/Resources 38 0 R Chai, Li and Wang [3] and Chai et al. /CropBox [0 0 490 700] Open Engineering, Vol.
Figure 3. As a summary, it can be stated that clustering has a major effect on correlation. 18 0 obj Then decant again to obtain a pulp at the third density. /Count 8 10 (Issue 1), pp. In the actual data analysis, twenty-six variables from the thickener feed, thickener and paste line were used. /Type /Page Water balance of a high-density thickener in an iron ore concentrator plant. For more information contact our technical team atsales@plapl.com.auor call us on +61 3 9786 1711, Most common problems in thickener operations (part 2), Strategies to reduce water consumption in concentrator plants (part 1), Strategies to reduce water consumption in concentrator plants (part 2), Category: Blog, Process Control, SmartDiver, Tags: Thickener control, Thickener operations, Thickener optimisation. the dominant (eg. The regression coefficients are obtained as the least squares solution given by. /Parent 5 0 R
/Rotate 0 This was defined by the value of the current in amperes measurement. Usually it is desired to discharge pulp from the thickener at its final density as shown in the above test. /Type /Page Thickening is the most economical of several dewatering techniques. The research problem in question is that the outgoing paste is sometimes difficult to pump. Control Eng Pract. endobj /Rotate 0 /Kids [16 0 R 17 0 R 18 0 R 19 0 R 20 0 R] << The whole data set contained altogether 73 measurements from February 2017 to February 2018. /Contents 31 0 R S+Q = F and F/100 f = Q/100-q + S = 100-s endobj The modern world is highly dependent on materials. Let W= weight of a given volume of water (1 gram = 1 cc.). /MediaBox [0 0 490 700] This produces mineral settling. 65 https://doi.org/10.1016/j.mineng.2018.11.00610.1016/j.mineng.2018.11.006Search in Google Scholar, [6] Remes A, Aaltonen J, Koivo H. Soft-sensor estimation of an apatite thickener operation at the Siilinjrvi concentrator, IFAC Proceedings Volumes, Volume 42, 2009, 167-17210.3182/20091014-3-CL-4011.00031Search in Google Scholar, [7] Bergh L., Ojeda P., Torres L., Expert control tuning of an industrial thickener, IFAC-PapersOnLine, 2015, 48-17, 086-091 7010.1016/j.ifacol.2015.10.083Search in Google Scholar, [8] Segovia JP, Concha F, Sbarbaro D. On the control of sludge level and underflow concentration in industrial thickeners, IFAC Proceedings Volumes, Volume 44, 2011, 8571-857610.3182/20110828-6-IT-1002.02667Search in Google Scholar, [9] Ruhanen E, Kosonen M, Kauvosaari S, Meintjes C. Performance optimization of paste thickening at the Yara Siilinjrvi Plant. Correlation coefficients in different operation areas. 2 0 obj The cosine parameter was used as a distance measure. /Parent 5 0 R endobj Chai T, Jia Y, Li H, Wang H. An intelligent switching control 60 for a mixed separation thickener process. Repeat readings of settlement as above. The data tubes can be reasonably identified in the three cluster cases. Very high on-line operation availability is required from a thickener. >> /Type /Page One of them is a narrow operating window as a small change in the underflow solids concentration may have a major impact on the properties (for example pumpability and flowability) of the underflow.
/Resources 52 0 R D (in feet)= D (Gp 1) Gs/40.8 (Gs 1). The analysis is focused on Thickener 1 due to better availability of measurements. Dividing the data based on pressure difference (X-axis paste line pressure difference and Y-axis the number of values divided into different bins). 13 0 obj
/Resources 32 0 R Ws = Gp-1/Gs-1 x GsW If the pulp reached its final density during the 19 hour test, a standard depth thickener is considered adequate. /Producer (Acrobat Distiller 5.0 \(Windows\)) The delay value was defined by the mill experts based on their knowledge of the process. The saying: What you cant grow, you need to dig is true and it means that people need different kinds of materials to produce tools and necessities for their day-to-day use. /Parent 5 0 R /Type /Page Error 0.3 tons due to slight inaccuracies in original data. /CropBox [0 0 490 700] 20 0 obj /Parent 6 0 R /Parent 3 0 R /Resources 40 0 R >> endobj /Annots [30 0 R] The phenomena leading to this situation are not well known.
R = Settling rate in feet per hour. 1 0 obj endobj
Next, the variables with a correlation higher than 0.5 were taken for closer analysis. /Contents 61 0 R >> /MediaBox [0 0 490 700] /Rotate 0 >> The MLR model structure can capture the major interactions even though it is limited to linear relationships. /Parent 3 0 R /Parent 6 0 R /Contents 51 0 R
endobj endobj /Type /Page
Course Hero, Inc. /Rotate 0 /Filter /FlateDecode Based on the correlations, no single variable can be found that could explain the changes within the pressure difference. Remes, Aaltonen and Koivo [6] have developed a Kalman filter based soft sensor to monitor the thickener operation to reduce process disturbances. End of preview. HtVMs6WH?z6L3, Designing for Paste Thickening Testwork and Sizing for Paste Thickeners. Final Density D = 1:1. /Type /Page << The process was analysed by dividing the data first into high and low pressure difference operation areas and then clustering the data from the variable of Paste line 1 and the response variable. Clusters from variable Paste line 1 and response during the usage of booster pump KA7403; on the left there are the two cluster cases and on the right three cluster cases. The relationship between %solids and shear stress is exponential so that small changes in %solids generate a progressive increase in shear stress, and consequently the required torque. The knowledge of the variables found to influence the pressure difference can be utilized in further development. Linear regression models for both booster pumps were created separately. Sands (spigot) andOverflow, respectively. Two different booster pumps, KA7402 and KA7403, were used. << Want to read all 3 pages. This leads to a need for extra maintenance and even stoppages, therefore it would be beneficial to understand these phenomena better. /Parent 7 0 R 24 0 obj
Terms.
