Effective Extraction of Vanadium and Chromium from High Chromium Content Vanadium Slag by Sodium Roasting and Water Leaching

2016 ◽  
Vol 863 ◽  
pp. 144-148 ◽  
Author(s):  
Ming Li ◽  
Liang Xiao ◽  
Jing Jing Liu ◽  
Zhi Xin Shi ◽  
Zi Bi Fu ◽  
...  
Keyword(s):  
Chromium Content ◽  
Leaching Rate ◽  
Vanadium Slag ◽  
Water Leaching ◽  
Sodium Salts ◽  
High Chromium ◽  
Effective Factor ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Roasting Time

The extraction of vanadium and chromium from high chromium content vanadium slag by salt roasting and water leaching process has been investigated, which uses mixed sodium salts (Na2CO3 and NaOH) as additive agent in roasting process. The mineralogical morphology was prospected by TG-DSC, XRD, SEM and EDS. The oxidation of slag and transversion of V/Cr-containing phase and sodium salts have been discussed. It has been demonstrated that the presence of NaOH contributes to decompose spinel and olivine phases, which is beneficial to reduce the roasting temperature and elevate V, Cr leaching ratio. The roasting parameters have been studied as a function of roasting temperature, roasting time and ratio of alkali, in which the roasting temperature is the most effective factor on the leaching rate of vanadium and chromium. Under the optimum condition, the leaching rates of V and Cr reached 95.8% and 97.6%, respectively.

Microwave Roasting and Acid Leaching of Vanadium and Chromium from High Chromium Vanadium Slag with CaCO3

2019 ◽  
Vol 294 ◽  
pp. 86-91
Author(s):  
Hui Yang Gao ◽  
Tao Jiang ◽  
Ying Zhe Xu
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Vanadium Slag ◽  
Sulfuric Acid Leaching ◽  
High Chromium ◽  
Microwave Roasting ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Irradiation Technology ◽  
Roasting Time

In this study, microwave irradiation technology was used for the calcification roasting followed by sulfuric acid leaching process. The effect of roasting temperature, m (CaO)/m (V2O5), and roasting time on the leaching ratio of vanadium were investigated and the roasted samples were characterized by TG-DSC, XRD, and SEM. The leaching ratio of vanadium can be significantly enhanced with the increasing in roasting temperature, m (CaO)/m (V2O5), and roasting time. The leaching ratio of chromium decreased with roasting temperature and increased with m (CaO)/m (V2O5), and roasting time. The optimal roasting parameters were roasting temperature of 850 °C, the m (CaO)/m (V2O5) of 0.85, and roasting time of 90 min. Under the optimal roasting parameters, the leaching ratio of vanadium reached 88.81%. While the leaching ratio of chromium is 3.98%. During roasting process, vanadium is oxidized to acid-soluble CaV2O5, Ca2V2O7, and CaMgV2O7. After leaching, chromium mainly exists in form of chromohercynite (FeCr2O4) and chrome-manganese spinel (Mn1.5Cr1.5O4) in leaching residues.

Sequential extraction of vanadium and chromium from chromium-bearing vanadium slag through two-stage soda roasting-water leaching

2018 ◽  
Vol 115 (6) ◽  
pp. 607
Author(s):  
Helin Fan ◽  
Huamei Duan ◽  
Wenjie He ◽  
Dengfu Chen ◽  
Tao Liu ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Extraction Process ◽  
Water Soluble ◽  
Leaching Rate ◽  
Vanadium Slag ◽  
X Ray Diffraction ◽  
Water Leaching ◽  
Two Stage ◽  
Experimental Conditions ◽  
Roasting Process

The sequential extraction of vanadium and chromium from the chromium-bearing vanadium slag through two-stage soda roasting-water leaching was proposed. The precipitation order and thermodynamic stability of Cr-spinel and V-spinel were thoroughly calculated with FactSage 6.3 software. The mechanism of the sequential extraction process is further determined by X-ray diffraction (XRD). Thermodynamic calculations show that the precipitation order of main phases in the chromium-bearing vanadium slag is as follows: Cr-spinel → V-spinel → Fe-olivine, while the priority of the reaction between main phases with Na2CO3 follows the order of Fe-olivine → V-spinel → Cr-spinel. XRD results reveal that the vanadium-bearing phase in roasted slag is water-soluble NaVO3, while the chromium-bearing phase in roasted slag is Cr-spinel ((Mn, Fe) Cr2O4) and solid solutions ((Fe0.6Cr0.4)2 O3) with the soda amount of 21% and temperature of 800 °C. The different evolution route of vanadium-bearing phase and chromium-bearing phase during the roasting process ensures preferential extraction of vanadium from the chromium-bearing vanadium slag. The leaching rates of vanadium and chromium reach 89.36% and 4.91% with optimized experimental conditions. The high leaching rate of vanadium and low leaching rate of chromium show good results of preferential extraction of vanadium from the chromium-bearing vanadium slag.

