Vietnam will invest $456m into changing technology from shaft kiln to rotary kiln for 20 cement plants.  The process is expected for completion in 2009 and the 20 plants will attain annual capacity of 6.54Mt, three times higher than their current capacity.   The Government will not allow building shaft kiln cement plants and targets to remove the old technology in Vietnam before 2020, said the Construction Material Department under the Ministry of Construction. Besides blast furnace plants, the Government will also not license any new independent cement grinding stations. All grinding stations must therefore use local clinker production and not be allowed to import clinker as before.   Published under Cement News