Sawing Waste Research Articles

RESULTS OF EXPERIMENTAL RESEARCH ON OBTAINING LOW- CEMENT WALL MATERIALS FROM WASTE OF SAMING OF LOCAL LIME STONES

The results of experimental studies are presented on the production of single low-cement modified dry-pressed bricks from limestone stone sawing waste from Martakert stone quarries. The technological parameters for the manufacture of these bricks and their physical and mechanical properties have been established. A high convergence of the properties of the resulting wall material was determined in comparison with ceramic and silicate bricks used in construction. Using the method of analogy, the compliance of the quality indicators of experimentally obtained bricks with the requirements of regulatory documents was proven. The fundamental possibility of producing low- cement bricks from stone sawing waste from local quarries, as well as their use in construction, has been established. The production of low-cement bricks makes it possible to increase construction efficiency and reduce the cost of operating completed facilities. This also leads to a reduction in environmental risks from the accumulation of stone sawing waste in large areas and pollution of the air and water basins of the region.

Peningkatan Produktivitas Tanah Sulfat Masam dan Hasil Padi Menggunakan Bioarang dari Limbah Industri Penggergajian Kilang Kayu

The study aims to analyze three aspects. (1) Formulation of biochar from wood refinery sawmill waste at pyrolysis temperatures of 450°C and 550°C with pyrolysis times of 2 and 4 hours. (2) The best wood refinery sawing waste biochar dosage to improve the chemical quality of acidic sulfate soil through improving soil pH, Al-dd, N, P, and K of the soil. (3) Growth and production of paddy on acidic sulfate soils by application of ameliorant biochar of waste sawmill wood mill. The research was conducted in acidic sulfate soil in a screen house in the Experimental Garden of the Faculty of Agriculture, Syiah Kuala University. Soil samples and biochar were analyzed at the Soil and Plant Research Laboratory of the Faculty of Agriculture. The study was an experiment using a factorial complete randomized design with two factors: the temperature and pyrolysis time and the dose of biochar. The results showed that the application of biochar waste from sawmill wood refineries had a very significant and significant effect on improving the quality of acidic sulfate soil and the growth and production of rice fields. The formulation of biochar at a pyrolysis temperature of 550°C for 2-hour pyrolysis with 20 tons/ha is the best improvement in acid sulfate soil quality, growth, and rice field production.
 
 Keywords: acid sulphate, biochar, paddy

Valorization of natural stone sawing waste as a functional additive in ceramic tile production

Valorization of natural stone sawing waste as a functional additive in ceramic tile production

Improving flotation separation of micro Si/SiC particles from silicon sawing waste by surface hydrophilic modification

Silicon sawing waste (MSW) produced by mortar cutting causes serious environmental issues and a waste of high-purity silicon. The major obstacle in the recovery of high-purity silicon (Si) is the separation of microscale Si and silicon carbide (SiC) in MSW. In this study, micro Si/SiC in silicon sawing waste was separated effectively by bulk-oil flotation after surface hydrophilic modification of Si particles. The structural evolution of micro Si surface after wet oxidization in water and acid was characterized by FT-IR, TEM, and XPS. Specifically, the wet oxidization process reduced the contact angle from 63 ± 0.3° to 18.5° of Si surface for the coating of an amorphous oxide with hydroxy groups on Si particles enhanced the wettability. The amorphous oxide layer with hydroxy coated on Si particles played a key role in enhancing the wettability of Si particles. The wet oxidization is essential to the subsequent flotation separation for the contact angle of SiC keeping at around 60.3°. The wettability of silicon sawing waste was further examined by the absorption of diesel. The effects of pH value and solid concentration on separation efficiency were studied. The best result obtained was 95% in Si recovery and 97.1 wt% in Si purity.

