Strength Of Briquettes Research Articles

Effects of Process Variables on Physico-Mechanical Properties of Abura (Mitrogyna ciliata) Sawdust Briquettes

Efficient utilization of biomass requires conversion into forms that can be optimally applied in energy generation. Briquetting involves the compaction of biomass into solid blocks that are more efficient than raw biomass, and provides ease of transport and handling. These are improved when the briquettes possess a high density, shatter index, and compressive strength. Due to differences in nature and composition, it is imperative to define optimum conditions for the production of quality and durable briquettes for individual biomasses that are compacted into briquettes. This study investigated the effects of process variables on the strength, durability, and density of biomass briquettes produced using Abura sawdust. The lateral compressive strength and drop shatter index were investigated whilst varying the temperature (100–150 °C), pressure (9–15 MPa), and hold time (15–30 min). The compressive strength ranged between 2.06 and 5.15 MPa, whilst the shatter index was between 50 and 600. Briquette density was between 518.8 and 822.9 kg/m3. The pressure was significant to the determination of the compressive strength (p < 0.1) and the shatter index (p < 0.05). The pressure, temperature, and hold time are significant to the briquette density. Physical and mechanical characteristics of the binderless Abura sawdust briquettes can be improved by optimizing the densification variables during the briquetting process when moderate pressures are used for compaction.

Compressive strength of manganese fine-grained material and molasses briquettes regarding binder content and curing time

In the production of raw materials for the manufacture of ferroalloys, up to 50% of the material mined is discarded as fine-grained tailings. Those tailings are deposited in dams, which are considered an environmental liability. To avoid this, an alternative would be to agglomerate the tailing dam materials using the briquetting process. Therefore, this work aims to evaluate the compressive strength of briquettes made of manganese fine-grained material (with particle size < 2.00 mm) and molasses regarding curing time and percentage of binder. To achieve the objective, 45 briquettes were made with fine-grained manganese ore, with 3 different molasses content (binder), these were put into 3 weeks of curing, to analyze the impact of binder content and curing time. The result was that the longer the curing time, the better the compressive strength and that increasing binder content reduces its compressive strength. Finally, the best results were obtained with 5 % binder and 3 weeks of curing time, in which the agglomerate produced had a compressive strength of 9,0 MPa.

Physical Properties of Varied Composition of Peanut Shell and Palm Oil Shell’s Briquettes

This research aims to determine the physical properties of briquettes made from peanut shell (KKT) and palm oil shell (CKS) waste. The manufacturing process is carried out using a briquette press with a pressure of 70 N/m2, and each KKT and CKS is measured at 100 mesh. Two grams of starch adhesive and 15 ml of water are used in the process. This research method involves varying the quantities of KKT and CKS with the following ratios: S1(18:0), S2(16:2), S3(14:4), S4(12:6), S5(10:8), S6(8:10), S7(6:12), S8(4:14), S9(2:16), S10(0:18). The results of this research show that the lowest density of briquettes, 708.38 kg/m3, was produced by sample S6, while the highest density, 876.91 kg/m3, was produced by sample S3. The lowest elastic modulus of briquettes, 7 MPa, was recorded for sample S6, and the highest elastic modulus, 60 MPa, was observed for sample S10. Similarly, the lowest ultimate strength of briquettes, 1.35 MPa, was found in sample S6, while the highest ultimate strength, 6.03 MPa, was achieved in sample S10.

Technology for Producing Composite Solid Fuel From Coals of Kyzyl-Bulak and Kozho-Kelen Deposits and Heated Bitumen

