Residue Burning Research Articles

Pengaruh Bentuk Permukaan Piston Rata (Flat) Dan Piston Cembung (Dome) Terhadap Performa Dan Emisi Gas Buang Pada Mesin Sport 200cc

The aim of this research is to determine the effect of engine performance (torque and power), as well as exhaust emissions after replacing the piston. Tests were carried out on a 200CC engine with flat piston specifications with a diameter of 65.0 mm and replaced with a convex piston with a diameter of 65.0 mm using pertalite fuel. The research results obtained by replacing the convex piston (dome) caused the volume of the combustion chamber to decrease resulting in increased torque and power. There was an increase in torque of 0.02607 ft-lbs and an increase in power of 41.95384 HP, then the compression ratio increased by 0.5%. In exhaust gas emissions containing CO, HC, O2, CO2 using a gas analyzer with the results of research on flat pistons and dome pistons, it can be seen that emissions from convex pistons (dome) have increased compared to flat pistons. with the highest increase in stationary of 6.17% in CO emission content due to incomplete combustion residue, which means that the type of piston has a significant influence on exhaust gas emissions. Then the exhaust gas emission test results also show an increase in the O2 emission content on the flat piston at RPM 5000 with a value of 4.24% due to the mixture of oxygen and fuel being more perfect, but on the convex piston (dome) there is a significant increase Compared to a flat piston only at RPM 6500 with a value of 4.53% in O2 emission content. The HC and CO2 emissions content shows unstable or changing values. Apart from that, variations in engine speed also affect the exhaust emissions produced.

Crop residue burning in China (2019–2021): Spatiotemporal patterns, environmental impact, and emission dynamics

Crop residue burning (CRB) is a major contributor to air pollution in China. Current fire detection methods, however, are limited by either temporal resolution or accuracy, hindering the analysis of CRB's diurnal characteristics. Here we explore the diurnal spatiotemporal patterns and environmental impacts of CRB in China from 2019 to 2021 using the recently released NSMC-Himawari-8 hourly fire product. Our analysis identifies a decreasing directionality in CRB distribution in the Northeast and a notable southward shift of the CRB center, especially in winter, averaging an annual southward movement of 7.5°. Additionally, we observe a pronounced skewed distribution in daily CRB, predominantly between 17:00 and 20:00. Notably, nighttime CRB in China for the years 2019, 2020, and 2021 accounted for 51.9%, 48.5%, and 38.0% respectively, underscoring its significant environmental impact. The study further quantifies the hourly emissions from CRB in China over this period, with total emissions of CO, PM10, and PM2.5 amounting to 12,236, 2,530, and 2,258 Gg, respectively. Our findings also reveal variable lag effects of CRB on regional air quality and pollutants across different seasons, with the strongest impacts in spring and more immediate effects in late autumn. This research provides valuable insights for the regulation and control of diurnal CRB before and after large-scale agricultural activities in China, as well as the associated haze and other pollution weather conditions it causes.

Evaluation of the Thermal Energy Potential of Waste Products from Fruit Preparation and Processing Industry

In the context of a changing climate and increasing efforts to use renewable energy sources and waste materials and to green the environment, new sources and technologies for energy recovery from waste are being sought. This study evaluates the possibilities of energy generation potential from waste products of fruit species used in the food processing industry. The results indicate good potential for energy use of materials from fruit processing due to low input moisture content of around 15 wt. %, an average energy lower heating value (LHV) of 16.5 MJ·kg−1, an average low ash content of 4.9% and meeting most of the emission limits of similar biofuels. Elemental analysis and combustion residue studies indicate safe operation within existing standards. The results of our analyses and experience from similar studies allow us to recommend most of the studied waste materials for energy generation use directly in processing plants at the local level.

