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Granulation of the sinter mix is an important step in the iron ore sintering process. This article presents the results of various studies conducted to understand the rheological aspects and methods implemented in industrial‐scale sinter plants to sustain productivity over the last decade. The intergranular bonding material in the mixing and nodulizing drum is characterized to understand its influence on the granulation. Calcined lime, when increased from 20 to 40 kg t−1 of sinter, increases the granulation index and helps in achieving higher productivity. Up to 20 kg t−1, calcined dolo increases productivity, beyond which a decline is noticed. Lignosulfonate and polymer binders in the range of 0.2%–0.7% in the sinter mix, respectively, increase the granulation of the microfines (0.25 and 0.5 mm size). When a magnetic field is applied to water, the granulation improves. Higher electrical conductivity and lower contact angle of the recycled water are found to improve the bonding of the particles. Zeta potentials of fly ash and bentonite solution in water are positive and negative in the cases of calcined lime and calcined dolo. It is suggested to use fly ash as a binder of microfines. [ABSTRACT FROM AUTHOR]

Abstract An integrated steel plant generates 200–250 kg of steel making slag for every tonne of steel produced. These slags contain non-uniformly distributed iron in metallic form, inevitably carried into the slag pot during de-slagging. The steel slag is subjected to crushing/magnetic separation to generate different sizes of slag products with varying metallic values. Based on size and metallic content, these products are recycled in sinter base mix, iron making units and as scrap in steel making process. Hence accurate analysis of Fe-metallic in these samples is imperative for better process control. Due to non-uniform mixing and solidification of steel & slag in de-slagging and dumping practice, precise quantification of the metallic portion in these samples is extremely difficult. Existing methods followed by slag processing agencies has always been doubtful. Moreover, uniformity of constituents in a small sample size cannot be ensured even by best of the sampling techniques. In the present work, all the slag products have been subjected to different measurement techniques to develop a method to determine the metallic iron content accurately in the steel-making slags. Separate methods have been formulated for low metallic and high metallic content slag samples based on the dominant characteristics. Specific density balance and grinding-sieving methods are proposed for more practical and accurate measurement. Best sampling technique and optimum sample size have also been suggested for each method. In addition to increase in the efficiency of the process, where it is recycled, accurate analysis of Fe-metallic in slag helps in improving the magnetic separation technique and the process of its application. [ABSTRACT FROM AUTHOR]

Iron ore sinter, constituting a major proportion of blast furnace burden, significantly impacts the blast furnace performance. The chemical composition of iron ore fines, particularly alumina, sinter basicity and sinter MgO together with the thermal conditions that sinter blends are subjected to play an important role in the formation of mineral phases in sinter. To increase the sinter proportion (70-80%) in blast furnace, lowering of CaO in sinter mix is a vital parameter to balance the flux supply without affecting the slag volume and productivity. At present, the alumina content in the sinter grade iron ore fines at JSW Steel varies from 4 to 6%. The quality of iron ore presently being used calls for extensive investigations to produce low basicity sinter with high alumina iron ore. Studies have been carried out on low and high alumina iron ore fines to know the influence of sinter basicity and fuel (coke breeze) addition on sinter mineralogy, properties and productivity. It is found that with increase in sinter basicity, sinter productivity and reduction degradation index (RDI) decreased and tumbler index (TI) increased for both low and high alumina sinter at coke breeze rate of 65 kg t−1 of sinter. The low alumina sinter showed higher productivity and strength, and lower RDI due to the presence of higher silico ferrites of calcium and aluminium (SFCA) and magnetite phase, and lower pore phase as compared to high alumina iron ore sinter. The sinter productivity decreased and physical and metallurgical properties improved with increase in coke breeze addition by increasing the sinter basicity for high alumina sinter. [ABSTRACT FROM AUTHOR]

Optimized microstructure and mechanical properties are the key requirements for line pipe steels. In the hot rolling process, it can be achieved through optimization in rolling schedule and cooling process. The present study uses hot strip mill modeling (HSMM) interface to model hot rolling process. Two API line pipe grades equivalent to 'API X-70 & API X-80' have been modeled for its final microstructure and mechanical properties based on thermal, mechanical, and microstructural changes occurring during hot rolling. The model has been validated with plant data and test results. Austenite recrystallization model has been validated against calculated flow stresses from actual roll forces applied. Phase transformation model has been validated with the final microstructure and mechanical properties. The API X-70 grade shows strain accumulation (i.e., no recrystallization) in the finish rolling stage only, while the X-80 grade carries the strain accumulation from the roughing passes also, resulting in very fine grain ferrite. It is due to high retained strain before the phase transformation on run out table. The predicted properties by the model are in close proximity for multiple coils and different locations in the coil for both the grades. [ABSTRACT FROM AUTHOR]