Silicon recovery from Si sawing waste through slag refining

• Slag refining was employed for Si recovery from Si saw waste because of θ SiC/ CaO–SiO2–MgO < θ SiC/Si . • The movement and dissolution behaviors of SiC were observed in situ and in real-time using HT-LSCM. • A prolonged slag refining time was conducive to increasing the SiC removal efficiency. Recycling Si from Si sawing waste is a good approach aiming at meeting the rapidly increasing demand for Si, and the separation of Si and SiC particles plays a key role in the production of high-quality Si. In this work, Si was successfully recovered from Si sawing waste by using a CaO–51mol%SiO 2 –15mol%MgO slag. This recovery included measurement of the contact angle between a CaO–SiO 2 –MgO slag and SiC using the sessile drop method. The results, θ SiC/SiO2–CaO–MgO < θ SiC/Si (i.e., 21.7° < 38°) at 1753 K, confirmed the feasibility of applying the slag refining technique to SiC particle removal. Furthermore, with the help of high-temperature laser-scanning confocal microscopy, the movement and dissolution behaviors of SiC were observed in situ and in real-time. A prolonged slag refining time provided sufficient time for SiC particle transfer across the Si/slag interface and dissolution in slag, thereby resulting in a high SiC particle-removal efficiency.

Porosity of Calcium Silicate Hydrates Synthesized from Natural Rocks.

In this work, the suitability of natural raw materials with various modifications of SiO2—granite sawing waste (quartz) and opoka (a mixture of cristobalite, tridymite, quartz, and an amorphous part)—for the 1.13 nm tobermorite and xonotlite synthesis is examined, and their specific surface area, pore diameter and volume, and the predominant pores are determined. Hydrothermal syntheses were carried out at 200 °C for 12 and 72 h from mixtures with a molar ratio of CaO/SiO2 = 1.0. X-ray diffraction analysis, simultaneous thermal analysis, and scanning electronic microscopy were used, which showed that in the lime–calcined opoka mixture the formation of crystalline calcium silicate hydrates takes place much faster than in the lime–granite sawing waste mixture. The high reactivity of amorphous SiO2 results in the rapid formation of 1.13 nm tobermorite and xonotlite (12 h). According to Brunauer, Emmet and Taller (BET) analysis data, this product features a specific surface area of ~68 m2/g, a total pore volume of 245 × 10−3 cm3/g, and has dominating 1–2.5 nm and 5–20 nm diameter pores. This porosity of the material should provide good thermal insulation properties of the products made from it as no air convection occurs in the fine pores.

Influence of wood additives on pyrolysis products composition of mixed fuels based on 3B grade lignite

Experimental analysis of the influence of wood biomass on the composition of pyrolysis products of mixtures based on crushed coal (“Lignite” (3B)) and fine wood (lumber sawing waste) has been performed. Ash residue composition of the main components of fuels and mixtures based on them has been determined experimentally using X-Supreme 8000 element analysis device. Fuel mixture samples were used with a percentage of coal / wood – 100 % / 0 %, 90 % / 10 %, 75 % / 25 %, 50 % / 50 by weight. The experiments have been performed in an inert gas (Argon) environment at temperatures of 400 °C, 600 °C, and 800 °C. It has been established that during pyrolysis of two-component fuels based on 3B grade coal and dispersed wood biomass, there is growth of calcium and aluminum sulfates in the solid products of thermal decomposition of such mixtures (ash) due to a complex of reactions between pyrolysis products of coals and wood when the concentration of the wood component in the mixture changes from 10% to 50 %. Results of experimental studies allow substantiating previously formulated hypothesis about the mechanism of sequestering of sulfur oxides formed during coal pyrolysis as a result of interaction with gaseous products of thermal decomposition of wood and solid products of coal pyrolysis.

Preparation of Low-Boron Silicon from Diamond Wire Sawing Waste by Pressure-Less Sintering and CaO–SiO2 Slag Treatment

In order to recover silicon from diamond wire sawing waste, silicon extraction and boron removal are two key issues that need to be addressed. In this study, a combined process of pressure-less sin...