Mineralisation of CO2 in wood biomass ash for cement substitution in construction products

This study extends our exploration of the potential of biomass ashes for their CO2-reactivity and self-cementing properties. The ability of three hardwood-based biomass ashes to mineralise CO2 gas and partially replace CEM I in mortars was investigated. The three hardwoods were English oak (Quercus rober), English lime (Tilia x europaea), and beech (Fagus sylvatica). The woody biomass wastes were incinerated at 800°C to extract their key mineral phases, which are known to be reactive to CO2 gas to form carbonates. The selected biomass ashes were analysed for their CO2-reactivity, which was in the range of 32–43% (w/w). The ashes were used to replace CEM I at 7 and 15% w/w and this “binder” was mixed with sand and water to produce cylindrical monolithic samples. These monoliths were then carbonated and sealed cured over 28 days. The compressive strength, density and microstructure of the carbonate-hardened monoliths were examined. The ash-containing monoliths displayed mature strengths comparable to the cement-only reference samples. The CO2 uptake of oak containing monoliths was 7.37 and 8.29% w/w, for 7 and 15% ash substitutions, respectively. For beech and English lime they were 4.96 and 6.22% w/w and 6.43 and 7.15% w/w, respectively. The 28 day unconfined compressive strengths for the oak and beech ashes were within the range of ~80–94% of the control, whereas lime ash was 107% of the latter. A microstructural examination showed carbonate cemented sand grains together highlighting that biomass ash-derived minerals can be very CO2 reactive and have potential to be used as a binder to produce carbonated construction materials. The use of biomass to energy ash-derived minerals as a cement replacement may have significant potential benefits, including direct and indirect CO2 emission savings in addition to the avoidance of landfilling of these combustion residues.

Rice residue management alternatives in rice–wheat cropping system: impact on wheat productivity, soil organic carbon, water and microbial dynamics

In the Indo-Gangetic Plains (IGP), rice–wheat cropping system (RWCS) predominates, producing large quantity of crop residue and its management is major concern. Farmers usually burn the residue to clear the field for succeding crop, and burning damages soil microbes, resulted in loss of soil organic matter. Hence, current study was conducted to assess the impact of different Happy seeder based residue management options on changes in microbial dynamics, enzyme activities and soil organic matter content and also to know that alternative method for attaining sustainable wheat productivity in sandy loam soils of Haryana, India. Results revealed that Zero tillage wheat (ZTW) with partial and full residue retention treatments sown with Happy seeder (after using chopper and spreader), and ZTW with anchored stubbles significantly enhanced soil microbial count by 47.9–60.4%, diazotropic count by 59.0–73.1% and actinomycetes count by 47.3–55.2%, grain yield by 9.8–11.3% and biomass yield by 7.4–9.6% over conventional tilled (CT) residue burning and residue removal plots. ZTW sown with surface retention of rice crop residue increased the organic carbon by 0.36–0.42% and the soil moisture content by 13.4–23.6% over CTW without residue load. Similarly, ZTW sown with Happy seeder with full residue enhanced alkaline phosphatase activity from 95.3 µg TPF g−1 soil 24 h−1 in 2018–2019 to 98.6 µg TPF g−1 soil 24 h−1 in 2019–2020 over control plots. Likely, microbial population and enzymatic activity showed strong positive correlation under variable residue retention practices. However, increased microbial population reduced the soil pH from 7.49 to 7.27 under ZTW with residue retention plots. The wheat yield enhanced by 9.8–11.3% during 2018–2019 and 2019–2020 under ZTW with Happy seeder with full residue load over residue burning and residue removal plots. ZTW sown with Happy seeder under full residue retention, achieved maximum net return 43.16–57.08 × 103 ₹ ha−1) and B-C ratio (1.52 to 1.70) over CTW without residue. Therefore, rice residue needs to be managed by planting wheat using appropriate machinery under ZT for sustaining higher productivity in RWCS and improve soil health and environment under IGP regions.

