Cement Mill Research Articles

Prediction of cement specific surface area in the cement mill grinding process: A method combining dual-frequency principal component analysis and extreme gradient boosting

The cement specific surface area is an important indicator of cement quality. The accurate prediction of the cement specific surface area aims to guide operators to control the cement grinding process to improve product quality while reducing system energy consumption. However, due to the complexity of the cement grinding process, the process variables have coupling, time-varying delay, nonlinear characteristics, and different sampling frequency. Herein, we proposed the specific surface area prediction model, which combined dual-frequency principal component analysis and extreme gradient boosting (DF-PCA-XGB). In order to solve the problem of difficulty in modeling due to different sampling intervals of related data, this paper analyzes the low-frequency sampling data and high-frequency sampling data under multiple working conditions, and establishes prediction models respectively. Aiming at the data redundancy problem of high-frequency and low-frequency variable data in the introduced time window, a method based on the combination of principal component analysis (PCA) and extreme gradient boosting (XGB) cross-validation is proposed to reduce data redundancy while retaining most of the characteristics of the data. The final specific surface area prediction results were obtained by weighting the high-frequency data model and the low-frequency data model. The simulation results showed that the prediction method in this paper can improve the prediction accuracy of the specific surface area of the finished cement product under multiple working conditions with high stability and has promising application in the cement manufacturing process.

Effects of Exposure of Cement Dust on Platelet Count in Workers of a Cement Mill

Introduction: Cement dust is emitted during the different steps of cement production. This dust is composed of chemical components that may have unfavourable effects on the haematological system. The workers in these factories are exposed daily to this toxic dust. Those exposed to the cement dust may suffer from changes in platelet count and eventually suffer from damaging effects on the cardiovascular system. Objective: Assess the effects of cement dust on platelet count of cement mill workers. Materials and Methods: Conduction of this cross sectional study took place in the Department of Physiology, Dhaka Medical College, Dhaka between July 2017 to June 2018. After fulfilling the ethical consideration, 46 apparently healthy male cement mill workers, working for 2 or more years in a cement mill , with range of age of 20 to 50 years (study group) and 46 BMI, age and socioeconomic condition matched apparently healthy male subjects from Dhaka city were control group. The platelet count was estimated using automated haematology analyzer in Dhaka Medical College Hospital, Dhaka. Data was collected in a pre-designed structured questionnaire form. Unpaired Student’s ‘t’ test and Pearson’s correlation coefficient test were performed for statistical analysis. Results: In this study, the platelet count was significantly (p < 0.05) higher than those of control group. The platelet count was directly related with duration of cement dust exposure. Conclusions: This study concludes that the cement dust has harmful effect on the platelet count and the duration of exposure to cement dust also has an effect on this parameter. Medicine Today 2022 Vol.34(1): 44-46

Analysing Company Policies at PT. Semen Baturaja Tbk

When it was founded on November 14, 1974, the company was born under the name PT Semen Baturaja (Persero) with a 45% share ownership owned by PT Semen Gresik and 55% PT Semen Padang. The company runs a business specifically in the production of slag with the production center located in Baturaja, South Sumatra. Meanwhile, the cement milling and bagging process are carried out at the Baturaja Factory, Palembang Factory, and Panjang Factory which are then distributed to the Company's marketing areas. PT Semen Baturaja (Persero) Tbk is a company engaged in the cement industry and is aware of the risks arising from its operations to workers and the environment. The COVID-19 pandemic period greatly affected the company's work system in all fields, including the PT. Semen BATURAJA Tbk, because many projects are delayed or constrained. By developing corporate strategy, improving employee performance, conducting periodic checks on corporate governance in detail, and increasing the efficiency of the use of raw materials.