In the coal and mineral beneficiation industries, screening is one of the crucial physical separation methods carried out to separate the undersized fine particles from the oversize coarse particles. The vibratory screener is a relatively advanced screening technology applied for coal and iron ore beneficiation. This paper deals with the experimental investigation for assessing the efficiency of screening coal and iron ore in the vibratory screener. Furthermore, a comparative study between the test performance of screening coal and iron ore was carried out depending on moisture and density variation. Test results show that the vibratory screener can provide a high recovery of fines and increased efficiency for screening iron ore than coal material. The maximum efficiency of iron ore was attained at a higher angular position, such as 3 and 5 degrees in an upward slope, whereas the maximum efficiency of coal was attained at 1 degree in an upward slope. [ABSTRACT FROM AUTHOR]

A prematurely failed vertical turbine pump shaft was investigated for root cause analysis. The analysis involves operating conditions, visual examination, chemical composition, bulk hardness, microstructure, and fractured surface analysis. Visual examination clearly showed that the shaft had failed at the step region; however, no evidence of fatigue striations/beach marks was seen on the fractured surface. The chemical composition matched with the ASTM A276-410 (hardened and tempered), but, higher carbon content was found than the specification. The tempered martensitic microstructure indicates that the steel was heat-treated. The bulk hardness of the shaft was found to be 314–319 HB, which corresponds to 538 °C tempering, which is embrittlement zone of the steel, as can be found from the literature. The fractured surface of the shaft clearly showed intergranular brittle fracture, which arises due to embrittlement. Hence, it is inferred that the tempering heat treatment temperature was wrongly chosen (538 °C) leading to temper embrittlement, which resulted in premature failure of the shaft in service. [ABSTRACT FROM AUTHOR]

The present research work evaluates the influential process parameters such as moisture content, angle, and frequency for separating coal in the vibrating screen. The design of the experiment for three factors with three levels was obtained using Taguchi's and Response surface methodology's (RSM) method. Taguchi's L27 and RSM Box–Behnken design (BBD) method was used to conduct the separation experiment on a vibrating screen. The main effect plot of Taguchi's L27 and BBD method was used to evaluate the optimized condition for obtaining the highest separation efficiency of the vibrating screen. The optimized condition obtained was lower moisture content (4%), lower angle (1 degree in upward slope), and medium frequency (9 Hz). The interaction plot of Taguchi's L27 and BBD method was used to evaluate the interaction between the process parameters. From the interaction plot and ANOVA results, it was clear that the moisture content is the most significant parameter compared with the angle and frequency parameter for separating coal in a vibrating screen. From the prediction results, it was also clear the regression coefficient of Taguchi's L27 was higher when compared with the RSM BBD method. This shows that Taguchi's L27 is the most suitable optimization method compared with RSM. [ABSTRACT FROM AUTHOR]

The availability of low-grade coal with a high amount of ash has urged the improvisation of separation equipment with minimal or no water utilization. The present work addresses the study on the separation equipment performance with different moisture coal. The experimental results were obtained in terms of separation efficiency. After obtaining the experimental results, the mathematical modeling results were obtained using different techniques. The cubic regression and cascade neural network models were considered to study the mathematical correlation with experimental results. The R-squared value of each mathematical modeling technique was correlated with the model fitting to check the model's validity. The results clearly showed that the cubic model fitting for the experimental condition had provided an excellent R-squared value varying from 92% to 99%. The cascade model fitting for the experimental condition has provided a higher R-squared value, i.e., more than 99%. Results show that for all experimental conditions, the cascade model fitting of the neural network technique provides the significant mathematical modeling technique suitable for predicting the separation equipment's performance compared to the cubic model of the regression technique. [ABSTRACT FROM AUTHOR]

Coal separation was usually carried out using the wet coal beneficiation technique. The waste generated by this technique pollutes the environment. So, in this work, a new mechanism of screening machine for dry coal beneficiation was developed. Dry coal screening removes ash impurities from the coal and improves its energy productivity. Hence, a new screening machine was developed with flexibility in changing the screen mesh, screen angle, and frequency of vibration. In this work, coal feed of less than 6 mm were divided into three groups of −6 + 4 mm, −4 + 2 mm, and −2 + 0.5 mm size fractions. Each size fraction was screened individually in the new screening machine by changing the screen mesh to the required perforation. The screening efficiency was determined for each size fraction by varying operational variables such as screen angle and frequency of vibration. This new screening machine provides maximum screening efficiency of 87.36%, 80.52%, and 66.42% for screening coal feed of 6 + 4 mm, −4 + 2 mm, and −2 + 0.5 mm size fractions, respectively. Highly efficient screening and higher removal of ash from coal were obtained due to the design and operational flexibilities of the screening machine. [ABSTRACT FROM AUTHOR]

