Types Of Ash Research Articles

Exploring the influence of wood ash, maize cob ash, and tequesquite (alkaline rock) on nixtamalization of maize

Nixtamalization, an ancient process vital for maize processing, enhances maize's nutritional value, texture, flavor, and shelf life while reducing mycotoxin contamination, making it a cornerstone technique in maize processing with both nutritional and food safety implications. Initially performed with ashes, modern nixtamalization relies on food-grade calcium hydroxide or calcium oxide (lime). However, regions lacking lime deposits or processing technology necessitate alternative nixtamalization options for sustainable maize processing. This study aimed to assess the mineral composition of alkaline rocks (tequesquite) and two types of ash (wood and maize cob) and determine the optimal cooking conditions to achieve tortillas comparable to those made from lime-nixtamalized maize. Different ash and tequesquite concentrations (5%, 10%, and 15%) were tested with nixtamalization durations of 40, 50, and 60 min. Quality parameters of nixtamal and tortillas were evaluated. Data were analyzed using a completely randomized design with Tukey's comparison of means (p ≤ 0.05) and principal components analysis. Results revealed potassium as the predominant element in the ash, while sodium prevailed in tequesquite. Although significant differences were observed in nixtamalization variables, tortillas made with 5% maize cob ash or tequesquite closely resembled those treated with lime in terms of quality parameters.

Effect of Binary Blended Fillers on the Durability Performance of Recycled Cold-Mix Asphalt

Cold-mix asphalt is a greener alternative to pavement construction, processed at 10–40 °C, which is typically lower than other techniques like warm-mix asphalt and hot-mix asphalt. Huge amounts of construction and demolition waste, such as broken bricks, recycled concrete aggregates, reclaimed asphalt pavement, ceramic waste, etc., are generated every year due to the acceleration in infrastructure development. The production of such massive amounts causes landfilling issues, and their disposal is a serious issue nowadays. This study examines the effect of binary blended fillers on the performance of cold asphalt mixes using emulsified binders and 50% reclaimed asphalt pavement materials. Moreover, three types of binary blended fillers (BBFs), cement, fly ash, and Stabil Road, were used at different dosages. Overall, 500 samples were prepared for the mix design, and the optimum emulsion content was determined as 11% and 9% for the CM and 50R mixes, respectively, based on the Marshall stability peak value and volumetric properties such as voids in the mineral aggregates, total voids, and dry density. The moisture susceptibility of the recycled cold-mix asphalt (RCMA) mixture was evaluated using the tensile strength ratio. Cantabro abrasion loss was used to assess the cohesion resistance of the mixtures. The dynamic response of the mixes to the applied load was evaluated using the resilient modulus. The results of the present study reveal that using BBFs in the RCMA improved the inter-particle bonding and strength. Furthermore, BBF incorporation enhanced the performance of the recycled cold-mix asphalt.

Comparative performance of M-S-H cement vs. portland cement in fiber cement incorporating bamboo leaf ash and cellulosic fibers

This study evaluates the potential of alternative materials such as Hydrated Magnesium Silicate (M-S-H) cement, bamboo leaf ash (BLAsh), and cellulose fibers to enhance the sustainability and performance of fiber cement composites. Innovative in its approach, the research incorporates BLAsh and cellulose fibers into M-S-H and Portland cement (OPC) matrices using an innovative production process: extrusion. For the characterization of different formulations, a comparative analysis was conducted on samples with M-S-H and Portland cement matrices, with BLAsh replacing limestone and the addition of unbleached pine cellulose fibers. The analysis covered the physical, mechanical, and microstructural properties of the composites. After a 7-day curing period, they were subjected to 200 cycles of accelerated aging to evaluate durability. Microstructural analysis revealed the binding potential of the M-S-H matrix used in this study due to the pronounced formation of M-S-H gel and reduced content of Mg(OH)2 over time. The formation of C–S–H and M-S-H gel as the main phase for each type of cement is even more evident in samples incorporating BLAsh, indicating the interaction between both types of matrices and bamboo leaf ash. The study demonstrated that adding BLAsh to the composites significantly improved the modulus of rupture of the OPC samples (approximately 32 %), while considerably reducing water absorption for the M-S-H samples (around 50 %). Aging affected water absorption differently in OPC and M-S-H samples, with OPC showing decreased absorption and the M-S-H showing increased absorption post-aging. The study proved both types of cement suitable for producing composites that meet NBR 15498 standards for external applications. This demonstrates the technical feasibility of these compounds for their production by 3D printing.

