This batch model was extended to a continuous model that simulated three leaching and seven carbon-in-leach tanks. The effect of processing the oxide and sulphide ores studied was examined and the model shown to satisfactorily describe the extraction of gold from the Telfer oxide ore. A sensitivity analysis of the effect of process changes
The kinetics of water leaching of the acid-baked model samples was investigated in DI water at 25 °C. The (H 3 O)Fe(SO 4) 2-containing sample dissolved considerably faster than the Fe 2 (SO 4) 3-containing sample, confirming the proposed mechanism. …
The acid leaching of copper oxide ores generates a vertical acid concentration gradient in the ore heap, which is not generally observed in sulfide deposits. Shafer et al have verified Roman’s model and were able to predict the leaching behavior for a relatively large scale column test on coarse ore.
The leaching of zinc and copper from Nigerian bulk sulphide ore with sulphuric acid in the presence of hydrogen peroxide was studied. The aim of the study was to investigate the effectiveness of hydrogen peroxide as an oxidant for the sulphuric acid leaching of zinc and copper from a …
The results for two case studies, namely, an industrial gold heap leaching and a pilot column copper acid leaching, showed that the model successful predict the general features of the process time evolution. Keywords: leaching processes, solid-fluid reaction, extractive metallurgy.
Other articles where Acid leaching is discussed: uranium processing: Leaching: Acid leaching is commonly performed by agitating an ore-leach mixture for 4 to as long as 48 hours at ambient temperature. Except in special circumstances, sulfuric acid is the leachant used; it is supplied in amounts sufficient to obtain a final leach liquor at about…
a reaction model of shrinking core, and the leaching process can be divided into three stages in the system investigated. Moreover, the leaching e ciency of copper can reach up to a level higher than 90%. Although many experimental studies have been performed to gain a better understanding of the leaching process and its operation, there are ...
Mar 22, 2017· Technical Approach •Proposed technology: concentration of rare earth oxides and recovery of leach acid •Patented Acid Digestion Process previously demonstrated for metal leaching and acid recovery at 70 lb/hr •Synergistic with current DOE/OCDO Project for direct coal liquefaction 6 Rare earth oxides Commercial
The rate of dissolution increases with calcination temperature, calcination time and leach temperature. A first-order kinetic model is developed by considering the clay to consist of two types of aluminium sites - one that is activated and another that is refractory.
Nov 11, 2015· A 1-D dynamic HTPEMFC model was adopted from literature and a mechanism is proposed for the acid leaching process in PBI membrane, which was integrated into the dynamic model. The dilution of phosphoric acid in HTPEMFC membrane has been assumed to occur, leading to a drop in viscosity of the proton conducting electrolyte.
A Population Balance (PB) model was developed for the sulfuric acid leaching of a roasted zinc concentrate (RZC). Considering that no previous work has validated with experimental data a PB model for this system, leaching experiments were done in order to validate and refine the proposed model.
Sulfuric acid is the main inorganic acid found in leaching environments. It is formed ... 4.2 Models of Leaching Mechanisms Originally, a model with two types of mech-anisms which are involved in the microbial ... How-8 Microbial Leaching of Metals-2 4 4 (1)] ...
T1 - A kinetic model for the hydrochloric acid leaching of kaolinite clay in the presence of fluoride ions. AU - Gajam, Soliman Younes. AU - Raghavan, Srini. PY - 1985. Y1 - 1985. N2 - The dissolution of kaolinite clay in hydrochloric acid solutions has been carried out in the presence of fluoride ions.
A model has been derived for predictive analysis of the concentration of dissolved lead during leaching of galena in butanoic acid solution. The model; Pb = Antilog exp (γ/α) 0.7407 shows that ...
A new mathematical model was developed for leaching of zinc ores containing silicates such as hemimorphite which produce a gel during leaching with sulfuric acid.
leaching[8], atmospheric acid leaching[9] and high pressure acid leaching[10−11]. McDONALD and WHITTINGTON[12] reviewed the processes reported in the past 30 years that can be used to extract nickel and cobalt with the focus on atmospheric acid leaching and high pressure acid leaching. At present, the high pressure acid leaching is the only ...
Development of a predictive model 555 Acid leaching by dilute HCl dissolves calcium carbonate and concentrated HCl to decompose bastnasite. The main reaction of the latter type is shown by equation (13): 3 3 +6𝐻 H= 2 3+ 3+3𝐻2 +3 2 (13) REE fluorides remain in the waste after the decomposition of HCl.