Process-to-market matrix mapping: A multi-criteria evaluation framework for industrial processes’ electricity market participation feasibility

Industrial consumers have a high potential to directly participate in short-term electricity markets to provide flexibility to the electricity system, particularly due to their large electricity consumption and accurate control of electricity-consuming processes. However, the different market participation options available in a deregulated electricity market context make participation feasibility unclear, as each (sub)market option has different market regulations. To address this issue, this paper proposes a process-to-market matrix mapping framework to evaluate the most feasible electricity (sub)markets for a given industrial process based on a set of techno-regulatory criteria. There are three stages in this framework: at stage 1, the properties of the industrial consumer and the market options are described in terms of standardised criteria; at stage 2, a matrix is developed to link consumer flexibility criteria (horizontal dimension of the matrix) to the relevant market criteria (vertical dimension); at stage 3, a scoring system is applied to evaluate the participation barrier level for each criterion link in the matrix. This paper uses the Danish electricity (sub)markets to illustrate the evaluation framework, and takes an industrial greenhouse, a cement mill and a cooling house as industrial process case studies to implement the developed method. Results show the main participation barriers, both from a market regulation and an industrial consumer perspective. From these, it appears that the type of industrial process significantly influences the choice of (sub)market to participate in. Barriers can be minimised by choosing market options with regulations better aligned with the consumer’s flexibility criteria. The importance of flexibility at the organisational level for market participation feasibility is also underlined. The developed framework provides a systematic method to evaluate the market participation feasibility, which can be used as a decision support tool for market participation and to overcome identified techno-regulatory barriers.

Impact of the Sampling Period on the Design of Digital PID Controllers

The impact of the sampling period on the parameterization of a digital PID controller in the frequency domain is attempted using three different digital approximations of the integral action. The controller is implemented in the industrial process of regulation of the cement sulphates in the cement mill outlet. The maximum sensitivity, Ms, has been utilized as a main robustness criterion. For the same Ms, proportional and differential gain, a rise of the sampling period leads to a decrease of the integral gain ki for all the three approximations. For the same sampling period, the function between proportional and integral gain differs for the three approximations studied. If the design satisfies two criteria simultaneously, maximum sensitivity and phase margin in the current study, then the permissible PID gains zone becomes narrower.

Geochemical And Mineralogical Assessment Of Secondary Gypsum In Al-Najaf, Iraq And Employment As Raw Material For Cement Industry

The Portland cement industry is one of the strategic industries in any country. The basis of an industry success is the availability of raw materials and, the low extraction in addition to transportation costs. The Bahr Al-Najaf region is abundant with limestone rocks but lacks primary gypsum. An investigation had been carried out to identify the source of secondary gypsum as an alternative to primary gypsum. Twelve boreholes were drilled for a depth of 2 m, as the thickness of suitable secondary gypsum layer ranges from 1 to 1.5 m. The mineralogical study revealed the predominance of gypsum followed by quartz and calcite, with an average of 62.9%, 19.6% and 14.35%, respectively. The geochemical analysis revealed that the content of SO3 is appropriate and ranging from 41.92% to 32.89% with an average of 37.73%. The SO3 content is within an acceptable range. The mean abundance of the major oxides of the study area may be arranged as SO3 > CaO> SiO2> MgO> Al2O> Fe2O3. The insoluble residue was at an acceptable rate. The laboratory experiments for milling secondary gypsum with clinker has successfully proven the production of Portland cement that matches the limits of the Iraqi Quality Standard (IQS) No. 5 of 1984. Great care must be taken when using secondary gypsum; secondary gypsum must be mixed well to maintain the chemical properties before blending with clinker and utilizing in the cement mill in the cement plant.

Automation and Fuzzy Control of a Manufacturing System

The automation of manufacturing systems is a major obligation to the developments because of exponential industrial equipment, and programming tools, so that growth needs and customer requirements. This automation is achieved in our work through the application programming tools from Siemens, which are PCS 7 (Process Control System) for industrial process control and FuzzyControl++ for fuzzy control. An industrial application is designed, developed and implemented in the cement factory in Ain-Touta (S.CIM.AT) located in the province of Batna, East of Algeria. Especially in the cement mill which gives the final product that is the cement.