Harnessing Ash for Sustainable CO2 Absorption: Current Strategies and Future Prospects.

This review explores the potential of using different types of ash, namely fly ash, biomass ash, and coal ash etc., as mediums for CO2 capture and sequestration. The diverse origins of these ash types - municipal waste, organic biomass, and coal combustion - impart unique physicochemical properties that influence their suitability and efficiency in CO2 absorption. This review first discusses the environmental and economic implications of using ash wastes, emphasizing the reduction in landfill usage and the transformation of waste into value-added products. Then the chemical/physical treatments of ash wastes and their inherent capabilities in binding or reacting with CO2 are introduced, along with current methodologies utilize these ashes for CO2 sequestration, including mineral carbonation and direct air capture techniques. The application of using ash wastes for CO2 capture are highlighted, followed by the discussion regarding challenges associated with ash-based CO2 absorption approach. Finally, the article projects into the future, proposing innovative approaches and technological advancements needed to enhance the efficacy of ash in combating the increasing CO2 levels. By providing a comprehensive analysis of current strategies and envisioning future prospects, this review aims to contribute to the field of sustainable CO2 absorption and environmental management.

Late-Pleistocene rejuvenated volcanism and flank collapse deposits on a Cretaceous seamount near El Hierro, Canary Archipelago

Henry Seamount is a Cretaceous submarine volcano located 40 km southeast of El Hierro, the youngest of the Canary Islands, at 3700 m water depth. On the seamount's summit region, a widespread layer of heterolithologic volcaniclastic ash and lapilli beneath centimeters to decimeters of pelagic sediment was discovered and sampled during R/V Meteor cruise 146. The dominant lithology is a glassy basaltic ash that is depleted in highly incompatible elements and enriched in sulfur (S/K2O ratios of 0.10–0.20) compared to El Hierro lavas, suggesting an origin by a deep-sea volcanic eruption on Henry Seamount. Uranium-series disequilibria constrain the age of this ash to <350 ka, which implies rejuvenated volcanic activity of the seamount after up to 126 Ma of dormancy. This rejuvenated activity is possibly related to the Canary hotspot, where heating of lithosphere that had become amphibole-metasomatized during the formation of Henry Seamount led to renewed melt production. In contrast to the dominant ash type, most other volcaniclastic samples are geochemically indistinguishable from El Hierro lavas. The variety of lithologies, the angular to edge-rounded shapes of many fragments, and intimate mixture with the predominant ash suggest that this group of volcaniclastics was transported from El Hierro to Henry Seamount by a submarine debris avalanche and associated turbidity current. This implies a runup of up to 700 m even for centimeter-sized basaltic clasts after up to 40 km of lateral transport. ArAr age constraints for two samples are ∼190–200 ka, which is consistent with the southeast-directed giant Las Playas II landslide from El Hierro as the most likely source. Henry Seamount thus provides a rare example where collapse-induced deposits from another volcanic edifice are found on top of a seamount and are mingled with ash to lapilli from previous rejuvenated volcanism. Mingling and reworking of the tephra may explain the lack of a discernible eruption center on top of the seamount.

