scholarly journals An Alternative Method for the Obtention of Ceramic Foams from Gold and Silver Tailings with High Pyrite Content

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1897
Author(s):  
Cristian Salazar ◽  
Lina Uribe
Keyword(s):  
Mechanical Strength ◽  
Apparent Density ◽  
Mine Drainage ◽  
Flotation Process ◽  
Foaming Agent ◽  
Ceramic Foams ◽  
Foaming Process ◽  
Mineral Phases ◽  
Pyrite Content ◽  
High Sulfide

Mining extraction operations generate a large number of tailings that contain different mineral phases such as quartz (principally), complex silicates, metallic elements, etc. Tailings impose a serious concern as it is possible to have acid mine drainage potential, leaching, and percolation events of heavy metals into the environment under certain conditions. The objective of this work was to evaluate the technical feasibility of producing ceramic foams from gold and silver tailings with high sulfide gangue through a previous flotation process to eliminate impurities associated to this gangue, as it can produce SO2 in the foaming process, and to analyze the effect of the sintering time and the temperature on the characteristics of foams obtained with this type of waste. The results showed that the inverse flotation reduced the presence of impurities associated to sulfides. In addition, it was possible to observe that in the absence of a foaming agent, it was possible to obtain ceramic foams with an apparent density and a mechanical strength near to 1.0 g/cm3 and 0.5 MPa, respectively, when a higher sintering temperature and time were used. On the other hand, the presence of the foaming agent reduced the apparent density to 0.5 g/cm3 without decreasing to a great extent the mechanical strength of ceramic foams at lower sintering temperatures.

Study on the Influences of Foaming Gypsums Performance

2013 ◽  
Vol 743-744 ◽  
pp. 222-227 ◽  
Author(s):  
Bin Huang ◽  
Yi Zhang ◽  
Dong Xu Li
Keyword(s):  
Mechanical Strength ◽  
Pore Structure ◽  
Chemical Reaction ◽  
Apparent Density ◽  
Weight Ratio ◽  
Insulation Property ◽  
Foaming Agent ◽  
Fgd Gypsum ◽  
Foaming Process ◽  
Thermal Insulation Property

Utilizing the chemical reaction principles H2O2 was catalyzed by MnO2, instead of being catalyzed by warm water. In the gypsum slurry, due to the chemical reaction of hydrogen peroxide a large number of bubbles were produced, and the material was self-foaming. The H2O2 foaming agent and the method of foaming affected the performance of the foaming gypsum, such as mechanical strength, apparent density, thermal conductivity, and the pore structure of foaming gypsum. The result showed that with adding H2O2, the apparent density and mechanical strength decreased; the different water/plaster weight ratio ranged from 0.65 to 0.75, affecting the foaming process. The thermal insulation property of FGD gypsum is related to the content of H2O2, the water/plaster weight ratio, and the pore structure of foaming gypsum.

THERMAL INSULATING MATERIAL WITH HIGH MECHANICAL STRENGTH MADE FROM CLAY BRICK WASTE AND COAL ASH USING THE MICROWAVE ENERGY

2020 ◽  
Vol 26 (2) ◽  
pp. 28-34
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE
Keyword(s):  
Mechanical Strength ◽  
Coal Ash ◽  
Microwave Energy ◽  
Raw Material ◽  
Clay Brick ◽  
High Mechanical Strength ◽  
Foaming Agent ◽  
Insulating Material ◽  
Thermal Insulating ◽  
Foaming Process

The paper presents the results of experimental research for manufacture a high mechanical strength thermal insulating material using the microwave energy. Clay brick waste (75 - 83 mass %) and coal ash (15 - 23 mass %) as raw material and silicon carbide (2%) as a foaming agent have been used as a powder mixture. The porous product obtained by a sintering/ foaming process at 1115 - 1145 ºC had relatively low density and thermal conductivity (0.50 - 0.68 g/cm3 and 0.078 - 0.095 W/mK, respectively) and high compressive strength (up to 7.5 MPa). This remarkable combination of some physical and mechanical characteristics of the insulating material allows its use in applications involving mechanical stress resistance.

