A PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COAL/NON COKING COALS FOR METALLURGICAL AND THERMAL APPLICATION

摘要

This invention relates to a process to produce low ash clean coal from high ash coals for coke making along with beneficiation of mineral values form coal comprising the steps of crushing clean coal obtained through froth-flotation or coal as received to -30 to -72 BS mesh size containing 15 to 16.5% ash, preparing a sample of the coal on oven drying at 105° C to 110° C and cooled, treating the cooled coal sample in a reactor with alkali (NaOH) solution at concentration of 10 - 50% at 80 85°C under reflux with or without stirring for 1.5-7 hours, washing the treated coal repeatedly with water and/or Hcl and then dried, treating the washed coal with 10-20% acidic (H2SO4/Hcl) solution for 1 to 5 hour at 80 - 85°C, filtering the treated coal, washing the filtered coal and dried followed by characterize evaluation of chemical, rheological and petroghaphical properties such as ash, volatile matter, alkali (Na2O and K2O) content, ash constituents - (Fe, CaO, SiO2, AL2O3, MnO, TiO2, P and S), calorific value and Crucible Swelling Number to ensure final ash content of the treated coal to around 5% suitable for coke making.