Interactive effects of long-term management of crop residue and phosphorus fertilization on wheat productivity and soil health in the rice–wheat

In the context of degradation of soil health, environmental pollution, and yield stagnation in the rice–wheat system in the Indo-Gangetic Plains of South Asia, an experiment was established in split plot design to assess the long-term effect of crop residue management on productivity and phosphorus requirement of wheat in rice–wheat system. The experiment comprised of six crop residue management practices as the main treatment factor with three levels (0, 30 and 60 kg P2O5 ha–1) of phosphorus fertilizer as sub-treatments. Significant improvement in soil aggregation, bulk density, and infiltration rate was observed under residue management (retention/incorporation) treatments compared to residue removal or residue burning. Soil organic carbon (SOC), available nutrient content (N, P, and K), microbial count, and enzyme activities were also significantly higher in conservation tillage and residue-treated plots than without residue/burning treatments. The residue derived from both crops when was either retained/incorporated improved the soil organic carbon (0.80%) and resulted in a significant increase in SOC (73.9%) in the topsoil layer as compared to the conventional practice. The mean effect studies revealed that crop residue management practices and phosphorus levels significantly influenced wheat yield attributes and productivity. The higher grain yield of wheat was recorded in two treatments, i.e. the basal application of 60 kg P2O5 ha–1 without residue incorporation and the other with half the P-fertilizer (30 kg P2O5 ha–1) with rice residue only. The grain yield of wheat where the rice and wheat residue were either retained/incorporated without phosphorus application was at par with 30 and 60 kg P2O5ha–1. Phosphorus levels also significantly affected wheat productivity and available P content in the soil. Therefore, results suggested that crop residue retention following the conservation tillage approach improved the yield of wheat cultivated in the rice–wheat cropping system.

Ecological restoration reduces mercury in corn kernel and the distinction of mercury in corn plants in rural China – A case in Wuchuan mercury mining area

Corn is a crucial crop in China and is widely cultivated in the mercury (Hg) mining region of Guizhou. This study analyzed the Hg content in soil and corn plant samples from the Wuchuan Hg mining area (WCMA) and the surrounding non-Hg mining regions (SNMR). The findings suggest that ongoing ecological rehabilitation and environmental conservation measures in the WCMA have significantly decreased the Hg content in corn kernels. The Hg concentration in different parts of the corn plant varied, being higher in the roots, tassels, and leaves and lower in kernels and stalks. Hg stored in corn plant growing in the WCMA primarily originates from the soil (55.4%), while in the SNMR, it mainly comes from the atmosphere (74.9%). Despite counted only about 7% of the total plant mass, corn roots play a crucial role in soil Hg pollution remediation when corn is used for remediation. Household corn residues burning release about 58.5% and 66.9% of the stored Hg in corn plants growing in the WCMA and the SNMR, respectively, into the atmosphere. Our findings indicate that corn cultivation acts as a reservoir for both soil and atmospheric Hg in the SNMR, while in the WCMA, it serves as a source of atmospheric Hg.

Overcoming Common Pitfalls to Improve the Accuracy of Crop Residue Burning Measurement Based on Remote Sensing Data

Crop residue burning (CRB) is a major source of air pollution in many parts of the world, especially Asia. Policymakers, practitioners, and researchers have invested in measuring the extent and impacts of burning and developing interventions to reduce its occurrence. However, any attempt to measure burning, in terms of its extent, impact, or the effectiveness of interventions to reduce it, requires data on where burning occurs. These data are challenging to collect in the field, both in terms of cost and feasibility, because crop-residue fires are short-lived, each covers only a small area, and evidence of burning disappears once fields are tilled. Remote sensing offers a way to observe fields without the complications of on-the-ground monitoring. However, the same features that make CRB hard to observe on the ground also make remote-sensing-based measurements prone to inaccuracies. The extent of crop burning is generally underestimated due to missing observations, while individual plots are often falsely identified as burned due to the local dominance of the practice, a lack of training data on tilled vs. burned plots, and a weak signal-to-noise ratio that makes it difficult to distinguish between the two states. Here, we summarize the current literature on the measurement of CRB and flag five common pitfalls that hinder analyses of CRB with remotely sensed data: inadequate spatial resolution, inadequate temporal resolution, ill-fitted signals, improper comparison groups, and inadequate accuracy assessment. We take advantage of data from ground-based monitoring of CRB in Punjab, India, to calibrate and validate analyses with PlanetScope and Sentinel-2 imagery and illuminate each of these pitfalls. We provide tools to assist others in planning and conducting remote sensing analyses of CRB and stress the need for rigorous validation.