Study the effect of cement dust exposure on the hematological variables in the workers of new badoosh cement factory in mosul city, Iraq

The present study was carried in the New Badoosh Cement factory in Mosul city belonged to Ministry of Industry and Minerals/Iraq. The continuous exposure to cement dustleads to many respiratory and health problems. So the current study aimed to determine the negative effects of this dust and the continuous exposure to them in hematological variables in the blood of 150 workers of non-smoking males working, by 25 blood samples for each of the units and productive stages as following: The administrative unit (indirect exposure group), and the groups of the productive stages (direct exposure), which included stage of mechanical workshop, material milling, ovens, cement milling and packing. Their ages ranged between (23-59)years, exposure periods were divided according to the working years into (5-10), (11-20) and ( >20 ) years, then comparison with 30 healthy, non-smoking males of the same age as workers residents in the Rabea sub-district (Al-Owainat village) outside the city and were used as a control group. The results showed a significant decrease in the hemoglobin concentration (Hb), packed cell volume (PCV%)andred blood cells count (RBCs). Also the results showed a significant increase in count of white blood cells (WBCs), lymphocytes and granules in the blood of workers inadministrators (indirect exposure group) and indifferent productive stages (direct exposure group) during the three exposure periods, as these results showed that different exposure periods and special ( >20 ) years had a clear effect on these studied blood components. It is concluded from this study that exposure of workers in different productive stages and administrative unit to cement dusthas caused clear negative effects on the blood components with an increase in the exposure period and a disrupted in metabolic and physiological processes.

Improving Wear Resistance for Grinding Balls of Horizontal Cement Mill in Cement Plant by Nanocoating Technique

Improving Wear Resistance for Grinding Balls of Horizontal Cement Mill in Cement Plant by Nanocoating Technique

Dust Emission Monitoring in Cement Plant Mills: A Case Study in Romania.

This paper presents aspects of monitoring material dust emissions from stationary emission sources (monthly dust measurements performed on cement mill stacks—mill outlet and separator outlet). Additionally, the Portland cement mill technological process (its component parts), as well as the solutions regarding the reduction of the air emissions level, following the emission limit values (VLE), established in the integrated environmental authorization (AIM) from a cement factory in Romania, were analyzed. The paper focused on analyzing the data obtained in three different years for PM10 and dust concentrations (2018–2020). For each year, the measurements have been done in 3 months, each in a different season. The average values for each year for working conditions were: 30.22 mg/m3 (2018), 27.38 mg/m3 (2019), and 27.51 mg/m3 (2020) for working conditions and for normal conditions: 34.22 mg/m3 (2018), 30.49 mg/m3 (2019), and 30.16 mg/m3 (2020). For all 3 years, the values measured in spring were higher than the other two, both for work and normal conditions.

Using the Quality Control to Determine the Factors of Failure Operation in Cement Sector

Quality control technic is an important method of designing a strategic plan for many productive industries. The Shewhart control chart is that it uses only the information observation. Cumulative sum (CUSUM) and Exponentially weighted moving average (EWMA) two very effective alternatives to the Shewhart control chart may be used when small process shifts are of interest. This paper discusses data on failure time of five cement mills in Sulaimani Mass cement factories, used, the reliability methods for analysis the failure time. The quality of the products manufactured in this factory has been estimated according to a quality control process through the use of specific control chart one of the chart Exponentially Weighted Moving Average (EWMA) chart. Whereas reliability concerns functioning under specified time. So, it can be said that the reliability is a relation between production with expected period time in quality. This study investigates the implementation of reliability and quality control. The findings indicate that factors that affecting the function of mills which will increase the failure rate of mills and lower their life span, through which quality of products will be affected.

Ventilation Prediction for an Industrial Cement Raw Ball Mill by BNN-A "Conscious Lab" Approach.

