Papers by Keyword: Roasting

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Authors: Zi Fang Xu, Ming Xu Zhang, Jin Bo Zhu
Abstract: Abstract: The fly ash and coal gangue were used as main raw materials to roast solid insulating brick.Lower than solid clay brick (300 °C) which belongs to low temperature roasting , roasting time cycle is 24 h ,the ratio of fly ash and coal gangue is 60% :35%. the B7 admixing expanded pearlite compressive strength is 30.25 MPa . Strength reach general clay brick MU30 high-class level .Thermal coefficient of conduction is 0.4 W/(m.K), lower than general clay brick thermal coefficient of conduction 0.78 W/(m.K); In addition , B7 XRD pattern has evident quartz、mullite diffraction character peak and TGA-DTA pattern between 900°C~1200°C, following temperature rise, green body heat-absorbing , begin melt 、glass reduction .The result is high in strengths . SEM scanning show : after being roasted in 950°C , globular solid glass bead 、pearlitic drusy pearlite 、flocculation aluminosilicate phase and so on , raw materials particle interstices were filled with viscous hyaline, so that B7 turned out high strengths . Acidproof、alkaliproof、freezing test and strengths results show: the lasting quality of solid insulating brick was best.
Authors: Zhao Hui Zhang, Bai Long Liu, Jian Tao Ju, Hong Zhou Ma, Fu Cai Zhao
Abstract: Aiming at the difficulties of aurum leaching from arsenic gold ore, the behavior of arsenic and aurum leaching by the roasting pretreatment of arsenic gold ore is discussed. The result indicates as the following: the rate of aurum extraction is only 14.16% to this kind of refractory gold ore by choosing normal method of aurum extraction. However, the rate of fixing arsenic is up to 95.77% and the aurum extraction rate is 78.45% through the pretreatment of fixing arsenic roasting under optimum roasting conditions like adding amount of CaCO3 by 3%, roasting temperature 650°C and roasting time 4 hours. The result is satisfactory.
Authors: Jie Sun, Jin Zhu Zhang
Abstract: The oolitic hematite with a lower iron content and a higher phosphorus content will be a potential source of raw iron ore for the Chinese iron and steel industry. The magnetization reducing roasted and magnetic separation is a practical beneficiation process. The results show that the iron content in the concentrate can be increased to 57.63% from 45.95%, the iron recovery up to 73.12%, when the parameters are as follows, the roasting temperature is 900°C, the residence time 70 min, the ratio of reducing agent 5%, the grinding time 7 min, and the magnetic field strength 0.15T. The phosphorus content in the concentrate can be reduced to 0.23% from 0.39% by means of acid leaching.
Authors: Yan Xiong, Li Xiong, Xue Wen Wu, Li Qun Rao, Qun Hong Ai
Abstract: The effects of thermal processing methods on antioxidant properties (DPPH, ABTS and FRAP) of black sesame seeds (BSS) were investigated. In this study, all samples were thermally processed by steaming, roasting and microwaving, and the effects on the levels of total phenolic content (TPC), tannins content (TC) and total flavonoid content (TFC) were also studied. The thermal processes applied in the present study were: steaming (80 kPa for 15 min and 30 min), roasting (160 °C for 5 min and 10 min) and microwaving (4 min and 8 min). The results showed that the steaming process led to significant (p oC for 10min. Despite the higher level of total phenolics and tannins content observed in roasted sample, roasted BSS extract showed the lowest antioxidant activity in DPPH (15.2%), ABTS (45.6%) and FRAP (110.0 10-3mM Fe2+ /100 g). Steamed BSS at 80 kPa for 30 min exhibited the highest antioxidant activity, suggesting that steaming is the preferred thermal processing method to get better health-related quality of BSS products.
Authors: Dan Liu, Shu Ming Wen, Yong Jun Xian, Hai Ying Shen, Shao Jun Bai, Hai Lei Zheng
Abstract: A technology of “arsenic removing- sulfuric acid producing- residuals for ironmaking” is proposed for comprehensive utilization of pyrite with high content of arsenic. The effect of roasting temperature and time on arsenic removing was investigated. The arsenic removed residuals obtained under the optimal arsenic removed conditions, was used to be proceeded for sulphur volatilization test. The results demonstrate that final residuals with 63.53% of Fe can be used for steel industry. This technology can be used to fully utilize sulphur and produce high quality concentrate as iron-bearing feed for steel industry, which will help to reduce the pollution of arsenic and extend raw material sourcing for Chinese steel industry.
