Stabilization of heavy metals on spent fluid catalytic cracking catalyst using marine clay

2001 ◽  
Vol 44 (10) ◽  
pp. 285-291 ◽  
Author(s):  
D.D. Sun ◽  
J.H. Tay ◽  
C.E.G. Qian ◽  
D. Lai
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
Metal Leaching ◽  
Leaching Tests ◽  
Physical Barrier ◽  
Marine Clay ◽  
Clay Matrix ◽  
Petroleum Refineries

Spent fluid catalytic cracking catalyst is a hazardous solid waste generated by petroleum refineries containing vanadium and nickel. The marine clay was used as a matrix to stabilize vanadium and nickel and produce bricks which were then fired at various temperatures. TCLP leaching tests indicated that stabilizing brick had low metal leaching, with a maximum of 6.4 mg/l for vanadium and 19.8 μg/l for nickel. Compressive strength of stabilizing brick was found to range between 20 N/mm2 and 47 N/mm2. It is believed that stabilization and encapsulation mechanisms are responsible for the stabilization of vanadium and nickel. Encapsulation is a process whereby the marine clay matrix forms a physical barrier around the heavy metals which are thus prevented from leaching out into the environment. Incorporation involves the formation of bonds between the marine clay matrix and the heavy metals which thus become incorporated in the clay microstructure.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

Encapsulation of heavy metals on spent fluid catalytic cracking catalyst

1998 ◽  
Vol 38 (4-5) ◽  
pp. 211-217 ◽  
Author(s):  
D. Sun ◽  
X. Z. Li ◽  
M. Brungs ◽  
D. Trimm
Keyword(s):  
Catalytic Cracking ◽  
Environmental Problem ◽  
Effective Means ◽  
Fluid Catalytic Cracking ◽  
Leaching Tests ◽  
Weight Percentage ◽  
Spent Fcc Catalyst ◽  
Fcc Catalyst ◽  
Standard Specimens ◽  
Fcc Catalysts

Vanadium and nickel were found as major contaminants on spent FCC catalyst at levels of 3518 ppm and 3225 ppm, respectively. XPS results indicated that vanadium and nickel were in oxide form on spent FCC catalysts. Leaching tests (TCLP) showed that vanadium from spent FCC catalysts poses an environmental problem if disposed by landfill. It was found that encapsulation treatment with up to 60 wt % spent FCC catalyst in Portland cement, is an effective means of stabilization. The strength of standard specimens containing catalyst was much lower than that of standard specimens made with same weight percentage of sand.

scholarly journals EXPERIMENTAL RESEARCH INTO LEACHING OF METALS FROM IMMOBILIZED CIS SOLAR MODULE WASTE

2016 ◽  
Vol 24 (4) ◽  
pp. 269-277 ◽  
Author(s):  
Saulius VASAREVIČIUS ◽  
Gintautas SKRIPKIŪNAS ◽  
Vaidotas DANILA
Keyword(s):  
Heavy Metals ◽  
Physical Properties ◽  
Experimental Research ◽  
Indium Selenide ◽  
Copper Indium Selenide ◽  
Metal Leaching ◽  
Leaching Tests ◽  
Solar Module ◽  
Copper Indium ◽  
Cu And Zn

The aim of this research is to determine metal leaching from concrete specimens containing different quantities of waste recovered from copper indium selenide (CIS) solar module by replacing a certain share of sand aggregate. During the first stage of research the CIS solar module was shredded and leaching tests were performed on recovered waste by analysing six metals – Na, Mg, Fe, Cd, Cu and Zn. It has been determined that out of all metals analysed, the highest leaching was observed for sodium, while the highest leaching out of the heavy metals was found for zinc. In Phase II of the study concrete specimens with shredded CIS module waste were made and the physical properties of these specimens as well as the leaching of the same metals was determined. The results have shown that three metals, namely Fe, Cd, Zn, were successfully immobilised and did not leach from the specimens.

scholarly journals Immobilization of Heavy Metals in Boroaluminosilicate Geopolymers

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 214
Author(s):  
Piotr Rożek ◽  
Paulina Florek ◽  
Magdalena Król ◽  
Włodzimierz Mozgawa
Keyword(s):  
Mechanical Properties ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Phase Composition ◽  
Molar Ratio ◽  
Metal Leaching ◽  
Heavy Metal Leaching ◽  
Composition Structure ◽  
Structure And Microstructure

