Mechanisms for selective coalescence of coals: Fossil Energy quarterly report, April 1, 1987-June 30, 1987. [Zeta potential]

Technical Report · Sat Aug 01 04:00:00 EDT 1987

OSTI ID:6110877

Wheelock, T D; Markuszewski, R; Fan, C W; Venkatadri, R; Labuschagne, B C.J.; Tyson, D; Druding, M

Measurement of the zeta potential of fresh Illinois No. 6 coal and similar coal which had been mildly oxidized by exposure to air at room temperature for one week showed only slight differences in the electrokinetic properties of the two materials. However, when the two materials were agglomerated with heptane, the recovery of the oxidized coal was significantly lower than the recovery of the unoxidized coal. On the other hand, the sulfur and ash contents of the product were the same for both materials. The recovery of the unoxidized coal with a small amount of heptane (5 w/w %) was improved significantly by traces of sodium oleate. For pure mineral pyrite, the state of oxidation of the surface was shown to greatly affect both the electrokinetic properties and oil agglomeration characteristics of the material. Various methods of oxidation, including prolonged exposure to air at room temperature, seemed to generate both hydrophilic and hydrophobic oxidation products on the surface of the pyrite. The hydrophilic products were partially removed by hot water and more completely removed by boiling hydrochloric acid, whereas the hydrophobic product was removed by acetone. This evidence suggests that the hydrophilic products included various species such as ferric oxide and ferric sulfate while the hydrophobic product was probably elemental sulfur. The acid-cleaned pyrite responded readily to oil agglomeration whereas the acetone-cleaned pyrite did not. Recovery of the acid-cleaned material was suppressed by adding salt to the agglomeration system, while recovery of oxidized pyrite was greatly enhanced by adding traces of either sodium laurate or sodium palmitate to the system. 4 refs., 13 figs., 4 tabs.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6110877
• Report Number(s): IS-4932; ON: DE88000663
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010300 -- Coal
Lignite
& Peat-- Preparation-- (1987-)
010600* -- Coal
Lignite
& Peat-- Properties & Composition
AGGLOMERATION
ALKANES
CARBONACEOUS MATERIALS
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COAL PREPARATION
ELECTROPHORESIS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HEPTANE
HYDROCARBONS
IRON COMPOUNDS
IRON SULFIDES
MATERIALS
MINERALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDATION
PH VALUE
PYRITE
SEPARATION PROCESSES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SURFACE PROPERTIES
SURFACTANTS
TRANSITION ELEMENT COMPOUNDS