Some remarks on the reactor network synthesis for gold cyanidation

Lima, L. R. P. de Andrade

doi:10.1016/j.mineng.2005.08.004

Cited by 19 publications

(40 citation statements)

References 15 publications

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“…The plant measurements at the dynamic state usually include more useful process information. The dynamic mechanistic model consists of the following mass conservation equations of gold and cyanide:

\frac{Q s_{i}}{M s_{i}} (C s_{i - 1} - C s_{i}) - r_{A u, i} = \frac{d C s_{i}}{d t}

\frac{Q l_{i}}{M l_{i}} (C l_{i - 1} - C l_{i}) + \frac{M s_{i}}{M l_{i}} r_{A u, i} = \frac{d C l_{i}}{d t}

\frac{Q l_{i}}{M l_{i}} (C c n_{i - 1} - C c n_{i}) + \frac{Q c n_{i}}{M l_{i}} - r_{c n, i} = \frac{d C c n_{i}}{d t}

and the two corresponding kinetic reaction rate expressions:

r_{A u, i} = (1.13 \times 10^{- 3} - 4.37 \times 10^{- 11} {true \overset{d}{true}}^{2.93}) \times {(C s_{i} - C s_{\infty} (\bar{d}))}^{2.13} \times C c {n_{i}}^{0.961} \times C {o_{i}}^{0.228}

…”

Section: Background and Contextmentioning

confidence: 99%

“…

true \bar{d}

is the average diameter of the ore particles. The residual gold concentration in the solid

C s_{\infty}

is a function of

true \bar{d}

C s_{\infty} (\bar{d}) = 0.357 [1 - 1.49 \exp (- 1.76 \times 10^{- 2} \bar{d})]

…”

Section: Background and Contextmentioning

confidence: 99%

“…Furthermore, if all the reactants in the leaching tanks are mixed perfectly and segregation can be neglected, the average residence time

τ_{i}

can be calculated according to

Q s_{i}

Q l_{i}

, the solid density

ρ s

, the liquid density

ρ l

, and the net reactor volume V i :

τ_{i} = \frac{V_{i}}{\frac{Q s_{i}}{ρ s} + \frac{Q l_{i}}{ρ l}} \times 1000

where

Q l_{i}

is estimated by

Q s_{i}

and the weight concentration of solid in the pulp

C w_{i}

Q l_{i} = Q s_{i} (\frac{1}{C w_{i}} - 1)

…”

Section: Background and Contextmentioning

confidence: 99%

“…The undissolved gold in the solid is transformed into the easy‐to‐dissolve gold cyanide complex by means of reaction with both sodium cyanide and oxygen . In practice, a cascade of leaching tanks in series are configured in order to increase the residence time of slurry and hence ensure a longer reaction time . As the most important procedure in hydrometallurgy, the performance of the leaching process has a significant impact on the subsequent procedures and ultimately determines the gold recovery.…”

Section: Introductionmentioning

confidence: 99%

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Serial Hybrid Modelling for a Gold Cyanidation Leaching Plant

et al. 2015

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In this paper, a serial hybrid model of a gold cyanidation leaching process is proposed. The serial hybrid model consists of mass conservation equations of gold and cyanide as well as two kernel partial least square (KPLS) models, which are used as the estimators of the unknown kinetic reaction rates without the complicated kinetic model structures considered. The proposed serial hybrid model makes full use of both the a priori process knowledge and the ability of a data-driven model to discover the information behind data sets. Moreover, before training the KPLS models, the proposed estimation strategy based on Tikhonov regularization is used to estimate the kinetic reaction rates, which can mitigate the effect of measurement noise on the estimation results effectively. The proposed serial hybrid model has been applied to a gold cyanidation leaching plant to predict the gold leaching rate. The prediction results show that the proposed serial hybrid model can track the real leaching rate of gold closely and has the best prediction accuracy at both dynamic and steady states compared with the pure KPLS and mechanistic models, thereby laying an important foundation for the successful implementation of optimization and control of the leaching process.Keywords: leaching process, mechanistic model, hybrid model, kinetic rate, Tikhonov regularization INTRODUCTION C yanidation has been the main method to recover gold from ores, concentrates, and tailings for the past century. It has the advantages of being a mature technology, having high gold recovery, having a low production cost, and being applicable to a diverse variety of ore types. [1,2] Usually, a gold cyanidation leaching process occurs in an aerated continuous stirred tank reactor (CSTR) containing a solution of sodium cyanide and oxygen. The undissolved gold in the solid is transformed into the easy-to-dissolve gold cyanide complex by means of reaction with both sodium cyanide and oxygen. [2,3] In practice, a cascade of leaching tanks in series are configured in order to increase the residence time of slurry and hence ensure a longer reaction time. [4] As the most important procedure in hydrometallurgy, the performance of the leaching process has a significant impact on the subsequent procedures and ultimately determines the gold recovery. The most important quality index for the leaching process is the leaching rate, which is directly related to gold recovery, production efficiency, and overall yield. The ideal leaching rate of 100 % is required in all plants, however this is not realistic in practice due to the impossibilities of infinitely small ore particles, infinitely long residence time, and complete reaction. [5] In industrial applications, the lowest production cost is usually required under the condition that the leaching rate is ensured to be equal to or greater than the index determined by the plant-wide decision. The above optimal operation can usually be obtained by solving the model-based optimization problem of the leaching process -namely, dete...

