Whitening process and mechanism of coal gangue by sodium salt calcination
The resource utilization of coal gangue by calcination is important. In terms of the problems of high energy consumption and low efficiency, the use of sodium salt types and calcination process for coal gangue whitening has been investigated. ... However, the calcination at 950 ℃ resulted in generation of spherical mullite, and a significant ...
Valorization of calcined coal gangue as coarse aggregate in …
Calcination is an effective method to improve the strength of CG as aggregate. In this paper, the characteristics of the calcined, activated, and sorted CGAs and their influences …
Properties of coal gangue-Portland cement mixture with …
In recent years, various studies have been performed on the utilization of coal gangue to pavement construction, manufacture of sintered brick [10], replacement of the clay for cement clinker calcination, concrete aggregates or mineral admixture for replacing partial cement [11], [12]. Nevertheless, the incorporation level of coal gangue in ...
Life cycle assessment of coal gangue composite cements: …
The uncertainty caused by the variation of calcination temperature and kaolinite content of coal gangue were assessed by Monte-Carlo analysis. Results show that ternary composite cement is more recommended in comparison to binary composite cement, considering the very minimal emissions from limestone production, and a calcination temperature of ...
Performance of cement-based materials containing calcined coal gangue
Fig. 13 shows the apparent color of coal gangue after calcination and it can be seen that the color of calcined CG was different from cement. The different thermally treated CG were photographed and parameterized through the Photoshop software of 9 points to determine the RGB value (RGB represents the colors of the three channels of red, green ...
Evaluating thermal activated coal gangue as alternative filler …
The multi-channel utilization for solid waste has prompted widespread concern around the world [1], [2], [3]. As a substantial component of industrial solid waste, coal gangue (CG) is a by-product discharged in process of coal mining and washing, which accounts for 8–20 % by weight of the total coal output [4].
Research on the regulatory mechanism of pore structure in …
Combined with the pore distribution of coal gangue in calcination for 15 min at different temperatures, reactions (1), (2), and (3) occur at 500 and 600 °C, and some large pores (>0.03 mm) will be formed. Increasing gas phase and total porosity. There are some small pore structures in coal gangue raw materials, but with the oxidation of carbon ...
Thermal Activation of Coal Gangue with Low Al/Si Ratio as …
1. Introduction. Coal gangue (CG), a solid waste from coal mining and processing, has low carbon content and high hardness [1,2].Notably, the annual generation of CG solid waste reaches up to 37–550 million tons [], and its effective utilization is still less than 15% [].Long-term accumulation of CG in the open air can lead to land occupation, spontaneous combustion, …
The Effect of Physical Separation and Calcination …
This paper focused on examining the feasibility of physical separation (screening and float-sink tests) and calcination treatment for the enrichment of critical elements (Li, Ga, and rare earth elements plus yttrium …
Frontiers | Synthesis and characterization of low …
Suspension calcination was a new technique for gangue calcination. Powder with particle sizes of 100 μM or less is used as a raw material and is carried by a conveying bed, which significantly reduces the …
Kinetics of alumina extraction from coal gangue by …
It can be seen from Fig. 13 that the particle size distribution patterns of coal gangue before and after calcination are basically the same, but after leaching for 2 h with hydrochloric acid, not only did D50 become smaller, but the largest and smallest particles disappeared, and the particle size distribution was more concentrated.
Evaluating thermal activated coal gangue as alternative filler …
The multi-channel utilization for solid waste has prompted widespread concern around the world [1], [2], [3].As a substantial component of industrial solid waste, coal gangue (CG) is a by-product discharged in process of coal mining and washing, which accounts for 8–20 % by weight of the total coal output [4].In China, more than 7 billion tons of CG have been …
Spontaneous combustion coal gangue-based composite …
Spontaneous combustion coal gangue is a widely occurring type of coal gangue activated through natural self-ignition rather than artificial calcination as used in most studies [2]. In 2015, it was reported that nearly one-third of China's coal gangue piles were undergoing or had completed spontaneous combustion [ 2 ].
Analysis of calcination activation modified coal gangue and …
This study investigated the optimal calcination temperature for acid activation of coal gangue, characterized the gangue at different temperatures using various analytical methods, and found that the acid reactivity of coal gangue was the highest at 650°C.
Influence of Curing Temperature on the Performance of …
The coal gangue was collected from Huainan City, Anhui Province. Table 1 summarizes the chemical composition of each material. After being received, the coal gangue was further dried, crushed, ground and finally calcined at 800 °C for 2 h. Figure 1a shows the XRD patterns of the coal gangue before and after calcination. As observed, mica ...
Sustainable and clean utilization of coal gangue: …
In this study, coal gangue mixed with calcium carbonate and corn stalk powder is used as a raw material to produce gangue-based silicon fertilizer through high-temperature activation.