In cement mills, ventilation is a critical key for maintaining temperature and material transportation. However, relationships between operational variables and ventilation factors for an industrial cement ball mill were not addressed until today. This investigation is going to fill this gap based on a newly developed concept named “conscious laboratory (CL)”. For constructing the CL, a boosted neural network (BNN), as a recently developed comprehensive artificial intelligence model, was applied through over 35 different variables, with more than 2000 records monitored for an industrial cement ball mill. BNN could assess multivariable nonlinear relationships among this vast dataset, and indicated mill outlet pressure and the ampere of the separator fan had the highest rank for the ventilation prediction. BNN could accurately model ventilation factors based on the operational variables with a root mean square error (RMSE) of 0.6. BNN showed a lower error than other traditional machine learning models (RMSE: random forest 0.71, support vector regression: 0.76). Since improving the milling efficiency has an essential role in machine development and energy utilization, these results can open a new window to the optimal designing of comminution units for the material technologies.

ВЛИЯНИЕ РАЗНЫХ АССОРТИМЕНТОВ ДВУХШАРОВОЙ МЕЛЮЩЕЙ ЗАГРУЗКИ НА ПРОИЗВОДИТЕЛЬНОСТЬ ШАРОВОЙ МЕЛЬНИЦЫ ОТКРЫТОГО ЦИКЛА

The ball mill has an energy efficiency of no more than 3.5 % (taking into account the measures taken to intensify the process of grinding the material). This is due to the imperfection of the design of the grinding unit, which consists in the fact that it is impossible to completely convert the mechanical energy accumulated by the grinding load into grinding energy (i.e., energy directly spent on the destruction of material particles). Most of the stored energy is converted into heat, noise, and vibration. The existing directions of intensification of the grinding process are as follows: improvement of the design, internal equipment of the cement mill; changes in the physical and chemical properties of the grinding medium; improvement of the grinding scheme. The authors of this article work in the direction of improving the internal equipment, which is reflected in the scientifically based selection of the range of grinding media for the fine grinding chamber, since the rational composition of the grinding load can significantly reduce the energy consumption of the grinding process. The authors continue to study the possibility of using a two-ball loading in a fine grinding chamber. This article provides a brief overview of the different ranges of two-ball grinding loadings, which differ from each other only in the range of grinding media. The possibility of a significant increase in the productivity of the mill when replacing the traditional grinding load with a rational two-ball is shown

Using genetic algorithms for operational planning of cement mills loading

The article discusses the problem automating the construction of schedules for cement production. The necessity using a computer system for planning the loading of technological equipment is substantiated in order to develop the optimal use of available resources for the timely and high-quality execution production tasks. The essence of the problem is shown, which is to allocate resources (cement mills and produced brands of cement) the production system for a given target plan so as to exclude deviations the real plan from the target, as well as to reduce the number of mill switchings to a minimum. The formalization the task planning the loading the mills is carried out and those essential parameters of the process are given, which are selected as the initial data for solving the task planning the operation of grinding mills. The solution to the problem constructing schedules for the operation of cement mills is based on the use of a genetic algorithm, for which an implementation sequence is proposed. The results solving the problem are also presented, which confirm the correctness the chosen method and its implementation.

Effect of heat treatment on hardness and wear resistance of high carbon-high chromium steel (FMU-11)

In the present study, microstructure, hardness, and abrasion resistance of a heat-treated high carbon-high chromium steel (FMU-11) used in the cement mills were investigated. To investigate the best heat-treating cycle for the FMU-11 steel, three sets of samples were heat treated. The first set was tempered two times, the second set was re-hardened, and the third set was cryogenically heat treated. These samples were then compared with the conventionally heat-treated samples. The samples' microstructure was studied using an optical microscope, where traditional black and white etching, as well as color etching, were used. Scanning electron microscopy (SEM) was applied for higher magnification studies and in-depth analysis of the chemical composition. The mechanical properties were investigated by measuring the hardness and the wear resistance for the samples heat-treated in different cycles. The results showed that the cryogenic treatment and double-tempered samples had the highest hardness and wear resistance. In addition, the results showed that the re-hardening operation caused the carbides to be finely separated and evenly distributed in the steel matrix. The wear test results illustrated that the wear mechanism could be the delamination wear and the abrasive wear combined.

