water leaching
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Fuel ◽  
2022 ◽  
Vol 312 ◽  
pp. 122744
Author(s):  
Miguel J. Fernández ◽  
Veronika Chaloupková ◽  
Ruth Barro

2022 ◽  
pp. 105820
Author(s):  
Xiufeng Zhang ◽  
Zhichao Chen ◽  
Sohrab Rohani ◽  
Minyu He ◽  
Xiumin Tan ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7700
Author(s):  
Andrei Shoppert ◽  
Irina Loginova ◽  
Dmitry Valeev

The most promising source of alumina in the 21st century is the coal fly ash (CFA) waste of coal-fired thermal plants. The methods of alumina extraction from CFA are often based on the pressure alkaline or acid leaching or preliminary roasting with different additives followed by water leaching. The efficiency of the alumina extraction from CFA under atmospheric pressure leaching is low due to the high content of acid-insoluble alumina phase mullite (3Al2O3·2SiO2). This research for the first time shows the possibility of mullite leaching under atmospheric pressure after preliminary desilication using high liquid to solid ratios (L:S ratio) and Na2O concentration. The analysis of the desilicated CFA (DCFA) chemical and phase composition before and after leaching has been carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The morphology and elemental composition of solid product particles has been carried out by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). An automated neural network and a shrinking core model (SCM) were used to evaluate experimental data. The Al extraction efficiency from DCFA has been more than 84% at T = 120 °C, leaching time 60 min, the L/S ratio > 20, and concentration of Na2O-400 g L−1. The kinetics analysis by SCM has shown that the surface chemical reaction controls the leaching process rate at T < 110 °C, and, at T > 110 °C after 15 min of leaching, the process is limited by diffusion through the product layer, which can be represented by titanium compounds. According to the SEM-EDX analysis of the solid residue, the magnetite spheres and mullite acicular particles were the main phases that remained after NaOH leaching. The spheric agglomerates of mullite particles with non-porous surface have also been found.


2021 ◽  
Vol 12 (2-2021) ◽  
pp. 111-113
Author(s):  
V. A. Imideev ◽  
◽  
A. O. Berbenev ◽  
P. V. Aleksandrov ◽  
◽  
...  

The article describes a perspective combined method of treatment molybdenite concentrate based on roasting with sodium carbonate and following water leaching process. This method is characterized by almost completely binding of the sulfur compounds into water-soluble sodium sulfate, conversion of molybdenite into water-soluble odium molybdate, and if concentrate contains rhenium - transform into water-soluble sodium perrhenate.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1369
Author(s):  
Tülay Türk ◽  
Zeynep Üçerler ◽  
Fırat Burat ◽  
Gülay Bulut ◽  
Murat Olgaç Kangal

Potassium, which is included in certain contents in the structure of K-feldspar minerals, has a very important function in the growth of plants. Turkey hosts the largest feldspar reserves in the world and is by far the leader in feldspar mining. The production of potassium salts from local natural sources can provide great contributions both socially and economically in the agriculture industry along with glass production, cleaning materials, paint, bleaching powders, and general laboratory purposes. In this study, potassium extraction from K-feldspar ore with an 8.42% K2O content was studied using chloridizing (CaCl2) roasting followed by water leaching. Initially, to produce wollastonite and calcite concentrates, froth flotation tests were conducted on wollastonite-calcite ore after comminution. Thus, wollastonite and calcite concentrates with purities of 99.4% and 91.96% were successfully produced. Then, a calcite concentrate was combined with hydrochloric acid (HCl) under optimal conditions of a 1 mol/L HCl acid concentration, a 60 °C leaching temperature, and a 10 min leaching time to produce CaCl2. To bring out the importance of roasting before the dissolution process, different parameters such as roasting temperature, duration, and feldspar—CaCl2 ratios were tested. Under optimal conditions (a 900 °C roasting temperature, a 60 min duration, and a 1:1.5 feldspar—CaCl2 ratio), 98.6% of the potassium was successfully extracted by the water leaching process described in this article.


2021 ◽  
Vol 49 (12) ◽  
pp. 1839-1849
Author(s):  
Yan-jing LIU ◽  
Ting-gui YAN ◽  
Yan AN ◽  
Wei ZHANG ◽  
Yang DONG

2021 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Stergi Kapelari ◽  
Platon N. Gamaletsos ◽  
Tom Van Der Donck ◽  
Yiannis Pontikes ◽  
Bart Blanpain

To tackle the challenge of bauxite residue (BR), generated during the alumina production, as well as to recover some of its metal content, three combinatory H2-based processes were utilized. Firstly, Greek BR was mixed with NaOH to produce water soluble Na-aluminates and was roasted under pure H2 gas in order to reduce the Fe+3 content. Then the first process combined water leaching and magnetic separation, the second water leaching and melting and the last included wet magnetic separation. The water media resulted in the dissolution of Na-aluminate phases and the production of Al, Na-ion rich leachates. From these, pregnant leaching solutions recovery of Al was 78%, 84% and for the third case it reached 91%. Concerning Na recovery, it could reach 94%. Both melting process and magnetic separation aimed for Fe recovery from the material. The former case however still needs to be optimized, here its concept is introduced. The magnetic fraction, after the dry magnetic separation, varied in Fe content from 31.57 wt.% to 38.50 wt.%, while after the wet magnetic separation it reached 31.85 wt.%.


Fuel ◽  
2021 ◽  
Vol 305 ◽  
pp. 121480
Author(s):  
Jinxia Fu ◽  
Gabriel Allen ◽  
Sarah Weber ◽  
Scott Q. Turn ◽  
William Kusch

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