History of cement in the world
Cement is a product including lime as the primary curing ingredient. Throughout history, it is seen that in the ancient world, ever since civilizations first started to build, cementing materials have always played the vital role and were widely used The Egyptians used calcined gypsum mortar as a binding factor for building structures like pyramids. The Greeks made further improvements and then the Romans developed cement that produced structures of remarkable durability. Most of the building foundations in the roman forum were constructed of a strain of concrete. The Romans succeeded in producing cement by mixing lime and pozzolana, a volcanic ash from mount Vesuvius. The process of mixing this together produced cement capable of hardening under water. In the eighteenth century Britain, the interests of industry and empire corresponded with the need to build lighthouses on exposed rocks to prevent shipping losses. The constant loss of merchant ships and warships drove cement technology forwards. From the turn of the 20th century, rotary cement kilns gradually replaced the original vertical shaft kiln’s, used originally for making lime. Rotary kilns heat the clinker mainly by radiant heat transfer and this is more efficient at higher temperatures, enabling higher burning temperatures to be accomplished. Also, because the clinker is constantly making a motion within the kiln, a fairly uniform clinkering temperature is achieved is the hottest part of the kiln, the burning zone. Over the centuries the cement has played a major role in different countries and its purposes.
History of cement in Nepal
The use of cement in Nepal as a mandatory material came into upshot from the commencement of early 1950’s. As no native cement manufacturing industry existed, early users of cement were dependent on imports from India and to meet their demands. Progressively, around 1965 the supply of cement was started to import in commercial scale only in the early 1970’s it was imported from countries like China, South Korea, North Korea, Burma, Indonesia, Thailand, Japan, Hong Kong and many other states. In 1975 the first cement plant, Himal Cement Company Limited came into existence as being to provide Nepal’s first state- owned cement-manufacturing facility. Its production capacity initially was 160 tpd. But the company was dissolved in 2002 due to environmental cause. At present, the cement company has outgrown to be one of the largest companies and manufacturers with high competition and quality.