Phosphorus Release Dynamics from Ashes during a Soil Incubation Study: Effect of Feedstock Characteristics and Combustion Conditions

Recovering phosphorus (P) through combustion from waste streams, like wastewater sludge and animal manure, offers a promising solution. This research explores the P release patterns in different ashes derived from secondary raw materials, using a long-term soil incubation lasting 160 days. The study evaluated the P release dynamics in five types of ashes from enhanced biological phosphorus removal (EBPR) systems and pig slurry burned at different temperatures. According to the results, a primary effect was observed on P bioavailability during the initial incubation period. All tested ashes release more than 50% of the total P applied between days 5 and 10. Ashes from EBPR exhibited higher P release than those from pig manure, indicating ash origin as a key factor in P release. Additionally, combustion temperature was crucial, with higher temperatures resulting in increased P release rates. Furthermore, the Pearson correlation revealed a strong relationship between the characteristics of the ashes and the amount of P release. Overall, these findings suggest that ashes could be a valuable P-source for agriculture avoiding the process of wet chemical P extraction, thus reducing both economic and environmental costs.

Immediate traceability of ash based on laser-induced breakdown spectroscopy and machine learning

This article reports on an advanced level physical laboratory experiment designed for college level undergraduate education and for scholars who need specialized training on using and interpreting Laser-Induced Breakdown Spectroscopy. The technical principle, experimental operation and sample preparation of Laser-Induced Breakdown Spectroscopy are introduced in detail. A presentation and discussion of the use of Laser-Induced Breakdown Spectroscopy in the traceability of four common samples is emphasized. Combining Laser-Induced Breakdown Spectroscopy with Machine Learning, two distinct datasets are constructed through the extraction of spectral features. Dimensionality reduction of spectral data is performed using Linear Discriminant Analysis, while the Random Forest model is employed for provenance classification. Finally, the interpretability of the Random Forest model is leveraged to explore the contributions of different spectral elements to provenance tracing. Results demonstrated the system’s effectiveness in not only accurately identifying ash types but also in elucidating the influential chemical components, offering significant implications for material analysis and environmental monitoring. On an educational standpoint, this paper will allow any reader, in particular, undergraduate and graduate students, to gain a better understanding of the theory and practice of Laser-Induced Breakdown Spectroscopy and machine learning.

Effects of Rest Time and Curing Regime on Short- and Long-Term Strength of Class C Fly Ash-Based Alkali-Activated Mortars.

This study investigated how different rest times affect the strength development of fly-ash-based alkali-activated mortar (AAM) over a period of 90 days. Two types of fly ash with varying calcium oxide contents of 37 and 21% were used. The rest times ranged from 2 to 36 h, and three curing methods (ambient, oven, and steam) were tested. The results showed that the rest time significantly influenced the compressive strength of the AAM. The optimal rest time was found to be between 12 and 30 h depending on the curing method and fly ash type. Beyond this range, there were only minor changes in strength. One type of fly ash (FA21) showed higher strength with longer rest times up to 30 h, while the other type (FA37) had the highest strength within a rest time range of from 12 to 24 h. Over the 90-day period, the specimens cured under ambient, oven, and steam conditions at 55 °C (131 °F) experienced increasing strength, but those steam-cured at 80 °C (176 °F) showed a decrease in strength. Analysis revealed the formation of hydration products in FA37, while FA21 showed a reduction in peaks for its main compounds. Additionally, XRD analysis revealed the formation of hydration products (CSH and CASH) in FA37, while FA21 displayed a reduction in peaks for its main compounds. EDS analysis indicated the presence of partially unreacted FA particles, highlighting the impact of curing methods on dissolving FA particles and the formation of geopolymer products (NASH and CNASH) responsible for compressive strength development.

Application of Arc Furnace Flue Ash in Casting Heat Insulation Riser

Iron black commonly employs in thermal insulation riser sleeves due to its ability to react with aluminum powder, generating heat. However, the complex production process and unstable composition of iron black lead to high production costs. The potential of using arc furnace flue ash (AFFA) as a complete substitute for iron black and MnO2 and KNO3 oxidizing agents in conventional riser sleeves was investigated in this study. Waste material can be transformed into a valuable resource, while production costs can be reduced by utilizing arc furnace flue ash. The research examined the impact of varying types and amounts of arc furnace flue ash on riser sleeve temperature and holding time by conducting single-factor and orthogonal optimization experiments. The orthogonal optimization experiment determined that the optimum ratio of each oxidant was 6 % arc flue ash, 3 % MnO2 and 6 % KNO3. At this time, the highest temperature was 1512 ℃ and the holding time was 244 s. Results indicated that different types of arc furnace flue ash used as an oxidizing agent demonstrated superior holding capacity and heat generation performance compared to iron black. Additionally, a comparative analysis of factory casting experiments using ductile iron 600-3 (IS) revealed that both arc furnace flue ash and iron black risers effectively countered shrinkage. However, arc furnace flue ash risers exhibited improved mechanical properties, as evidenced by the hardness of the castings.

