Recovery of Valuable Metals from Zinc Plant Residues by Two-Stage Selective Atmospheric Leaching Process

2011 ◽  
Vol 396-398 ◽  
pp. 552-555 ◽  
Author(s):  
Cun Xiong Li ◽  
Chang Wei ◽  
Hong Sheng Xu ◽  
Zhi Gan Deng ◽  
Ji Qiang Liao ◽  
...  
Keyword(s):  
Plant Residue ◽  
Optimum Operating ◽  
Plant Residues ◽  
Zinc Plant ◽  
Second Stage ◽  
Leaching Process ◽  
Valuable Metals ◽  
Atmospheric Leaching ◽  
Leaching Solution ◽  
Conditional Tests

A hydrometallurgical process was used for selectively extraction of valuable metals from zinc plant residues. The process includes the following two steps. (1) The zinc plant residue is treated by sulfuric acid atmospheric leaching process with KMnO4 as oxidatant to selectively dissolve zinc while leaving most (above 98 pct) of indium and germandium in the iron residues. (2) The iron residues are treated by acidic atmospheric leaching process with NaClO3 as oxidant to dissolve indium and germanium. The valuable metals of indium and germanium in the second leaching solution can be reclaimed by further treatment. The optimum operating parameters of the first stage and the second stage were established by conditional tests. The experimental data indicated that under the conditions employed the zinc extraction in the first stage was above 95%, and the leaching percentage of indium and germanium in the second stage reached 91.6% and 90.7%, respectively.

scholarly journals Process optimization of nickel extraction from hazardous waste

2012 ◽  
Vol 38 (3) ◽  
pp. 29-40
Author(s):  
Mahdi Gharabaghi ◽  
Mehdi Irannajad ◽  
Amir Reza Azadmehr ◽  
Majid Ejtemaei
Keyword(s):  
Hazardous Waste ◽  
Acid Concentration ◽  
Plant Residue ◽  
Liquid Ratio ◽  
Nickel Extraction ◽  
Zinc Plant ◽  
Valuable Metals ◽  
Solid Liquid ◽  
Main Effects ◽  
The Relationship

Abstract Zinc plant residue is a hazardous waste which contains high quantity of nickel and other valuable metals. Process parameters such as reaction time, acid concentration, solid-liquid ratio, particle size, stirring speed and temperature for nickel extraction from this waste were optimized using factorial design. Main effects and their interactions were obtained by the analysis of variance ANOVA. Empirical regression model was obtained and used to predict nickel extraction with satisfactory results and to describe the relationship between the predicted results and the experiment results. The important parameters for maximizing nickel extraction were identifi ed to be a leaching time solid-liquid ratio and acid concentration. It was found that above 90% of nickel could be extracted in optimum conditions.

scholarly journals Fate of carbon and nitrogen from plant residue decomposition in a calcareous soil

2011 ◽  
Vol 52 (No. 3) ◽  
pp. 137-140 ◽  
Author(s):  
F. Nourbakhsh
Keyword(s):  
Biochemical Properties ◽  
Plant Residue ◽  
Plant Residues ◽  
Order Kinetic ◽  
Nitrogen Transformations ◽  
Plant Materials ◽  
Carbon And Nitrogen ◽  
Residue Decomposition ◽  
N Concentration ◽  
Order Kinetic Model

Carbon and nitrogen transformations in soil are microbially mediated processes that are functionally related. The fate of C and N was monitored in a clay-textured soil (Typic Haplocambid) which was either unamended (control) or amended with various plant materials at the rate of 10 g residue C/kg soil. To evaluate C mineralization, soils were incubated for 46 days under aerobic conditions. Nitrogen mineralization/immobilization was evaluated at the end of eight-week incubation experiment. All CO<sub>2</sub> evolution data conformed well to a first-order kinetic model, C<sub>m&nbsp;</sub>= C<sub>0</sub> (1 &ndash; e<sup>&ndash;Kt</sup>). The product of K and C<sub>0 </sub>(KC<sub>0</sub>) was significantly correlated with some chemical and biochemical properties of the plant residues, including N concentration (r = 0.83, P &lt; 0.001), C:N (r = &ndash;0.64, P &lt; 0.05) and lignin:N (r = &ndash;0.81, P &lt; 0.001). Among the plant residue composition characteristics, N concentration (r = 0.96, P &lt; 0.001), C:N (r = &ndash;0.69, P &lt; 0.01) and lignin:N (r = &ndash;0.68, P &lt; 0.01) were significantly correlated with the net rates of N mineralization/immobilization (N<sub>m/i</sub>).

scholarly journals Changes in Denitrifier Abundance, Denitrification Gene mRNA Levels, Nitrous Oxide Emissions, and Denitrification in Anoxic Soil Microcosms Amended with Glucose and Plant Residues

2010 ◽  
Vol 76 (7) ◽  
pp. 2155-2164 ◽  
Author(s):  
Sherri L. Henderson ◽  
Catherine E. Dandie ◽  
Cheryl L. Patten ◽  
Bernie J. Zebarth ◽  
David L. Burton ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Organic Carbon ◽  
Plant Residue ◽  
Plant Residues ◽  
Barley Plant ◽  
Mrna Levels ◽  
Soil Microcosms ◽  
Denitrification Gene ◽  
Gene Mrna ◽  
Amended Soil