A food-energy-water-carbon nexus framework informs region-specific optimal strategies for agricultural sustainability

Agricultural sustainability is threatened by pressures from water scarcity, energy crises, escalating greenhouse gas (GHG) emissions, and diminishing farm profitability. Practices that diversify crop rotations, retain crop residues, and incorporate cover crops have been widely studied for their impacts on soil organic carbon and crop production. However, their associated usage of natural resources and economic returns have been overlooked. Here, we employed a food-energy-water-carbon (FEWC) nexus framework to assess the sustainability of crop rotations plus various management strategies across three sub-regions of New South Wales (NSW) in Australia. We found that compared with residue burning and fallowing, residue retention and cover cropping contributed to GHG abatement, but the latter consumed more energy and water per hectare. The composite sustainability scores, calculated with the FEWC framework, suggested that legume-inclusive rotations were generally more sustainable. Furthermore, in northern NSW (with existing sorghum/wheat/chickpea/wheat rotation), residue retention with cover cropping was most suitable combination, while the use of residue retention with fallow yielded greater benefits in southern NSW (with existing wheat/field pea/wheat/canola rotation). Regional disparities in climate, soil, cropping systems, and on-farm costs prompted region-specific strategies to address the unbalanced distribution among FEWC domains. Our study provides assessments for identifying feasible management practices to advance agricultural sustainability.

Sustainable paddy residues management through mushroom cultivation in India

AbstractFarmers' open‐field burning of paddy straw and the indoor burning of paddy residues as domestic fuels are significant environmental concerns since they emit dangerous pollutants. The worldwide burning of paddy residues totals 90 million tons (MT). Around 24 MT emanated from India, accounting for approximately 27% of the world's paddy straw burning. Burning residues emit smog particles, polyaromatic amines, nitrous oxides, sulfur dioxide, carbon dioxide, and carbon monoxide, methane, seriously degrading the air quality and risking human health. The combustion of dry paddy straw emits massive volumes of methane and nitrous oxide, 65 and 1.6 kilotons, respectively. This study analyzes the consequences of burning paddy residue outdoors and indoors by reviewing the relevant literature and data. Open‐field burning causes air pollution, damages soil health, and harms human health. Indoor burning of paddy residues as domestic fuels harms women's and children's health in rural areas. To mitigate the adverse effects of this practice, we magnified our research using the various literature and recent statistics to link with mushroom cultivation as an alternative to paddy residue burning. Recently, India produced almost 240,000 tons of mushrooms; Odisha, Maharashtra, and Bihar are the three leading states for mushroom production. The cultivation of mushrooms is considered advantageous for both health and the environment. This study has concentrated on mushrooms' economic potential, medicinal value, and health benefits.

An original set of nanometer-scale mineralogical analyses of cookeite and the implications for Li enrichment: No. 21 coal, Mengjin Mine, western Henan