The pitch-based silicon-carbon composites fabricated by electrospraying technique as the anode material of lithium ion battery

Silicon is regarded as one of the most promising anode materials for high performance lithium-ion battery (LIB) due to its high theoretical specific capacity. However, the low electrical conductivity and the severe volume change during charging and discharging process result in poor cyclic performance. In this study, a low cost, high-purity silicon powder from the sawing waste in photovoltaic industry was used as the active material. Pitch from petroleum residue was used as carbon source to provide a good conductive pathway and prevent the drastic volume changes of Si. The pitch-based silicon-carbon composites with a porous structure were fabricated by electrospraying technique followed by a sequence of thermal processes. The results of the charge/discharge showed that the 100th charge capacity of 1515 mAh/g at 0.2 C with the retention of 73.95% while the 200th charge capacity of 929 mAh/g at 0.5 C with the retention of 70.61% (Pitch-Si-0.5) can be obtained. On the other hand, the sample with medium content of Si showed charge capacity of 522 mAh/g at 0.5 C with the extremely high retention of 94.99% after 200 cycles. The rate capability indicated that the soft carbon derived from pitch provided a good rate capability because of its amorphous structure. We demonstrated that industrial wastes can form a superior anode material for LIB application.

Peculiarities of xonotlite synthesis from the raw materials with different SiO2 activities

In this work, the peculiarities of xonotlite hydrothermal synthesis at 200 °C from lime and SiO2 materials with different pozzolanic activities (AP) were investigated: calcinated opoka (Ap = 170.1 mgCaO kg−1), granite sawing waste (Ap = 52.2 mgCaO g−1) and reagent SiO2·nH2O (Ap = 336.8 mgCaO kg−1). By XRD, DSC, TG, SEM, FT-IR methods have been shown that the formation of crystalline calcium silicate hydrates and the sequence of the intermediate phases existence are influenced not only by SiO2 component activity, but by other factors too. The use of the most active raw meal with SiO2·nH2O results in a very rapid formation of z-phase, C–S–H(I) and gyrolite, which hardly recrystallize into thermodynamically stable mineral—xonotlite. The impurities in the starting materials may promote the formation of some other compounds and retard the synthesis of stoichiometric ones: high content of Al-containing minerals in granite sawing waste (15.41% of Al2O3) predetermines that 1.13 nm tobermorite even after 72 h of hydrothermal curing did not recrystallize into xonotlite. Regardless of its average activity, calcinated opoka is an excellent material for the synthesis of crystalline calcium silicate hydrates. Amorphous SiO2 from opoka begins to react first, followed by tridymite and cristobalite. 1.13 nm tobermorite and xonotlite are formed at the beginning of the hydrothermal synthesis (4 h), and this greatly reduces the probability of the existence of amorphous phases.

SIFAT FISIK DAN MEKANIK PAPAN SEMEN DARI LIMBAH PENGGERGAJIAN BERDASARKAN UKURAN PARTIKEL DAN KOMPOSISI SEMEN

This study aims to examine the physical and mechanical properties of cement boards from sawing waste based on raw material composition and particle size, as well to get the best sawing waste particle size and raw material composition according to JIS A5417-1992 standard. The research was carried out at the Wood Workshop Laboratory, Wood Technology Laboratory, Wood Processing Laboratory and PT Duta Pertiwi Nusantara Pontianak. This study uses a completely randomized factorial design (CRD) with two factors, namely factor A (Particle Size) and factor B (composition of cement). The results showed the average value of density ranged from 0.6878 to 0.8094 gr / cm3, moisture content value ranged from 6.7057 to 10.0246%, thickess swelling value ranged from 0.3996 to 0.8773%, water absorption value ranged from 27.8949 - 49.0375%, MOE ranged from 412.6563-1411.7847 kg / cm2 and MOR value ranged from 2.1529-4.5909 kg / cm2. The particle size that affects the physical properties is the value of water absorption, while the composition of the material that affects the physical properties is the density, water content, thickness development and water absorption capacity. The particle size and composition of the material which influence the mechanical properties, namely the value of the flexural firmness and fracture firmness. Based on the results of cement board testing with particle composition and cement (1:2) with particle size passing 10 mesh restrained 20 mesh yields the best physical properties of cement board that meet the standards of JIS A 5417: 1992, while none of the cement boards MOE and MOR meet the testing standards mechanical properties according to JIS A 5417: 1992.Keywords: Cement board, composition of cement, particle size, sawing waste

