scholarly journals Development of an empirical model for copper extraction from chalcocite in chloride media

2020 ◽  
Vol 74 (5) ◽  
pp. 285-292
Author(s):  
Manuel Saldaña ◽  
Freddy Rodríguez ◽  
Anyelo Rojas ◽  
Kevin Pérez ◽  
Palma Angulo
Keyword(s):  
Copper Sulfide ◽  
Mining Industry ◽  
Chloride Concentration ◽  
Analytical Models ◽  
Quadratic Model ◽  
Copper Extraction ◽  
Multivariate Models ◽  
Independent Variables ◽  
Dependent Variables ◽  
Optimization Methodology

Multivariate models are a useful tool when studying the effects of independent variables on one or more dependent variables, since this approach allows modeling of the dynamics of complex systems based on simple analytical models with considerable certainty. Due to the decrease in the copper oxide mineral grades, leaching of copper sulfide minerals (secondary sulfides) has positioned itself as a benchmark of operation for the Chilean mining industry. The present work proposes the study of the effects of sulfuric acid, chloride concentration and time on the extraction of copper from sulfuric minerals (chalcocite), considering an experimental design, the surface optimization methodology and the adjustment of a quadratic model. The experimental data were adjusted by multiple regression analysis and were statistically analyzed. A model was developed to represent the copper extraction from the Cu2S mineral as a function of the statistically significant variables (chloride concentration and time) that contribute to explain the variation of the response variable under the set of parameters sampled.

scholarly journals Development of an Analytical Model for the Extraction of Manganese from Marine Nodules

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 903 ◽  
Author(s):  
Saldaña ◽  
Toro ◽  
Castillo ◽  
Hernández ◽  
Trigueros ◽  
...  
Keyword(s):  
Particle Size ◽  
Analytical Model ◽  
Value Chain ◽  
Analytical Models ◽  
Copper Extraction ◽  
Independent Variables ◽  
Dependent Variables ◽  
Extended Value ◽  
Mn Recovery ◽  
By Products

Multivariable analytical models provide a descriptive (albeit approximate) mathematical relationship between a set of independent variables and one or more dependent variables. The current work develops an analytical model that extends a design of experiments for the leaching of manganese from marine nodules, using sulfuric acid (H2SO4) in the presence of iron-containing tailings, which are both by-products of conventional copper extraction. The experiments are configured to address the effect of time, particle size, acid concentration, Fe2O3/MnO2 ratio, stirring speed and temperature, under typical industrial conditions. The recovery of manganese has been modeled using a first order differential equation that accurately fits experimental results, noting that Fe2O3/MnO2 and temperature are the most critical independent variables, while the particle size is the least influential (under typical conditions). This study obtains representative fitting parameters, that can be used to explore the incorporation of Mn recovery from marine nodules, as part of the extended value chain of copper sulfide processing.

scholarly journals Statistical Study for Leaching of Covellite in a Chloride Media

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 477
Author(s):  
Kevin Pérez ◽  
Norman Toro ◽  
Manuel Saldaña ◽  
Eleazar Salinas-Rodríguez ◽  
Pedro Robles ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Statistical Study ◽  
Sulfuric Acid Concentration ◽  
Chloride Concentration ◽  
Quadratic Model ◽  
Copper Extraction ◽  
Optimization Methodology ◽  
Composite Face ◽  
Central Composite

Covellite is a secondary copper sulfide, and it is not abundant. There are few investigations on this mineral in spite of it being formed during the leaching of chalcocite or digenite; the other investigations on covellite are with the use of mineraloids, copper concentrates, and synthetic covellite. The present investigation applied the surface optimization methodology using a central composite face design to evaluate the effect of leaching time, chloride concentration, and sulfuric acid concentration on the level of copper extraction from covellite (84.3% of purity). Copper is dissolved from a sample of pure covellite without the application of temperature or pressure; the importance of its purity is that the behavior of the parameters is analyzed, isolating the impurities that affect leaching. The chloride came from NaCl, and it was effectuated in a size range from –150 to +106 μm. An ANOVA indicated that the leaching time and chloride concentration have the most significant influence, while the copper extraction was independent of sulfuric acid concentration. The experimental data were described by a highly representative quadratic model obtained by linear regression (R2 = 0.99).

