Detailed Project Report (DPR) on Lime Putty

LIME PUTTY

[EIRI/EDPR/1002] J.C.: 9640XL

INTRODUCTION

Applied processes and techniques in lime manufacturing

The lime making process consists of the burning of calcium and/or magnesium carbonates at and to obtain the derived oxide (CaCO3 ® CaO + CO2). For some processes significantly higher burning temperatures are necessary, for example dead-burned dolomite. The calcium oxide product from the kiln is generally crushed, milled and/or screened before being conveyed to silo storage. From the silo, the burned lime is either delivered to the end user for use in the form of quicklime, or transferred to a hydrating plant where it is reacted with water to produce hydrated or slaked lime.

Lime processes mainly contain the following basic steps, which are illustrated in Figure 

• Winning of limestone

• Limestone storage and preparation

• Fuels storage and preparation

• Calcination of limestone

• Quicklime processing

• Quicklime hydration and slaking

• Storage, handling and transport 

The Winning of limestone

The raw material for lime production is limestone or, to a lesser extent, dolomite or dolomitic limestone. Dolomite and dolomitic limestone are mixtures of calcium carbonate and up to 44% magnesium carbonate. While limestone deposits are relatively abundant in many countries, only a small proportion are suitable for commercial extraction. High purity limestone or dolomite is quarried, crushed, and in some cases washed. It is then screened and transported to the kiln. Limestone is normally obtained by surface quarrying, generally adjacent to the lime plant, but in some cases sea dredging or even underground mining are used. A typical mining process includes:

• Removal of the overburden (i.e., the soil, clay and loose rock overlying the deposit).

• Blasting of rock.

• Loading and transportation of the blasted rock to the crushing and screening plant.

Limestone preparation and storage

Limestone is crushed to the appropriate size range, which is normally 5 to 200 mm depending upon the kiln used. Primary crushers receive quarry rocks as large as one metre in diameter and reduce their size down to 100-250 mm. Crushed stone from the primary crushers is transported via conveyors to vibrating screens, where large pieces are separated and recycled while those passing through are used as kiln charge, or may be fed into the secondary crushers located further down thenprocess line.

Secondary crushers yield pebbles of 10 to 50 mm, which after screening are transported on belt conveyors and/or bucket elevators to limestone storage silos or compartments for storage prior to feeding the dryer or the lime kiln.

Depending on the nature of the rock (hardness, lamination, size etc.) various types of primary crushers are used, such as: jaw crushers, gyratory crushers and impact crushers. As the kiln charge does not have to be very fine, jaw and impact crushers are also often used as secondary crushers, as are hammer mills. Sometimes crushing plants are located at the quarry and are mobile. The particle size distribution must be compatible with the requirements of the kiln. This generally requires the stone to be positively screened to give a size distribution of, ideally 2 to 1, or at least 3 to 1.

Washing is sometimes used to remove natural impurities such as silica, clay and the very fine particles of limestone. This washing aids the burning process by leaving free space between the stones for combustion air circulation, thus reducing the amount of excess air and saving electrical energy. Techniques for piling the limestone, for better cleaning, have been developed. Screened sizes of limestone are stored in bunkers and in outdoor stockpiles. Fine grades are usually stored in sealed bunkers. In a very limited number of installations (for example, where the calcium carbonate is in the form of a sludge or filter cake), it is necessary to dry the feed material. This is generally done by using the surplus heat from kiln exhaust gases.

COST ESTIMATION

Plant Capacity            10 MT/Day

Land & Building (2000 sq.mt.)    Rs. 1.46 Cr

Plant & Machinery                    Rs. 22.00 Lac

Working Capital for 3 Months    Rs. 38.03 Lac

Total Capital Investment          Rs. 2.13 Cr

Rate of Return                          51%

Break Even Point                      37%

CONTENTS

INTRODUCTION

APPLIED PROCESSES AND TECHNIQUES IN LIME MANUFACTURING

LIME PROCESSES MAINLY CONTAIN THE FOLLOWING BASIC STEPS, WHICH ARE ILLUSTRATED IN FIGURE

WINNING OF LIMESTONE

LIMESTONE PREPARATION AND STORAGE

FUELS

THE CHOICE OF FUEL(S) FOR A LIME-BURNING OPERATION IS IMPORTANT FOR THE FOLLOWING REASONS:

CALCINING OF LIMESTONE

THE LIME BURNING PROCESS TYPICALLY INVOLVES:

GAS SUSPENSION CALCINATION PROCESS

FIGURE 2.8: GAS SUSPENSION CALCINATION PROCESS

QUICKLIME PROCESSING

PRODUCTION OF GROUND QUICKLIME

PRODUCTION OF SLAKED LIME

PRODUCTION OF HYDRATED LIME

FIGURE

FIGURE: FLOWSHEET OF A 3-STAGE LIME HYDRATOR

PRODUCTION OF MILK OF LIME AND LIME PUTTY

STORAGE AND HANDLING

STORAGE

STORAGE OF QUICKLIME

STORAGE OF HYDRATED LIME

STORAGE OF MILK OF LIME

HANDLING

MARKET POSITION

TABLE A

CURRENT PRODUCTION OF INDUSTRIES USING HYDRATED LIMEAND PRECIPITATED CALCIUM CARBONATE

DEMAND FORECAST

REQUIREMENT OF HYDRATED LIME

TABLE B

DEMAND FORECAST FOR HYDRATED LIME IN INDIA

CHART 1

COMPOSITION OF HYDRATED LIME MARKET IN INDIA

TABLE C

DEMAND FORECAST FOR HYDRATED LIME IN WESTERN REGION

HYDRATED LIME INDUSTRY IN INDIA

TABLE F

MAJOR MANUFACTURERS OF HYDRATED LIME

TABLE G

SMALL-SCALE MANUFACTURERS OF HYDRATED LIME

PROCESS TECHNOLOGY

CONCLUSION

LIME-BASED PLASTERING MATERIAL COMPOSITIONS

EXAMPLE 1

INDUSTRIAL APPLICABILITY

ORGANIC LIME SLURRY AND METHOD OF PREPARATION

HYDRATED LIME DISPERSED IN WATER ( H 2 O-MOL SAMPLES):

METHOD AND APPARATUS FOR HYDRATING LIME

CEMENTITIOUS FORMULATIONS AND PROCESSES

LIQUID COMPOSITION ADDITIVE TO REDUCE CURING TIME OF SURFACE COATINGS

MANUFACTURE OF LIME PUTTY

SUPPLIER OF RAW MATERIAL ON LIME AND LIME PUTTY

LIME STONE

SUPPLIER OF PLANT AND MACHINERY

FURNACE

PULVERIZER

REACTION KETTLES

APPENDIX – A:

01. PLANT ECONOMICS

02. LAND & BUILDING

03. PLANT AND MACHINERY

04. OTHER FIXED ASSESTS

05. FIXED CAPITAL

06. RAW MATERIAL

07. SALARY AND WAGES

08. UTILITIES AND OVERHEADS

09. TOTAL WORKING CAPITAL

10. TOTAL CAPITAL INVESTMENT

11. COST OF PRODUCTION

12. TURN OVER/ANNUM

13. BREAK EVEN POINT

14. RESOURCES FOR FINANCE

15. INSTALMENT PAYABLE IN 5 YEARS

16. DEPRECIATION CHART FOR 5 YEARS

17. PROFIT ANALYSIS FOR 5 YEARS

18. PROJECTED BALANCE SHEET FOR (5 YEARS)