Construction machinery sales hits cement plants

 

Jaw crusher sales from Kobelco Construction Machinery division were -18% from JPY 97.7 billion (US$ 1.25 billion) to JPY 80.1 billion (US$ 1.02 billion), while revenues for Kobelco Cranes fell -19% from JPY 11.8 billion (US$ 151 million) a year ago to JPY 9.5 billion (US$ 122 million).
The first important reaction to occur is the calcining of limestone (calcium carbonate) into lime (calcium oxide) and carbon dioxide, which occurs in the lower-temperature portions of the kiln–up to about 1650°F (900°C). The second reaction is the bonding of calcium oxide and silicates to form dicalcium and tricalcium silicates. Small amounts of tricalcium aluminate and tetracalcium aluminoferrite are also formed. The relative proportions of these four principal compounds determine the key properties of the resultant portland cement and the type classification (Type I, Type II, etc.). These reactions occur at very high temperatures with the ingredients in molten form.Kobelco's sales of construction equipment totalled JPY 89.6 billion (US$ 1.15 billion) in the first quarter of the fiscal year from April to June, a -18% decline on the same period last year. The company said that despite improved demand elsewhere in Asia, the slowdown in China had hit its jaw crusher sales. It added that demand for crawler cranes was up, but a move towards smaller models had seen revenues fall.
As the new compounds cool, they solidify into solid pellet form called clinker. The clinker is then ground to a fine powder, a small amount of gypsum is added, and the finished cement is bagged or shipped bulk to ready mix concrete plants.
Demand for equipment to help reconstruction efforts in Japan increased domestic sales of both jaw crushers and cranes in the first quarter, and Kobelco said demand was also strong in South East Asia. However, it saw a fall in jaw crusher sales in China compared to a year ago. "Monetary tightening in China, a major market, caused unit sales to go down sharply in comparison to the same period last year, when demand was strong after the Chinese Lunar New Year," the company said in a statement.
Concrete is produced by mixing cement with fine aggregate (sand), coarse aggregate (gravel or crushed stone), water, and–often–small amounts of various chemicals called admixtures that control such properties as setting time and plasticity. The process of hardening or setting is actually a chemical reaction called hydration. When water is added to the cement, it forms a slurry or gel that coats the surfaces of the aggregate and fills the voids to form the solid concrete. The properties of concrete are determined by the type of cement mill used, the additives, and the overall proportions of cement, aggregate, and water.