The paper presents the results of a study of the production of composite solid fuels (CSF) from compositions of coal from the Kyzyl-Bulak and Kozho-Kelen deposits and a bitumen binder. The possibilities of producing CSF from a mixture of bitumen and preheated coals have been studied. To determine the dependence of the quality of the resulting CSF on the grinding size, the above coal was crushed into three fractions: a fraction with a particle size of 0-1mm, a fraction with particles of 0-3 mm and a fraction of 0-5 mm. These 3 fractions of coal were subjected to sieve analysis and the granulometric composition was determined, then each fraction individually was subjected to briquetting on a hydraulic press, in a mold with a diameter of 40 mm. Based on the task, pressing took place at 3 parameters, namely: at a pressure of 10 MPa, 15 MPa and 20 MPa. The use of different pressures made it possible to trace the dependence of the quality of the resulting CSF on the pressing pressure and determine the optimal pressure parameter. Briquetting was also carried out at different concentrations of the charge and the mechanical properties of the CSF were determined at a binder concentration of 6, 8, 10%. It has been established that the use of a bitumen-like product (bitumen) as a binding material, obtained as a result of thermal dissolution of coal with oil waste at a temperature of 320-380°C, produces mechanically strong briquettes that have compression resistance up to 106 kg/cm2 and bending resistance up to 7.5 kg/cm2. It has been shown that the mechanical strength of briquettes increases with increasing degree of coal grinding, and also an increase in pressing pressure increases the mechanical strength of briquettes. As the moisture level of coal increases, the mechanical strength of the briquette decreases. The optimal parameters for producing CHP have been established: coal size 0-3 mm: humidity 6.5%, pressing pressure 200 kg/cm2.

Evaluation of Compressive Strength of Manganese Oxidized Ore Briquettes: Effects of Compaction Pressure, Curing Time, and Percentage of Binder

ABSTRACT Agglomeration is a common process to safely recycle wastes from the mining and metallurgical sectors. In this process, the mineralogical and chemical characteristics of manganese ores exert a significant influence on the reduction reactions within the electric furnace. Therefore, a systematic work has been done to evaluate the compressive strength of briquettes composed of manganese oxidized ore fines, ferromanganese dust, charcoal fines, and three different binders, bentonite, pregelatinized starch, and slaked lime + molasses. A response surface methodology was used to evaluate the effects of compaction pressure, curing time, and % binder, whose response was measured in terms of compressive strength. The results were assessed by Analysis of Variance and a regression model was generated. The study showed that briquettes with bentonite demonstrated an optimized compressive strength of 2.54 MPa with a compaction pressure of 52.5 MPa, 11 days of curing time, and 11.5% bentonite content. Briquettes with slaked lime + molasses achieved a compressive strength of 3.70 MPa with a compaction pressure of 62.12 MPa, a curing time of 24 days, and an addition of 16.2% slaked lime + molasses. For briquettes produced with pre-gelatinized starch, the design of the proposed variables resulted in a lack of fit to the model. Optimization studies revealed that briquettes made with bentonite and slaked lime + molasses are viable alternatives to replace oxidized lump ore in electric furnaces.

Optimization of briquetting conditions and influencing factors of high-strength sludge briquette

With the increase of sewage sludge production in China, there is an urgent need for a clean and efficient sludge treatment, and the coupling utilization of sludge and coal to produce briquette is a potential sludge treatment method. In this work, sludge (with blending ratio higher than 40 wt%, dry basis) and one Chinese low-rank pulverized coal were used as raw materials to prepare sludge briquette by cold pressing method without binder. The effect of sludge moisture content (SMC), briquetting load (BL), blending ratio (BR), and particle size distribution of coal (PSD) on the compressive strength of the briquette were explored. Through FTIR, contact angle, Zeta potential, and SEM analysis, the briquetting mechanism of sludge briquette was clarified. The response surface method (RSM) was used to optimize the briquetting process conditions. The results showed that the order of influence of various factors on the compressive strength of the briquette is as follows: BL > PSD > SMC > BR. The results also showed that the interaction among SMC, BL, and PSD is the main factor affecting the compressive strength of sludge briquette. According to regression analysis, the optimum briquetting conditions are SMC of 14.11%, BL of 46.54 MPa, the weight proportion of sludge of 60%, and the weight proportion of R1 in coal of 52.68%. The quadratic regression model was established by RSM, and the predicted value is close to the experimental value.