Valorization of waste wood fly ash in environmentally friendly lime-based plasters with enhanced strengths for renovation purposes

Waste wood fly ash (WWFA) generated during wood chips combustion in a power plant does not have any application nowadays and is commonly disposed of or landfilled. Nevertheless, considering its composition and reactivity in the presence of calcium hydroxide, it is one of the promising materials that could be used as an active admixture for modification and partial replacement of lime in lime plasters. This solution seems to be a suitable step to both improve the properties of the traditional lime plaster and reduce carbon dioxide emissions. Therefore, this comprehensive study describes a wide range of properties of lime plaster with WWFA (up to 50 wt% lime replacement) as an active admixture. Compositions of studied plasters were firstly analyzed with the help of XRD, DSC, and SEM, and then the effect of WWFA on the physical, mechanical, hygric, and thermal properties was investigated. The obtained results showed that the application of WWFA led to lower total porosity, highly improved mechanical properties, higher thermal conductivity, and lower water transport capability, which could be attributed to its pozzolanic activity. The performed experiments fundamentally broadened the existing insufficient knowledge about the utilization of WWFA for lime-based plasters improvement. All tested lime-based plasters (with 10, 20, 30 and 50% lime replacement by WWFA) have a high potential for common use in practice, especially in the historical buildings renovation. The originality of this paper lies, among others, in using a specific type of fly ash (originating from waste wood, not coal) and in testing a wider range of characteristics and properties of designed lime-based plasters with WWFA with respect to their changes over time, which enables prediction of plasters' durability.

Risk control of heavy metal in waste incinerator ash by available solidification scenarios in cement production based on waste flow analysis

Incineration is a common method in municipal solid waste management, which has several advantages such as reducing the volume of waste, but with concerns about exhaust gas and ash management. In this study, heavy metals in bottom ash, secondary furnace ash and fly ash of two waste incinerators in Tehran and Nowshahr were analyzed and its control in cement production was investigated. For this purpose, twelve monthly samples of three types of incinerator ash were analyzed. By combining the studied ashes in the raw materials, the quantity of metals in the cement was analyzed. Finally, by investigating four scenarios based on quantitative variations in the routes of municipal solid waste, ash quantity and the related risk caused by its heavy metals were studied. The results showed that the concentration of heavy metals in the three ash samples of the studied incinerators was 19,513–23,972 µg/g and the composition of the metals included Hg (less than 0.01%), Pb (2.93%), Cd (0.59%), Cu (21.51%), Zn (58.7%), As (less than 0.01%), Cr (15.88%), and Ni (0.91%). The best quality of produced cement included 20% ash and 10% zeolite, which was the basis of the next calculations. It was estimated that the reduction of the release of metals into the environment includes 37 gr/day in best scenario equal to 10.6 tons/year. Ash solidification can be considered as a complementary solution in waste incinerator management.