/Count 5 /Parent 6 0 R 2018-05-29T10:02:54+08:00 Tan, Bao and Bickert [2] propose a model predictive control with rake torque constraint. Part 1 will cover problems in thickener operations caused by thickener design errors and changes in ore properties. Decant sufficient clear water or solution to establish a pulp with intermediate density. "Data analysis of a paste thickener". Based on regression: variables Thickener 14, Thickener 12, Thickener 15, Outotec Analyzer 2 and Thickener 17. 23 0 obj /Keywords () /Parent 6 0 R /Type /Pages Your documents are now available to view. /Type /Page << /MediaBox [0 0 490 700]
Arbuthnot, I.M 2016;57:6171. 2016;57:6171.10.1016/j.conengprac.2016.07.007Search in Google Scholar, [5] Langlois JI, Cipriano A. Gp =specific gravity of pulp= Wp/W >> Weight per cubic foot = Gp/32.038 tons = 62.425 Gp pounds 12 0 obj << 55, Chai T, Li H, Wang H. An intelligent switching control for the intervals of concentration and flow-rate of underflow slurry in a mixed separation thickener, IFAC Proceedings Volumes, Volume 47, 2014, 338-345. The data analysis was done using the paste line pressure difference as a response variable and by dividing the data collected from Yaras Siilinjrvi mill into two parts: operation areas with high and low pressure difference. 16 0 obj In the high pressure difference operation area the correlations are weak (close to zero). Mine planning is necessary to control the fines content under the specified values in the design. Jari Ruuska, Riku-Pekka Nikula, Eemeli Ruhanen, Janne Kauppi, Sakari Kauvosaari, Mika Kosonen, Classical and Ancient Near Eastern Studies, Library and Information Science, Book Studies, https://doi.org/10.1016/j.mineng.2018.11.006, https://doi.org/10.1007/978-1-4757-3462-1, Fabrication of aluminium covetic casts under different voltages and amperages of direct current, Inhibition effect of the synergistic properties of 4-methyl-norvalin and 2-methoxy-4-formylphenol on the electrochemical deterioration of P4 low carbon mold steel, Autonomous vans - the planning process of transport tasks, Logistic regression in modeling and assessment of transport services, Drivers reaction time research in the conditions in the real traffic, Design and evaluation of a new intersection model to minimize congestions using VISSIM software, Mathematical approaches for improving the efficiency of railway transport, An experimental analysis of the drivers attention during train driving, Risks associated with Logistics 4.0 and their minimization using Blockchain, Service quality of the urban public transport companies and sustainable city logistics. /Contents 45 0 R /Parent 7 0 R endobj Harrell FE Jr. Regression modelling strategies with applications to linear models, logistic regression, and survival analysis. endstream
Springer; 2001. https://doi.org/10.1007/978-1-4757-3462-110.1007/978-1-4757-3462-1Search in Google Scholar, 2020 J. Ruuska et al., published by De Gruyter. Information about the performance optimization of paste thickening can be found for example in [9]. The scope of this study covers the measurements from the feed line, thickener and underflow. A = Thickener area in square feet per ton of dry solids thickened in 24 hours. F = Q 100-f/100-q x q-s/f-s = S 100 f- (a-s)/100 s-(a-f)
/Rotate 0
Miner Eng. Particle size variations (settling rate variation). This is not known precisely, even by the process operators them-selves. endobj << These specifications commonly have high variability and are required to adjust to the programmed processing tonnages during the life of the mining project. Moreover, some sort of indicator would be needed to tell when there really are pumping problems. The solids content of slurry is typically increased in thickeners. Part 2 will discuss in detail the problems caused by mechanical and maintenance issues (including issues with thickener instrumentation and control) and what can be done to solve them. The flocculant rate and underflow rate are the two independent variables that are typically used for control. Draw a line on the paper at the top of the pulp and mark 0 minutes. Figure 2. << The goal is to gain better understanding of the phenomena after this phase. The pulp just tested was at 3:1 dilution, so decanting one- third of the water will give 2:1 dilution, water to solids. Applying this data to above formula, you obtain: Normally a 25 per cent factor of safety is allowed in determining the thickener area size. >> /Contents 59 0 R endstream << Two and three clusters were tested. The dependent variables include rake torque, underflow density, overflow turbidity, solids interface level (bed depth), solids inventory (bed pressure), solids settling rate and underflow viscosity. In this paper, we concentrate on the data analysis of a paste thickener to find the affecting factors, utilizing a data set from an industrial thickener. At 3:1dilution R = 0.30 feet per hour application/pdf /MediaBox [0 0 490 700] At 2:1dilution R = 0.15 feet per hour In the worst-case scenario these phenomena cause clogging in the piping. The most common problems in thickener operations include the presence of suspended solids in the recovered water and the density or percentage of solids of the thickener discharge outside the set targets. /CropBox [0 0 490 700] Paste and Thickened Tailings: A 50 Guide. It can be concluded that dividing the data between high pressure and low pressure difference operation areas is not enough to explain all the interactions within the process. However, when the pressure difference grows extremely high it will cause problems. The sedimentation rate is strongly influenced by the particle size, so that the variations in the grinding stage are transferred to the thickening stage. endobj /CreationDate (D:20180529100254+08'00') /Rotate 0 /MediaBox [0 0 490 700] 8 0 obj Australian Centre for Geomechanics, University of Western Australia; 2002.Search in Google Scholar, [2] Tan CK, Bao J, Bickert G. A study on model predictive control in paste thickeners with rake torque constraint, J. /Contents 47 0 R
