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16 pages, 4794 KiB

Open AccessArticle

Modeling and Simulation of Hydroxyapatite Recovery in the Desliming Circuit of the Tapira Industrial Plant, Brazil

by Adalto Silveira, Jr., Homero Delboni, Jr. and Maurício Guimarães Bergerman

Minerals 2024, 14(3), 272; https://doi.org/10.3390/min14030272 - 04 Mar 2024

Viewed by 860

The modeling and simulation of industrial mineral processing operations are traditionally used for cyclone sizing and optimizations of industrial operations. However, the main models used are based on the total population of particles in the pulp, thus not distinguishing the individual minerals. This [...] Read more.

The modeling and simulation of industrial mineral processing operations are traditionally used for cyclone sizing and optimizations of industrial operations. However, the main models used are based on the total population of particles in the pulp, thus not distinguishing the individual minerals. This article presents the results of an innovative method that investigated the optimization of the metallurgical recovery of P₂O₅ in the desliming circuit of a phosphate ore processing plant in Brazil. A survey campaign was carried out in the existing industrial circuit, followed by determining the partition curves for the overall particles and specifically for the hydroxyapatite particles. The results were used to calibrate the Narasimha–Mainza cyclone model. From a Base Case determined with reference to the industrial survey, three optimization scenarios were simulated through cyclone geometries and respective operating conditions changes. Simulated scenarios indicated the possibility of P₂O₅ metallurgical recovery increasing from 9.4% to 12.7% compared to the Base Case. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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13 pages, 5946 KiB

Open AccessArticle

Using Discrete Element Method to Analyse the Drop Ball Test

by Ngonidzashe Chimwani, Murray Mulenga Bwalya and Oliver Shwarzkopf Samukute

Minerals 2024, 14(3), 220; https://doi.org/10.3390/min14030220 - 21 Feb 2024

Viewed by 639

Abstract

The drop ball test (DBT) is a common quality control procedure used in many grinding media manufacturing units to evaluate the quality of manufactured balls. Whilst DBTs have provided reasonable data over many years, the quantitative comparison of the energy that the balls [...] Read more.

The drop ball test (DBT) is a common quality control procedure used in many grinding media manufacturing units to evaluate the quality of manufactured balls. Whilst DBTs have provided reasonable data over many years, the quantitative comparison of the energy that the balls are subjected to during the DBT and in high-impact loading environments such as semi-autogenous grinding (SAG) mills remains a grey area. To that end, DBT experiments were conducted, and the discrete element method (DEM) was used to assess the grinding media collision behaviour and the extent of ball impact loading to determine the impact energy spectra of the ball collisions. The impact energy spectra data obtained were used to quantify the energy that the grinding balls are exposed to in the DBT environment. The results showed that larger balls were exposed to relatively higher energy levels and had a higher probability of fracture than smaller balls. Furthermore, early ball breakage in a grinding environment is mostly attributed to the existence of imperfections or pre-existing defaults within the ball, whilst continuous wear is a gradual consequence that deplete balls in the mill. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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9 pages, 2366 KiB

Open AccessArticle

Extensive Validation of a New Rock Breakage Test

by Marcos de Paiva Bueno, Thiago Almeida and Malcolm Powell

Minerals 2023, 13(12), 1506; https://doi.org/10.3390/min13121506 - 30 Nov 2023

Viewed by 945

Abstract

Comminution is the most power-demanding stage, and the lack of geometallurgical testing, often for financial reasons, may result in an inefficient operation. The Geopyörä rock breakage test was developed with the objective of making mineral variability data more accessible by providing both standard [...] Read more.

Comminution is the most power-demanding stage, and the lack of geometallurgical testing, often for financial reasons, may result in an inefficient operation. The Geopyörä rock breakage test was developed with the objective of making mineral variability data more accessible by providing both standard comminution parameters and rock mechanical properties at low cost and with a modest sample size, allowing a larger number of samples to be tested to reduce uncertainties and assure productivity. The objective of this work is to present the results of an extensive validation of this new rock breakage method against two of the main tests currently in use, namely the SMC and Bond ball mill work index tests. More than 100 samples have been tested and the results compared, showing that the new method can accurately estimate the parameters of the traditional tests. This confirms that the new test is a reliable tool for performing comminution and geometallurgical tests. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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25 pages, 19188 KiB

Open AccessFeature PaperArticle

The Effect of HPGR and Conventional Crushing on the Extent of Micro-Cracks, Milling Energy Requirements and the Degree of Liberation: A Case Study of UG2 Platinum Ore

by Titus Nghipulile, Sandile Nkwanyana and Niyoshaka Lameck

Minerals 2023, 13(10), 1309; https://doi.org/10.3390/min13101309 - 10 Oct 2023

Cited by 1 | Viewed by 862

Abstract

Comparative high pressure grinding rolls (HPGR) and cone crusher pilot-scale tests were conducted using Upper Group 2 (UG2) platinum-bearing ore in order to determine the impact of micro-cracks in HPGR products toward energy requirements in ball mills and the degree of liberation. The [...] Read more.

