Resource utilization status and development trend of bulk solid waste of coal-based ash/slag

In recent years, the rapid development of the coal industry has provided important energy security and raw material support for the national economy. At the same time, coal-fired power plants, industrial, civil boilers and other equipment produce large quantities of coal-based ash/slag (fly ash, coal-fired slag, gasification slag) and other industrial solid waste during the coal combustion and gasification processes, which have a significant impact on the ecological environment.Taking coal-based ash/slag represented by fly ash and gasification slag as an example, China emits about 800 million tons of fly ash and 35 million tons of gasification slag every year. However, limited by the national energy structure, industrial policy and other factors, as well as the resource distribution of coal-based ash/slag and the nature of the origin of the constraints. At present, the efficient resource utilisation of coal-based ash/slag is still to be improved. Among them, the comprehensive utilization rate of fly ash is 70%, and that of gasification slag is only 30%. In the future, China's bulk solid waste still faces the dilemma of large output, inadequate utilization of resources and low added value of comprehensive utilization products. Therefore, to further improve the comprehensive utilization level of bulk solid waste, comprehensively improve the efficiency of resource utilization, actively implement the national ‘carbon peak’ and ‘carbon neutrality’ related policies.Completing the relevant work in the ‘14th Five-Year Plan’ of the coal industry is an important issue for coal development and utilisation at present. Based on this, a lot of exploration has been carried out for the properties of coal-based ash/slag, such as classification, separation, quality and other technical research. Targeted process technologies and equipment have been developed, partially realising bulk solid waste resource utilisation and high value-added utilisation of coal-based ash/slag. In view of the characteristics of coal-based ash/slag with large specific surface area, developed pore structure, high carbon content, rich in aluminium and silicon content, it has been widely used as a raw material in construction and building materials, environmental protection, ecology, chemical industry and other fields.In this paper, the utilization of bulk solid waste resource and the utilization of high value-added in deep processing of coal-based ash/slag are discussed. ① Construction, building materials and other application fields are still important directions to improve the resource utilization of bulk solid waste of coal-based ash/slag. However, due to the problems of coal-based ash/slag resource utilization, such as decarbonization, carbon-ash separation technology, equipment need to be improved, difficulties in dewatering and drying, and possible precipitation of heavy metals, etc., which need to be followed up with in-depth research. ② Extraction of useful components and used in the preparation of functional carbon materials, environmental pollution control and other fields can realize the deep processing of coal-based ash/slag with high value-added utilization. However, it is necessary to effectively treat the acid, alkali or heavy metal waste liquid generated in the production process to reduce the pollution to the environment. In view of the existing problems in the resource utilization of bulk solid waste of coal-based ash/slag, its future development trend was discussed.It is expected to provide reference for the resource utilization of bulk solid waste of coal-based ash/slag as well as the high-end, low-carbon and green development of the coal chemical industry

The Prevalence and Clinical Relevance of the DFS Immunofluorescence Staining Pattern in a Large ANA-Positive Cohort

BackgroundAlthough the dense fine speckled (DFS) immunofluorescence staining pattern has been studied by various researchers in recent years, its clinical associations remain unspecified. Thus, we performed a retrospective study in a non-selective population to explore the prevalence of this enigmatic antinuclear antibody (ANA) pattern and to determine its possible clinical associations with any identifiable pathology.MethodsWe retrieved the results of ANA testing ordered by various departments in 2019 to study the prevalence of DFS pattern. Demographic characteristics and clinical features of these participants were also collected from the electronic medical record system. Correlation analysis was made to study its clinical associations and a p-value < 0.05 was considered statistically significant.ResultsThe prevalence of ANA positivity was 37.4% among 72,204 serum samples of which the median age was 44 (interquartile range: 31, 56) years old and 68.0% were women. The prevalence of the DFS staining pattern was 1.1% in the total population and accounted for 3.1% in the ANA-positive population. There were 97.6% of these cases displaying the DFS pattern with a low titer of ANA (≤1:320; starting serum dilution: 1:100). We found that this pattern correlated with several pathological conditions, such as skin disorders (25.1%), alopecia (4.6%), and obstetric complications (6.6%).ConclusionThe presence of the DFS immunofluorescence staining pattern may accompany several pathological conditions and may be a signal of localized inflammation within certain organs or tissues, especially the skin