scholarly journals Relative importance analysis with multivariate models: Shifting the focus from independent variables to parameter estimates

2020 ◽  
Vol 4 (2) ◽  
pp. 1-20
Author(s):  
Joseph N. Luchman ◽  
Xue Lei ◽  
Seth Kaplan
Keyword(s):  
Statistical Models ◽  
Likelihood Estimation ◽  
Parameter Estimate ◽  
Theory And Practice ◽  
Parameter Estimates ◽  
Relative Importance ◽  
Multivariate Models ◽  
Independent Variables ◽  
Dependent Variables ◽  
Independent Variable

Conclusions regarding the relative importance of different independent variables in a statistical model have meaningful implications for theory and practice. However, methods for determining relative importance have yet to extend beyond statistical models with a single dependent variable and a limited set of multivariate models. To accommodate multivariate models, the current work proposes shifting away from the concept of independent variable relative importance toward that of parameter estimate relative importance (PERI). This paper illustrates the PERI approach by comparing it to the evaluation of regression slopes and independent variable relative importance (IVRI) statistics to show the interpretive and methodological advantages of the new concept and associated methods. PERI’s advantages above standardized slopes stem from the same fit metric that is used to compute PERI statistics; this makes them more comparable to one another than standardized slopes. PERI’s advantages over IVRI stem from situations where independent variables do not predict all dependent variables; hence, PERI permits importance determination in situations where independent variables are nested in dependent variables they predict. We also provide recommendations for implementing PERI using dominance analysis with statistical models that can be estimated with maximum likelihood estimation combined with a series of model constraints using two examples.

scholarly journals Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 780 ◽  
Author(s):  
Norman Toro ◽  
Williams Briceño ◽  
Kevin Pérez ◽  
Manuel Cánovas ◽  
Emilio Trigueros ◽  
...  
Keyword(s):  
Sea Water ◽  
Chloride Concentration ◽  
Xrd Analysis ◽  
Quadratic Model ◽  
Copper Extraction ◽  
Copper Ore ◽  
Copper Dissolution ◽  
Rapid Dissolution ◽  
Chloride Environment ◽  
Kinetics Of

Chalcocite is the most important and abundant secondary copper ore in the world with a rapid dissolution of copper in an acid-chloride environment. In this investigation, the methodology of surface optimization will be applied to evaluate the effect of three independent variables (time, concentration of sulfuric acid and chloride concentration) in the leaching of pure chalcocite to extract the copper with the objective of obtaining a quadratic model that allows us to predict the extraction of copper. The kinetics of copper dissolution in regard to the function of temperature is also analyzed. An ANOVA indicates that the linear variables with the greatest influence are time and the chloride concentration. Also, the concentration of chloride-time exerts a significant synergic effect in the quadratic model. The ANOVA indicates that the quadratic model is representative and the R2 value of 0.92 is valid. The highest copper extraction (67.75%) was obtained at 48 h leaching under conditions of 2 mol/L H2SO4 and 100 g/L chloride. The XRD analysis shows the formation of a stable and non-polluting residue; such as elemental sulfur (S0). This residue was obtained in a leaching time of 4 h at room temperature under conditions of 0.5 mol/L H2SO4 and 50 g/L Cl−.

scholarly journals Stability of a colloidal suspension of yacon (Smallanthus sonchifolius) intended for spray drying

2019 ◽  
Vol 72 (2) ◽  
pp. 8863-8871
Author(s):  
Maria Isabel Arango Torres ◽  
Misael Cortés Rodriguez ◽  
Esteban Largo Ávila
Keyword(s):  
Spray Drying ◽  
Colloidal Stability ◽  
Colloidal Suspension ◽  
Added Value ◽  
Quadratic Model ◽  
Independent Variables ◽  
Smallanthus Sonchifolius ◽  
Perishable Product ◽  
Dependent Variables ◽  
Repulsive Forces