Silicon recovery from silicon sawing waste by removal of SiC impurity via CaO–SiO2–Na2O slag absorption

The removal of SiC restricts the recycling of silicon from wire sawing waste. Although the silicon in sawing waste can be easily enriched to around 90 wt%, it is difficult to further increase the purity. In this study, silicon ingot was successfully recovered from silicon sawing waste by using a CaO–SiO2–Na2O slag refining method. CaO–SiO2 slag was selected to absorb SiC particles from liquid silicon owing to its excellent wettability on SiC. Na2O was used to decrease the slag viscosity and improve the SiC transfer. SiC mass transfer coefficients in molten slag were calculated for different Na2O contents. The effects of operating variables on SiC removal and silicon yield were investigated, including the Na2O content, refining time, and slag/silicon ratio. The best result was a decrease of SiC content to less than 0.19 wt% from 9.07 wt% in the silicon ingot and a silicon yield of 76.5%.

Silicon Waste from the Photovoltaic Industry - A Material Source for the Next Generation Battery Technology?

In the photovoltaic industry a total of 100,000 tons of silicon is lost as waste per year. This waste is originating from several cropping and sawing steps of the high purity silicon blocks and ingots during the solar cell wafer production, resulting in a silicon containing suspension. Among different approaches to recycle the silicon from this waste is the utilization of hydrocyclones, which can be used to separate or classify particles by weight and size. In this work the use of a hydrocyclone was evaluated to upgrade the silicon fraction from a typical sawing waste. A potential field of use for the recycled silicon particles might be as anode material for next generation lithium ion batteries.

A Novel Approach for the Recycling and Reusing of Silicon Slurry Waste

In silicon wafer manufacturing for solar cells, the hazardous sawing waste results in serious environmental problems. In this paper, a novel approach for the recycling and reusing of slurry waste is reported. The results show that slurry waste is recycled and reused completely, and composite material of Si3N4-Si2N2O-SiC is prepared. The residual gas from oxygen enrich gas production is used, which reduced cost effectively. In addition, the reaction is exothermic, which is also energy saving and ensure the production to be continuous without external heat source. The mechanism was also discussed in this paper.

Reusing granite sawing waste in self‐compacting concrete with polypropylene fiber at low‐volume fractions

This study aims to experimentally investigate the possibilities of reusing Granite Sawing waste (GSW) in Fibre Reinforced Self Compacting Concrete (FRSCC) using Polypropylene (PP) fibers. The effectiveness of GSW at 5, 10, 15, and 20% by weight instead of cement was investigated. The PP fibers were used at volume fractions of 0.05, 0.1, and 0.15%. In order to study the microstructure and to identify the elements of the FRSCC, SEM was used. Fresh and hardened properties were evaluated. Flyash was used as an additional mineral admixture while superplasticizer was also added to achieve required flow parameters. The GSW along with PP fibers increases the compressive strength of FRSCC. An improvement in splitting tensile strength was also observed.

Applications of green materials for the preparation of eco-friendly bricks and pavers

The most basic and primary building material for construction of houses is the conventional brick. The rapid growth in today’s construction industry has obliged the civil engineers in searching for more efficient and durable alternatives far beyond the limitations of the conventional brick production [1-2]. A number of studies have been made and serious steps have been taken in manufacturing of bricks from several waste materials. However, the traditional mean of bricks production which has brought hazardous impacts to the context has not yet been changed or replaced by more efficient and sustainable one [3], [4]. Most of the researches went through enhancing the clay brick quality and properties by mixing the clay with various recycled wastes as foundry sand, granite sawing waste, harbour sediments, perlite, sugarcane, baggase ash, clay waste and fine waste of boron, sewage sludge, waste glass from structural wall and other different wastes. Compile this state of the art work of manufacturing bricks in the past and the current trend in the bricks industry with respect to the raw materials, ways of manufacturing and the out- comings.This project presents an experimental study on the utilization of waste materials which replaces clay with (Plastic covers, Ceramic Powder, Egg Shell Powder, GGBS, Silica Fume, Rice Husk Ash and Lime Powder) and Fine Aggregate with (Recycled glass, Dry Grass, Dead Leaves, Tree barks powder, Sugar cane powder, crumbed rubber) to produce eco-friendly Bricks. This project is an attempt to fill the gap of the past studies and suggest more sustainable and sophisticated methods of brick manufacturing in the future. 40 percent replacement of fine aggregate with crumbled rubber and dry grass in mortar bricks have given encouraging results, also the replacement of cement by egg shell powder at 20% has given a considerable result