The strongest interactions between the variables and pressure difference for booster pump KA7402 were: Based on correlation: variable Paste line 1, Based on regression: variables Paste line 1, Paste line 2, Thickener 16 and Thickener 2. For example, between ten and thirty bars, two different positive correlating tubes can be observed. As the amount of rock crushed increases, the amount of waste rock also increases. /Contents 41 0 R /Rotate 0 Mix thoroughly. /Length 1552 /Contents 43 0 R 65, Remes A, Aaltonen J, Koivo H. Soft-sensor estimation of an apatite thickener operation at the Siilinjrvi concentrator, IFAC Proceedings Volumes, Volume 42, 2009, 167-172, Bergh L., Ojeda P., Torres L., Expert control tuning of an industrial thickener, IFAC-PapersOnLine, 2015, 48-17, 086-091 70, Segovia JP, Concha F, Sbarbaro D. On the control of sludge level and underflow concentration in industrial thickeners, IFAC Proceedings Volumes, Volume 44, 2011, 8571-8576, Ruhanen E, Kosonen M, Kauvosaari S, Meintjes C. Performance optimization of paste thickening at the Yara Siilinjrvi Plant. /CropBox [0 0 490 700] 5 0 obj Sand Tonnage S = F 100-s/100-f x q f/q -s = 150 100-31/100-49 x 82-49/82-31 = 150 69/51 x 33/51 =131 tons sands. /Type /Page >> The main changes that affect the thickener are: throughput variations, particle size variation, increase in coarse mineral and clay and ultrafine content variation. endobj Variables for the models were selected using the forward selection method. Jewell RJ, Fourie AB, Lord ER.
25 0 obj Springer; 2001. % >> /Resources 62 0 R << The response was scaled between 0 and 1. Many industrial sectors use these vessels. Yield stress vs solids concentration. 4 0 obj This is by no means the whole truth, as often the quality is good with high pressure differences. << 21 0 obj Scatter graphs between variables: Outotec Analyzer 1, Paste line 1, Thickener 12, Thickener 14 and response during the usage of booster pump KA7403. /Rotate 0 Let us try to determine these operating conditions using clustering. The data set was divided so that 20% of the data was chosen randomly for the testing data set. Thickener-Design-2.pdf - MIP Thickener Design The following is a short cut to designing your own thickener: (a) Size of Thickener As a first stab. Total..149.7 tons O+S = Feed response variable) did not change were removed.
>> Mix pulp thoroughly. /Parent 3 0 R Knowing how to size a thickener and determine thecapacity required to handle a pre-determined tonnage of a certain pulp, by overflowing a clear solution and obtaining the desired pulp density of thickener discharge, depends upon the settling rate of that particular pulp. New 80 York. A clean overflow and maximum solids concentration in the underflow are the general targets. Gs = specific gravity of solids= Ws/W (Wp-Ws) /Pages 3 0 R /MediaBox [0 0 490 700] /Kids [21 0 R 22 0 R 23 0 R 24 0 R 25 0 R] 2015 - 2022 Precision Light and Air All Rights Reserved. stream This preview shows page 1 - 2 out of 3 pages.
Fourie (Eds. For example, it may be necessary to shut a filter down for repairs and at the same time keep the balance of the mill in operation. The bin size of the histogram is 0.5 bar. As the pressure difference fifteen-minute average is over 13 bars, it belongs in the high-pressure difference operation area. To determine content of any one pulp, the other twomoisture contents must be known as well as all the tonnages. sales@plapl.com.au Additionally, the selection of an adequate safety factor that represents the variability of the mineral to be processed must be considered. Thickeners are continuous sedimentation equipment used to perform solid-liquid separation in finely ground slurry ore as mineral concentrates or tailings (figure 1). Clay and ultrafine content variation (rheology change). Fourie (Eds. 2017;105:5262. A multivariable linear regression (MLR) model is given by Harrel [10]: where y is the output variable (N1), X is the input variable matrix (NM) and b is the vector of regression coefficients (M1). These layers can be monitored with systems such as SmartDiver and can be used to automatically control throughput variability.
/Rotate 0 The aim is to investigate the behaviour and variables that affect the paste-thickening vessel in order to make the operation cost-efficient. /MediaBox [0 0 490 700] Depending on the configuration of the plant, the type of mineral and the thickener technology, the recovery of water can vary between 65% to 95% of the process water, as shown in figure 2. The modelling results are presented in Tables 1 and 2. /Parent 5 0 R /Parent 5 0 R /CropBox [0 0 490 700] Pulp Calculations forCLASSIFIERS AND THICKENERS. Course Hero member to access this document, Critical_review_of_thickener_design_meth.pdf, Hilton Nyamwanza final project.. thickener sizing.docx, Module 1 - Introduction to Comminution and Sizing.pdf, Exercise Four FINAL 3rd edition - EXERCISE(2).docx, University of Cape Town ELECTRICAL EEE4099f, Faculty of Sciences and Technology CS DEPARTM 101, ICAO - Airport services manual - Part 2, Pavement Surface Confitions.pdf, ICAO-Annex 14, Vol I, Aerodrome Design and Operations, Ed-4.July 2004.pdf, CATALOGUES DES NORMES MAROCAINES 2011.pdf, Requirements_Management_in_Enterprise_Architect.pdf, Copyright 2022. Let, f, s, and q be percent of Moisture in Feed, Sandsand Overflow, respectively. Ruuska, J., Nikula, R., Ruhanen, E., Kauppi, J., Kauvosaari, S. & Kosonen, M. (2020). The blog will be divided in two parts.