USE OF THE MICROWAVE ENERGY FOR ALUMINUM WASTE FOAMING

2019 ◽  
Vol 25 (4) ◽  
pp. 43-49
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE ◽  
ANA CASANDRA SEBE
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Porous Structure ◽  
Powder Mixture ◽  
Aluminum Foam ◽  
Fine Powder ◽  
Microwave Energy ◽  
Raw Material ◽  
Foaming Agent ◽  
Foaming Process

The paper presents an aluminum foam experimental technique using the microwave energy. The raw material was recycling aluminum waste processed by ecological melting and gas atomizing to obtain the fine powder required in the foaming process. The powder mixture was completed with dolomite as a foaming agent. The products had a fine and homogeneous porous structure (pore size between 0.4-0.9 mm). The density (1.17-1.19 g/cm3), the compressive strength (6.83-7.01 MPa) and the thermal conductivity (5.71-5.84 W/m·K) had values almost similar to the foams made by conventional methods.

scholarly journals Pluvial percolation in pyrite-bearing coal stockpiles

2009 ◽  
Vol 62 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Danielle Andrade Pimentel ◽  
José Aurélio Medeiros da Luz
Keyword(s):  
Heavy Metal ◽  
Acid Mine Drainage ◽  
Metal Content ◽  
Environmental Problem ◽  
Mine Drainage ◽  
Leaching Process ◽  
Polymeric Reagents ◽  
Dissolved Species ◽  
Sulfide Ore ◽  
Pyrite Content

Acid mine drainage is a main environmental problem linked to coal and sulfide ore mining. Its treatment usually involves alkalinization and subsequent precipitation and immobilization of the dissolved species. Rainfalls over stockpiles can cause a very similar phenomenon. This work aimed to study the effluents from such a leaching process in steam-coal stockpiles Brazilian coal with a high pyrite content was used. The effluents have been chemically characterized. Effluent clarification by aggregation and settling in an attempt to simultaneously deplete heavy metal content was studied. Settling experiments were carried out with coal suspensions, in order to evaluate the efficiency of inorganic and polymeric reagents in the process.

scholarly journals Effect of the Operational Conditions in the Characteristics of Ceramic Foams Obtained from Quartz and Sodium Silicate

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1806
Author(s):  
Lina Uribe ◽  
Juan D. Giraldo ◽  
Alejandro Vargas
Keyword(s):  
Pressing Pressure ◽  
Melting Points ◽  
Statistical Software ◽  
Powder Mixtures ◽  
Foaming Agent ◽  
Ceramic Foams ◽  
Cellular Solid ◽  
Operational Conditions ◽  
Volumetric Expansion ◽  
Foaming Temperature

Ceramic foams were fabricated without using melting pots through the direct foaming of compacted powder mixtures of commercial quartz (SiO2) with fluxing agents (Na2CO3 and CaO) and a foaming agent (Na2SiO3·5H2O) at a relatively low temperature range (850−870 °C). The effects of the pressing pressure of the powders, the foaming time, foaming temperature, and mixture content were evaluated. The obtained cellular solid materials presented an acceptable volumetric expansion at a pressing pressure of 4 t. The materials only presented porosity at a minimum temperature of 850 °C and at a minimum time of 30 min. All the foamed samples showed an acceptable symmetric expansion and non-appreciable fissures. The study of the mixture content through the statistical software MODDE® shows that the porosity of the samples was principally affected by the Na2SiO3 content and the foaming temperature. The samples obtained at the optimum controlling factors proposed by this statistical software presented an apparent density, porosity, and mechanical strength of 1.09 ± 0.03 g/cm3, 56.01% ± 1.12%, and 3.90 ± 0.16 MPa, respectively. Glass and ceramics foams such as those obtained in this work become attractive as insulation materials in applications where high temperatures occur due to their higher melting points.

scholarly journals Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

2011 ◽  
Vol 78 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Doug Bertel ◽  
John Peck ◽  
Thomas J. Quick ◽  
John M. Senko
Keyword(s):  
Mine Drainage ◽  
Low Ph ◽  
Content Type ◽  
X Ray ◽  
First Order ◽  
Geochemical Conditions ◽  
Sulfate Reducing ◽  
Mineral Phases ◽  
Magnetic Analysis ◽  
Acid Tolerant