Implementing the planned execution of experiments will optimize the resources and time of a newly developed process or equipment. In the present work, the screening machine is newly developed equipment designed for the separation of coal. The present work was carried out to evaluate the performance of separation efficiency of the screening machine using generalized and forward selection fractional factorial experimental design. Further, the present work will also determine the significance of each operational variable, such as moisture content, angle, and frequency, for increasing separation efficiency. A cube plot was developed from the experimental design, which shows the highest and lowest condition of separation efficiency for each level of the operational variables. Further, a Pareto chart was developed to evaluate the significant operational variable for the screening machine. The results of the generalized method and forward selection method of fractional design show that the moisture content was the most significant operational variable, followed by angle and frequency. The results also show that the screen blinding of a screening machine plays an important role in reducing the separation efficiency of a screening machine. [ABSTRACT FROM AUTHOR]

In the present work, optimization of the newly developed vibrating screen's operational parameters was carried out to obtain a high response parameter. The operational parameters considered in the present work were moisture content, angle, and frequency. The Taguchi L27 design technique was used to optimize three different operational parameters to obtain high screening efficiency of coal in the vibrating screen. The maximization of screening efficiency was obtained by selecting the "larger the better" condition for developing the model. The regression coefficient of 99.6% shows the close relationship between the predicted and experimental values. The lower value mean error and standard deviation of normal probability indicate that the developed model has less error. From the optimization results, it was clear that the 4% moisture content (low level), 1-degree angle (low level), and 9 Hz frequency (medium level) yielded high screening efficiency. Further, a confirmation test was carried out with the optimized condition, which has yielded a screening efficiency of 84.40%. The results showed that the Taguchi technique could be applied to study the influential operational parameters for maximizing the vibrating screen efficiency. [ABSTRACT FROM AUTHOR]

During sintering process, iron ores, fluxes and coke are agglomerated into a desirable blast furnace feed. The degrading iron ore quality and environmental norms has forced sinter producers to look for additives which can improve the sintering process efficiency. For the current work, use of calcined colemanite as an additive was studied by adding it from 0% to 4% within the sinter raw blend through lab-scale pot trials. During the sintering process, calcined colemanite forms a Calcium Borosilicate (Ca11B2Si4O22) phase at temperature above 400 °C which latter gets dissociated within the liquid melt thus increasing the liquid slag formation. Increasing calcined colemanite up to 2% increases tumbler index from 56.27% to 61.67%, decreasing thereafter to 55.33% at 4% of calcined colemanite. The sinter yield (+5 mm) is also found to be maximum of 89.39% at 2% of calcined colemanite. An increase in calcined colemanite from 0% to 4% increases sintering time from 20 to 26 min, decreasing the overall sinter productivity from 2.35 to 1.99 t/m2/h. Before integrating calcined colemanite within the sintering process at plant scale, its cost and efficacy must be considered. An alternate approach can be combining it with an organic binder where the two can complement each other in providing the required sinter properties. [ABSTRACT FROM AUTHOR]

In this paper, coal screening in vibrating screen was carried out with the size ranges of −6 mm + 4 mm, −4 mm + 2 mm, and −2 mm + 0.5 mm. The vibrating screen was newly designed with flexibility in angle and frequency. The vibrating screen experimentation was carried out by varying screen mesh, angle, and screen frequency. During the screening, the angle was kept constant, and frequency was varied to obtain each size range's screening efficiency. The experimental results of screening efficiency were evaluated for each size fraction range of coal. The maximum efficiency for screening coal with −6 mm+4 mm, −4 mm+2 mm, and −2 mm+0.5 mm size range obtained was 87.60%, 80.93%, and 62.96%, respectively. Further, the prediction model was developed for each size range using a feed-backward artificial neural network (ANN) to consider the back-propagation error technique. For each screening condition, 10 ANN models were developed with the variation in 1–10 different neurons. ANN has provided mathematical models with a 99.9% regression coefficient for predicting each size range's screening efficiency. Furthermore, the residuals of each optimal ANN model were analyzed using a normal probability plot and histogram. The ANN model's accuracy was obtained from the residual analysis by evaluating four different model conditions, i.e., independence, homoscedasticity, normality, and mean error. [ABSTRACT FROM AUTHOR]