endobj Tons of dry solids per foot depth for round tanks of diameter. /Type /Page Assume the following data was obtained from the above tests: At 4:1 dilution R = 0.50 feet per hour S=percent of solids in pulp=100 x Gp-1/Gs-1 x Gs/Gp /CropBox [0 0 490 700] Platinum Tailings) or feed flow rate (e.g. /Rotate 0 >> Privacy The dependent variables include rake torque, underflow density, overflow turbidity, solids interface level (bed depth), solids inventory (bed pressure), solids settling rate and underflow viscosity [7]. /Resources 58 0 R endobj A paste thickener can be used to lower the water content. In 75 R.J. Jewell and A.B. +61 3 9786 1711. << <<
/MediaBox [0 0 490 700] << /Kids [5 0 R 6 0 R 7 0 R] >> However, if additional time was required to reach final density, the thickener volume would have to be large enough to retain the pulp for this extra time. The model was optimized on the grounds of the internal validation data set. >> Find the Potential Energy (ft-lb) of an aircraft weighing 10,000 lbs at 5,000 ft true altitude and 125 KTS True Air Speed? uuid:63016ae5-b8af-4b55-abbd-702c72ed5df0 endobj >> Under 'Cluster Selection,' select, Maximum wing loading on an elliptical airfoil occurs: throughout with a uniform distribution near the wing tip near the wing root at the MAC, What is the most important thing that all sedimentary rocks can tell you, specifically referring to depositional environment? However, there is a great risk of drawing misleading conclusions unless sufficient process knowledge is available. A. New 80 York. >> /Type /Page 10 0 obj endobj
It should be noted that the equation above is written for a single output variable. The main design errors include: The ore fed to the thickener is essentially variable due to changes in upstream operations (mined sector, milling and concentration). These tests are carried out with representative samples of mineral and different granulometry. /Resources 36 0 R << Data analysis of a paste thickener. Miner Eng. Wp= weight of an equal volume of pulp, or by wettingsolids to make water level equal. Four feed and three Thickener 1 measurements were delayed for eight hours because the thickener delay was estimated to be eight hours. These problems are classified according to whether they are caused by thickener design errors, changes in ore properties, or mechanical and maintenance issues. endobj /Contents 35 0 R
/Parent 5 0 R /CropBox [0 0 490 700] The affecting variables were not investigated at this stage, but via modelling it can be assumed that there may be more operation areas, especially in the high pressure difference area. Six data sets were formed using the booster pumps and the paste line pressure difference as dividers. /CropBox [0 0 490 700] /CropBox [0 0 490 700] /CropBox [0 0 490 700] The product of the ore extracted from the open pits is apatite concentrate, from which fertilizers and phosphoric acid are the final products. /MediaBox [0 0 490 700] viscosity and shear stress increase making thickening difficult.
A typical thickener used in mineral processing [7]. /Type /Page Although the variables of Thickener 1 - 5 had stronger correlation in cluster 3 than in cluster1, the same observation can be made for the variables of Paste line 1 and Thickener 12 too. Modelling was done using repeated 10-fold cross-validation and a testing data set. >> Q = F 100-q/100-f x f-s/q-s = 150 100-82/100-49 x 49-31/82-31 = 150 81/51 x 18/51 =18.7 tons overflow. >> The thickening process normally occurs in large-diameter tanks where solid particles settle under the influence of gravity, i.e. Cosmic Distance Ladder,' 'HR Diagram Star Cluster Fitting Explorer.' /CropBox [0 0 490 700] ), Paste 2018 - Proceedings of the 21st international seminar on paste and thickened tailings, Perth, Australia: Australian Centre for Geomechanics, 75-88. << << 15 0 obj
Cubic Feet per ton=32.038/Gp The tests also evaluate different dosages of flocculant. /Type /Page /MediaBox [0 0 490 700] The safety factor can vary between 1.15 and 1.30. Similar interactions for booster pump KA7403 were: Based on correlation: variable Thickener 14. /Rotate 0 For example, the tailings from flotation circuits contain a lot of water and it is beneficial to reduce the water content before storing in tailings ponds. endobj Design errors appear after start-up when flow throughput or rheology variations exceed applied factors. Division into operation areas was made based on the pressure difference of the paste line. In this blog, we will explore the most common problems that affect the operations and efficiency of thickeners. /Resources 60 0 R Types of organisms present B. The switching mechanism uses rule-based reasoning. A lot of attention is being paid to make it as efficient as possible. /Parent 5 0 R /Resources 50 0 R N is the number of data points and M is the number of variables. 2019;131:1319. /Resources 34 0 R /Type /Catalog Clustering was also done for KA7402, but the result was not as good as for KA7403. Triglavcanin, R.A <<
In thickener design, there are two specifications that will define the tank efficiency to process minerals: thickener area and drive torque. For five minutes, at one-minute intervals, mark the point to which the solids have settled. /Contents 55 0 R The phenomena leading to this situation are not well known. /ModDate (D:20180529100303+08'00') >> endobj
>> /MediaBox [0 0 490 700] Paste and Thickened Tailings: A 50 Guide. When the content of fine particles (clays or micas) increases more than 20% above their normal value, due to their high specific surface, problems of excessive increase in rheology are generated e.g. Repeat settling measurements at one-minute intervals for five minutes. 3 0 obj /CropBox [0 0 490 700]
The correlations in the whole operation area and the low pressure difference are mostly close to each other.
