Detailed Project Report on silica from rice husk ash

SILICA FROM RICE HUSK ASH 

 [CODE NO.4186] 

Silica (SiO2) is one of the valuable inorganic multipurpose chemical compounds. It can exist in gel, crystalline and amorphous forms. It is the most abandon material on the earth?s crust. However, manufacture of pure silica is energy intensive. A variety of industrial process, involving conventional raw materials require high furnace temperatures (more than 700 degree C). In our Project, a simple chemical process is described which uses a non-conventional raw material rice husk ash for extraction of silica. Rice Husk ash is one of the most silica rich raw materials containing about 90-98% silica (after complete combustion) among the family of other agro-wastes. Rice husk is a popular boiler fuel and the ash generated usually creates disposal problems. The chemical process discussed not only provides a solution for waste disposal but also recovers a valuable silica product, together with certain useful associate recoveries. The other associate recovery is sodium sulphate. Effluent wash water obtained after washing precipitated silica (wet impure silica) contains sodium sulphate. By evaporation of water in multiple effect evaporators, followed by crystallization, filtration and drying, crystals of sodium sulphate are obtained. The residue ash in sodium silica production can be utilized for making good quality bricks. Retained sodium silicate in residue ash acts as a binder and with incorporation of suitable ingredients high quality bricks can be manufactured. From rough estimation the production of paddy in the country about twenty five million tons of rice husk is obtained from rice mills. This is usually burnt resulting in mounts of ash in and around the mills, causing major health problem and pollution. Using rice husk as the raw material two million tons of pure high grade silica can be produced to meet the high demand of various industries that are using it. The main states with large number of rice mills are Andhra Pradesh, Tamil Nadu, Karnataka, and Kerala etc.

The conventional process of manufacturing silica is the reaction of sand with soda ash at about 1500ºC. In our project, a new method of manufacturing silica by reacting rice husk ash with caustic soda is developed. 

In Advantage of using rice husk as raw material for precipitated silica are superior and cost effective compared to present technology of producing Silica from quartz. Starts from a raw material of little or no cost and value, which otherwise would cause environmental pollution. Processis energy efficient and also consumes much lower energy compared to an alternative process involving fusion of selected quality of sand.

Rice husk or paddy husk - an agricultural residue is available abundantly in rice producing countries. India alone produces approximately 12 million tons of rice husk annually. Rice husk is generally not advocated as cattle feed because of low cellulose and other sugar contents in it. Furfural and rice bran oil are extracted from rice husk. Rice husk is used by industries as fuel in boilers and for power generation. Rick husk has a high ash content varying from 18-20%. Silica is the major constituent of rice husk ash. High silica (SiO2) content in rice husk ash is economically feasible to extract silica, which has wide market.

 Rice is the seed of the monocot plants Oryza sativa (Asian rice) or Oryza glaberrima (African rice). It is normally grown as an annual plant, although in tropical areas it can survive as a perennial and can produce aratoon crop for up to 30 years. Since a large portion of maize crops are grown for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one fifth of the calories consumed worldwide by the human species. The rice plant can grow to 1–1.8 m (3.3–5.9 ft) tall, occasionally more depending on the variety and soil fertility. It has long, slender leaves 50–100 cm (20–39 in) long and 2–2.5 cm (0.79–0.98 in) broad. The small wind-pollinated flowers are produced in a branched arching to pendulous inflorescence 30–50 cm (12–20 in) long. The edible seed is a grain (caryopsis) 5–12 mm (0.20–0.47 in) long and 2–3 mm (0.079–0.12 in) thick. Rice is the staple food of over half the world's population. It is the predominant dietary energy source for 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa. Rice provides 20% of the world’s dietary energy supply, while wheat supplies 19% and maize 5%.

Rice Husk 

Rice husks are the hard protecting covering of grains of rice. Rice hulls are the coating for the seeds, or grains, of the rice plant. To protect the seed during the growing season, the hull forms from hard materials, including opaline silica and lignin.