Phases Transition and Consolidation Mechanism of High Chromium Vanadium-Titanium Magnetite Pellet by Oxidation Process

2016 ◽  
Vol 35 (7) ◽  
pp. 729-738
Author(s):  
Jue Tang ◽  
Man-sheng Chu ◽  
Cong Feng ◽  
Feng Li ◽  
Zheng-gen Liu
Keyword(s):  
Phase Transition ◽  
Oxidation Process ◽  
Consolidation Process ◽  
High Chromium ◽  
Oxidized Pellet ◽  
Three Stages ◽  
Roasting Temperature ◽  
Vanadium Titanium ◽  
Roasting Time ◽  
Titanium Magnetite

AbstractBased on the fundamental characteristics of high chromium vanadium-titanium magnetite (HCVTM), the effects of roasting temperature and roasting time on the phase transition and oxidation consolidation during the oxidation were investigated systematically. It was shown that the oxidation of HCVTM pellet was not a simple process but complex. With increasing roasting temperature and time, the compressive strength of oxidized pellet was improved. The phase transition during oxidation was hypothesized to proceed as follows: (1) Fe3O4 → Fe2O3; (2) Fe2.75Ti0.25O4 → Fe9TiO15 + FeTiO3 → Fe9TiO15 + Fe2Ti3O9; (3) Fe2VO4 → V2O3 → (Cr0.15V0.85)2O3; (4) FeCr2O4 → Cr2O3 → Cr1.3Fe0.7O3 + (Cr0.15V0.85)2O3. The oxidation consolidation process was divided into three stages: (1)oxidation below 1,173 K; (2) recrystallization consolidation at 1,173 – 1,373 K; (3) particle refining recrystallization-consolidation by the participation of liquid phase at 1,373 – 1,573 K. To obtain the HCVTM oxidized pellet with good quality, the rational roasting parameters included a roasting temperature of 1,573 K and a roasting time of 20 min.

scholarly journals Effects of sodium roasting on the leaching rate of boron-bearing tailings and its mechanism analysis

2018 ◽  
Vol 5 (8) ◽  
pp. 172342
Author(s):  
Chengxi Zou ◽  
Zhenyu Tang ◽  
Wei Xie ◽  
Hanguang Fu ◽  
Jiacai Kuang ◽  
...  
Keyword(s):  
Scientific Basis ◽  
Raw Material ◽  
Sodium Borate ◽  
Mechanism Analysis ◽  
Leaching Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Theoretical Amount

The study reported was intended to improve the leaching rate of boron-bearing tailings, using a method of sodium roasting that uses boron-bearing tailings as the raw material and Na 2 CO 3 as the sodium agent. The effects of the roasting temperature and Na 2 CO 3 amount on the leaching rate of boron-bearing tailings are mainly evaluated. The morphology and composition of the samples after sodium roasting are analysed by scanning electron microscopy and X-ray diffraction. The results show that sodium roasting can significantly improve the leaching rate of boron-bearing tailings. Under the optimal conditions where roasting temperature is 950°C, Na 2 CO 3 amount is five times the theoretical amount and roasting time is 2 h, the leaching rate of boron-bearing tailings is up to 86.78%. Based on the analysis of the characterization results and the mechanism analysis of the sodium roasting process, the main reason for the increase of leaching rate is the reaction between Na 2 O produced by the decomposition of Na 2 CO 3 and the boron in boron-bearing tailings resulting in soluble sodium borate. The results provide a scientific basis for the efficient comprehensive use of boron-bearing tailings.