/Rotate 0 This was defined by the value of the current in amperes measurement. Usually it is desired to discharge pulp from the thickener at its final density as shown in the above test. /Type /Page Thickening is the most economical of several dewatering techniques. The research problem in question is that the outgoing paste is sometimes difficult to pump. Control Eng Pract. endobj /Rotate 0 /Kids [16 0 R 17 0 R 18 0 R 19 0 R 20 0 R] << The whole data set contained altogether 73 measurements from February 2017 to February 2018. /Contents 31 0 R S+Q = F and F/100 f = Q/100-q + S = 100-s endobj The modern world is highly dependent on materials. Let W= weight of a given volume of water (1 gram = 1 cc.). /MediaBox [0 0 490 700] This produces mineral settling. 65 https://doi.org/10.1016/j.mineng.2018.11.00610.1016/j.mineng.2018.11.006Search in Google Scholar, [6] Remes A, Aaltonen J, Koivo H. Soft-sensor estimation of an apatite thickener operation at the Siilinjrvi concentrator, IFAC Proceedings Volumes, Volume 42, 2009, 167-17210.3182/20091014-3-CL-4011.00031Search in Google Scholar, [7] Bergh L., Ojeda P., Torres L., Expert control tuning of an industrial thickener, IFAC-PapersOnLine, 2015, 48-17, 086-091 7010.1016/j.ifacol.2015.10.083Search in Google Scholar, [8] Segovia JP, Concha F, Sbarbaro D. On the control of sludge level and underflow concentration in industrial thickeners, IFAC Proceedings Volumes, Volume 44, 2011, 8571-857610.3182/20110828-6-IT-1002.02667Search in Google Scholar, [9] Ruhanen E, Kosonen M, Kauvosaari S, Meintjes C. Performance optimization of paste thickening at the Yara Siilinjrvi Plant. Correlation coefficients in different operation areas. 2 0 obj The cosine parameter was used as a distance measure. /Parent 5 0 R endobj Chai T, Jia Y, Li H, Wang H. An intelligent switching control 60 for a mixed separation thickener process. Repeat readings of settlement as above. The data tubes can be reasonably identified in the three cluster cases. Very high on-line operation availability is required from a thickener. >> /Type /Page One of them is a narrow operating window as a small change in the underflow solids concentration may have a major impact on the properties (for example pumpability and flowability) of the underflow.
/Resources 52 0 R D (in feet)= D (Gp 1) Gs/40.8 (Gs 1). The analysis is focused on Thickener 1 due to better availability of measurements. Dividing the data based on pressure difference (X-axis paste line pressure difference and Y-axis the number of values divided into different bins). 13 0 obj
/Resources 32 0 R Ws = Gp-1/Gs-1 x GsW If the pulp reached its final density during the 19 hour test, a standard depth thickener is considered adequate. /Producer (Acrobat Distiller 5.0 \(Windows\)) The delay value was defined by the mill experts based on their knowledge of the process. The saying: What you cant grow, you need to dig is true and it means that people need different kinds of materials to produce tools and necessities for their day-to-day use. /Parent 5 0 R /Type /Page Error 0.3 tons due to slight inaccuracies in original data. /CropBox [0 0 490 700] 20 0 obj /Parent 6 0 R /Parent 3 0 R /Resources 40 0 R >> endobj /Annots [30 0 R] The phenomena leading to this situation are not well known.
R = Settling rate in feet per hour. 1 0 obj endobj
Next, the variables with a correlation higher than 0.5 were taken for closer analysis. /Contents 61 0 R >> /MediaBox [0 0 490 700] /Rotate 0 >> The MLR model structure can capture the major interactions even though it is limited to linear relationships. /Parent 3 0 R /Parent 6 0 R /Contents 51 0 R
endobj endobj /Type /Page
Course Hero, Inc. /Rotate 0 /Filter /FlateDecode Based on the correlations, no single variable can be found that could explain the changes within the pressure difference. Remes, Aaltonen and Koivo [6] have developed a Kalman filter based soft sensor to monitor the thickener operation to reduce process disturbances. End of preview. HtVMs6WH?z6L3, Designing for Paste Thickening Testwork and Sizing for Paste Thickeners. Final Density D = 1:1. /Type /Page << The process was analysed by dividing the data first into high and low pressure difference operation areas and then clustering the data from the variable of Paste line 1 and the response variable. Clusters from variable Paste line 1 and response during the usage of booster pump KA7403; on the left there are the two cluster cases and on the right three cluster cases. The relationship between %solids and shear stress is exponential so that small changes in %solids generate a progressive increase in shear stress, and consequently the required torque. The knowledge of the variables found to influence the pressure difference can be utilized in further development. Linear regression models for both booster pumps were created separately. Sands (spigot) andOverflow, respectively. Two different booster pumps, KA7402 and KA7403, were used. << Want to read all 3 pages. This leads to a need for extra maintenance and even stoppages, therefore it would be beneficial to understand these phenomena better. /Parent 7 0 R 24 0 obj
Terms.