Evolution behavior and kinetic analysis of vacuum-extruded iron-rich dust briquette in blast furnace

The vacuum extrusion iron-rich dust briquette was prepared by vacuum extrusion of iron ore concentrates, blast furnace dust and Portland cement. The evolution behavior and kinetic analysis of briquette in blast furnace was studied by high temperature process interrupted experiment. The phase transformation, metallurgical strength, microstructure and three-dimensional structure of dust briquette during high temperature reduction process were analyzed by X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and micro computed tomography. It is found that the high temperature reduction process of briquette can be divided into six stages, and the mechanical strength of briquettes under reducing atmosphere decreases with the increase of reduction degree and metallization rate, from 4.58 KN at 100 °C to 0.52 KN at 1100 °C. As the temperature increases, the metal iron and porosity inside briquette gradually increase. The ratio of the volume of metallic iron at 700 °C, 900 °C and 1100 °C was 1.47%, 3.70% and 6.60%, and the porosity is 10.32%, 34.1% and 47.1%, respectively. Furthermore, the non-isothermal kinetic reduction process of briquette was analyzed, and the evolution mechanism was revealed. The reduction process of briquettes is mainly controlled by diffusion, and only in the fourth stage (510 °C–840 °C) is limited by the reduction reaction of magnetite and decomposition reaction of calcium carbonate. This paper provides a theoretical support for the efficient and economical recycling of dust in iron and steel enterprises.

Hot Briquetting Technology for Ferrous Metal Waste in Molds with Movable Matrix

The paper describes the technology of hot briquetting of structurally heterogeneous metalworking waste in molds with a movable matrix, which differs from known analogues in the possibility of improving the quality of briquettes with a minimum number of preparatory operations. The aim of the work is to improve the process of hot briquetting. The tasks to be solved are to develop a technological scheme and a physical and mathematical model of the process, reduce the forces of contact friction and tool wear, and optimize the energy-power parameters according to the criteria for the density and strength of briquettes. The technological scheme of briquetting is represented by a mold with a movable matrix, in which compressed air is used as an elastic support. During the briquetting process, the matrix and the pressed metal move in the same direction. The lateral friction force is active, directed towards the briquetting force. As a result, the force and work of briquetting, mold wear are reduced, and the briquette itself is of high quality – uniform in density and without internal defects.As a result of the numerical calculation of the model, the dependences of the stress state of the pressing and pressing pressure on the coordinates and density on the contact surfaces and in the depth of the material were obtained, which makes it possible to calculate the strength of the mold parts and select equipment for the briquetting process. The regularities of formation of the briquette structure are studied, the advantages of using the proposed technological scheme in comparison with briquetting in a fixed matrix are shown. The proposed technology eliminates the implementation of the preliminary operation of coolant removal by centrifugation or other known methods. Coolant is removed by thermal sublimation, partially burned in the furnace firebox, partially condensed in the “wet” cleaning system.

The Choice of Binder for the Production of Briquettes from Highly Dispersed Dust of Ferroalloy Production

Based on the information analysis, the briquetting process is defined as the optimal way to dispose of highly dispersed dust (HDD) of ferroalloy production. Initial studies have been conducted on the choice of a binder for briquetting (HDD). The obtained results showed the possibility of utilization of highly dispersed dust of Kazakhstan content by briquetting. As a binder, liquid glass and caustic soda were used in an amount of 10% by weight each. To ensure the necessary mechanical strength of briquettes, the pressing pressure below 40 kN seems impractical.

Effect of chemical structure on mechanical-seepage characteristics of briquette under different heating temperatures