Yacon (Smallanthus sonchifolius) is a tuber with a high content of active compounds that offer health benefits, so its productive chain seeks new alternatives to generate yacon products with added value; however, it tends to be a perishable product due to its high aw, chemical composition, and enzymatic activity. The influence of both composition and homogenization in the colloidal stability of yacon suspensions was evaluated for later use in spray drying. Response surface methodology and a central composite design were used, considering three independent variables: homogenization time (TH) (4-6 min), xanthan gum (XG) (0.1-0.2%), and acidity (0.1-0.3%); and the following dependent variables: zeta potential (ζ), color (CIELab), viscosity (μ), stability index by spectral absorption (R), and particle size (D10, D50, and D90). The values of the independent variables that best fit the experimental optimization criteria were: XG=0.16%, acid=0.3%, and TH=4.8 min. The values of the experimental dependent variables and the variables predicted by the quadratic model were ζ=-33.8±4.0 and -37.6 mV, µ=1143.0±93.4 and 1000 cP, R=0.45±0.1 and 0.48, D10=127.8±8.2 and 138.1 µm, D50=251.2±16.3 and 267.7 µm, D90=424.3±28.7 mm and 463.9 µm, L*=41.7±1.4 and 41.8, a*=0.02±0.85 and 1.6, and b*=15.0±1.3 and 14.8, respectively. The colloidal suspension showed adequate physicochemical stability, favored mainly by repulsive forces, homogenization, and rheology of the continuous phase; reaching a content of total solids of 12.5%.

scholarly journals Accelerating Copper Leaching from Sulfide Ores in Acid-Nitrate-Chloride Media Using Agglomeration and Curing as Pretreatment

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 250 ◽  
Author(s):  
Pía C. Hernández ◽  
Junior Dupont ◽  
Osvaldo O. Herreros ◽  
Yecid P. Jimenez ◽  
Cynthia M. Torres
Keyword(s):  
Copper Sulfide ◽  
Chloride Concentration ◽  
Copper Extraction ◽  
Copper Dissolution ◽  
Three Samples ◽  
Copper Leaching ◽  
Sulfide Ore ◽  
Higher Temperature ◽  
Pretreatment Conditions ◽  
Copper Sulfide Ore

This work investigates the effect of an agglomeration and curing pretreatment on leaching of a copper sulfide ore, mainly chalcopyrite, using mini-columns in acid-nitrate-chloride media. Ten pretreatment tests were conducted to evaluate different variables, namely the addition of nitrate as NaNO3 (11.7 and 23.3 kg/ton), chloride as NaCl (2.1 and 19.8 kg/ton), curing time (20 and 30 days) and repose temperature (25 and 45 °C). The optimum copper extraction of 58.6% was achieved with the addition of 23.3 kg of NaNO3/ton, 19.8 kg of NaCl/ton, and after 30 days of curing at 45 °C. Under these pretreatment conditions, three samples of ore were leached in mini-columns. The studied parameters were temperature (25 and 45 °C) and chloride concentration (20 and 40 g/L). The optimum copper extraction of 63.9% was obtained in the mini-column leaching test at 25 °C, with the use of 20 g/L of chloride. A higher temperature (45 °C) and a higher chloride concentration (40 g/L) negatively affected the extraction. The pretreatment stage had favorable effects, in terms of accelerating copper dissolution and improving leaching of copper sulfide ore in acid-nitrate-chloride media. Waste salts from caliche industry and waste brine from reverse osmosis can be used for providing the nitrate and chloride media.

ANALISA PENGARUH IKLIM ORGANISASI DAN KOMPETENSI TERHADAP KINERJA PEGAWAI PT HUTAMA KARYA

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Erik Wardhana, MM.
Keyword(s):  
Organizational Climate ◽  
Employee Performance ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
Free Variable ◽  
Independent Variables ◽  
Dependent Variables ◽  
Correlational Approach ◽  
Survey Research Methods ◽  
The Relationship

This study entitled "Analysis of Effect of Climate Organization and Competence Againt Employee PT. Hutama Karya ". The purpose of this study was to obtain information on the relationship between the free variable that organizational climate (X1) and competence (X2) with the dependent variable is employee performance (Y), either partially or simultaneously, This study used survey research methods with the correlational approach and predictive, which aims for the relationship and influence between independent and dependent variables. The sampling technique can be done randomly (simple random sampling) of 852 employees, which is considered to resprentatif is 89 people. And to solve problems, to analyze and examine the relationship and influence between the independent variables on the dependent variable used models kausalistik through regression analysis with SPSS 14.0