Critical elements in coal deposits, such as lithium (Li), have attracted attention recently due to their economic value. Many studies have suggested that the high enrichment of Li in coals is predominantly associated with cookeite, a Li–bearing chlorite mineral of hydrothermal origin. However, the identification of cookeite in coal has primarily relied on indirect methods, owing to the low atomic number of Li, which presents significant challenges for precise observation. The Shanxi Formation No. 21 coal in North China is enriched in Li. This study established a nanometer–scale mineralogical analytical technique (including high–resolution transmission electron microscopy (HR–TEM), fast Fourier transformation (FFT), and standard mineral simulation single-crystal diffraction (SSCD)) for the identification of the cookeite and evaluated the Li enrichment mechanism and recovery in this coal (low–volatile bituminous to semi–anthracite) based on a model for the Li mineralization. The Li content of the No. 21 coal ranges from 25.2 to 203 ppm. The Li content shows a strong correlation with the ash yield, Al2O3, SiO2, and detrital elements, indicating a dominant aluminosilicate affinity and detrital origin. The major aluminosilicate minerals in coal are kaolinite, chlorite, and illite. The geochemical indicators (the Al2O3/TiO2 ratio and its relationships with the Zr/TiO2, Nb/Y, and Nb/Yb ratios) indicate that the sediment sources are determined to be intermediate–felsic igneous rocks, probably the Mesoproterozoic moyite (a type of K– feldspar granite) in the Yinshan Oldland. Additionally, the coal can be divided vertically into three sections (Sections I, II, and III), corresponding to three stages of peat formation. Overall, from Section I to Section III, the degree of detrital input increased, and the groundwater and marine influences strengthened and weakened, respectively. Section II exhibits anomalous Li enrichment mainly associated with reducing environments and the geochemical barrier caused by the interaction between infiltrating seawater and groundwater. The detrital kaolinite assemblage with authigenic minerals such as secondary REE–rich minerals (bastnasite), chamosite, and quartz, as well as the REY enrichment patterns, suggests that the No. 21 coals, mainly Section II, may have existed the hydrothermal alteration. Cookeite is identified primarily in Section II and coexists with kaolinite based on TEM observations, suggesting that the cookeite is of hydrothermal origin and formed from pre–existing Li–rich kaolinite. Most samples from Section II meet the mining grade of Be–Li–Nb–Ta ore deposits (Li2O > 0.2%). Thus, this study offers valuable insights into the extraction and recovery of Li from coal combustion residues, particularly when cookeite is the primary Li–bearing mineral.

Artificial formation of benzene polycarboxylic acids during sample processing of black carbon analysis: the role of organic carbon amount

Black carbon is also known as pyrogenic carbon formed by partial combustion of organic material under limited oxygen supply. It occurs along a continuum from original organic slightly charred material to highly aromatic combustion residues such as charcoal, graphite, and soot. Black carbon is extensively studied in various environments due to its ubiquity. It is also important for the biochar community because it can specifically trace the stable polycondensed part of biochar. Different methods have been adopted for black carbon determination; among them using benzene polycarboxylic acids (BPCA) as molecular markers for the polycondensed aromatic moieties of charred materials. However, different researchers have shown interferences from organic matter during BPCA analysis. Therefore, the aim of this work was to assess if artificial formation of BPCA occurs in soil samples when the organic carbon load exceeds 5–10 mg. For this purpose, we conducted black carbon analysis of different soil samples with varying TOC contents of up to 20 mg. In addition, organic matter-rich plant materials were used as a black carbon-free control (leaves of Ivy and Beech, leaves/needles of Spruce and needles of Thuja). To exclude the high-pressure digestion as source of artificial black carbon formation, a comparison between the conventional and a microwave-assisted extraction (MAE) oxidation process was included. Our results show that for soil samples, no artificial BPCA formation occurred at least up to 20 mg of total organic carbon. Higher sample weights are unrealistic for BPCA analysis of soils using current methodology. Therefore, our results clearly demonstrate that there is no artificial BPCA formation during properly performed black carbon analysis of soil samples. On the contrary, for some samples, BPCA contents tended to decrease with increasing sample weight, and thus increasing amount of TOC. In contrast, for plant samples, artificial BPCA formation of up to 3 g kg−1 occurred when more plant material equivalent to 10 mg total organic carbon was used. However, there was no amount dependence of artificial BPCA formation. The reason for artificial BPCA formation was not the high-pressure digestion, as microwave-assisted digestion showed comparable results. However, for real-world analysis, this artificial BPCA formation is not relevant because such high soil sample weights cannot be used. Nevertheless, when using organic-rich material such as peat and charred materials, the samples should contain less than 10 mg of total organic carbon.Graphical