Study on the calorific value and cementitious properties of coal gangue
After calcination, the coal gangue generates a large amount of amorphous SiO 2 and Al 2 O 3, which have strong pozzolanic activity. The hydration mechanism can be divided into two processes: (1) the hydration of cement to form calcium hydroxide, C-S-H gel, ettringite, hydrated calcium aluminate, and hydrated calcium iron oxide, among other ...
Preparation and properties of autoclaved aerated concrete …
Calcination may also cause insufficient bonding between the silica and alumina octahedra, thus generating a great deal of bond breakage at the free ends. Research has shown that coal gangue calcined at 700 °C exhibited greater activity [16]. Therefore, it could be expected that the activity of coal gangue would be improved by calcination.
Define the following terms. (i) Mineral (ii) Ore (iii) Gangue …
Gangue: Gangue is an unwanted substance or impurity that surrounds the mineral in an ore deposit, such as sand, rock, or some other material. Mineral dressing, mineral processing, or ore dressing are terms used to describe the method of separating gangue from mineral. Suggest Corrections. 226.
Investigation of the interactions of arsenic with gangue …
It was concluded that arsenic is carried on the surface of gangue minerals in the calcination process. Moreover, the decrepitated arsenic compounds tend to accumulate back on solid surfaces thus the amount of arsenic was found to be higher than the amount found in literature which is lower than 100 ppm. Therefore the affinity of arsenic ...
Medium-temperature calcination and acid pressure leaching …
(1) Medium-temperature calcination and acid pressure leaching effectively improved the extraction ratio of Al 2 O 3 from the Fuxin coal gangue. At a calcination temperature of 650 °C, calcination time of 2 h, HCl concentration of 8 mol L −1, acid pressure leaching temperature of 160 °C, and acid pressure leaching time of 6 h, the ...
Synergistic performance of microwave-activated coal gangue …
Coal gangue: The coal gangue (CG) used in this study is untreated raw coal gangue, sourced from Lingshou County, Hebei Province, China. Its appearance mostly presents as flakes or blocks of black-gray rocks, and the shape and size of CG vary. ... and the combined water content is calculated based on the difference in weight between the samples ...
Pozzolanic activity experimental dataset of calcined coal gangue
The dataset encompasses the reactivity of raw coal gangue under various calcination schemes. The coal gangue is subjected to a process of drying, crushing, and grinding, followed by high-temperature calcination using a muffle furnace with a heating rate of 4 ℃/min. The effects of calcination temperature (600 ℃, 700 ℃, 800 ℃, 900 ...
Fuel nitrogen conversion and release of nitrogen oxides …
The pollution emission during the widespread utilization of coal gangue in construction industry has long been neglected. In present study, the NO x release behaviors in a simulation experiment of coal gangue calcination in construction industry were systematically investigated. The corresponding evolution of nitrogen functionalities in coal gangue was also …
Cementitious properties of coal-based metakaolin prepared …
Coal gangue is the largest emission of solid waste in the coal industry, and its large accumulation has posed serious hazards to environment. Low-quality coal gangue can be transformed into an auxiliary cementing material (coal-based metakaolin) with pozzolanic activity after calcination.However, the conventional calcination has slow heating rate, high energy …
Cementitious properties of coal-based metakaolin prepared …
Coal gangue is the largest emission of solid waste in the coal industry, and its large accumulation has posed serious hazards to environment. Low-quality coal gangue can be transformed into an auxiliary cementing material (coal-based metakaolin) with pozzolanic activity after calcination.
Study on the leaching behavior differences of rare earth …
Currently, the extraction of REY from coal gangue is still in its infancy, and there are few related research reports. The extraction methods include direct acid leaching [16], sulfuric acid roasting-water leaching [17], alkali fusion roasting-acid leaching [18], and calcination-acid leaching [19], [20], [21].However, the leaching efficiency of REY by direct acid leaching is low.
Mechanical properties and solidification mechanism of coal gangue …
This study utilizes polymers based on coal gangue and blast furnace slag to solidify engineering slurry with high silt content. Response surface methodology was employed to investigate the effects of polymer composition, alkali activator modulus, and coal gangue calcination temperature on the unconfined compressive strength of stabilized soil.
Aluminum extraction from activated coal gangue with …
The dissolution rate of alumina after direct calcination of coal gangue and acid leaching is about 70% [8], [9]. The fluorite and limestone added in the thermal activation process to improve the activation effect, the final aluminum extraction rate can reach more than 90% [10], [11]. But high activation temperature and high energy consumption ...
Research on the Preparation of Kaolin from Coal Gangue by …
In order to find a better collector for the separation of carbon and kaolin from coal gangue flotation, and to explore the action mechanism of collectors, this paper selected 12 kinds of collectors for systematic comparison, including five non-polar organics with different carbon chain lengths, and polar organic matters with double bonds, triple bonds, benzene, as well as …