Presentation on theme: "ABS BLENDED CEMENT We believe we are AT PAR WITH THE World's BEST"— Presentation transcript:
ABS BLENDED CEMENT We believe we are AT PAR WITH THE World's BEST http://cementconsultant.org/ http://cementconsultant.org/
LOOKING BEYOND ORDINARY PORTLAND CEMENT The Cement Industry with annual worldwide production of around 1.5 billion tons is one of the largest users of high-grade limestone, coal, electricity & other minerals. Each ton of cement requires 1.3 tons of limestone, 0.2 tons of coal & around 100 kwh of electricity. Worldwide, cement production now accounts for more than 1.6 billion tons of CO2, or over 8% of total CO2 emissions from all human activities (Wilson 1993). It was the oil crisis of the 70’s that made the world understand the evils of prolificacy of natural resources. The French, the Germans, the Japanese took the lead cause these were the countries blessed with little natural resources. VSK in operation
BLENDED CEMENT This led to the resurgence of blended cements. The thrust was clearly on conservance of natural resources, usage of waste materials & on the durability of concrete. According to figures released by Cembureau (the European Cement Association), blended cement production in Europe during 1994 increased by 21 percentage points to 51% of total cementitious production (from 30% in 1992). Portland cement production during the same period declined to 37% (from 52% in 1992). In the period from 1990 to 1995, The average clinker factor during this period (worldwide average) was reduced by more than 6%. Rotary Cement Plant
BLENDED CEMENT IN INDIA Lafarge is the world leader in blended Cement technology Lafarge spends 5% of its turnover on R&D Lafarge introduced a 16MPa one day strength cement with only 35% clinker ratio in the Indian market in 1999. Indian cement companies have been unable to decrease the clinker/cement ratio below 75% while maintaining the one day bench mark strength of 16MPa. However blended cement production is up 15% points now totalling 35% in the last two years as the Indian companies grapple to bring down costs & improve cement quality in face of stiff competition from multinationals like CEMEX, LAFARGE etc Blending Silos
The NEED ABS Cement was set up at a cost of $ 4,00,000 in 1991, with a term loan of $ 2,50,000 to manufacture 70 tpd OPC (Ordinary Portland Cement) using VSK technology. ABS made profits since inception & repaid almost 50% of the loan by 1996. However ABS had to be shut down for want of Limestone in 1996 as the Dehradun Limestone mines were closed following an order of the honourable Supreme Court. New product lines were required for survival. A need thus arose for the manufacture of Blended Cement. Our VSK & RAW MILL were sold in 2001
The cost of the Rotary Clinker in India is $ 44 PMT almost equivalent to the selling price of Cement. It is a well known fact that Clinker gives cement the early strength while the pozollan the later age strength. In 1998 we re-commenced production of Cement with 65% clinker content balance being locally available pozollans. Our experiments to decrease the clinker content led to a cement with low one/three day strength which was unacceptable in the Indian Market. Rotary Clinker received at ABS Cement being packed THE BEGINNING
ACI-Effect of fineness on cement The startling finding that the one/three day strength increases almost three fold if the fineness of cement goes up from 2500 blaines to 4500 blaines( provided we maintain the desirable residue) was an important breakthrough. “The effect of fineness on cement” was published online by the American Concrete Institute in 1999.
Cement Fineness Cement Fineness As our cement mill is designed for manufacturing cement at a maximum fineness of 3500 blaines further R&D was required. With trial & error we achieved our bench mark. Eight major changes had to be made to our cement mill to achieve the required fineness. These changes included 1. Installing an on line Jaw crusher, 2. Tinkering with the RPM of the cement mill, 3. Changing Grinding media distribution etc etc. On Line Jaw Crusher at ABS
FLY ASH FLY ASH The only world class pozollan available near us was Class F Flyash containing less than 1% Carbon Fly is priced at a reasonable $8 PMT. This fly ash became the natural ingredient around which our research evolved. In1999 ABS trial marketed fly ash blended cement with 32% fly ash content. Indian standard IS: 1489 permitted a maximum of 25% fly ash content in cement. It was on our letter that the IS: 1489 was AMMENDED to allow 35% fly ash addition in cement in 2001. It was on our letter that the IS: 1489 was AMMENDED to allow 35% fly ash addition in cement in 2001. We realized that if our technique was adopted the world can gainfully utilize 400 million tons of fly ash per year in cement alone. Class F Fly Ash with 1% Carbon Note the colour is off-white
Introduction of a pozollan is a time consuming affair as any material requires at least 6 months of extensive laboratory testing & field trials. Emboldened we extended our research to calcined clay, & low grade limestone & their usage in cement. Our discussions with Bureau of Indian Standards (BIS), National Council For Cement & Building Materials (NCCBM), & the FLY ASH MISSION also paved way for the allowance of addition of low- grade raw limestone up to 5% in OPC cement. Further amendments including the allowance of more performance improvers in cement are under consideration. Crushed Brick bats Crushed Limestone Calcined Clay & Limestone
Cement Manufacture is all about incoming & outgoing freight. Cement being an inexpensive commodity. Addition of GGBFS was out of question as the landed price was $32 PMT. We settled on air cooled slag from a local mini steel plant that was free excepting for the freight of $5 PMT. Although worldwide research on Air Cooled Slag-for usage in cement is not documented, we realized we were on the right track. AIR COOLED SLAG Air Cooled SLAG
Alkali Activated Slag & Additives To increase the one day strength we activated the slag by lime sludge etc. Further activators/accelerators were added. The Clinker/Cement ratio in 2002 stands at 52%.down from 65% three year ago. Research being a continuous process we hope to bring down the ratio by four percentage point this year to 48% by Sept this year. Thanks to Blended Cement, ABS has since repaid all outstanding loans to financial institutions. The 500 tpd Nirmaan Cement appointed us consultants to improve cement quality & decrease their clinker ratio in 2001. Lime sludge Additives & Accelerators being added
Consistency in Cement ABS cement now had 7-8 pozollan/additives. We introduced the weighbridge system so that each ingredient could now be weighed for producing a cement consistent in quality.
CEMENT INDIA CEMENT INDIA The Journal Cement India showcased our cement for two years running on its website www.cementindia.net www.cementindia.net Several articles on blended cement and fly ash of ours were published by Cement India. At ABS our quest to produce better cement has just started…….