Boroaluminosilicate geopolymers were used for the immobilization of heavy metals. Then, their mechanical properties, phase composition, structure, and microstructure were investigated. The addition of borax and boric acid did not induce the formation of any crystalline phases. Boron was incorporated into the geopolymeric network and caused the formation of N–B–A–S–H (hydrated sodium boroaluminosilicate) gel. In the range of a B/Al molar ratio of 0.015–0.075, the compressive strength slightly increased (from 16.1 to 18.7 MPa), while at a ratio of 0.150, the compressive strength decreased (to 12 MPa). Heavy metals (lead and nickel) were added as nitrate salts. The loss of the strength of the geopolymers induced by heavy metals was limited by the presence of boron. However, it caused an increase in heavy metal leaching. Despite this, heavy metals were almost entirely immobilized (with immobilization rates of >99.8% in the case of lead and >99.99% in the case of nickel). The lower immobilization rate of lead was due to the formation of macroscopic crystalline inclusions of PbO·xH2O, which was vulnerable to leaching.

scholarly journals The Evaluation of the Heavy Metal Leaching Behavior of MSWI-FA Added Alkali-Activated Materials Bricks by Using Different Leaching Test Methods

2019 ◽  
Vol 16 (7) ◽  
pp. 1151 ◽  
Author(s):  
Peng Xu ◽  
Qingliang Zhao ◽  
Wei Qiu ◽  
Yan Xue
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Metal Leaching ◽  
Alkali Activation ◽  
Leaching Tests ◽  
Leaching Behavior ◽  
Heavy Metal Leaching ◽  
Environmental Compatibility ◽  
Alkali Activated

Alkali-activated materials (AAMs) not only have the potential to replace cement applications in architecture and civil engineering, but also have an excellent effect on the stabilization solidification of hazardous industrial wastes. This study used two types of municipal solid waste incineration fly ash (MSWI-FA)—grate firing fly ash (GFFA) and fluidized bed fly ash (FBFA)—as AAMs brick raw materials. It is discovered from this study that AAMs bricks with different weight ratios of GFFA and FBFA can both meet the required standard of GB21144-2007 (Solid concrete brick). From the results obtained from the four leaching tests, the equilibrium pH of the leachate varies, resulting in significant differences in the leaching of heavy metals in Raw GFFA, Raw FBFA, and AAMs bricks with GFFA and FBFA. The AAMs brick with the addition of GFFA and FBFA has an alkali activation system to encapsulate heavy metals. By comparing the results obtained from the CEN/TS 14429 leaching behavior test and the four batch leaching tests, it was found that the most influential factors for the heavy metal leaching concentration are whether the heavy metal has been solidified/stabilized in the samples. GFFA and FBFA tend to have consistent characteristics after being activated by alkali to form AAMs bricks. This can be confirmed by the acid neutralization ability concentrated on a specific pH range. The results obtained from CEN/TS14429 verified that the AAMs bricks with the addition of GFFA and FBFA have excellent environmental compatibility and that it provides a comprehensive evaluation on the environmental compatibility of the test materials and products. This demonstrated that the MSWI-FA is suitable for used as alkali-activated materials and its products have the potential to be commercially used in the future.

Numerical Simulation of an Industrial Fluid Catalytic Cracking Regenerator

2015 ◽  
Vol 7 (2) ◽  
Author(s):  
Guangwu Tang ◽  
Armin K. Silaen ◽  
Bin Wu ◽  
Chenn Q. Zhou ◽  
Dwight Agnello-Dean ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Catalytic Cracking ◽  
Catalyst Surface ◽  
Three Dimensional ◽  
Fluid Catalytic Cracking ◽  
Solid Catalyst ◽  
Reacting Flow ◽  
Momentum Exchange ◽  
Petroleum Refineries ◽  
Two Phases

Fluid catalytic cracking (FCC) is one of the most important conversion processes in petroleum refineries, and the FCC regenerator is a key part of an FCC unit utilized in the recovery of solid catalyst reactivity by burning off the deposited coke on the catalyst surface. A three-dimensional multiphase, multispecies reacting flow computational fluid dynamics (CFD) model was established to simulate the flow and reactions inside an FCC regenerator. The Euler–Euler approach, where the two phases (gas and solid) are considered to be continuous and fully interpenetrating, is employed. The model includes gas–solid momentum exchange, gas–solid heat exchange, gas–solid mass exchange, and chemical reactions. Chemical reactions incorporated into the model simulate the combustion of coke which is present on the catalyst surface. The simulation results were validated by plant data.

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