Innovative shielding solutions by geopolymer paste and fly ash as effective substitution of cement materials for sustainable protection

This study aimed to evaluate gamma radiation shielding material based on fly ash (FA) type ASTM C 618 Class F with a sodium silicate solution with two molarity values. The composite geopolymer paste was synthesized by activating the alkaline solution and curing at 70 °C for 1 h. The sodium silicate solution was added to the FA matrix with two molarity values of SiO2/Na2O (2.2 and 3.3). The density of each sample GPp1 and GPp2 are 2.121 g/cm3 and 2.212 g/cm3, respectively. The XRD patterns revealed the successful preparation of the prepared samples. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) determined the samples' surface morphology and elemental composition. The compressive strength of GPp2 sample was higher than for the GPp1 sample at 7 and 28 days, respectively. The density and tensile strength of the GPp2 sample are high compared to GPp1. Also, the thermal expansion coefficients for GPp2 are 5.16 × 10-4 K-1 while the GPp1 equals 2.65 × 10-4 K-1. To evaluate the photon shielding competences of the geopolymer samples, the parameters such as half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), effective electron density (Neff), and exposure buildup factor (EBF) were calculated. The highest Zeff was obtained for the GPp2 sample, whereas the lowest values were obtained for MFP, HVL, and Neff. Additionally, μm values were compared to theoretical Phy-X/PSD. It can be concluded that the investigated fly ash-based geopolymer paste is a promising material for gamma radiation shielding.

Evaluation of brown coal fly ash for stabilising expansive clay subgrade: A sustainable solution for pavement construction

Brown coal fly ash (BCFA) is a lower-quality type of fly ash produced through brown coal combustion, and its disposal in landfills raises environmental concerns. This study, for the first time, evaluates the feasibility of using BCFA for stabilising expansive clay subgrade in pavement construction. Various engineering tests were conducted, including unconfined compressive strength (UCS), repeated load triaxial (RLT), soaked California bearing ratio (CBR), direct shear, and shrink-swell tests. The results indicated that adding BCFA increased UCS, resilient modulus, soaked CBR, and cohesion while reducing shrinkage-swell index and shrinkage/swell strain. The highest resilient modulus (82.52 MPa) and soaked CBR (3.41 %) were achieved with 3 % BCFA content. These findings recommend using 3 % BCFA as the optimum content for stabilising expansive clay subgrade. This research fills a gap by assessing the application of BCFA for stabilising expansive clay soil, providing insights for sustainable utilisation of this abundant waste material in construction.

Transformation and environmental chemical characteristics of hazardous trace elements in an 800 t/d waste incineration thermal power plant

The hazardous trace elements (HTEs) emitted during the municipal solid waste incineration (MSWI) process have been widely concerned. In this work, the bottom ash (BA), heat recovery boiler ash (HA), and ash after desulfurization (SA) were collected to explore the occurrence forms of HTEs in the three types of ash and their relationship with minerals and leaching characteristics. The results show that the volatility of the seven studied HTEs follows the order of Cd, As > Ni, Zn > Pb > Cr, Cu. In the process of BA → HA → SA, the content of Cd, As, Zn, and Pb shows an increasing trend. The seven HTEs are mainly in the forms of chlorides and oxides. There is an obvious relationship between the occurrence forms and simulated existence form of HTEs. SiO2 and CaCO3 are the major mineral components in the three ashes, while SA also contains chlorine-containing compounds which are easily leached out. The risk assessment code and soluble ratio show that HTEs in SA are more leachable than BA and HA, where Cd, Pb and Ni need to be addressed to reduce their impact on soil or water during subsequent landfill treatment of SA.

Evaluation of selected burnt plant residues and mineral fertilizers on soil properties and nutrient uptake and growth parameters of oil palm seedlings