Solving the mysteries of Lahore smog: the fifth season in the country

South Asian smog is an annually recurring air pollution event that is characterized by high concentrations of air pollutants, low visibility, and severe socio-economic disruptions. It is most frequently observed across the north-western parts of the Indo-Gangetic Plains (IGP). Since 2016, it has become so frequent and pervasive that they are colloquially referred to as “the fifth season” in the region. During this season populations residing in this area including cities such as Lahore, Amritsar, Faisalabad, Multan, Delhi etc. are exposed to hazardous levels of air pollution. This study attempts to understand the reasons for the recent increase in the intensity and frequency of intense air pollution episodes by utilizing ground-based and satellite observations. Time-series analysis, seasonal and annual variations in PM2.5 and AOD were carried out. Satellite data of UVAAI, CO, and fire count were used to determine the fire incidences and aerosol characterization. The results indicate that during the last decade, there has been an increase in air pollution sources while crop residue burning, and motor vehicles have greatly contributed to the increased frequency and intensity of such events. The meteorological and topographical data analysis revealed that the IGP provides ample cloud-condensation nuclei and optimum conditions for the accumulations of pollutants, especially in the post-monsoon and winter periods. The Mann-Kendall test was performed to confirm the annual and seasonal trends of PM2.5. The major cities of South Asia such as Lahore, Delhi, Kathmandu, and Dhaka have recently shown a decreasing trend with respect to annual AOD. However, an increase has been observed for the period of post-monsoon especially for cities of Lahore and Delhi. To distinguish potential sources of air pollutants during extreme smog episodes in the region, Analytical Hierarchy Process (AHP) was conducted to estimate the most contributing factors to the annual smog episodes. According to the data, the transboundary pollution resulting from open-field agriculture fires has been assigned moderate importance over vehicular emissions. A HYSPLIT trajectory model coupled with ground observations and satellite data shows that the agricultural fires do have a profound impact on the air quality of the region. It highlights the importance of transboundary pollution and cooperation among cities, regions, and countries across the shared airshed of the Indo-Gangetic Plains.

Agricultural production and air pollution: An investigation on crop straw fires.

In numerous developing nations, the pervasive practice of crop residue incineration is a principal contributor to atmospheric contamination in agricultural operations. This study examines the repercussions of such biomass combustion on air quality during the autumnal harvest season, utilizing data acquired from satellite-based remote sensing of fire events and air pollution measurements. Employing wind direction information alongside difference-in-difference and fixed-effects methodologies, this investigation rectifies estimation inaccuracies stemming from the non-random distribution of combustion occurrences. The empirical findings reveal that agricultural residue burning precipitates an elevation in average PM2.5 and PM10 concentrations by approximately 27 and 22 μg/m3 during the autumnal incineration period, respectively. Furthermore, air pollution attributed to residue burning in prominent grain-producing regions exceeds the national average by approximately 40%. By integrating economic paradigms into agri-environmental inquiries, this study offers novel insights and substantiation of the environmental expenditures engendered by crop residue burning, juxtaposed with extant meteorological and ecological research findings.

Harnessing Technology and Entrepreneurship for Sustainable Crop Burning Remediation in India

This study explores the intersection of sustainability, technology, and entrepreneurship in addressing crop burning in India. Crop residue burning is a significant contributor to air pollution and environmental degradation, posing severe health risks and economic challenges. This research investigates the environmental and socio-economic impacts of crop burning, while also analysing current technological solutions such as the Happy Seeder and Pusa decomposer, which have shown promise in reducing residue burning. It also examines policy outcomes and entrepreneurial initiatives that aim to scale these solutions, driving adoption among farmers. Through a comprehensive review of relevant literature, data, and case studies, this paper highlights the real-world challenges faced during implementation, including financial barriers, awareness gaps, and policy constraints. It underscores that while subsidies, technological incentives, and policy directives are crucial, they must be complemented by sustained on-ground efforts through a collaborative CRM model that unites government initiatives, external agencies, entrepreneurial contributions, and grassroots-level farmer engagement.