Comparative high pressure grinding rolls (HPGR) and cone crusher pilot-scale tests were conducted using Upper Group 2 (UG2) platinum-bearing ore in order to determine the impact of micro-cracks in HPGR products toward energy requirements in ball mills and the degree of liberation. The ball mill was fed with HPGR and cone crusher products of similar particle size distributions (PSDs). Qualitative analysis of the degree of micro-cracking on the HPGR and cone crusher products performed using scanning electron microscope (SEM) and image analysis software showed that an HPGR product had more micro-cracks than the equivalent cone crusher product. Milling energy requirements were evaluated using size-specific energy consumption indices calculated based on three grind sizes of 300 µm, 150 µm and 75 µm. The effect of residual micro-cracks in the products of HPGR and cone crusher on the milling size-specific energy requirement is inconclusive. The kinetic parameter k in the cumulative rate kinetic model for ball milling cone crusher products and for ball milling HPGR products were similar. Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN) was used to determine the degree of liberation of various mineral phases in the mill products. At a coarser grind size (P₈₀ of 300 µm), the sulfides in the mill products pre-crushed using the cone crusher have consistently poorer liberation than in the equivalent HPGR pre-crushed sample. However, at a finer grind size (P₈₀ of 75 µm), the sulfides in the mill products pre-crushed using the cone crusher and using an HPGR showed similar liberation. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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21 pages, 3455 KiB

Open AccessArticle

Study on Grinding Behavior Characteristics under Low-Speed Grinding Condition

by Shaojian Ma, Xiaojing Yang, Hengjun Li, Wenzhe Xu, Xingjian Deng and Jinlin Yang

Minerals 2023, 13(6), 786; https://doi.org/10.3390/min13060786 - 08 Jun 2023

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Abstract

In order to explore the crushing mechanism of minerals, this paper attempts to eliminate the throwing effect of media and study the grinding characteristics of minerals only under the action of abrasion force. In this paper, the method of removing the throwing state [...] Read more.

In order to explore the crushing mechanism of minerals, this paper attempts to eliminate the throwing effect of media and study the grinding characteristics of minerals only under the action of abrasion force. In this paper, the method of removing the throwing state of media is to adjust the mill to a lower rotational speed, so that the grinding media are all in a cascading state. Three single-component pure minerals, quartz, pyrrhotite, and pyrite, commonly found in complex ores, were selected as research objects to study the grinding behavior characteristics of the three minerals only under the force of abrasion. The effects of mineral species, feed-particle sizes, grinding time, and other factors on the particle-size distribution and product-generation rate of grinding products are studied. The results show that from the particle-size distribution of grinding products, the yield of coarse particles is the highest, while the yield and t₁₀ value of other fine particles are very low. The feed-particle size and the hardness of the mineral sample affect the grinding behavior. The product particle size is mainly 0.71 times the feed-particle size, and the other fine particle sizes generated are less than 0.5 times the feed-particle size. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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19 pages, 3770 KiB

Open AccessArticle

Study on Impact Crushing Characteristics of Minerals Based on Drop Weight Tests

by Shaojian Ma, Hengjun Li, Xiaojing Yang, Wenzhe Xu, Xingjian Deng and Jinlin Yang

Minerals 2023, 13(5), 632; https://doi.org/10.3390/min13050632 - 30 Apr 2023

Cited by 2 | Viewed by 1257

Abstract

The degree of difficulty in crushing an ore depends on the composition of the ore itself. Due to different types and compositions of ores, the crushing mechanism of ores during the crushing process is also different. In order to quantitatively analyze the impact [...] Read more.

The degree of difficulty in crushing an ore depends on the composition of the ore itself. Due to different types and compositions of ores, the crushing mechanism of ores during the crushing process is also different. In order to quantitatively analyze the impact crushing characteristics of mineral components in ores, this paper takes pure mineral quartz, pyrrhotite, and pyrite as the research objects and uses the universal drop weight impact crushing test equipment and standard test methods developed by the JK Mineral Research Center of the University of Queensland, Australia, to conduct JK drop weight tests on these three pure mineral samples. The results show that the particle size distribution of impact crushing products is wide, covering all particle sizes from “0” to close to the feed particle size, and the yield distribution of each product particle size is relatively uniform. There are critical values and “energy barrier” effects for the impact-specific crushing energy. The impact-specific crushing energy has a significant impact on the particle size composition and crushing effect of the crushing product, and there is an interactive effect between the impact-specific crushing energy and the feed particle size and mineral type. The impact crushing resistance of the sample can be characterized by using Mohs hardness, impact crushing characteristic parameters, impact crushing resistance level, and the yield limit value t₁₀ of the characteristic crushing particle size. The overall characterization results have good consistency. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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16 pages, 4563 KiB

Open AccessFeature PaperArticle

A New Approach to the Grinding Kinetics of Magnetite Ore Based on the Population Balance Model

by Chengfang Yuan, Caibin Wu, Xin Fang, Ningning Liao, Jiaqi Tong and Yuqing Li

Minerals 2023, 13(3), 424; https://doi.org/10.3390/min13030424 - 16 Mar 2023

Viewed by 1134

Abstract

A new approach to batch grinding kinetics was established based on the conventional population balance model, with magnetite as the experimental object. The distribution function commonly used in the population balance model is a sum of two power functions, i.e., [...] Read more.