Quality attributes of commercial charcoals produced in Amapá, a Brazilian state located in the Amazonia

The charcoals of Amapa, a Brazilian state located in the Amazonia forest, have been produced from wastes of high-quality native and exotic wood species. However, there is no control to avoid mixing raw materials with different potentials for bioenergy. This work aimed to compare the quality of two brands of Amapa charcoals for domestic use, besides to analyze the variability of properties within and among packages. Charcoals of brands A and B were produced from harvesting wastes of Acacia mangium wood and sawing wastes of mixed native wood species, respectively. Five packages of each brand were acquired, from which thirteen samples were randomly selected for physical and chemical analyses. The higher heating value was estimated from the chemical composition. The brands were compared by analysis of variance or Wilcoxon–Mann–Whitney test. The variability within and between packages was investigated through box plots. The Amapa charcoals showed moisture content (≈ 7.3%) somewhat above the stipulated (5%) by the Brazilian standardization for domestic use. The proper quality of the charcoals was attested by high apparent density (≈ 0.568 g/cm3), high fixed carbon (≈ 87.2%), low volatile matter (≈ 11.7%), low ash content (≈ 1.0%) and high higher heating value (≈ 32,925.40 kJ/kg). The charcoal of the brand B showed better quality considering significant higher average apparent density, no outlier of ash content above the maximum ideal value and overall lower variability within and among packages of the properties. The apparent density greatly varied among packages, while a greater variation within packages was observed for the other properties.

Recovery of Submicron-Sized Silicon-Rich Powder from Silicon Sawing Waste for Electrocatalyst of Methanol Electrooxidation

Recovery of Submicron-Sized Silicon-Rich Powder from Silicon Sawing Waste for Electrocatalyst of Methanol Electrooxidation

Effect of grain direction on cutting forces and chip geometry during green beech wood machining

Proper valorization of the sawing wastes in industrial sawmills is a permanent issue with strong economic and environmental stakes. Most industrial sawmills are equipped with chipper-canter heads reducing the outer part of the logs into chips used in the pulp and paper industry. Optimization in canter use would increase the acceptable proportion of exploitable chips for this industry. With chipper-canters, the cutting direction varies along the cut. This study investigates the impact of the angle formed between the cutting direction and the grain direction on the required cutting force and the chips’ geometry. Orthogonal cutting is conducted to simulate the chipper-canter machining operation on green beech. To lower the cutting forces when machining, aiming for a cutting direction as parallel as possible to the wood fiber is necessary. However, if this angle is too low, the chips’ generated geometries prevent them from a proper valorization of this resource. A compromise with grain direction between 50° to 70° both limits the cutting forces and improves the steadiness of the chip fragmentation.

Durability studies on fibre reinforced self compacting concrete with sustainable wastes

The sustainable development in construction can be achieved by using industrial waste products in concrete. This work aims at developing a new composite by incorporating Granite Sawing Waste (GSW) in Poly Propylene fibre (PP) reinforced self compacting concrete along with Fly Ash(FA). Shrinkage studies and durability studies like water absorption, porosity, acid resistance, sulphate resistance and chloride penetration have been done. It is found that the shrinkage of Self Compacting Concrete (SCC) is considerably reduced by using GSW and PP fibre. Resistance against acid attack and chloride penetration are found to improve. Reduction in water absorption and porosity are found to be better than control concrete up to 10% of GSW and the sulphate resistance is improved.