Oil palm seeds are difficult to grow due to poor viability; that is why they are raised in nursery. Addition of right and adequate fertilizer is needed to improve soil fertility. Thus, an experiment was conducted in 2022 to compare the effect of empty palm bunch (EPBA) ash, cocoa pod husk ash (CPHA), kola pod husk ash (KPHA), NPK 20:10:10, urea, calcium ammonium nitrate (CAN) and muriate of potash (MOP) fertilizers on soil properties, nutrients uptake and growth parameters of oil palm seedlings in Ondo, southwestern Nigeria. Soil samples were collected from Adeyemi Federal University of Education oil palm plantation. Each of the dried empty palm bunch, kola pod husk and cocoa pod husk was burnt and applied as treatments at the rate of 0, 2, 4 and 6 g 900-g−1 soil while NPK 20:10:10, urea, MOP and CAN fertilizers were individually applied at 2 g 900-g−1 soil. The 16 treatments were replicated four times and arranged in completely randomized design. A 900 g of soil was put in each poly pot and planted with Tenera variety of oil palm and watered with 50 cl water daily. The native soil used for the experiment was deficient in major nutrients and adequate in minor nutrients. Relative to the control, application of 2, 4 and 6 g ash types significantly increased plant height, number of leaves, root length and plant girth. NPK, recorded the highest increase in plant height. Leaf length and root length were highest with the application of 6 g KPHA. Application of 6 g EPBA recorded the highest biomass, dry and wet weight and seedlings moisture content. Kola pod husk ash applied at 6 g plant−1. Empty palm bunch ash applied at 6 g plant−1 and cocoa pod husk ash applied at 4 g plant−1 compared favourably with mineral fertilizers in raising vigorous and healthy oil palm seedlings.

Characterization of Coal Combustion Products from Malaysian Power Plant for Building Materials Applications

Coal combustion by Products (CCPs) are produced during coal combustion in the process of electric generation. Without proper handling system, this will cause serious problems towards human and environmental. Nevertheless, with proper treatment, these ashes are applicable in many areas specially building construction materials. Coal Bottom Ash, Coal Fly Ash and Cenosphere are three main wastes produced from power plant. The aim of this study is to determine the characteristics of samples collected from different parts of Malaysia Power Plant. Characterization testing involved included surface morphology, chemical composition (oxides), chemical components, amorphousness, and particle size distribution testing. From this study, CBA have more angular-shaped particles compared to CFA which is smoother surface morphology. However, Cenosphere shown the most uniform and spherical shaped particles. EDS testing shown Existing CBA have highest Carbon content (46%) while Cenosphere is lowest (11.38%). The percentage oxides contents for all samples demonstrate more than 70% of Total SiO2 + Al2O3 + Fe2O3. Hence, all ashes considered as Class F (pozzolanic). CBA, SFA, CFA and cenosphere has significantly more amorphous phases of silica and alumina, and this will increase the concrete strength. Due to agglomeration of ashes on ash pond, the cumulative PSDs results shown that the particle size of the existing sample obtained larger than the new sample. Minimum particles size of SFA (New Dry) is 2 µm while SFA (Existing 2) is 20 µm. From characteristic determination above, it shown that each type of ashes has its own uniqueness and capability to be applied wide range of applications.

Removal of anionic dyes from wastewater using fly ash based adsorbent

Facing the great challenge of increasing solid waste and huge amount of wastewater, “treating the wastes with wastes” seems to be a proper and sustainable development method. Fly ash, a typical solid waste, has attracted much attention for its high-value applications. In this study, three types of fly ash were sampled from different power stations in China and used for multiple anionic dyes wastewater adsorption. According to the static adsorption, fly ash sourced from Chifeng (CF) was identified as Class C with a total amount of SiO2, Al2O3, and Fe2O3 of 67.65% via chemical composition analysis, and presented best adsorption performance on Reactive Brilliant Red K-2BP, Congo Red 4BS, and Acid Brilliant Red KN. Moreover, the pseudo-second-order kinetic fitted the adsorption processes of KN and 4BS with the theoretic adsorption capacity of 39.35 and 39.85 mg/g, respectively. However, the pseudo-first-order kinetic better described the adsorption process of K-2BP with the theoretical adsorption capacity of 43.24 mg/g. For the dynamic adsorption, the decolorization rate of K-2BP on CF increased from 82.6% to 96.5% as the flow velocity increased from 10 to 70 rpm. The metal cations on CF, such as Fe3+ and Al3+, could hydrolyze and work as flocculants and coagulants to remove dye molecules from wastewater. This study provides a research case and an application potential for the resource reutilization of fly ash to treat printing and dyeing wastewater.