ABSTRACTThe mineralogical transformations of Fe phases induced by an acid-tolerant, Fe(III)- and sulfate-reducing bacterium,Desulfosporosinussp. strain GBSRB4.2 were evaluated under geochemical conditions associated with acid mine drainage-impacted systems (i.e., low pH and high Fe concentrations). X-ray powder diffractometry coupled with magnetic analysis by first-order reversal curve diagrams were used to evaluate mineral phases produced by GBSRB4.2 in media containing different ratios of Fe(II) and Fe(III). In medium containing Fe predominately in the +II oxidation state, ferrimagnetic, single-domain greigite (Fe3S4) was formed, but the addition of Fe(III) inhibited greigite formation. In media that contained abundant Fe(III) [as schwertmannite; Fe8O8(OH)6SO4·nH2O], the activities of strain GBSRB4.2 enhanced the transformation of schwertmannite to goethite (α-FeOOH), due to the increased pH and Fe(II) concentrations that resulted from the activities of GBSRB4.2.

Porous Material Production and Material Properties

2019 ◽  
Vol 946 ◽  
pp. 84-90
Author(s):  
Liudmila Shtirc ◽  
Svetlana G. Vlasova ◽  
Dmitry Meshcherskikh
Keyword(s):  
Porous Material ◽  
Caustic Soda ◽  
Material Properties ◽  
Foaming Agent ◽  
Experimental Glass ◽  
Material Production ◽  
Foaming Process ◽  
Foaming Temperature ◽  
Glass Compositions

In our work we defined two directions for synthesizing porous material: pulping selected experimental glass compositions and using caustic soda as a foaming agent. We studied the foaming temperature settings, investigated the porous material properties. The intensity of the foaming process was estimated from the value of the foaming coefficient.

Experimental Study of the Foam Agent in Lightweight Aggregate Concrete

2012 ◽  
Vol 226-228 ◽  
pp. 1776-1779
Author(s):  
Yong Wei Wang ◽  
Bai Xiao Tang
Keyword(s):  
Compressive Strength ◽  
Apparent Density ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Optimal Dosage ◽  
Foaming Agent ◽  
Aggregate Concrete ◽  
Wall Strength ◽  
Different Content ◽  
Good Range

Different content of foaming agent in the lightweight aggregate concrete test, the apparent density and compressive strength of concrete assessment indicators. Studies have shown that, with the dosage increase, the variation of the apparent density of the concrete is first decreases and then increases when the content is 0.8kg/m3 dry apparent density minimum; as the foaming agent content continues to grow, dry apparent density continues to increase, but the magnitude of increase is less obvious. At this point, its 28 days compressive strength of only 0.7MPa, the wall strength of the material does not meet the insulation requirements. Taking into account the apparent density and strength of wall insulation materials, requirements, test data to determine the optimal dosage of the foaming agent should be 0.4 ~ 0.6kg, to determine the content of foaming agent in the lightweight aggregate concrete of the most good range.

The Composition of Biomass Cushion Packaging Material and the Study of its Influence on Product Performance

2013 ◽  
Vol 750-752 ◽  
pp. 1239-1243
Author(s):  
Gang Li ◽  
Fang Yi Li ◽  
Na Xie ◽  
Kai Kai Guan ◽  
Peng Liu ◽  
...  
Keyword(s):  
Active Agent ◽  
Packaging Material ◽  
Product Performance ◽  
Impact Behavior ◽  
Packaging Materials ◽  
Static Compression ◽  
Foaming Agent ◽  
Compression Performance ◽  
Foaming Process ◽  
The Impact

Nine groups of biomass packaging materials with different formula have been synthesized, which were made up of straw fiber and starch by foaming technique. In order to analysis the influence of main composites on cushion performance, a series of tests were conducted to measure the impact behavior, rebound property and static compression performance of materials. Measuring results show that material impact toughness increases with content of fiber. When the content of plasticizer is 10%, the material impact energy absorption is maximum, when the ratio of active agent and foaming agent is 1:1, a stable foaming process can be obtained, which makes the bubble uniform and increases rebound rate.

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