Based on the low strength and high permeability of briquette coal (BC) used in physical simulations of coal mine disasters, we propose a new briquette production method that can improve the mechanical strength and reduce the permeability of BC. The reduction of physical simulation experiments of coal and gas outburst was improved, which is of significance for the prevention and control of coal mine gas disasters. Based on this method, we developed a set of briquette hot-pressing systems and optimized the proportion of coal powder used in the briquette formation process. Mechanical property and seepage tests of the briquettes were carried out under uniaxial and triaxial compression. The effects of different temperatures on the physical (size, density, ignition loss rate) and mechanical (Poisson's ratio, elastic modulus and compressive strength) coal parameters and the effect of the permeability were analyzed using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analyses. The morphology and pore, crystallite, and molecular structures were used to determine the cause of the increase in the mechanical strength of BC. Based on the packing density theory, the optimal ratio of the 40–60, 100–120, and 180–200 mesh particle sizes is 91.77:5.87:2.35. With the increase in the temperature from 150 to 450 °C, the microstructure changes from loose to compact, the number of pores and cracks increase, the degree of order of the microcrystalline structure gradually increases, the distance between the microcrystalline layers d002 continuously decreases, aliphatic chains shorten, and the aromaticity increases. The rate of the change of the loss rate and density of the hot-pressed briquette first increase, then decrease, and then increase again. The mechanical parameters (strength and elastic modulus) first increase and then decrease, whereas the Poisson's ratio first decreases and then increases, and the permeability increases. Considering the density, strength, and permeability of hot-pressed briquettes, the optimal heating temperature at which the similarity between the hot-pressed BC and raw coal is the highest at 300 °C.

Manufacturing, curing and mechanical testing of BREX from electric arc furnace dust

At present the acute issue is utilization and recycling of metallurgical production wastes; one of which is electric arc steelmaking dust (EAF). In Russia there are up to 30 million tons of dust in the dumps of metallurgical plants and additionally up to 780 thousand tons are added to this amount annually. Considering the amount, the main value is zinc, which content reaches 25 wt%, as well as iron, which content varies from 20 to 50 wt%. The paper presents the results of studies on briquetting of the EAF dust using the technology of stiff extrusion and obtaining brackets. The chemical composition of the initial EAF dust was studied by X-ray spectral analysis using JEOL JSM-7001F electron microscope. The amount of reducing agent was selected based on results of thermodynamic modeling using the TERRA software package. The BREX were produced in a laboratory extruder assembled from an electric motor, a reduction gear, a screw, and a die. Two types of dies were used in the briquetting study. For each type the optimum moisture and binder were selected. The influence of the binder and moisture on the quality of the finished briquettes was evaluated. The BREX drying was studied in order to find out the optimum curing time in the air. In addition, drying at 110 °C was carried out for a comparative assessment of the strength of briquettes depending on the method of drying. The drop tests of the finished briquettes were carried out according to GOST 25471‒82 “Iron ores, sinter and pellets; method for determining dumping strength”. The test results showed the possibility of transportation of the EAF dust briquettes

Compressive Strength Behavior of Briquettes Produced from Manganese Ore Fines and Metal Dust: Optimization Using Response Surface Methodology

ABSTRACT Electric reduction furnaces cannot be fed fines in the production of manganese ferroalloy as they hinder gas permeability. Thus, agglomeration techniques can be used to minimize the environmental and economic impacts of storing fines. Among these techniques, briquetting is advantageous because it allows for cold agglomeration of the particles and is flexible in terms of particle sizes. Therefore, this work aimed to develop self-reductor briquettes composed of ore manganese fines, dust ferromanganese, charcoal fines, and three different binders. The compaction pressure, curing time, and % binder were optimized to enhance briquette strength through a multivariate experimental design consisting of a screening study using a 23 full factorial design followed by response surface methodology with a spherical central composite design. The results were assessed by analysis of variance, and a regression model was established. The study found that briquettes elaborated with bentonite exhibited an optimized compressive strength of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa and 12.71% bentonite. For briquettes elaborated with pregelatinized starch, a compressive strength of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pregelatinized starch. For briquettes agglomerated using slaked lime and molasses, an optimized compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a compressive strength of 1.63 MPa. These results suggest that briquettes containing bentonite and pregelatinized starch are feasible substitutes for lump ore in electric furnaces.

Research on the ring formation mechanism of magnesian flux pellets in rotary kiln

The forming of rings was a key problem of magnesian flux pellets in rotary kiln, which seriously limited production efficiency. Pellet powder and flux were the raw materials of the ring. Based on this, the bonding strength, melting behavior and microstructure of pellet powder and its mixed powder with flux were investigated. The influence of basicity (R = CaO/SiO2) on ring behavior of pellet powder was analyzed, and ring formation mechanism of magnesian flux pellets was clarified. The results showed that acid pellet powder was not easy to form rings due to lower bonding strength of briquettes. Due to changes in bonding process after mixing of flux, magnesian flux pellet powder produced ferrite and silicate liquid phase with lower melting point, which promoted diffusion and recrystallization of hematite and enhanced compressive strength of briquettes, then finally caused rings to form. Moreover, it is required to control roasting temperature below 1200 °C, which is a necessary condition for magnesian flux pellet powder to form an initial ring which was easy to be destroyed.