Resource Disposal and Products of Fly Ash from Domestic Waste Incineration in Zhejiang Province, China: Migration and Change of Hazardous Heavy Metals

At present, domestic waste incineration fly ash is classified as hazardous waste. The technical hurdle of fly ash detoxification and resource usage must be overcome in order to effectively utilize fly ash resources. In this study, we investigate the migration and transformation of heavy metal contaminants in the course of utilizing domestic waste incineration fly ash resources through the technology pathway of low-temperature pyrolysis, cyclic rinsing, and evaporation crystallization. Firstly, a comparative analysis was conducted on the fly ash (FA), pyrolysis ash (PA), and water-washing ash (WA) resulting from domestic waste incineration, revealing 24 types of metals, 3 types of non-metals, and 8 types of oxides. We observed the variations in heavy metal concentrations as well as the acidity and alkalinity in three types of ash resulting from the regenerated salt (RS) and incineration processes. Moreover, we analyzed the changes in heavy metal levels and acidity and alkalinity of treated saline water (TSW) and industrial brine (IB), which originate from the fly ash treatment process. The study’s results have confirmed that the heavy metal content in RS was below the detection limit following resource treatment. In addition, the regenerated salt product is determined to be a CaO-SiO2-Al2O3-Fe2O3 system, which enables the utilization of fly ash as a valuable resource. Notably, there were significant changes observed in heavy metal content in TSW and IB. Continued attention needs to be paid to the potential risk of environmental contamination from heavy metals and dioxins in FA infiltration. This research will prove beneficial in assessing resource utilization potential of products subjected to environmentally sound incineration fly ash treatment.

Application of the Min-Max Stock Method in the Inventory Control of the Raw Materials for the Cement Production at PT XYZ

PT XYZ is the largest cement manufacturer in Indonesia that produces cement with different types of cement, namely OPC, PCC, and PPC. The implementation of its production process, starts with the mixing of raw materials, processing, and packaging to the finished product, namely cement. PT XYZ has a problem in the form of raw material inventory that has not been well controlled because the raw materials are often placed outside the storage area provided by the company due to overloading, thus taking up space that should not be used as a raw material storage area. In this study, the minimum-maximum method is applied to 4 types of raw materials, silica sand, gypsum, trass, and fly ash. By determining the amount of safety stock, minimum stock, maximum stock, reorder point and order quantity, companies can effectively determine the raw material inventory policy to avoid overstock or stockout. The study uses a 99% service level with a 1% risk of out-of-stock products. The results of the study obtained the safety stock value of silica sand 3,854 tons; gypsum 4,405 tons; trass 10,456 tons; and Fly Ash 511 tons. Then, the minimum inventory calculation is carried out, it is known that the minimum inventory results are in Fly ash raw material of 776 tons while the results for maximum inventory are in Trass of 34,613 tons. After the min-max calculation, the ordering policy for each material can be obtained, silica sand 5,255 tons, gypsum 9,111 tons, trass 22,534 tons, fly ash 776 tons.

Correlation analysis of various characteristics of fly ash based on particle separation

Due to the diversity of fly ash particles, it is a scientific way to promote the comprehensive utilization of fly ash with high efficiency to sort and classify the particles. The correlation between sorting indices and various characteristics of fly ash is the theoretical basis for its separation and classified application. In this paper, fly ash from three different coal-fired power stations is separated according to particle size and apparent density. The composition, morphology, and pozzolanic activity of the separated fly ash particles were characterized by several test techniques including X-ray fluorescence, X-ray diffraction, polarized light microscopy, scanning electron microscopy and lime absorption test. The correlation laws between different characteristics common to three types of fly ash were analyzed. The results show that the alkaline oxide (CaO+MgO+K2O+Na2O) content of fly ash varies accordantly with particle size, apparent density, glass phase content and pozzolanic activity. 40 µm and 80 µm are the critical particle size for the obvious change of glass phase content and microstructure of fly ash particles, and 2.5 g·cm−3 is the critical apparent density for the change of phase composition. Pozzolanic activity is determined together by alkaline oxide content and acid oxide (SiO2 +Al2O3) content, and there is no obvious single factor relationship between pozzolanic activity and particle size or apparent density.