/Count 5 /Parent 6 0 R 2018-05-29T10:02:54+08:00 Tan, Bao and Bickert [2] propose a model predictive control with rake torque constraint. Part 1 will cover problems in thickener operations caused by thickener design errors and changes in ore properties. Decant sufficient clear water or solution to establish a pulp with intermediate density. "Data analysis of a paste thickener". Based on regression: variables Thickener 14, Thickener 12, Thickener 15, Outotec Analyzer 2 and Thickener 17. 23 0 obj /Keywords () /Parent 6 0 R /Type /Pages Your documents are now available to view. /Type /Page << /MediaBox [0 0 490 700]
Arbuthnot, I.M 2016;57:6171. 2016;57:6171.10.1016/j.conengprac.2016.07.007Search in Google Scholar, [5] Langlois JI, Cipriano A. Gp =specific gravity of pulp= Wp/W >> Weight per cubic foot = Gp/32.038 tons = 62.425 Gp pounds 12 0 obj << 55, Chai T, Li H, Wang H. An intelligent switching control for the intervals of concentration and flow-rate of underflow slurry in a mixed separation thickener, IFAC Proceedings Volumes, Volume 47, 2014, 338-345. The data analysis was done using the paste line pressure difference as a response variable and by dividing the data collected from Yaras Siilinjrvi mill into two parts: operation areas with high and low pressure difference. 16 0 obj In the high pressure difference operation area the correlations are weak (close to zero). Mine planning is necessary to control the fines content under the specified values in the design. Jari Ruuska, Riku-Pekka Nikula, Eemeli Ruhanen, Janne Kauppi, Sakari Kauvosaari, Mika Kosonen, Classical and Ancient Near Eastern Studies, Library and Information Science, Book Studies, https://doi.org/10.1016/j.mineng.2018.11.006, https://doi.org/10.1007/978-1-4757-3462-1, Fabrication of aluminium covetic casts under different voltages and amperages of direct current, Inhibition effect of the synergistic properties of 4-methyl-norvalin and 2-methoxy-4-formylphenol on the electrochemical deterioration of P4 low carbon mold steel, Autonomous vans - the planning process of transport tasks, Logistic regression in modeling and assessment of transport services, Drivers reaction time research in the conditions in the real traffic, Design and evaluation of a new intersection model to minimize congestions using VISSIM software, Mathematical approaches for improving the efficiency of railway transport, An experimental analysis of the drivers attention during train driving, Risks associated with Logistics 4.0 and their minimization using Blockchain, Service quality of the urban public transport companies and sustainable city logistics. /Contents 45 0 R /Parent 7 0 R endobj Harrell FE Jr. Regression modelling strategies with applications to linear models, logistic regression, and survival analysis. endstream
Springer; 2001. https://doi.org/10.1007/978-1-4757-3462-110.1007/978-1-4757-3462-1Search in Google Scholar, 2020 J. Ruuska et al., published by De Gruyter. Information about the performance optimization of paste thickening can be found for example in [9]. The scope of this study covers the measurements from the feed line, thickener and underflow. A = Thickener area in square feet per ton of dry solids thickened in 24 hours. F = Q 100-f/100-q x q-s/f-s = S 100 f- (a-s)/100 s-(a-f)
/Rotate 0
Miner Eng. Particle size variations (settling rate variation). This is not known precisely, even by the process operators them-selves. endobj << These specifications commonly have high variability and are required to adjust to the programmed processing tonnages during the life of the mining project. Moreover, some sort of indicator would be needed to tell when there really are pumping problems. The solids content of slurry is typically increased in thickeners. Part 2 will discuss in detail the problems caused by mechanical and maintenance issues (including issues with thickener instrumentation and control) and what can be done to solve them. The flocculant rate and underflow rate are the two independent variables that are typically used for control. Draw a line on the paper at the top of the pulp and mark 0 minutes. Figure 2. << The goal is to gain better understanding of the phenomena after this phase. The pulp just tested was at 3:1 dilution, so decanting one- third of the water will give 2:1 dilution, water to solids. Applying this data to above formula, you obtain: Normally a 25 per cent factor of safety is allowed in determining the thickener area size. >> /Contents 59 0 R endstream << Two and three clusters were tested. The dependent variables include rake torque, underflow density, overflow turbidity, solids interface level (bed depth), solids inventory (bed pressure), solids settling rate and underflow viscosity. In this paper, we concentrate on the data analysis of a paste thickener to find the affecting factors, utilizing a data set from an industrial thickener. At 3:1dilution R = 0.30 feet per hour application/pdf /MediaBox [0 0 490 700] At 2:1dilution R = 0.15 feet per hour In the worst-case scenario these phenomena cause clogging in the piping. The most common problems in thickener operations include the presence of suspended solids in the recovered water and the density or percentage of solids of the thickener discharge outside the set targets. /CropBox [0 0 490 700] Paste and Thickened Tailings: A 50 Guide. It can be concluded that dividing the data between high pressure and low pressure difference operation areas is not enough to explain all the interactions within the process. However, when the pressure difference grows extremely high it will cause problems. The sedimentation rate is strongly influenced by the particle size, so that the variations in the grinding stage are transferred to the thickening stage. endobj /CreationDate (D:20180529100254+08'00') /Rotate 0 /MediaBox [0 0 490 700] 8 0 obj Australian Centre for Geomechanics, University of Western Australia; 2002.Search in Google Scholar, [2] Tan CK, Bao J, Bickert G. A study on model predictive control in paste thickeners with rake torque constraint, J. /Contents 47 0 R