A new approach to batch grinding kinetics was established based on the conventional population balance model, with magnetite as the experimental object. The distribution function commonly used in the population balance model is a sum of two power functions, i.e.,

B_{i 1} = φ (\frac{x_{i - 1}}{x_{1}} + (1 - φ) {(\frac{x_{i - 1}}{x_{1}})}^{β}

. Based on the new finding that the cumulative mass fraction coarser than the size class of the discharge is consistent with the first-order grinding kinetic, the g_i function of the new approach is only a single power function, i.e.,

= + k_{1} x_{i}^{a}

, which will greatly reduce the parameter error and make the fit more accurate. The maximum error between simulation calculations and the actual experiment using the two methods did not exceed 1%, indicating that both models can accurately predict the fracture characteristics of magnetite. Because the new approach has fewer derived parameters, it addresses the conventional population balance model’s problems of large computational effort and poor fitting accuracy, making it more applicable to the study of the impact of parameters on the grinding status, with a simpler process and higher accuracy. In addition, this new method is applicable to minerals other than magnetite. Further research is required to verify its applicability to wide size ranges and continuous grinding. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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16 pages, 4774 KiB

Open AccessArticle

Performance Comparison of the Vertical and Horizontal Oriented Stirred Mill: Pilot Scale IsaMill vs. Full-Scale HIGMill

by Metin Can and Okay Altun

Minerals 2023, 13(3), 315; https://doi.org/10.3390/min13030315 - 23 Feb 2023

Viewed by 2026

Abstract

Varied types/geometries of stirred mills have been produced by different manufacturers, and the comparison task has been accomplished for some of the technologies, i.e., Tower mill vs IsaMill. However, the main drawbacks of these comparisons were the uncommon characteristics of the milling environment, [...] Read more.

Varied types/geometries of stirred mills have been produced by different manufacturers, and the comparison task has been accomplished for some of the technologies, i.e., Tower mill vs IsaMill. However, the main drawbacks of these comparisons were the uncommon characteristics of the milling environment, such as media size. In this study, HIGMill and IsaMill, which were vertically and horizontally chamber oriented, respectively, were compared for a regrinding process of copper ores with similar characterization and almost the same milling environment. Detailed characterization studies of the two ore types, such as work index, ore breakage and chemical composition, were performed. Modeling of the two mills was also performed to show the variation in the rate of breakage parameters. The entire assessments were based on comparing the signature plots, energy and shape of the product size distribution as well as the stress analyses. The results showed that HIGMill and IsaMill technologies behaved in a different manner for coarse and fine tail of comminution. IsaMill with horizontal orientation was found to be more energy-efficient, particularly at the fine grind size, and produced finer product when it was operated at the same stress level of HIGMill. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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Review

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19 pages, 2033 KiB

Open AccessFeature PaperReview

A Review of the Grinding Media in Ball Mills for Mineral Processing

by Nyasha Matsanga, Willie Nheta and Ngonidzashe Chimwani

Minerals 2023, 13(11), 1373; https://doi.org/10.3390/min13111373 - 27 Oct 2023

Cited by 1 | Viewed by 2747

Abstract

The ball mill is a rotating cylindrical vessel with grinding media inside, which is responsible for breaking the ore particles. Grinding media play an important role in the comminution of mineral ores in these mills. This work reviews the application of balls in [...] Read more.

The ball mill is a rotating cylindrical vessel with grinding media inside, which is responsible for breaking the ore particles. Grinding media play an important role in the comminution of mineral ores in these mills. This work reviews the application of balls in mineral processing as a function of the materials used to manufacture them and the mass loss, as influenced by three basic wear mechanisms: impact, abrasion, and corrosion. The effect of grinding media geometries and density on the mill performance was also reviewed to determine what the research has recommended as the most suitable grinding media for different grinding applications. Although considerable work has been carried out in that area, the influence of grinding media shape on the liberation of minerals, as well as the effect of various mill conditions on the performance of mixed grinding media shapes, are still poorly understood. Thus, the review opens up opportunities for further research to improve the grinding processes, especially considering that even a slight improvement in the process efficiency significantly reduces the production costs. Full article

(This article belongs to the Special Issue Comminution and Comminution Circuits Optimisation, Volume II)

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