Leaching is the process of extracting substances from a solid by dissolving them in a liquid, naturally. In the chemical processing industry, leaching has a variety of commercial applications, including separation of metal from ore using acid, and sugar from sugar beets using hot water.
A Solute Transport Model for the Acid Leaching of Copper in Soil Columns Juan Pablo Montero,* Jose Francisco Munoz, Roberto Abeliuk, and Michel Vauclin ABSTRACT depends on a number of phenomena such as fluid dynam Modeling solution mining technique has recently received much ics, mass transport, mineral chemistry, and sometimes attention in order to estimate metal recovery rates.
dissolution, manganese, uranium and copper leaching. Abstract — This paper critically reviews models employed in . various leaching processes. The aim of this work is to . study various leaching models for the development of a model that can predict both recovery and reagent consumption using available mineralogical data.
A model for assessment and computational analysis of the concentration of zinc dissolved during leaching of sphalerite in butanoic acid solution has been derived. The model Zn = Antilog [(exp(γ/α))0.6173] is dependent on the initial and final pH of the leaching solution. The validity of the model …
Abstract. The sulfuric acid leaching kinetics of South African chromite was investigated. The negative influence of a solid product layer constituted of a silicon-rich phase and chromium-rich sulfate was eliminated by crushing the chromite and by selecting proper leaching conditions.
Bodas (1996) for an efficient acid leaching of such materials, the content of the studied the leaching kinetics of two different zinc ores and noticed gangue minerals needs to be reduced which is usually attained by a that the leaching kinetics was diffusion-controlled with activation concentration step.
As a result, the specific details of Method 1311 and the numerical limits for the toxicity characteristic itself are linked together. Increasing the acid strength of the leaching fluid to leach a larger amount of any of the constituents changes the scenario that the test was designed to simulate.
these compounds. Doyle, Ranjan and Peters [2] developed a mathematical model to describe the leaching kinetics of ZnO in dilute acid solutions which assumed that the leaching rate is controlled by mass transport. Due to the homogenous composition of bulk oxides which would not change during the
Model for predicting the initial solution pH at pre-assumed final pH and concentration of dissolved zinc, during leaching of galena in butanoic acid solution has been derived. The model; α = 1.4γ/ln[(Zn) 1/3shows that the initial pH of the leaching is dependent on the values of the pre-assumed final solution pH and concentration of dissolved zinc.
Model for quantitative analysis of the concentration of phosphorus removed (relative to the final pH of the leaching solution) during leaching of iron oxide ore in oxalic acid solution has been derived. It was observed that the validity of the model is rooted in the expression lnP = (γ +Nlnγ)
results for two case studies, namely, an industrial gold heap leaching and a pilot column copper acid leaching, showed that the model successful predict the general features of the process time evolution. Keywords: leaching processes, solid-fluid reaction, extractive metallurgy. INTRODUCTION Industrial processes based in the selective
APPLICATION OF THE SHRINKING CORE MODEL TO THE ANALYSIS OF ALUMINA LEACHING FROM UKPOR CLAY USING NITRIC ACID By Regina O. Ajemba and Okechukwu D. Onukwuli Department of Chemical Engineering, Nnamdi Azikiwe University, P. M. B. 5025, Awka, Anambra
two and three phase reactors in Excel using the classic Population Balance Model approach. The application and usefulness of the model will be demonstrated with three examples taken from nickel hydrometallurgy: nickel sulphide precipitation, gypsum precipitation during acid neutralization, and pressure oxidative leaching of nickel sulphide.
In‐situ leaching (ISL) such as in‐situ acid leaching, neutral leaching, ... Fractures in the samples cause abnormal fractal dimensions in the classic geometry model. The leaching efficiency of uranium increases with the leaching time and reachs the maximum value (above 90%), and the whole leaching process of uranium sandstone can be divided ...
A leaching model is a hydrological model by which the leaching with irrigation water of dissolved substances, notably salt, in the soil is described depending on the hydrological regime and the soil's properties. The model may describe the process (1) in time and …
The approach of ISL mining is broadly the same for both acid and alkaline leaching. At the Khiagda project in Russia, where uranium is found in a series of paleochannels, SRK developed a reactive transport model coupling hydrogeological and geochemical capabilities to predict the dissolution of uranium with time.