The strongest interactions between the variables and pressure difference for booster pump KA7402 were: Based on correlation: variable Paste line 1, Based on regression: variables Paste line 1, Paste line 2, Thickener 16 and Thickener 2. For example, between ten and thirty bars, two different positive correlating tubes can be observed. As the amount of rock crushed increases, the amount of waste rock also increases. /Contents 41 0 R /Rotate 0 Mix thoroughly. /Length 1552 /Contents 43 0 R 65, Remes A, Aaltonen J, Koivo H. Soft-sensor estimation of an apatite thickener operation at the Siilinjrvi concentrator, IFAC Proceedings Volumes, Volume 42, 2009, 167-172, Bergh L., Ojeda P., Torres L., Expert control tuning of an industrial thickener, IFAC-PapersOnLine, 2015, 48-17, 086-091 70, Segovia JP, Concha F, Sbarbaro D. On the control of sludge level and underflow concentration in industrial thickeners, IFAC Proceedings Volumes, Volume 44, 2011, 8571-8576, Ruhanen E, Kosonen M, Kauvosaari S, Meintjes C. Performance optimization of paste thickening at the Yara Siilinjrvi Plant. /CropBox [0 0 490 700] 5 0 obj Sand Tonnage S = F 100-s/100-f x q f/q -s = 150 100-31/100-49 x 82-49/82-31 = 150 69/51 x 33/51 =131 tons sands. /Type /Page >> The main changes that affect the thickener are: throughput variations, particle size variation, increase in coarse mineral and clay and ultrafine content variation. endobj Variables for the models were selected using the forward selection method. Jewell RJ, Fourie AB, Lord ER.
25 0 obj Springer; 2001. % >> /Resources 62 0 R << The response was scaled between 0 and 1. Many industrial sectors use these vessels. Yield stress vs solids concentration. 4 0 obj This is by no means the whole truth, as often the quality is good with high pressure differences. << 21 0 obj Scatter graphs between variables: Outotec Analyzer 1, Paste line 1, Thickener 12, Thickener 14 and response during the usage of booster pump KA7403. /Rotate 0 Let us try to determine these operating conditions using clustering. The data set was divided so that 20% of the data was chosen randomly for the testing data set. Thickener-Design-2.pdf - MIP Thickener Design The following is a short cut to designing your own thickener: (a) Size of Thickener As a first stab. Total..149.7 tons O+S = Feed response variable) did not change were removed.
>> Mix pulp thoroughly. /Parent 3 0 R Knowing how to size a thickener and determine thecapacity required to handle a pre-determined tonnage of a certain pulp, by overflowing a clear solution and obtaining the desired pulp density of thickener discharge, depends upon the settling rate of that particular pulp. New 80 York. A clean overflow and maximum solids concentration in the underflow are the general targets. Gs = specific gravity of solids= Ws/W (Wp-Ws) /Pages 3 0 R /MediaBox [0 0 490 700] /Kids [21 0 R 22 0 R 23 0 R 24 0 R 25 0 R] 2015 - 2022 Precision Light and Air All Rights Reserved. stream This preview shows page 1 - 2 out of 3 pages.
Fourie (Eds. For example, it may be necessary to shut a filter down for repairs and at the same time keep the balance of the mill in operation. The bin size of the histogram is 0.5 bar. As the pressure difference fifteen-minute average is over 13 bars, it belongs in the high-pressure difference operation area. To determine content of any one pulp, the other twomoisture contents must be known as well as all the tonnages. sales@plapl.com.au Additionally, the selection of an adequate safety factor that represents the variability of the mineral to be processed must be considered. Thickeners are continuous sedimentation equipment used to perform solid-liquid separation in finely ground slurry ore as mineral concentrates or tailings (figure 1). Clay and ultrafine content variation (rheology change). Fourie (Eds. 2017;105:5262. A multivariable linear regression (MLR) model is given by Harrel [10]: where y is the output variable (N1), X is the input variable matrix (NM) and b is the vector of regression coefficients (M1). These layers can be monitored with systems such as SmartDiver and can be used to automatically control throughput variability.
/Rotate 0 The aim is to investigate the behaviour and variables that affect the paste-thickening vessel in order to make the operation cost-efficient. /MediaBox [0 0 490 700] Depending on the configuration of the plant, the type of mineral and the thickener technology, the recovery of water can vary between 65% to 95% of the process water, as shown in figure 2. The modelling results are presented in Tables 1 and 2. /Parent 5 0 R /Parent 5 0 R /CropBox [0 0 490 700] Pulp Calculations forCLASSIFIERS AND THICKENERS. Course Hero member to access this document, Critical_review_of_thickener_design_meth.pdf, Hilton Nyamwanza final project.. thickener sizing.docx, Module 1 - Introduction to Comminution and Sizing.pdf, Exercise Four FINAL 3rd edition - EXERCISE(2).docx, University of Cape Town ELECTRICAL EEE4099f, Faculty of Sciences and Technology CS DEPARTM 101, ICAO - Airport services manual - Part 2, Pavement Surface Confitions.pdf, ICAO-Annex 14, Vol I, Aerodrome Design and Operations, Ed-4.July 2004.pdf, CATALOGUES DES NORMES MAROCAINES 2011.pdf, Requirements_Management_in_Enterprise_Architect.pdf, Copyright 2022. Let, f, s, and q be percent of Moisture in Feed, Sandsand Overflow, respectively. Ruuska, J., Nikula, R., Ruhanen, E., Kauppi, J., Kauvosaari, S. & Kosonen, M. (2020). The blog will be divided in two parts.