Effects of alternative calcium sulphate-bearing materials on cement characteristics in vertical mill and storing

This study investigates the impact of gypsum, anhydrite and blends of them on cement and their impact on the vertical mill operation and cement storing. Mixtures of gypsum and anhydrite were prepared in the ratios: 100:0, 62.5:37.5, 50:50, 25:75 and 0:100. The results of setting time, compressive strength, soundness and moisture content showed that both gypsum and hemihydrate had the same performance in vertical cement mill as cement retarders with no noticeable change on physicomechanical properties of hardened pastes and blending both with different proportions can be used as a controller of cement setting and moisture result in improvement in cement mill operation and cement storing. In conclusion, gypsum can be replaced by anhydrite partially or completely in a vertical cement mill with no effect on cement properties. Additionally, gypsum and anhydrite blending can control moisture content in cement, improve cement storing and avoid storing problems.

Investigation on metallurgy and material strength enhancement of 20MnCr5 forged link chain in cement mill

Investigation on metallurgy and material strength enhancement of 20MnCr5 forged link chain in cement mill

Capacity of roller mill for cement grinding

Engineering for the cement industry is part of the heavy industry. The cement industry is the main supplier of raw materials for the production of concrete and reinforced concrete. For grinding cement, two types of mills are used - ball and roller. Recent decades have proven the great effectiveness of a vertical roller mill for grinding raw materials. Its effectiveness, combined with the implementation of drying, grinding and separation in one unit, gives it an undeniable advantage over a ball mill. This explains the significant increase in the share of roller mills in the cement mill market. The grinding process in such mills occurs due to abrasion, respectively, in the process of work wear of the rubbing parts of the mill occurs. The work evaluated the performance of a mill with smooth disk rolls. During the study, the cause of the destruction of the sectors of the mill produced by FLSmidth, operating in the Russian Federation, was identified. The study revealed the causes of the destruction of the details of the roller mill: with the simultaneous impact of the workload and the displacement of the sectors resulting from intensive wear, the total equivalent stresses exceed the value of the endurance limit under cyclic loading. Therefore, the accumulation of fatigue damage to the material, the formation and growth of cracks, which adversely affects the performance of the mill. A number of measures have been proposed to increase the operability of mills of this design.

Design of a breaking machine for separating pairs of high chromium grinding ball media

A high chromium grinding ball media coded NF6357A is a replacement casting produced by Nigerian Foundries limited, Lagos, Nigeria for cement mill grinding. The 30 mm diameter ball casting is produced by machine moulding. The balls come out in pairs after shakeout, and must be separated and heat-treated before delivery to the customers. In this study, a separating machine is designed to break the adjoining area of the pairs into a unit to overcome the challenges of the existing manual breaking. The machine composed of electric motor with reducer gear, chute/chute support, hammer and pulley. The ball pairs are manually fed into the chute and move by gravity for breaking by impact force of the hammer. The hammer is bolted firmly on the rotating pulley to hit the balls against the chute edge. Each separated unit of the ball falls off for collection and subsequent grinding/finishing operations. The breaker is designed to separate twenty (20) pairs of balls in about 7 minutes with shearing stress of about 450 N/mm2 and capable of producing 4.5 KN impact force. This breaking shear stress is sufficient enough to overcome the shear strength of the grinding media which is about 379 N/mm2.

Analysis of Raw Mill Machines Maintenance in Cement Industry

Cement processing plan is a state-owned enterprise engaged in the cement industry. The problem that this factory has is such as frequent damage to the engine. The machines used in cement production at the factory include raw mill machines, kiln machines, and cement mill machines. The more often a machine is damaged, the average time between failures of a machine is lower. So that it can cause the production process is hampered. In this study, the engine studied was the Raw Mill machine at plant. The raw mill machine functions as a main material grinder in the initial milling process such as limestone, silica stone, clay, and iron sand to become raw mix. To find out the frequency of damage to the machine or the time interval between damage to the tool (MTBF) and the length of time used to repair the tool (MTTR), the Total Productive Maintenance (TPM) method is used to perform maintenance by optimizing the effectiveness of the equipment and reducing / eliminating sudden damage (breakdown) by first identifying and then the cause of the problem is identified using fish bone analysis and Failure Mode and Effect Analysis (FMEA).