One practice, started in the seventeenth century, to separate the rice from hulls, it to put the whole rice into a pan and throw it into the air while the wind blows. The hulls are blown away while the rice fell back into the pan. This happens because the hull isn't nearly as dense as the rice. These steps are known as winnowing. Later pestles and a simple machine called a rice pounder were developed to remove hulls. In 1885 the modern rice hulling machine was invented in Brazil. During the milling processes, the hulls are removed from the raw grain to reveal whole brown rice, which may then sometimes be milled further to remove the bran layer, resulting in white rice. Rice husk is a by-product of the rice milling industry. It is a unique crop residue with uniform size and high content of ash (14–25%). The silica content of the rice husk ash (RHA) can be as high as 90–98% . This husk can be used as a fertilizer in agriculture or as an additive for cement and concrete fabrication. Due to its high silicon content, rice husk has become a source for preparation of elementary silicon and a number of silicon compounds especially silica silicon carbide and silicon nitride . India is a major producer of rice and finding ways to put the husk to use is imminent. The high silica content in the rice husk ash has attracted interest in discovering ways to use it commercially. Although silica occurs as a component of cells or cell walls in virtually all arial parts of the rice plant, it is most abundant in the husk. Owing to their small diameter, many technological applications, such as thermal insulators, composite fillers, etc., use ultrafine silica powders .We have investigated the possibility of producing high purity silicon from rice husk by purifying the rice husk silica followed by pelletizing and reduction in a modified electric arc furnace. The pelletizing was carried using carbon black as a reductant and sucrose as a binder. 