endobj Tons of dry solids per foot depth for round tanks of diameter. /Type /Page Assume the following data was obtained from the above tests: At 4:1 dilution R = 0.50 feet per hour S=percent of solids in pulp=100 x Gp-1/Gs-1 x Gs/Gp /CropBox [0 0 490 700] Platinum Tailings) or feed flow rate (e.g. /Rotate 0 >> Privacy The dependent variables include rake torque, underflow density, overflow turbidity, solids interface level (bed depth), solids inventory (bed pressure), solids settling rate and underflow viscosity [7]. /Resources 58 0 R endobj A paste thickener can be used to lower the water content. In 75 R.J. Jewell and A.B. +61 3 9786 1711. << <<
/MediaBox [0 0 490 700] << /Kids [5 0 R 6 0 R 7 0 R] >> However, if additional time was required to reach final density, the thickener volume would have to be large enough to retain the pulp for this extra time. The model was optimized on the grounds of the internal validation data set. >> Find the Potential Energy (ft-lb) of an aircraft weighing 10,000 lbs at 5,000 ft true altitude and 125 KTS True Air Speed? uuid:63016ae5-b8af-4b55-abbd-702c72ed5df0 endobj >> Under 'Cluster Selection,' select, Maximum wing loading on an elliptical airfoil occurs: throughout with a uniform distribution near the wing tip near the wing root at the MAC, What is the most important thing that all sedimentary rocks can tell you, specifically referring to depositional environment? However, there is a great risk of drawing misleading conclusions unless sufficient process knowledge is available. A. New 80 York. >> /Type /Page 10 0 obj endobj
It should be noted that the equation above is written for a single output variable. The main design errors include: The ore fed to the thickener is essentially variable due to changes in upstream operations (mined sector, milling and concentration). These tests are carried out with representative samples of mineral and different granulometry. /Resources 36 0 R << Data analysis of a paste thickener. Miner Eng. Wp= weight of an equal volume of pulp, or by wettingsolids to make water level equal. Four feed and three Thickener 1 measurements were delayed for eight hours because the thickener delay was estimated to be eight hours. These problems are classified according to whether they are caused by thickener design errors, changes in ore properties, or mechanical and maintenance issues. endobj /Contents 35 0 R
/Parent 5 0 R /CropBox [0 0 490 700] The affecting variables were not investigated at this stage, but via modelling it can be assumed that there may be more operation areas, especially in the high pressure difference area. Six data sets were formed using the booster pumps and the paste line pressure difference as dividers. /CropBox [0 0 490 700] /CropBox [0 0 490 700] /CropBox [0 0 490 700] The product of the ore extracted from the open pits is apatite concentrate, from which fertilizers and phosphoric acid are the final products. /MediaBox [0 0 490 700] viscosity and shear stress increase making thickening difficult.
A typical thickener used in mineral processing [7]. /Type /Page Although the variables of Thickener 1 - 5 had stronger correlation in cluster 3 than in cluster1, the same observation can be made for the variables of Paste line 1 and Thickener 12 too. Modelling was done using repeated 10-fold cross-validation and a testing data set. >> Q = F 100-q/100-f x f-s/q-s = 150 100-82/100-49 x 49-31/82-31 = 150 81/51 x 18/51 =18.7 tons overflow. >> The thickening process normally occurs in large-diameter tanks where solid particles settle under the influence of gravity, i.e. Cosmic Distance Ladder,' 'HR Diagram Star Cluster Fitting Explorer.' /CropBox [0 0 490 700] ), Paste 2018 - Proceedings of the 21st international seminar on paste and thickened tailings, Perth, Australia: Australian Centre for Geomechanics, 75-88. << << 15 0 obj
Cubic Feet per ton=32.038/Gp The tests also evaluate different dosages of flocculant. /Type /Page /MediaBox [0 0 490 700] The safety factor can vary between 1.15 and 1.30. Similar interactions for booster pump KA7403 were: Based on correlation: variable Thickener 14. /Rotate 0 For example, the tailings from flotation circuits contain a lot of water and it is beneficial to reduce the water content before storing in tailings ponds. endobj Design errors appear after start-up when flow throughput or rheology variations exceed applied factors. Division into operation areas was made based on the pressure difference of the paste line. In this blog, we will explore the most common problems that affect the operations and efficiency of thickeners. /Resources 60 0 R Types of organisms present B. The switching mechanism uses rule-based reasoning. A lot of attention is being paid to make it as efficient as possible. /Parent 5 0 R /Resources 50 0 R N is the number of data points and M is the number of variables. 2019;131:1319. /Resources 34 0 R /Type /Catalog Clustering was also done for KA7402, but the result was not as good as for KA7403. Triglavcanin, R.A <<
In thickener design, there are two specifications that will define the tank efficiency to process minerals: thickener area and drive torque. For five minutes, at one-minute intervals, mark the point to which the solids have settled. /Contents 55 0 R The phenomena leading to this situation are not well known. /ModDate (D:20180529100303+08'00') >> endobj
>> /MediaBox [0 0 490 700] Paste and Thickened Tailings: A 50 Guide. When the content of fine particles (clays or micas) increases more than 20% above their normal value, due to their high specific surface, problems of excessive increase in rheology are generated e.g. Repeat settling measurements at one-minute intervals for five minutes. 3 0 obj /CropBox [0 0 490 700]
The correlations in the whole operation area and the low pressure difference are mostly close to each other.