complete describes production of lime and its uses in civil engineering and other fields

1. LIME

2. INTRODUCTION
• UP UNTIL THE 20TH CENTURY , QUICK LIME WAS USED AS A DISINFECTANT,
USUALLY IN 10% SOLUTION CALLED MILK OF LIME. HOWEVER, IT HAD
DISADVANTAGE OF DECOMPOSING RAPIDLY ON EXPOSURE TO AIR AND
MOISTURE, AND THE BURNT LIME HAD TO BE FRESH AND UN SLAKED
• CALCIUM OXIDE (CAO)
COMMONLY KNOWN AS BURNT LIME, LIME OR QUICK LIME, IS A WIDELY USED
CHEMICAL COMPOUND. IT IS A WHITE CAUSTIC AND ALKALINE CRYSTALLINE
SOLID. AS A COMMERCIAL PRODUCT LIME OFTEN ALSO CONTAIN MAGNESIUM
OXIDE, SILICON OXIDE AND SMALLER AMOUNTS OF ALUMINIUM OXIDE, AND IRON
OXIDE.

3. CALCINATION OR LIME BURNING
• CALCIUM OXIDE IS USUALLY MADE BY THERMAL DECOMPOSITION OF MATERIALS
SUCH AS LIME STONE, THAT CONTAINS CALCIUM CARBONATE (CACO3; MINERAL
NAME: CALCITE) IN A LIME KILN. THIS IS ACCOMPLISHED BY HEATING THE
MATERIAL TO ABOVE 825 DEGREE CELSIUS , A PROCESS CALLED CALCINTAION
OR LIME BURNING, TO LIBERATE A MOLECULE A CO2. LEAVING CAO . THIS
PROCESS IS REVERSIBLE SINCE ONCE THE QUICK LIME PRODUCT HAS COOLED IT
IMMEDIATELY ABSORBS CO2 FROM AIR. UNTIL AFTER ENOUGH TIME, IT IS
COMPLETELY CONVERTED BACK TO CALCIUM CARBONATE. CALCINATION OF
LIME STONE IS ONE OF THE FIRST CHEMICAL REACTION DISCOVERED BY MAN
AND WAS KNOW IN PRE HISTORY

4. CALCINATAION PROCESS

5. SLAKED LIME, HYDRATED LIME, PICKLING
LIME
• IT IS A CHEMICAL COMPOUND WITH CHEMICAL FORMULA CA(OH)2. IT IS
COLORLESS CRYSTAL OR WHITE POWDER AND IS OBTAINED WHEN CALCIUM
OXIDE (CALLED LIME OR QUICK LIME) IS MIXED OR: “SLAKED” WITH WATER. IT
CAN ALSO BE PRECIPITATED BY MIXING AN AQUEOUS SOLUTION OF CALCIUM
CHLORIDE AND AN AQUEOUS SOLUTION OF SODIUM HYDROXIDE. THE NAME OF
THE NATURAL MINERAL IS PORTLANDITE
QUICK LIME CAN BE HYDRATED, THAT IS COMBINED WITH WATER.
HYDRATED LIME IS PRODUCED ACCORDING TO REACTION
REACTION
CAO+H20 CA(OH)2

6. LIME PRODUCTION PROCESS
• LIME STONE IS EXTRACTED FROM QUARRIES OR MINES.
• PART OF THE EXTRACTED STONE, SELECTED ACCORDING TO ITS CHEMICAL
COMPOSITION, AND GRANULOMETRY , IS CALCINATED ABOUT 1000 DEGREE
CELSIUS IN DIFFERENT TYPE OF KILN FIRED BY SUCH FUELS AS NATURAL GAS ,
COAL , FUEL OIL , LIGNITE ETC.
• QUICK LIME IS PRODUCED BY THE REACTION
CACO3+HEAT CAO+CO2

7. DIFFERENT TYPES OF LIME KILN
• INTERMITTANT KILN
• CONTINOUS KILN

8. USAGE OF LIME IN CIVIL ENGINEERING
• IT IS USED IN MORTAR AND PLASTER TO INCREASE THE RATE OF HARDENING AS
WELL AS TO IMPROVE ADHESION
• LIME IS ALSO USED IN GLASS PRODUCTION AND ITS ABILITY TO REACT WITH
SILICATES IS ALSO IN MODERN METAL PRODUCTION INDUSTRIES ( STEEL,
MAGNESIUM , ALUMINIUM AND OTHERS) TO REMOVE IMPURITIES AS SLAG
• IT IS ALSO USED IN WATER AND SEWAGE TREATMENT TO REDUCE ACIDITY TO
SOFTEN, AS A FLOCCULANTS AND TO REMOVE PHOSPHATES AND OTHER IMPURITIES
• IN PAPER MAKING TO DISSOLVE LIGNIN, AS A COAGULANT AND IN BLEACHING
• IT IS USED IN AGRICULTURE TO REMOVE ACIDIC SOILS

9. USAGE IN DAILY LIFE
• IT IS USED IN POLLUTION CONTROL, IN GAS SCRUBBERS TO DESULFURIZE WASTE
GASES AND TO TREAT MANY LIQUID INFLUENTS.
• IT IS TRADITIONALLY BEEN USED IN THE BURIAL OF BODIES IN OPEN GRAVES, TO
HIDE THE SMELL OF DECOMPOSITION , AS WELL AS FORENSIC SCIENCE , TO
REVEAL FINGER PRINTS .