Study on Process of Microwave Magnetizing Roast for Low-Grade Hematite

2011 ◽  
Vol 201-203 ◽  
pp. 1816-1820
Author(s):  
Jie Li ◽  
Bao Wei Li ◽  
Bang Wen Zhang ◽  
Lei Wang
Keyword(s):  
Carbon Content ◽  
Magnetic Separation ◽  
Low Grade ◽  
Percent Reduction ◽  
Iron Smelting ◽  
Magnetic Process ◽  
P Content ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Roasting Time

The microwave magnetic roasting process of low-grade hematite under low temperature was studied experimentally. The effects of roasting temperature, carbon content and roasting time on the reduction and magnetic separation were investigated. It shows that the best percent reduction is 10.96％(near to theoretical value 11.11%)which can be obtained under the condition of roasting temperature of 650°С , carbon content of 1.0% and roasting time of 10 minute. The results of magnetic separation show that the best magnetic separation grade for the sintered ore occurs at 570 instead of 650°С owing to the sintering of ore powders at high temperature of 650°С . Further ball-milling and magnetic separation of this concentrate produces two kind of final concentrate, one of which is in grade 65.6% with the recovery being 45.3%, and the other is in grade 63.4% with the recovery being 62.6％. After the magnetic separation, concentrate ore meets the iron-smelting requirements because of its low S and P content and high grade. This magnetic process results in the enrichment of RE and Nb in tailing ore, which can be reused for the extraction of Rare Earth and Nb.

Response Surface Methodology for Optimization of the Chloridizing Roasting Process for a High Copper Pyrite Cinder

2012 ◽  
Vol 524-527 ◽  
pp. 1070-1077
Author(s):  
Shao Jun Bai ◽  
Shu Ming Wen ◽  
Yu Chen ◽  
Hai Ying Shen ◽  
Dan Liu ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Quadratic Model ◽  
Pyrite Cinder ◽  
Iron Concentrate ◽  
High Copper ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Copper Pyrite ◽  
Roasting Time

This study aimed to obtain volatile copper from a high-copper pyrite cinder by optimizing the chloridizing roasting process using response surface methodology (RSM). The effect of key parameters, i.e., dosage of CaCl2 addition, roasting time and roasting temperature, on the copper volatile ratio was investigated and a quadratic model was suggested by the methodology to correlate the variables to this volatile ratio. The results indicated that the model was in good agreement with the experimental data at a correlation coefficient (R2) of 0.9782, and the most influential parameter on efficiency was identified as the dosage of CaCl2 addition. The optimum conditions for chloridizing roasting from the high copper pyrite cinder were identified as a dosage of CaCl2 addition of 4.8 wt%, a roasting time of 19.28 min and a roasting temperature of 1151.51 °C; under such conditions, a copper volatile ratio of 97.82% was achieved. The pellets obtained by this process are characterized by a high content of hematite, and the main impurity element contents are consistent with the requirements for iron concentrate, which is suitable for use in ironmaking.

scholarly journals Effect of Broken Coffee Beans Particle Size, Roasting Temperature, and Roasting Time on Quality of Coffee Beverage

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ezana Getaneh ◽  
Solomon Workneh Fanta ◽  
Neela Satheesh
Keyword(s):  
Particle Size ◽  
Temperature Distribution ◽  
Physical Properties ◽  
Initial Moisture Content ◽  
Coffee Bean ◽  
Sensory Acceptability ◽  
Coffee Beans ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Roasting Time

Optimum flavor and aroma of the coffee are developed during the roasting process. However, certain problems exist in the coffee roasting process such as partial charring, over roasting, and poor temperature distribution across the coffee bean (due to the low thermal conductivity of bean), if conditions are not optimized. Hence, uniform temperature distribution across the coffee bean in the roasting process is highly desirable. To achieve these requirements, the broken coffee beans were positioned in a single layer packed bed arrangement using the closed system by circulating hot air. In this experiment, three factors were arranged in a completely randomized design with three levels and three replications. The first factor considered was roasting temperature (200°C, 230°C, and 260°C), second factor was roasting time (5 min, 10 min, and 15 min), and third was particle size (4–6 mm, 2.36–3.35 mm, and 1.7–2.36 mm). The initial moisture content of raw beans (cv. Limu) was determined. The data were collected on selective physical properties of roasted coffee beans and sensory acceptability of prepared beverage. The results showed that the physical properties and sensory acceptability are significantly high ( P < 0.001 ). It depends on the interaction effect of all the studied factors. Among the studies parameters, roasting temperature of 230°C with a particle size range of 4–6 mm showed the steady transition in dry mass loss and change in bulk density with increase in roasting duration. Coffee roasted at 230°C for 10 min with a particle size of 4–6 mm showed the highest sensory acceptability score (89.21). In conclusion, it can be said that a temperature of 230°C, a time of 10 min, and a particle size between 2.36–3.35 mm and 4–6 mm are recommended conditions for the roasting process of coffee beans.

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