ABSTRACT In agricultural cropping systems, crop residues are sources of organic carbon (C), an important factor influencing denitrification. The effects of red clover, soybean, and barley plant residues and of glucose on denitrifier abundance, denitrification gene mRNA levels, nitrous oxide (N2O) emissions, and denitrification rates were quantified in anoxic soil microcosms for 72 h. nosZ gene abundances and mRNA levels significantly increased in response to all organic carbon treatments over time. In contrast, the abundance and mRNA levels of Pseudomonas mandelii and closely related species (nirS P) increased only in glucose-amended soil: the nirS P guild abundance increased 5-fold over the 72-h incubation period (P < 0.001), while the mRNA level significantly increased more than 15-fold at 12 h (P < 0.001) and then subsequently decreased. The nosZ gene abundance was greater in plant residue-amended soil than in glucose-amended soil. Although plant residue carbon-to-nitrogen (C:N) ratios varied from 15:1 to 30:1, nosZ gene and mRNA levels were not significantly different among plant residue treatments, with an average of 3.5 � 107 gene copies and 6.9 � 107 transcripts g−1 dry soil. Cumulative N2O emissions and denitrification rates increased over 72 h in both glucose- and plant-tissue-C-treated soil. The nirS P and nosZ communities responded differently to glucose and plant residue amendments. However, the targeted denitrifier communities responded similarly to the different plant residues under the conditions tested despite changes in the quality of organic C and different C:N ratios.

Tracing the nitrogen, sulfur, and carbon released from plant residues in a soil/plant system

Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 699 ◽  
Author(s):  
Yothin Konboon ◽  
Graeme Blair ◽  
Rod Lefroy ◽  
Anthony Whitbread
Keyword(s):  
Triticum Aestivum ◽  
Nutrient Cycling ◽  
Wheat Straw ◽  
Medicago Truncatula ◽  
Plant Residue ◽  
Plant Residues ◽  
Plant Nutrient ◽  
N Loss ◽  
Leaching Losses ◽  
Nutrient Demand

Matching plant residue mineralisation rate to plant nutrient demand is one way of increasing the efficiency of nutrient cycling. A glasshouse experiment was conducted in a Soloth soil with a C4d13 C signature using drained pots to examine the effect on the yield of Japanese millet (Echinochloa frumentocea) and the fate of 15 N, 35 S, and C (using d 13 C shift) from the C 3 plants Flemingia macrophylla, Medicago truncatula hay, and wheat (Triticum aestivum) straw applied at 3 t/ha in the presence of N and NPKS fertiliser. The yield of Japanese millet at 91 days was highest where medic hay had been added (13.7 g/pot) and lowest where wheat straw was used (11.5 g/pot). Recovery of 35 S by the millet was highest in the wheat straw and medic hay treatments (mean 11.5%), whilst recovery of 15 N was highest from medic hay (15.8%). Leaching losses of 35 S were highest in the Flemingia and medic treatments (mean 8.1%), and 15 N loss in leachate was highest in the medic hay treatment (6.6%). A maximum of 1.5% of the C added in residues was recovered in the leachate of the medic hay treatment.

Pb Recycling Through Leaching, Precipitation, and Cementation from Zinc Plant Residue

2021 ◽  
Vol 7 (1) ◽  
pp. 291-299
Author(s):  
Behrouz Taheri ◽  
Mahdi Gharabaghi ◽  
Sajjad Aghazadeh
Keyword(s):  
Plant Residue ◽  
Zinc Plant

scholarly journals Effects of Fe+2 and Fe+3 in Pretreatment and Leaching on a Mixed Copper Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 866
Author(s):  
María E. Taboada ◽  
Pía C. Hernández ◽  
Aldo P. Padilla ◽  
Nathalie E. Jamett ◽  
Teófilo A. Graber
Keyword(s):  
Chloride Concentration ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Curing Time ◽  
Ferrous Ions ◽  
Copper Ore ◽  
Second Stage ◽  
Acid Consumption ◽  
Nacl Concentration ◽  
Leaching Solution

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

scholarly journals Simulating soil organic C dynamics in managed grasslands under humid temperate climatic conditions

2020 ◽  
Author(s):  
Asma Jebari ◽  
Jorge Álvaro-Fuentes ◽  
Guillermo Pardo ◽  
María Almagro ◽  
Agustin del Prado
Keyword(s):  
Field Experiments ◽  
Model Performance ◽  
Climatic Conditions ◽  
Plant Residue ◽  
Plant Residues ◽  
Organic C ◽  
Natural Grasslands ◽  
Rothc Model ◽  
Below Ground ◽  
Intensively Managed

Abstract. Temperate grasslands are of paramount importance in terms of soil organic carbon (SOC) dynamics. Globally, research on SOC dynamics has largely focused on forests, croplands and natural grasslands, while intensively managed grasslands has received much less attention. In this regard, we aimed to improve the prediction of SOC dynamics in managed grasslands under humid temperate regions. In order to do so, we modified and recalibrated the SOC model RothC, originally developed to model the turnover of SOC in arable topsoils, which requires limited amount of readily available input data. The modifications proposed for the RothC are: (1) water content up to saturation conditions in the soil water function of RothC to fit the humid temperate climatic conditions, (2) entry pools that account for particularity of exogenous organic matter (EOM) applied (e.g., ruminant excreta), (3) annual variation in the carbon inputs derived from plant residues considering both above- and below-ground plant residue and rhizodeposits components as well as their quality, and (4) the livestock treading effect (i.e., poaching damage) as a common problem in humid areas with higher annual precipitation. In the paper, we describe the basis of these modifications, carry out a simple sensitivity analysis and validate predictions against data from existing field experiments from four sites in Europe. Model performance showed that modified RothC reasonably captures well the different modifications. However, the model seems to be more sensitive to soil moisture and plant residues modifications than to the other modifications. The applied changes in RothC model could be appropriate to simulate both farm and regional SOC dynamics from managed grassland-based systems under humid temperate conditions.

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