Coal is one of the chief energy sources having significant applications in the iron and steel industry. This research investigates the screening efficiency of coal of different size range. The experiments on the screening of coal with different size range in the screening machine were carried out using different mesh sizes. The screening efficiency for different screen angles and frequency of vibration was carried out. After experimentation, regression modeling was carried out for each screening condition. The maximum efficiency of screening coal with size range +4 mm-6 mm, +2 mm-4 mm, and +0.5 mm-2 mm obtained was 87.60%, 80.93%, and 62.96%, respectively. The experimental results show that the screening efficiency decreases with the decrease in size range for screening from +4 mm-6 mm to +0.5 mm-2 mm. The reduction in screening efficiency was due to the clogging of coal to the screen mesh. Linear and quadratic modeling were performed to estimate the efficiency of all the experimental results. After prediction, the validation using residual analysis was carried out, and the results illustrate that the quadratic prediction modeling was accurate. [ABSTRACT FROM AUTHOR]

In India, coal is one of the prime sources of energy used in the power generation and metallurgy sector. The processing of coal below 3 mm is not successfully carried out in India. The quality of coal below 3 mm can be improved by decreasing the coal's particle size, which reduces the ash percentage of coal. Screening is one of the significant beneficiation techniques used to reduce the size fraction of coal. The difficult to process coal of size −3 + 1 mm was selected in the present work. In this work, an attempt has been made to screen the coal of size −2 + 1 mm from −3 + 1 mm using a 2 mm screen mesh in the vibrating screen generated at different moisture content, angle, and frequency of the deck. The performance of the vibrating screen was evaluated using screening efficiency. Furthermore, prediction using a feed backward artificial neural network (ANN) model was developed on the experimental results for ten different neuron conditions. From the results, it was clear that the prediction results obtained from the ANN model were in good correlation with the experimental results. [ABSTRACT FROM AUTHOR]

Screening of coal is one of the processes carried out to produce clean coal suitable for the blast furnace. In this work, the screening of moist coal was carried out for different angles of the screen and frequencies. A 2 mm screen perforation was used to separate undersize coal of size +1 mm-2 mm from the +1 mm-3 mm coal samples. For each experimental condition, the screening efficiency was calculated. Maximum screening efficiency of 85.96%, 75.64%, and 63.46% was obtained at 4%, 6%, and 8% moisture content, respectively. As the moisture content of coal increases, the efficiency minimizes due to high screen clogging. After determining the screening efficiency, prediction was carried out using regression modeling. In this work, linear and second-order polynomial regression modeling was utilized to develop a prediction model for the experimental values. From the results, it was clear that the polynomial regression model has high regression coefficient (R2) percentage and low P-value in comparison with the linear regression model. After prediction, validation was carried out on the best fit model. The value of Variance Account For (VAF), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE) was in the acceptable range, which shows that the developed model was most effective. [ABSTRACT FROM AUTHOR]

A new vibrating screen was developed with a circular mode of vibration for dry screening of moist coal of size fraction −3 + 1 mm. Screen mesh of 2 mm aperture size will be used to separate the finer coal particles of size fraction −2 + 1 mm. The new vibrating screen has the flexibility in changing the operational parameters such as the angle of the screen in upward or downward sloping direction and frequency of vibration of the screen deck. The circular mode of vibration provided to the screen deck will incorporate the inertial force on the particle in the screen deck, reducing screen clogging. The present study involves the analysis of the screening performance of the new vibrating screen with the coal feed of varying moisture content of 4%, 6% and 8%. The maximum screening efficiencies obtained for screening the coal feed with the moisture contents of 4%, 6% and 8% were 85.96%, 77.84%, and 68.27%, respectively. The higher screening performance of new vibrating screen was obtained due to good exposure time, particle mixing, particle segregation and particle stratification of coal on the screen deck. The results of the new vibrating screen will be a breakthrough in dry screening technology and accelerate the pilot-scale development. [ABSTRACT FROM AUTHOR]