COST ESTIMATION

Plant Capacity                                   5 Ton/Day

Land & Building (2000 sq.mt.)  Rs. 1.14 Cr

Plant & Machinery                              Rs. 3.00 Cr

Working Capital for 2 Months    Rs. 1.15 Cr

Total Capital Investment                  Rs. 5.47 Cr

Rate of Return                                    33%

Break Even Point                               55%

• INTRODUCTION
• RICE HUSK
• CHEMICAL COMPOSITION OF RHA BEFORE AND AFTER BURNING OUT AT700°C FOR 6 H
• RAW MATERIALS
• COMPOSITION OF RICE HUSK ASH
• PRECIPITATED SILICA END-USE APPLICATIONS
• USES AND APPLICATION OF PRECIPITATED SILICA
• IMPORTANT APPLICATION SECTOR
• OTHER SECTORS
• APPLICATIONS
• 1. ADHESIVE:
• 2. CHAPPALS:
• 3. CONVEYOR BELT & TRANSMISSION BELT:
• 4. PVC SHEETS:
• 5. RAILWAY PADS:
• 6. RICE ROLLERS AND RUBBER ROLLERS:
• 7. RUBBER PRODUCTS AND RUBBER HOSES:
• 8. SILICON TUBES:
• PRECIPITATED SILICA IS USED IN SILICON RUBBER FOR FOLLOWING REASONS:
• 9. RUBBER AND SOLID TYRES:
• 10. TEXTILE COTS AND APRONS:
• NON RUBBER GRADE PRECIPITATED SILICA
• APPLICATIONS
• PESTICIDES:
• PRINTING INK:
• TOOTH PASTE AND TOOTH POWDER:
• SALT:
• COATINGS:
• FIRE EXTINGUISHING POWDERS:
• ADVANTAGE OF RICE HUSK FOR PRECIPITATED SILICA
• SILICA IN RICE HUSK
• SPECIFICATION OF PRECIPITATED SILICA
• IS SPECIFICATION
• PROPERTIES OF RICE HUSK
• A. PROPERTIES OF RAW MATERIAL
• B. COMPOSITION OF RICE HUS
• C. COMPOSITION OF RICE HUSK ASH
• MARKET OVERVIEW OF PRECIPITATED SILICA
• KEY MARKET TRENDS
• INCREASING DEMAND FROM THE BUILDING AND CONSTRUCTION INDUSTRY
• THE ASIA-PACIFIC REGION IS EXPECTED TO DOMINATE THE MARKET
• INDIAN PRECIPITATED SILICA MARKET
• • LOWER ENVIRONMENTAL IMPACT AND EASY ACCESS OF RAW MATERIAL (RICE HUSK ASH)
• • SURGING DEMAND FROM END USE INDUSTRIES
• • PRESENCE OF SUBSTITUTES AND HARMFUL EFFECTS OF PRECIPITATED SILICA
• MANUFACTURING PROCESS OF PRECIPITATED SILICA FROM RICE 
• HUSK ASH (INDIAN INSTITUTE OF SCIENCE PRECIPITATED SILICA TECHNOLOGY) CGPL PROCESS
• DIGESTION
• PRECIPITATION
• REGENERATION
• PROCESS FLOW DIAGRAM
• MANUFACTURING PROCESS IN DETAILS
• CALCULATION:
• 6.4 TON RICE HUSK-> 1.6 TON RHA->1 TON SILICA
• FIGURE: PHOTOGRAPHS OF (A) RICE HUSK (B) RICE HUSK ASH (C) 
• RICE HUSK SILICA POWDER
• FIGURE 1 FLOW CHART SHOWING THE PROCESS OF PRECIPITATED 
• SILICA FROM RICE HUSK ASH
• DIGESTION
• PRECIPITATION
• REGENERATION
• FIGURE 2 SHOWS A PHOTOGRAPH OF THE PILOT PLANT FOR 
• THIS PROCESS.
• TYPICAL PROPERTIES OF PRECIPITATED SILICA
• PROCESS FOR SILICA PRECIPITATION IN DETAILS
• A. DIGESTION:
• DIGESTION:
• ENERGY
• PRECIPITATION:
• ENERGY
• CONVENTIONAL PROCESS OF EXTRACTION OF SILICA FROM 
• RICE HUSK ASH
• PRECIPITATED SILICA USING RICE HUSK ASH
• 4.1 DIGESTION
• 4.2 PRECIPITATION
• 4.3 REGENERATION
• 4.4 CALCINATION AND SLAKING
• 4.1 DIGESTION
• 4.2 PRECIPITATION
• 1. SURFACE AREA
• 2. TAP DENSITY
• 4.3 REGENERATION
• 4.4 CALCINATION AND SLAKING
• TYPICAL PROPERTIES OF SILICA PRECIPITATED
• EXTRACTION METHOD OF SILICA
• THE REACTION IS:
• THE REACTION IS:
• MANUFACTURING PROCESS OF PRECIPITATED SILICA FROM QUART SAND
• STEP 1: PRECIPITATION
• STEP 2: WASHING
• STEP 3: DRYING
• STEP 4: FINISHING AND PACKAGING
• TYPICAL SILICA MANUFACTURING PROCESS
• ALTERNATE PROCESS OF SILICA MANUFACTURE
• A. CONVENTIONAL
• B. RICE HUSK, SUPERHEATED STEAM
• C. RICE HUSK, HF, NH3
• D. PROPOSED PROCESS
• B. PROCESS DESCRIPTION
• C. EXPERIMENTAL PROCEDURE
• EXTRACTION OF SILICA FROM RH/RHA
• COMBUSTION METHOD
• CHEMICAL METHOD
• EXTRACTION METHOD OF SILICA FROM RHA
• TECHNOLOGY SUPPLIERS FOR PRECIPITATED SILICA FROM RICE HUSK
• COMPLETE PLANT AND MACHINERY SUPPLIERS
• SUPPLIERS OF PLANT AND MACHINERIES (GLOBAL)
• SUPPLIERS OF PLANT AND MACHINERIES
• COMPLETE PLANT SUPPLIERS
• SUPPLIERS OF MUFFLE FURNACE
• SUPPLIERS OF FILTER PRESS
• SUPPLIERS OF MINI BOILER
• SUPPLIERS OF INDUSTRIAL DRYERS
• SUPPLIERS OF STORAGE VESSEL
• SUPPLIERS OF LABORATORY EQUIPMENTS
• SUPPLIERS OF MATERIAL HANDLING EQUIPMENTS
• SUPPLIERS OF INSTRUMENTATION AND PROCESS CONTROL EQUIPMENTS
• SUPPLIERS OF PACKAGING MACHINE
• HORIZONTAL PLATE FILTER PRESS (SPARKLER FILTERS)
• SUPPLIERS OF RAW MATERIALS (GLOBAL)
• SUPPLIERS OF RAW MATERIALS
• SUPPLIERS OF RICE HUSK
• SUPPLIERS OF CAUSTIC SODA
• SUPPLIERS OF SODIUM HYDROXIDE
• SUPPLIERS OF CALCIUM HYDROXIDE
• SUPPLIERS OF CARBON DIOXIDE GAS
• SUPPLIERS OF PACKAGING MATERIALS (HDPE BAGS)

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)