Effect of torrefaction on the properties of briquettes produced from agricultural waste

In this study, briquettes produced from cassava rhizome, sugarcane bagasse and straw were torrefied at 250 °C for 90 min to verify the effects of the process on their structure and properties such as density, durability, energy content, and energy density. The briquettes had a relaxed density of 1270 kg/m3 for those produced from cassava rhizome, 1240 kg/m3 from sugarcane bagasse, and 1300 kg/m3 from sugarcane straw. The torrefaction procedure increased calorific value of the briquettes by 9–13-fold. However, changes in briquette strength were identified after torrefaction, with a longitudinal deformation of 12.9–26.6 % and cracks in its bodies. Consequently, fragments were produced after durability testing. Moreover, briquette density decreased by 36 % for cassava rhizome, 50 % for sugarcane bagasse, and 55 % for sugarcane straw. The produced cassava rhizome briquettes exhibited the highest energy yield when torrefied. Combining these technologies facilitates the use of residues from agriculture for energy generation.

Recycling in the production of mineral wool

The main heat-insulating material used in Russia is mineral wool. One of the problems of waste reclamation of mineral wool products is returning of chips and globules back to the solid fuel furnace. To solve the problem, it is proposed to briquette waste before feeding it into the furnace. The author suggests using alumina cements of Russian production as a binder. The choice of the binder is conditioned by the chemical composition of the cement. The second factor that was considered when choosing the binding material was its strength in the early stages. Samples of a mixture of waste and binder were pressed into cylinders and then heat treated for an hour. As a result of the study, the dependences of the impact strength of the samples on steam curing temperature and the humidity of the samples have been obtained. It has been revealed that an increase in humidity has a greater effect on the rise in impact strength than an increase in temperature. Results: the dependence of the impact strength of briquettes made of the mineral wool industry waste and alumina cement on humidity and curing temperature has been revealed, which will make it possible to select optimal conditions for returning of waste to the furnace.

Laboratory research of coal briquette quality indicators

The research is based on the results of scientific research on the development of technology for the production of high-energy and environmentally friendly coal briquettes.The study of crushing of different sizes of coal, as well as the study of separation processes on the geometric size of the fine fraction of coal revealed high efficiency of hammer grinders and multi-layer screening devices for sorting, based on the consistency of briquette constituents, a technological system for the production of briquettes based on the use of a solution of biohumus and rice starch as effective biobinders, providing effective interaction of coal particles. The strength of briquettes obtained by increasing the amount of starch solution in coal compounds by 2%, 4%, 6% is 1.3-1.5 times, and when the pressing pressure is increased from 5 MPa to 40 MPa, the average strength of briquettes is from 2.8 MPa to 6.4 MPa. increase was detected.

Experimental study on the role of moisture in the cold binderless briquetting of low-rank coal

ABSTRACT Briquetting is needed to complete the upgrading process of low-rank coal, which commonly produces yield in a powder form. The process increases solid fuel’s energy density, handling, and transportability. The binderless briquetting is frequently selected over the conventional briquetting process since it utilizes the coal substance to bind the particle such that the coal property as fuel is unaltered. Unfortunately, the mechanism of how the coal particles are bonded remains unclear. This research investigated the binderless briquetting process at room temperature (cold binderless briquetting), employing moisture content (MC) as a binding agent. Experimental results show that, during the compaction process, the moisture acts as lubricants and provides deformability in the coal particle, which eases the particle interlocking at a higher density. However, the change of moisture in the briquette after the compaction process could induce swelling and shrinkage in the particle, causing a discrepancy in the particle interlocking system and reducing the briquette strength. From the investigation, the cold binderless briquetting of LRC is recommended to be conducted at 2500 bar compaction and using coal particles with the initial MC of 10–20%. The prediction of briquette strength at different moisture content is also proposed in this paper.