Background: Asian cultivars were predominantly represented in global rice panel selected for sequencing and to identify novel alleles for drought tolerance. Diverse genetic resources adapted to Indian subcontinent were not represented much in spite harboring useful alleles that could improve agronomic traits, stress resilience and productivity. These rice accessions are valuable genetic resource in developing rice varieties suited to different rice ecosystem that experiences varying drought stress level, and at different crop stages. A core collection of rice germplasm adapted to Southwestern Indian peninsular genotyped using SSR markers and characterized by contrasting water regimes to associate genomic regions for physiological, root traits and yield related traits. Genotyping-By-Sequencing of selected accessions within the diverse panel revealed haplotype variation in genic content within genomic regions mapped for physiological, morphological and root traits. Results: Diverse rice panel (99 accessions) were evaluated in field and measurements on plant physiological, root traits and yield related traits were made over five different seasons experiencing varying drought stress intensity at different crop stages. Traits like chlorophyll stability index, leaf rolling, days to 50% flowering, chlorophyll content, root volume and root biomass were identified as best predictors of grain yield under stress. Association mapping revealed genetic variation among accessions and revealed 14 genomic targets associated with different physiological, root and plant production traits. Certain accessions were found to have beneficial allele to improve traits, plant height, root length and spikelet fertility, that contribute to the grain yield under stress. Genomic characterization of eleven accessions revealed haplotype variation within key genomic targets on chromosomes 1, 4, 6 and 11 for potential use as molecular markers to combine drought avoidance and tolerance traits. Genes mined within the genomic QTL intervals identified were prioritized based on tissue specific expression level in publicly available rice transcriptome data. Conclusion: The genetic and genomic resources identified will enable combining traits with agronomic value to optimize yield under stress and hasten trait introgression into elite cultivars. Alleles associated with plant height, specific leaf area, root length from PTB8 and spikelet fertility and grain weight from PTB26 can be harnessed in future rice breeding program. [ABSTRACT FROM AUTHOR]

Background: Asian cultivars were predominantly represented in global rice panel selected for sequencing and to identify novel alleles for drought tolerance. Diverse genetic resources adapted to Indian subcontinent were not represented much in spite harboring useful alleles that could improve agronomic traits, stress resilience and productivity. These rice accessions are valuable genetic resource in developing rice varieties suited to different rice ecosystem that experiences varying drought stress level, and at different crop stages. A core collection of rice germplasm adapted to Southwestern Indian peninsular genotyped using SSR markers and characterized by contrasting water regimes to associate genomic regions for physiological, root traits and yield related traits. Genotyping-By-Sequencing of selected accessions within the diverse panel revealed haplotype variation in genic content within genomic regions mapped for physiological, morphological and root traits. Results: Diverse rice panel (99 accessions) were evaluated in field and measurements on plant physiological, root traits and yield related traits were made over five different seasons experiencing varying drought stress intensity at different crop stages. Traits like chlorophyll stability index, leaf rolling, days to 50% flowering, chlorophyll content, root volume and root biomass were identified as best predictors of grain yield under stress. Association mapping revealed genetic variation among accessions and revealed 14 genomic targets associated with different physiological, root and plant production traits. Certain accessions were found to have beneficial allele to improve traits, plant height, root length and spikelet fertility, that contribute to the grain yield under stress. Genomic characterization of eleven accessions revealed haplotype variation within key genomic targets on chromosomes 1, 4, 6 and 11 for potential use as molecular markers to combine drought avoidance and tolerance traits. Genes mined within the genomic QTL intervals identified were prioritized based on tissue specific expression level in publicly available rice transcriptome data. Conclusion: The genetic and genomic resources identified will enable combining traits with agronomic value to optimize yield under stress and hasten trait introgression into elite cultivars. Alleles associated with plant height, specific leaf area, root length from PTB8 and spikelet fertility and grain weight from PTB26 can be harnessed in future rice breeding program. [ABSTRACT FROM AUTHOR]

• Lifters with primary, secondary and tertiary plates were used at discharge end. • Discharge of desired particle size is directly related to critical speed of the mill. • Mill with lifters has maximum discharge of desired particle size. • Mill with lifters has minimum recirculating load compared with mill without lifters. The discharge end design of a ball mill plays an important role in discharging the desired particle sizes (−150 + 10 µm) and the percentage of recirculating load from the discharge end of the ball mill. In continuous wet ball mills, the composition of feed (hard ore or soft ore) to the mill varies continuously, leading to uncontrolled grinding in the mill. In view of this, a new design of the discharge mechanism has been implemented to remove the ground particles of desired particle size fraction with minimum recirculating load (+150 µm). The results from the discharge end with lifters (closed and open) show that the particle size fraction obtained from the discharge end has a maximum percentage of desired particle size fraction when the mill is operating at 60% critical speed. Discharge end without lifters has an uncontrolled particle size distribution in the discharge and the percentage of desired-size particles discharged was found to be very less. Also, the percentage of the recirculating load is minimum in the case of discharge end with lifter design compared with discharge end without a lifter. Hence, a new design of lifters in the discharge end leads to the discharge of the desired particle size fraction with minimum recirculating load. [ABSTRACT FROM AUTHOR]