show abstract

\frac{Q s_{i}}{M s_{i}} (C s_{i - 1} - C s_{i}) - r_{A u, i} = \frac{d C s_{i}}{d t}

\frac{Q l_{i}}{M l_{i}} (C l_{i - 1} - C l_{i}) + \frac{M s_{i}}{M l_{i}} r_{A u, i} = \frac{d C l_{i}}{d t}

\frac{Q l_{i}}{M l_{i}} (C c n_{i - 1} - C c n_{i}) + \frac{Q c n_{i}}{M l_{i}} - r_{c n, i} = \frac{d C c n_{i}}{d t}

and the two corresponding kinetic reaction rate expressions:

r_{A u, i} = (1.13 \times 10^{- 3} - 4.37 \times 10^{- 11} {true \overset{d}{true}}^{2.93}) \times {(C s_{i} - C s_{\infty} (\bar{d}))}^{2.13} \times C c {n_{i}}^{0.961} \times C {o_{i}}^{0.228}

…”

Section: Background and Contextmentioning

confidence: 99%

“…

true \bar{d}

is the average diameter of the ore particles. The residual gold concentration in the solid

C s_{\infty}

is a function of

true \bar{d}

C s_{\infty} (\bar{d}) = 0.357 [1 - 1.49 \exp (- 1.76 \times 10^{- 2} \bar{d})]

…”

Section: Background and Contextmentioning

confidence: 99%

“…Furthermore, if all the reactants in the leaching tanks are mixed perfectly and segregation can be neglected, the average residence time

τ_{i}

can be calculated according to

Q s_{i}

Q l_{i}

, the solid density

ρ s

, the liquid density

ρ l

, and the net reactor volume V i :

τ_{i} = \frac{V_{i}}{\frac{Q s_{i}}{ρ s} + \frac{Q l_{i}}{ρ l}} \times 1000

where

Q l_{i}

is estimated by

Q s_{i}

and the weight concentration of solid in the pulp

C w_{i}

Q l_{i} = Q s_{i} (\frac{1}{C w_{i}} - 1)

…”

Section: Background and Contextmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Serial Hybrid Modelling for a Gold Cyanidation Leaching Plant

et al. 2015

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show abstract

“…The results showed that the plant performance could be improved by using a sequence of increasing size reactors for the same total volume. The effect of different network configurations for a gold leaching circuit with five equal-sized reactors was investigated by De Andrade Lima (2006). It was shown that the best configuration was not identical for different gold content and cyanide concentration.…”

Section: Introductionmentioning

confidence: 99%

Real time optimization based on a serial hybrid model for gold cyanidation leaching process

Zhang

Mao

Jia

et al. 2015

Minerals Engineering

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Reaction Engineering in Metallurgical Processing

Provis

Deventer

2009

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Process Engineering to Optimize Metals Extraction 2.1. Residence Time Distributions: Plug Flow and Mixed Flow 2.2. Dispersion in Flow‐Through Systems 2.3. Networks of Reactor Components 2.4. Maximizing Extraction by Control of Equilibria 3. Modeling Complex Processes 3.1. Combining Mass Transfer with Other Rate‐Controlling Processes 3.2. Fitting Rate Expressions via Artificial Intelligence 3.3. Applicability of “Standard” Models in Nonstandard Situations 3.4. Population Balances in Reacting Systems

show abstract

Some remarks on the reactor network synthesis for gold cyanidation

Cited by 19 publications

References 15 publications

Serial Hybrid Modelling for a Gold Cyanidation Leaching Plant

Serial Hybrid Modelling for a Gold Cyanidation Leaching Plant

Real time optimization based on a serial hybrid model for gold cyanidation leaching process

Reaction Engineering in Metallurgical Processing

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