Inorganic Geochemistry of Coal

1. Preview

1.1 Scope of inorganic geochemistry of coal

1.2 Significance of inorganic geochemistry of coal

2. Analytical methods of elements in coal

2.1 Coal sampling

2.2 Determination methods of concentrations of elements in coal

2.2.1 X-ray fluorescence spectrometry (XRF)

2.2.2 Proton induced gamma ray spectrometry (PIGIE)

2.2.3 Inductively coupled plasma-mass spectrometry (ICP-MS)

2.2.4 Inductively coupled plasma - optical emission spectrometry (ICP-OES)

2.2.5 Instrumental neutron activation analysis (INAA)

2.2.6 Atomic absorption spectrometry (AAS)

2.2.7 Atomic fluorescence spectroscopy (AFS)

2.2.8 Pyrohydrolysis in conjunction with an ion-selective electrode

2.3 Determination methods of mode of occurrence of elements in coal

2.3.1 Indirect methods

2.3.1.1 Statistical analyses

2.3.1.2 Float-sink methods

2.3.1.3 Selective leaching method (SLM)

2.3.2 Direct methods

2.3.2.1 Optical microscopy

2.3.2.2 X-ray diffraction (XRD)

2.3.2.3 Transmission electron microscopy (TEM)

2.3.2.4 Scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDS)

2.3.2.5 Electron microprobe analyzer (EMPA)

2.3.2.6 Proton induced X-ray emission (PIXE)

2.3.2.7 X Synchrotron applications

2.3.2.8 Secondary ion mass spectrometry (ion microprobe)

2.3.2.9 Time-of-flight of secondary ion mass spectrometry (TOF-SIMS)

2.3.2.10 X-ray photoelectron spectroscopy (XPS)

2.3.2.11 Laser ablation - inductively coupled plasma-mass spectrometry (LA-ICP-MS)

2.3.2.12 Tescan Integrated Mineral Analyzer (TIMA)

2.3.2.13 Chemical investigations

3. Abundance of elements in coal

3.1 Major elements

3.2 Trace elements

4. Enrichment mechanism of elements in coal

4.1. Terrigenous origin

4.2. Hydrothermal fluids

4.3 Volcanic ashes

4.4 Biogenic origin

4.5 Seawater

4.6 Pore waters in coal

4.7 Groundwaters

5. Definition and importance of modes of occurrence of elements in coal

5.1 What are the modes of occurrence of elements in coal?

5.1.1 Types of modes of occurrence of elements in coal

5.1.2 Coal composition in comparison with the Earth’s Upper Crust

5.2 The importance of the modes of occurrence of elements in coal

5.2.1 Geologic/Geochemical Significance

5.2.1.1 Textural evidence of the source of elements

5.2.1.2 Geochemical significance of elements hosted in syngenetic minerals

5.2.2 Economic By-product Recovery

5.2.3 Technological Importance (abrasion, corrosion, fouling, and slagging)

5.2.4 Environmental Impacts

5.2.5 Human Health Impacts

6. Modes of occurrence of elements in coal

6.1 Major elements

6.1.1 Silicon (Si) and aluminum (Al)

6.1.2 Sulfur (S)

6.1.3 Titanium (Ti)

6.1.4 Iron (Fe)

6.1.5 Calcium (Ca)

6.1.6 Magnesium (Mg)

6.1.7 Sodium (Na)

6.1.8 Potassium (K)

6.1.9 Modes of occurrence of non-mineral major elements in coal

6.1.10 Contributions of non-mineral major elements to ash formation

6.2 Modes of occurrence of trace elements in coal

6.2.1 Lithium (Li)

6.2.2 Beryllium (Be)

6.2.3 Boron (B)

6.2.4 Fluorine (F)

6.2.5 Phosphorus (P)

6.2.6 Chlorine (Cl) and bromine (Br)

6.2.7 Scandium (Sc)

6.2.8 Vanadium (V)

6.2.9 Chromium (Cr)

6.2.10 Manganese (Mn)

6.2.11 Cobalt (Co)

6.2.12 Nickel (Ni)

6.2.13 Copper (Cu)

6.2.14 Zinc (Zn) and cadmium (Cd)

6.2.15 Gallium (Ga)

6.2.16 Germanium (Ge)

6.2.16.1 General geochemistry of Ge in coal

6.2.16.2 Wulantuga coal-hosted Ge deposit

6.2.16.3 Lincang coal-hosted Ge deposit

6.2.16.4 Spetzgli coal-hosted Ge deposit

6.2.17 Arsenic (As)

6.2.18 Selenium (Se)

6.2.19 Rubidium (Rb) and cesium (Cs)

6.2.20 Strontium (Sr) and barium (Ba)

6.2.21 Zirconium (Zr) and Hafnium (Hf)

6.2.22 Niobium (Nb) and tantalum (Ta)

6.2.23 Molybdenum (Mo)

6.2.24 Platinum group elements (PGE), silver (Ag), and gold (Au)

6.2.25 Indium (In)

6.2.26 Tin (Sn)

6.2.27 Antimony (Sb)

6.2.28 Tellurium (Te)

6.2.29 Iodine (I)

6.2.30 Rare earth elements and Y (REY)

6.2.30.1 Geochemistry of REY in coal

6.2.30.2 Recovery of REY from coal ash

6.2.31 Tungsten (W)

6.2.32 Rhenium (Re)

6.2.33 Mercury (Hg)

6.2.34 Thallium (Tl)

6.2.35 Lead (Pb)

6.2.36 Bismuth (Bi)

6.2.37 Radium (Ra)

6.2.38 Thorium (Th)

6.2.39 Uranium (U)

6.2.40 Rare Gases

7. Minerals in coal as the hosts of chemical elements

7.1 The significance of minerals in coal

7.2 Minerals found in coal

7.3 Summary of minerals and mineral groups as hosts of chemical elements

8. Selected toxic elements and their effects on human health

8.1 Arsenic

8.2 Fluorine

8.3 Selenium

8.4 Iodine

8.5 Mercury

8.5 Naturally occurring radioactive materials

8.6 Coal smoke and lung cancer

8.6 Uncontrolled coal fires

8.7 Health impacts of coal mining

8.8 Premature deaths

9. Critical Elements in coal

9.1 Overview

9.2 Uranium

9.3 Germanium

9.3.1 Wulantuga Ge deposit

9.3.2 Lincang Ge deposit

9.3.3 Spetzgli Ge deposit

9.4 Gallium and Al

9.5 Rare earth elements and yttrium

9.5.1 Classification and sources

9.5.2 Assessment criteria for coal ashes as REY raw materials

9.5.3 REY-rich coal ashes

9.5.4 REY distribution patterns

9.5.5 Anomalies of REY (Eu, Ce, La, Gd, Y)

9.5.6 Determination problems of Eu

9.6 Other critical elements

9.7 Benefits and future prospects

10. Future directions and applications