Search

The present experimental work was carried out to scale of Demonstrative Unit of Production (UDP) in the Leaching Plant of the Punta Gorda in Cuba with the objective of establishing a sure procedure for the diagnosis of the technological efficiency of the miniseries work, which allows to detect on time: the obstructions in the system and the unequal distribution of pulp with the purpose of operating the aeration parameters of the optimum form, and so to negotiate the cleaning of the pipes with readiness to avoid the extended unbalances of the Ni and Co leached (LixNi-Co) in the Series of the first leaching stage (IraEL). This to proceed was demonstrated, and validated the order of their parts, which consists of three steps: First, the daily study of the pulp densities in the system: Contacts Tanks (TC)-Series of IraEL to detect the critical values of the densities; Second to achieve tests of LixNi-Co in the two miniseries when this values of densities advise it; Third - to determine the distribution of the pulp flow in each miniseries from the residence time to confirm the results of the two previous steps and to calculate again the volumetric flows of air for each miniseries and turbo-aereator. It was established that the critical values of densities that permit to predict an excessive obstruction for each pipe of the miniseries are: 1 175 kg/m³ in relation with the ρprom in TC of (1160-1165) kg/m³, as it is the 1 185 kg/m³, in regard to ρprom near or smaller than 1170 kg/m³. [ABSTRACT FROM AUTHOR]

In the present experimental work it was obtained, on a Production Demonstration Unit (UDP) of leaching commercial plant, an exponential statistical mathematical model with a distribution coefficient (R² = 0,9998), characterized by the equation TR = 13297*(Qpulpa)-0.999;min, to determine the real residence time (TR) of the pulp in the miniseries of first stage of the leaching plant (IraEL) in "Punta Gorda", as a function of the pulp flow (Qpulpa) that is feeded to each miniserie of turbo-aereator (TA) inside the range of values of (105 at 282) m³/h, that makes valid, also, the effectiveness of the modification to the methodology of processing of the experimental results, obtained when using the Na2CO3 like tracer, based on the method of successive approaches that facilitates to determine the TR under the peculiar industrial conditions of the ammonia - carbonate leaching of lateritic reduced ores, in whose process, the useful volume of the miniseries diminishes with the operation time. This premise will allow to optimize in future works at commercial scale, the specific velocity of the air [Qa, m³/(t·min)] and its corresponding: specific volumes of air (Va, m³/t) and volumetric air flows (Ga, m³/h) in each TA with the economic purpose of increasing those leached of Ni and Co in the IraEL. [ABSTRACT FROM AUTHOR]

In this paper was confirmed for the experimental conditions of the QT test, that the redox potential of the pulp as a function of the C(Fe) in liquor, plotted by the Nernst equation, is divided into three well defined zones for different content of Fe2+ in MR. The first two zones are of most interest to regulate Qa in industrial practice by controlling the redox potential of the pulp. For the zone I, were obtained statistical equations that predict the values of the electrochemical potentials of the pulp as a function of the inverse content of Fe2+ in MR: at the end of mixing (MR - liquor), just before starting the aeration [Eºx, t = 0]; the «rupture» potential [Eºx, r] limiting the term zero-order reaction. While the redox potential more negative [Eºx, m], which initiates the zero-order reaction, reaching the maximum concentration of Fe in the liquor during the first minutes of leaching, described as an equation based on the variation of Qa and the % Fe2+ in MR. For the zone II, was obtained the equation that predicts the values of the electrochemical potential of the pulp [E0x ZII] as a logarithmic function of the C(Fe) by the first-order reaction by C(Fe), wherein the concentration of ions sulfur, unlike the zone I, exerts a statistically significant effect. [ABSTRACT FROM AUTHOR]

In the nickel Cuban companies of carbonate-amoniacal technology it is carried out the calcination of the Basic Carbonate of Nickel (CBN) with addition of the NiS that recovers from the efluent generated in the distillation of the liquor product (LP) of the leaching. This new situation introduced a modification in the operation of the furnace for what was carried out an investigation, to industrial scale, to establish a methodology of energy balance that allowed to determine the new norm of consumption of fuel to settle down; to verify the relationship of mass previously established CBN/NiS and to diagnose the energy process in the furnace of industrial rotational drum. It is demonstrated that the used methodology of balance is valid and that the relationship CBN/NiS = 3/1 is optimum. [ABSTRACT FROM AUTHOR]

The experimental scale as a topic is approached in this paper with the objective of evaluating the behavior of the recovery of Ni and Co in the ammoniacal-carbonate technology and in a test bank for the reduction roasting and leaching. This test bank was built by a company that needs to carry out these tests periodically. In the present work it have been analyzed the most frequent errors made while carrying out this kind of research. The analysis has been made by means of the study of a real case. During the analysis it was recommended to consider the convenience of building a multi-purpose installation for the company, at mini-plant scale of continuous and transportable work in order to diminish the costs of any type of research, including any type of technological innovation in the roasting-leaching technological circuit. Besides this installation will make easier the technological evaluation, in a more reliable way, of other useful components present in the laterite with lower contents in comparison with the one of Co. [ABSTRACT FROM AUTHOR]

In the present paper it is shown a synthesized critical analysis of the different kinds of losses of cobalt during the process of ammoniacal carbonate leaching of the reduced lateritic ores. The analysis has been carried out by means of correlating the world industrial practice with the results of the main researches that have proved its scientific foundations. On these bases it is proposed a procedure of leaching that includes several lines of investigation to be carried out at miniplant scale, and four alternatives to be evaluated for two reduction conditions: The current one and the one for the future improvement that guarantee Ni and Co extractions over 90 and 70% respectively. The most important feature of the procedure is based on the process of ruling the Fe oxidation through the air controlled by redox potential under conditions of high concentrations of Fe in the liquor. [ABSTRACT FROM AUTHOR]