Serum CHI3L1 as a biomarker of interstitial lung disease in rheumatoid arthritis

BackgroundInterstitial lung disease (ILD) is a relatively prevalent extra-articular manifestation of rheumatoid arthritis (RA) and contributes to significant morbidity and mortality. This study aimed to analyze the association between chitinase-3 like-protein-1(CHI3L1) and the presence of RA-ILD.MethodsA total of 239 RA patients fulfilling the American Rheumatism Association (ACR) 1987 revised criteria were enrolled and subclassified as RA-ILD and RA-nILD based on the results of high-resolution computed tomography scans (HRCT) of the chest. The disease activity of RA was assessed by Disease Activity Score for 28 joints (DAS28) and categorized as high, moderate, low, and remission. Chemiluminescence immunoassays were applied to determine the serum levels of CHI3L1. Univariate analysis was performed and the receiver operating characteristics (ROC) curves were plotted to evaluate the correlation between RA-ILD and CHI3L1.ResultsAmong the eligible RA patients studied, 60 (25.1%) patients were diagnosed with RA-ILD. Compared with RA-nILD, RA patients with ILD had significantly higher median age (median [IQR], 68.00 [62.00-71.75] vs 53.00 [40.00-63.00], p<0.001) and a higher proportion of males (21 (35.0%) vs 30 (16.8%), p=0.003). Notably, differences in DAS28 scores between the two groups were not observed. The serum level of CHI3L1 was significantly higher in RA-ILD patients (median [IQR], 69.69 [44.51-128.66] ng/ml vs 32.19 [21.63-56.99] ng/ml, p<0.001). Furthermore, the areas under the curve (AUC) of CHI3L1 attained 0.74 (95% confidence interval [CI], 0.68-0.81, p<0.001) in terms of identifying patients with RA-ILD from those without ILD. Similar trends were seen across the spectrum of disease activity based on DAS28-ESR.ConclusionOur findings of elevated serum CHI3L1 levels in RA-ILD patients suggest its possible role as a biomarker to detect RA-ILD noninvasively

High-energy ball milling-induced facile preparation and controllable surface oxidation of black phosphorus for improving fire safety of epoxy resin via synergistic effect

Here we directly converted red phosphorus (RP) into black phosphorus (BP) through a facile and green one-step high-energy ball milling method. The surface oxidation degree of BP could be tuned by changing milling time and rotation speed. The partially oxidized BP was then utilized to improve fire safety of epoxy resin. Specifically, the peak heat release rate (PHRR) and the total heat release (THR) of epoxy composites were reduced by 36 % and 42 % with incorporating only 1.5 wt% BP, respectively. Comparatively, adding the same amount of conventional RP failed to achieve a reduction in smoke production, while the total smoke production (TSP) of epoxy composites with BP decreased by 20 %, suggesting a promising smoke suppression ability of milled BP. The morphology and composition results of char residue demonstrated that the elemental phosphorus and its oxidized products possessed a significant synergistic catalytic effect on promoting char formation in the condensed phase

Ionic effect of NaCl and KCl on the flotation of diaspore and kaolinite using sodium oleate as collector

The major type of bauxite in China is low-grade diasporic bauxite, which is mainly composed of diaspore and kaolinite. Separation of silicate minerals by flotation technology can meet the requirements of Bayer process, but Na, K and Cl deriving from mineral dissolution and entrainment in flotation water will inevitably mix in the flotation slurry, which will affect the flotation of bauxite. The results of flotation show that NaCl and KCl have little effect on the flotation of diaspore, but NaCl has a beneficial effect on kaolinite flotation. It may be attributed to the ion size order Na\ua0<\ua0K\ua0<\ua0Cl. Na has the ability to enter the layer spacing of kaolinite due to its smaller size, which increases the zeta potential and the dipole-dipole force between kaolinite and sodium oleate, therefore improving the flotation of kaolinite. In addition, Na has “salt effect” on the anionic collector, which also promotes the flotation of kaolinite. This study may have some reference significance to the industry flotation of diasporic bauxite

Numerical Simulation Study on the Multi-Physical Field Response to Underground Coal and Gas Outburst under High Geo-Stress Conditions

Based on thermal–fluid–solid coupling law in coal and gas outburst, a multi-physical field numerical analysis model is built for the whole outburst process. The response laws of stress, gas pressure, temperature, and seepage in different areas and different time nodes around coal and rock mass in the coal and gas outburst under high stress condition are discussed. Research results show: Firstly, the stress response law of the coal and rock mass around the burst hole is initial vibration–sudden attenuation–late stability. Secondly, the gas pressure response law in different areas is that the gas pressure response rate decreases gradually with the increase of the distance from the outburst. Thirdly, the adsorbed gas contained in the broken coal near the outburst port is desorbed rapidly and expands to do work, and the temperature changes dramatically after outburst occurs. In contrast, with the increase of stress, the proportion of elastic potential in total coal and gas outburst energy increases, and the proportion of elastic potential is positively correlated with stress. The critical gas pressure under the energy condition of coal and gas outburst decreases with the increase of stress. It illustrates that the lower gas pressure can also meet the energy condition of coal and gas outburst under high stress