM). The factors affecting the metal uptake such as pH, time, and initial feed metal concentration were investigated. It is found that at pH 5 and after 240 minutes the maximum adsorption amount are 178, 161, 117, and 110 mg/g for Pb2+, Zn2+, Co2+, and Ni2+ respectively.

Pyrolysis of Microalgae Chlorella sp. using Activated Carbon as Catalyst for Biofuel Production

Microalgae, as a potential raw material for biofuel, has several advantages compared to other biomass. One effective way to convert microalgae into biofuel is by thermal cracking or pyrolysis, and using a catalyst or not. So far, studies on the use of microalgae, that are converted into biofuels, is still use highly concentrated catalysts in packed bed reactors, which is not economical. Therefore, the aim of this study is to convert Chlorella sp. into biofuels with conventional pyrolysis without and using an activated carbon catalyst using packed bed reactor with bubble column. The reaction temperature is 400–600 °C, pyrolysis time is 1–4 hours, and the active carbon catalyst concentration is 0–2%. The 200 grams of Chlorella sp. and the catalyst was mixed in a fixed bed reactor under vacuum (−3 mm H20) condition. Next, we set the reaction temperature. When the temperature was reached, the pyrolysis was begun. After certain time was reached, the pyrolysis produced a liquid oil product. Oil products are measured for density and viscosity. The results showed that the conventional pyrolysis succeeded in converting microalgae Chlorella sp. into liquid biofuels. The highest yield of total liquid oil is obtained 50.2 % (heavy fraction yield, 43.75% and light fraction yield, 6.44%) at the highest conditions which was obtained with 1% activated carbon at a temperature and pyrolysis time of 3 hours. Physical properties of liquid biofuel are density of 0.88 kg/m3 and viscosity of 5.79 cSt. This physical properties are within the range of the national biodiesel standard SNI 7182-2012. The packed bed reactor completed with bubble column is the best choice for converting biofuel from microalgae, because it gives different fractions, so that it is easier to process further to the commercial biofuel stage. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Granulometric composition predicting models after explosion in open-pit mining

Introduction. Drilling and blasting operations are first in the workflow and significantly determine the economic efficiency of the entire mining and primary processing workflow in the enterprise. The cost of drilling and blasting operations is a significant part of total production costs of large mining companies. In this context, mining engineers today are facing a crucial technological problem, i.e. the reduction of the off-gauge fraction yield after the explosion. Research aims to develop the models which forecast the granulometric composition of the rock mass taken down as the original factor in reducing the economic waste of the entire workflow. Methodology. The parameters which influence the results of rock mass fragmentation and the techniques of rock mass granulometric composition forecasting in the course of drilling and blasting were analyzed. Results. The present paper gives a brief overview of the global mineral output; provides information on the extraction of key types of minerals (mineral fuel, ferrous metals, non-ferrous metals, precious metals, and construction materials), as well as revenues derived from their sale. On the example of domestic companies, approaches to the issue of forecasting the off-gauge fraction yield after the explosion. Summary. Direction for future actions in creating the model forecasting rock mass yield of a certain fraction after the explosion.

Research into the crushing and grinding processes of iron ore with its simultaneous effect by mechanical load and electric field of ultra-high frequency

Main properties of the processes of iron ore destruction in terms of its simultaneous effect by mechanical load and electric field of ultra-high frequency have been studied. That was compared with the case when only mechanical load is applied. Theoretically, it has been proved that in the first case, quartz crystals accumulate more energy, and this effect is manifested mostly in terms of resonance. For the first time, the iron ore samples of cubic geometry were tested using a non-uniform volumetric compression unit. Application of the ultrahigh frequency field resulted in ultimate strength reduction by 1.5 – 2.0 times and significant increase in plasticity of the destruction. At the same time, density of the sample destruction energy in a volume unit is significantly lower than that in the case of mechanical load (1.05 and 2.6 MJ/m3, respectively). There is also a tendency of reducing large fraction yield and increasing fine fraction yield along with the increase up to 11% in iron content in the products after grinding. The results of theoretical and numerous experimental studies have been substantiated the necessity to continue the research and development work on adapting the proposed jaw crusher to the production conditions.

Development of ecologicallyclean technology of iron ores concentration

Actuality of studies on development of new, economically effective technologies of concentration is stipulated by expanding involvement of hard-concentrated and poor by Fe content ores while continuously increasing requirements to the quality of concentrates, obtained of them.An ecologically clean technology of iron ores concentration developed by application of electro-magnetic waves of SHF range, which enabled to intensify the concentration and processing processes, suitable for Lisakovsk deposit ores. Influence of heating by SHF radiation on magnetic properties of Lisakovsk ore concentrate studied.It was determined, that existence of magnetic properties in roasted materials enable to applicate a magnetic separation for concentration and estimate the quality of obtained concentrates, heated in SHF furnaces, depending on magnetic fraction yield. Optimal coarseness of roasted concentrate crushing determined, suitable for further concentration.Comprising of concentration technologies of hydro-goethite ores carried out: deep concentration and concentration by application of SHF heating. Distinctive feature of concentration technologies by SHF heating considered.Advantages of concentration technology of Lisakovsk ores by SHF energy application considered, the main being a possibility of rich low-silicon concentrates allocation, which can be used for complex processing of Lisakovsk ores. A sequence developed, including their separate agglomeration, BF smelting for phosphorous-vanadium hot metal and helenite slag obtaining, suitable for production of alumina and cement as a raw material.