MSW Management in Two Italian Mountainous Areas

Abstract Two case studies are reported in the present work. They regard municipal solid waste (MSW) management trends in the last decades in two Italian provinces selected to analyse some issues of waste management in mountainous areas. The first case study refers to a selective collection (SC) rate expected to reach 80 % soon. This scenario assumes SC mainly in kerbside mode. The scenario is based on specific local conditions: the absence of a thermo-chemical plant in the territory (but with a part of the residual MSW burnt in a neighbour province), the presence of local plant of anaerobic, and a sanitary landfill for pre-treated residual MSW. The adopted tariff helped increasing the SC rate: indeed, since 2013, a tariff calculated at user level, depending on the behaviour of each user, has been adopted. This is called punctual tariff. The second case study concerns an area where SC reached about 75 %. The punctual tariff has been recently introduced. In this scenario, an incineration plant and a Solid Recovered Fuel (SRF) plant allow implementing an industrial symbiosis solution in conjunction with a cement factory. The work demonstrates that SC can be the core of a correct MSW management and that kerbside collection is fully compatible with mountainous area. However, other issues remain to be optimized yet: the low density of mountain areas makes difficult to implement enhanced solutions of SC (e.g. for diapers) and increases costs for light packaging collection; moreover, the presence of tourist fluxes can significantly affect SC efficiency.

The Impact of Minimum Support Price (MSP) On Crop Residue Burning (CRB) In Punjab and Haryana: Consequences for Air Quality in Delhi

The Impact of Minimum Support Price (MSP) On Crop Residue Burning (CRB) In Punjab and Haryana: Consequences for Air Quality in Delhi

Quantifying the dominant sources influencing the 2016 particulate matter pollution episode over northern India

Contribution of anthropogenic, biomass-burning and natural sources to the spatiotemporal extent of the episode across northern India.

Separation of coal combustion residue for critical element extraction and other bulk uses

Critical rare earth elements are enriched in the >250 μm size fraction of ash with an outlook coefficient > 2.0. Co-extraction with alumina is advantageous. Ash disposal policies should explore size fractions to preserve enriched ash fractions.

Study on flame retardancy of EPDM reinforced by ammonium polyphosphate.

Currently, the most widely used material for solid rocket motor (SRM) insulation is ethylene propylene diene monomer (EPDM) filled with flame-retardant and ablation-resistant fillers. Researchers have been working hard to find a flame-retardant filler that can simultaneously meet the complex requirements of mechanical strength, density, flame retardancy and ablative performance of the insulation layer. This requires research on the flame retardant properties of flame retardants in oxygen-poor environments. In this paper, ammonium polyphosphate (APP) is used as a flame retardant filler, which is filled into an EPDM premix (p-EPDM) containing fumed silica and aluminum hydroxide to prepare composite materials. By creating an anoxic environment, the flame retardant behavior of APP under anoxic conditions on EPDM was studied. The results show that composites prepared with APP show better flame retardant properties in tests such as limiting oxygen index and UL-94, with less impact on mechanical strength and density. The surface morphology and elemental composition of the composite combustion residues were studied using Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). In an oxygen-depleted environment, APP will thermally decompose to form ammonia, water vapor and phosphorus-containing acidic substances. These gases dilute the flammable gas and reduce the thermal conductivity. The acidic substances containing phosphorus are concentrated on the surface of the pyrolysis layer to promote the formation of the carbon layer. This provides guidance for us to design insulation layer materials with properties that are more in line with actual use requirements.