Research and analysis of characteristics of fuel from organic and industrial waste

The article is devoted to the actual problem of utilisation of agricultural and industrial waste as a solution to the problem of replacing traditional energy sources.
 As an alternative fuel, researchers suggest using briquettes from biomass (leafy debris, waste paper, sunflower and buckwheat husks), as well as their combination with industrial waste (coal dust). The choice of these sources of raw materials is determined by their presence in the north-eastern part of Kazakhstan.
 Studies of the physical and mechanical and thermophysical characteristics of fuel briquettes from organic mass and bio-charcoal briquettes were carried out. The studies showed the following results: the moisture content of the samples we studied lies in the range from 3.86 to 8 %; ash content of briquettes from vegetable raw materials varies from 2.05 % to 3.6 %, combined briquettes from foliage and coal dust varies from 10 % to 14 %; average density values varies from 979.91 to 1172.63 kg/m3; mechanical strength is in the range from 90 to 100 %; the yield of volatile studied samples ranges from 9 to 21.4 %. Analysis of the obtained characteristics of fuel briquettes demonstrated that they meet the requirements of existing standards. Herewith, the lower calorific value of briquettes (15290‑19048 kJ/kg) is comparable to the calorific value of coal from the Ekibastuz deposit.
 The authors studied the influence of the parameters of the briquetting process on the briquette’s strength characteristics from leaves and waste paper, and obtained a regression dependence of these briquette’s calorific value on their characteristics. The analysis of regression dependencies showed that the pressure and pressing time have the greatest influence on the briquette strength, and its composition, i.e., the ratio of leaves and waste paper in the feedstock, has the greatest influence on the lower calorific value

Comparative Study on the Seepage Characteristics of Gas-Containing Briquette and Raw Coal in Complete Stress-Strain Process.

In this study, triaxial compression and seepage tests were conducted on briquette and raw coal samples using a coal rock mechanics-seepage triaxial test system (TAWD-2000) to obtain the complete stress–strain curves of the two samples under certain conditions. On this basis, the different damage forms of the two coal samples and the effect of their deformation and damage on their permeability were analyzed from the perspective of fine-scale damage mechanics. Moreover, the sensitivity of permeability to external variables and the suddenness of coal and gas outbursts were discussed. The results show that the compressive strength of raw coal is 27.1 MPa and the compressive strength of briquette is 17.3 MPa, the complete stress–strain curves of the two coal samples can be divided into four stages and show a good correspondence to the permeability–axial strain curves. Since briquette and raw coal have different structural properties, they present different damage mechanisms under load, thus showing great diversity in the permeability-axial strain curve, especially in the damage stage. The deformation affects the seepage characteristics of briquette mainly in the latter two stages, while it affects raw coal throughout the test. The four stages of the complete stress–strain seepage test of raw coal can well explain the four stages of coal and gas outburst process, i.e., preparation, initiation, development, and termination. Hence, the law of coal permeability to gas variation can be utilized for the coal and gas outburst prediction and forecast. The research results are valuable for exploring the real law of gas migration in coal seams.

The role of the alkaline promoter on the formation of strength and burning of coal briquettes

Coal fines formed in the process of coal mining are of no commercial value and accumulate in dumps, harming the environment. At the same time, they can be used as a source of low-smoke fuel used by the population for domestic needs. To create such a product, it is necessary to solve many technical problems related to selecting binders for coal, providing mechanical strength, and initiating the combustion process of coal briquettes. This study presents the results of obtaining briquette fuel from fine particles of brown coal. Low-temperature pyrolysis determined the qualitative and quantitative composition of volatile components and proposed a mechanism for forming a porous structure of coal after thermal exposure. A composition of a mixture of caustic soda and grain processing waste was used as a binder for the production of briquettes. The mechanism of the formation of adhesive properties of the binder material is explained, and the optimal concentration of sodium hydroxide in it is determined. The positive role of caustic soda as a catalyst for the burning of briquettes is shown, and the activation energy of the burning process is calculated.