Effect of pH on the removal of pyritic sulfur from coal by oxydesulfurization

Journal Article · Fri Oct 01 00:00:00 EDT 1982 · Ind. Eng. Chem. Process Des. Dev.; (United States)

DOI:https://doi.org/10.1021/i200019a010· OSTI ID:6482286

Joshi, J B; Shah, Y T; Albal, R S

The effect of pH on the removal of pyritic sulphur in air/water chemical coal cleaning was investigated. The pH was varied by adding sulphuric acid sodium carbonate to a coal-water slurry. The effect of nearly neutral pH (about 7) was determined in a buffer solution of sodium dihydrogen phosphate and disodium hydrogen phosphate. Data were taken in the temperature range of 130 to 190 C, oxygen partial pressure of 0.32 to 1.36 MPa, and reaction times up to 3600 s. The rate of pyrite oxidation was to be minimum at the nearly neutral conditions. Under otherwise identical conditions, the rate of pyrite oxidation was greater in basic pH than in acidic pH. The enhancement in the rate of pyrite oxidation is explained on the basis of electrochemical reactions. Under nearly neutral conditions, the overall reaction is shown to be controlled by the surface reaction, whereas under acidic as well as basic conditions, diffusion of oxygen through the product ash layer as well as the surface chemical reaction seems to be important.

• OSTI ID: 6482286
• Journal Information: Ind. Eng. Chem. Process Des. Dev.; (United States), Vol. 21:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL
DESULFURIZATION
CHEMICAL REACTION KINETICS
CLEANING
COAL PREPARATION
HIGH TEMPERATURE
MEDIUM PRESSURE
OXIDATION
PH VALUE
PYRITE
REMOVAL
SLURRIES
WATER
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COMMINUTION
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
IRON COMPOUNDS
IRON SULFIDES
KINETICS
MATERIALS
MINERALS
MIXTURES
OXYGEN COMPOUNDS
REACTION KINETICS
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SUSPENSIONS
TRANSITION ELEMENT COMPOUNDS
010402* - Coal
Lignite
& Peat- Purification & Upgrading