Authors: Anton V. Kotlyar, Kira A. Lapunova, Yana V. Lazareva, Marina E. Orlova
Abstract: The article provides an overview of the argillites raw material of Russia. It describes chemical and mineralogical characteristics of argillites and their main properties. It indicates that argillites chemistry has some peculiarities like high content of A2O3 – from 17 to 23 %, К2О – from 2,5 to 4,3 % and iron oxides from 4 to 7 %. Mineralogy of argillites includes two types of hydra micas: an isometric one being allothigenous constituent and a bladed one being the transformation product of montmorillonite underwent catageneses. Also argillites always contain kaolinite, chlorite, glauconite, quartz, plagioclase. The article contains the main requirements for paving clinker and ceramic tile and major trends of their production. Information about dependence of the effect of argillites reduction ratio and firing temperature on strength, absorption capacity and density of the samples is provided. Influence of their interconnected nature on the properties of the product is described. It is specified that due to finer argillites reduction in the size range of 0-0.16 – 0-1.25 mm, the samples strength increases 1.5-2.5 times. Higher firing temperature in the range from 900 to 1100 °C allows increasing strength 2-4 times. In given intervals of reduction ratio and firing temperature the index of water absorption capacity of less than 5 % needed for ceramic tile is achieved by size reduction of 0 – 0.315 mm and firing temperature of 1000 °C and higher. The water absorption capacity of less than 2.5 % needed for paving clinker is achieved by size reduction of 0 - 0.315 mm and firing temperature of 1050 °C and higher. Rationale for production perspectiveness of paving clinker and ceramic tile of low-temperature sintering based on argillites is provided.
Authors: Jun Tao Chen, Shu Fang Ding, Chun Hua Bai, Hui Ping Wang, Yan Xu
Abstract: Fly ash roasted by different temperature, XRD analysis of fly ash after roasting, specific surface area and pore properties of fly ash roasted before and after were tested. Results showed that roasting influenced significantly on pore properties of fly ash; Specific surface area, pore volume and amount of middle pore of fly ash increased with roasting temperature increased , then reached maximum at 700 °C, and decreased with roasting temperature increased.
Authors: Zhao Cai Wang, Man Sheng Chu, Shi Qiang Chen, Zheng Gen Liu, Jue Tang, Xiang Xin Xue
Abstract: The metallurgical properties of oxidized pellets are of great importance to achieve high efficiency and smooth running of blast furnace and gas-based direct reduction shaft furnace. In this study, the new method of adding B-Mg compound additive has been put forth to improve metallurgical properties of pellets. The effects of adding B-Mg additive on the strength of green balls, cold compressive strength, reduction swelling, and the strength after reduction and cooling of oxidized pellets are investigated through the experiments and microstructure analysis. The results revealed that, the B-Mg additive has not-so-remarkable effects on the properties of green balls. The rational addition amount of B-Mg additive is 0.6 %, and B-Mg additive make it feasible to reduce roasting temperature of the pellets. High temperature properties show remarkable improvement with the increase of B-Mg additive amount, the RSI decrease from 14.7% to 7.17%, and the strength of pellets after reduction and cooling increase from 162.5 N to 650.8 N when the addition amount increases from 0 to 0.6%.
Authors: Chen Huang, Yi Miao Zhu, Hou Lei Zhang, Xin Zhi Liu
Abstract: Rice husk ash (RHA) is the product of rice husk pyrolysis or combustion, which contains inherent ash in original rice husk and non-converted fixed carbon. Due to large amounts of inherent silicon dioxide in rice husk, the decarbonized residue of RHA has great value as industrial materials. One basic method to remove carbon from RHA is roasting. Because of low carbon content in RHA and low roasting reaction velocity, the roasting process takes a long time. In this case, fixed-bed roasting is suitable for removing carbon from RHA. In the present work, experimental study on RHA decarbonization is conducted based on a specially-designed multi-section fixed-bed roasting. The experimental results show that under the experimental conditions, the flame propagation spread of RHA in fixed beds is in the range 0.833 to 0.121mm/s. The results documented in this paper provide the basis for further developing large-scale engineering devices.
Authors: Xian Zhong Cheng, Kai Xu Chen, Huai Cheng, Li Ping Zhang
Abstract: In this paper, the extraction of vanadium from Chinese black shale by roasting with mixture salt addition was studied. The effect of salt additions, temperature and time on the recovery of vanadium were investigated by mixture salt roasting and 2% H2SO4 leaching. The mixture additions of Na2CO3-BaSO4 was used in the roasting process. The optimal roasting conditions for black shale were determined to be 2.5 hours roasting at 760 °C with the mixture additive SB of 10-15%. After being leached with 2% sulphuric acid, the leaching efficiency of vanadium was obtained in 85%. The pollution of waste gas was decreased in the presence of BaSO4-Fe2O3.
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