A preliminary analysis of smooth roll crushers

Austin, L.G.; Orden, D.R. Van; Perez, J.W.

doi:10.1016/0301-7516(80)90028-9

Cited by 31 publications

(17 citation statements)

References 5 publications

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“…In the breakage of urea, the double-roll crusher is preferred over other comminuting equipments because narrow size distributions, low dust, and limited noise generation are expected. 18 The crusher model was presented in a previous contribution 4 and is based on the one developed by Austin et al 19 for the mineral processing industry. It was validated using industrial data from a large- scale urea plant.…”

Section: Crushers Screens Granulator and Cooler Mathematical Modelsmentioning

confidence: 99%

Dynamic Simulation and Optimization of a Urea Granulation Circuit

Cotabarren

Bertin

Romagnoli

et al. 2010

Ind. Eng. Chem. Res.

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A dynamic model for a complete urea granulation circuit is presented in this work. The flowsheet includes a fluidized bed granulator, a cooling unit, a vibrating double-deck screen, and a double-roll crusher. This contribution is based on mathematical models for all the equipments, some of them previous validated against industrial data. All the units are modeled by means of the population balance equation (PBE). In addition, the granulator energy and mass balances for urea and air (used as a cooling medium and fluidization agent) are solved simultaneously with the PBE to properly represent the unit dynamics. Furthermore, mass, energy, and population balances are developed for the cooler. The individual units are successfully integrated under the gPROMS Model Builder Environment, which allows one to have a powerful tool for the circuit simulation and optimization. A sensitivity analysis is performed by running several dynamic and steady-state gPROMS simulations in order to evaluate the influence of different operating variables on the particle size distributions and mass flow rates of the circuit streams, as well as the mass holdup and thermal conditions in the granulator and cooler. The results indicate that both screen deck apertures, together with the crusher lower gap, are the variables that most affect the circuit performance. The circuit stability is also analyzed. Finally, different optimization scenarios are carried out to determine the values of the selected manipulated variables that maximize production on specification, minimize the recycle fraction, and allow a plant revamping. The urea granulation process simulator (including mass, energy, and population balances) constitutes a powerful tool to study the circuit responses under different disturbances, determine the optimal combination of operating and design variables in order to meet the production requirements and explore new process flow diagrams.

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Section: Crushers Screens Granulator and Cooler Mathematical Modelsmentioning

confidence: 99%

Dynamic Simulation and Optimization of a Urea Granulation Circuit

Cotabarren

Bertin

Romagnoli

et al. 2010

Ind. Eng. Chem. Res.

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“…Breakage matrix approach was first introduced by Broadbent and Callcot [8][9][10] to describe cone milling of coal, and later used to study milling of stone [11,12], coal [13] and wheat [6,14,15]. used the same sieve sizes for both feed and product size distributions, giving a square breakage matrix (dimension N × N), where the above diagonal values are equal to zero.…”

Section: Introductionmentioning

confidence: 99%

Solution of the breakage matrix reverse problem

et al. 2014

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“…The favourable influence of HPGR performance on downstream beneficiation operations has also been proved, for example, in the ore flotation process [17]. HPGR also appears to have a less negative impact on the environment in terms of lower dust and noise emissions [18].With regard to the description of the model, the mechanism of breakage by compression and shear is dominant in roll crushers [19]. In HPGR, two main breakage mechanisms are observed: single particle compression and bed compression [20][21][22].…”

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confidence: 97%

“…With regard to the description of the model, the mechanism of breakage by compression and shear is dominant in roll crushers [19]. In HPGR, two main breakage mechanisms are observed: single particle compression and bed compression [20][21][22].…”

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confidence: 99%

“…(A) Altered granite particles being comminuted between the rolls in single particle and bed compression; (B) Calc-silicate particles in a compressed cake; (C) Altered granite in a compressed cake; (D) Magnification of the calc-silicate cake, showing the particles after comminution under a high-pressure roll crusher. [6,19] for several steps of comminution in high pressure roll crusher. represents the feed for each sub-process, with i = 1 … n, and n is the particle size distribution (PSD) vector length: Furthermore, j = 1 … Nt, and Nt is the number of stages of the whole process.…”

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confidence: 99%

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An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores

et al. 2018

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An improved approach is presented to model the product particle size distribution resulting from grinding in high-pressure roll crusher with the aim to be used in standard high-pressure grinding rolls (HPGR). This approach uses different breakage distribution function parameter values for a single particle compression condition and a bed compression condition. Two materials were used for the experiments; altered Ta-bearing granite and a calc-silicate tungsten ore. A set of experiments was performed with constant operative conditions, while varying a selected condition to study the influence of the equipment set-up on the model. The material was comminuted using a previously determined specific pressing force, varying the feed particle size, roll speed and the static gap. A fourth group of experiments were performed varying the specific pressing force. Experimental results show the high performance of the comminution in a high-pressure environment. The static gap was the key in order to control the product particle size. A mathematical approach to predict the product particle size distribution is presented and it showed a good fit when compared to experimental data. This is the case when a narrow particle size fraction feed is used, but the fit became remarkably good with a multi-size feed distribution. However, when varying the specific pressing force in the case of the calc-silicate material, the results were not completely accurate. The hypothesis of simultaneous single particle compression and bed compression for different size ranges and with different parameters of the distribution function was probed and reinforced by various simulations that exchanged bed compression parameters over the single particle compression distribution function, and vice versa.The main advantages of HPGR lie in energy savings and the simplicity of the process [7]. However, the particle size reduction ratio is lower than that in some other types of mills, such as ball and rod mills. HPGR are used in various configurations such as pre-grinding, hybrid grinding and finish grinding, among others [4]. This is mainly due to the comminution effect under the action of high-pressure rolls, which generates many more internal fractures of particles than other devices [13][14][15], and also generates material with latent cracks for a second stage of milling or even enough to liberate the ore [4,16]. The favourable influence of HPGR performance on downstream beneficiation operations has also been proved, for example, in the ore flotation process [17]. HPGR also appears to have a less negative impact on the environment in terms of lower dust and noise emissions [18].With regard to the description of the model, the mechanism of breakage by compression and shear is dominant in roll crushers [19]. In HPGR, two main breakage mechanisms are observed: single particle compression and bed compression [20][21][22]. Single particle compression is more efficient, but larger particles cause unnecessary liner wear issues [21] and also result in the separatio...

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A preliminary analysis of smooth roll crushers

Cited by 31 publications

References 5 publications

Dynamic Simulation and Optimization of a Urea Granulation Circuit

Dynamic Simulation and Optimization of a Urea Granulation Circuit

Solution of the breakage matrix reverse problem

An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores

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