PENGARUH PERSONAL BACKGROUND, POLITICAL BACKGROUND DAN PENGEATAHUAN DEWAN TENTANG ANGGARAN TERHADAP PERAN DPRD DALAM PENGAWASAN KEUANGAN DAERAH

2008 ◽  
Author(s):  
Yesi Mutia Basri ◽  
Rosliana Rosliana
Keyword(s):  
Multivariate Analysis ◽  
Significant Influence ◽  
Political Activity ◽  
Primary Data ◽  
Financial Control ◽  
Independent Variables ◽  
Dependent Variables ◽  
Political Background ◽  
Activity Dependent

This research aim to examine the influence of personal background, political background, and council budget knowledge towards the role of DPRD on region financial control. This research is motivated by the fact that individual background will effect to individual behavior on political activity. Dependent variables in this research are personal background, political background, and council budges knowledge towards the role of DPRD on region financial control Independent variables are the role of DPRD on region financial control in planning, implementing, and responsibility steps. The data in this research consist of primary data that taken from questionnaires distributed directly to respondents. The collected are from 34 Respondents that members of DPRD at Pekanbaru. Hypothesis of this research are examine by using Multivariate Analysis of Variances (MANOVA). The result of this research HI personal background political background and budget knowledge have significant influence toward the role of DPRD on region financial control in planning steps.H2 personal background, politico I background and budget knowledge have no significant influence toward the role of DPRD on region financial control in Implementing steps. H3 personal background political background and budget knowledge have no significant influence toward the role of DPRD on region financial control in Controlling steps.

scholarly journals Weight Feedback-Based Harmonic MDG-Ensemble Model for Prediction of Traffic Accident Severity

2021 ◽  
Vol 11 (11) ◽  
pp. 5072
Author(s):  
Byung-Kook Koo ◽  
Ji-Won Baek ◽  
Kyung-Yong Chung
Keyword(s):  
Traffic Accidents ◽  
Average Rate ◽  
Modern Society ◽  
Rate Of Change ◽  
Weighted Voting ◽  
Independent Variables ◽  
Dependent Variables ◽  
Accident Severity ◽  
Harmonic Average ◽  
Bagging Method

Traffic accidents are emerging as a serious social problem in modern society but if the severity of an accident is quickly grasped, countermeasures can be organized efficiently. To solve this problem, the method proposed in this paper derives the MDG (Mean Decrease Gini) coefficient between variables to assess the severity of traffic accidents. Single models are designed to use coefficient, independent variables to determine and predict accident severity. The generated single models are fused using a weighted-voting-based bagging method ensemble to consider various characteristics and avoid overfitting. The variables used for predicting accidents are classified as dependent or independent and the variables that affect the severity of traffic accidents are predicted using the characteristics of causal relationships. Independent variables are classified as categorical and numerical variables. For this reason, a problem arises when the variation among dependent variables is imbalanced. Therefore, a harmonic average is applied to the weights to maintain the variables’ balance and determine the average rate of change. Through this, it is possible to establish objective criteria for determining the severity of traffic accidents, thereby improving reliability.

scholarly journals A Student’s Guide to the Classification and Operationalization of Variables in the Conceptualization and Design of a Clinical Study: Part 1

2021 ◽  
Vol 43 (2) ◽  
pp. 177-179 ◽  
Author(s):  
Chittaranjan Andrade
Keyword(s):  
Clinical Study ◽  
Significant Relationship ◽  
Research Experience ◽  
Process Variables ◽  
Know How ◽  
Independent Variables ◽  
Cause And Effect ◽  
Confounding Variables ◽  
Dependent Variables ◽  
The Relationship

Students without prior research experience may not know how to conceptualize and design a study. This article explains how an understanding of the classification and operationalization of variables is the key to the process. Variables describe aspects of the sample that is under study; they are so called because they vary in value from subject to subject in the sample. Variables may be independent or dependent. Independent variables influence the value of other variables; dependent variables are influenced in value by other variables. A hypothesis states an expected relationship between variables. A significant relationship between an independent and dependent variable does not prove cause and effect; the relationship may partly or wholly be explained by one or more confounding variables. Variables need to be operationalized; that is, defined in a way that permits their accurate measurement. These and other concepts are explained with the help of clinically relevant examples.

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