After the success of the first Maerz PFR kiln in the Calidra Group at Cal Química Mexicana in San Luis Potosí, Calidra decided to expand its plant in Acajete near Puebla. In 1998, the order was placed for two identical natural gas-fired PFR kilns, each with a production capacity of 400 t/d - at that time still with a refractory lining with pillars to support the arches. 5 years later, these two kilns were upgraded with a firing system for petroleum coke in order to have more flexibility in the choice of fuel.
The second step followed one year later: in order to increase the output of the quarry, two identical PFR kilns were again installed - this time in the Finelime® version with a capacity of 300 or 400 t/d (depending on the grain size) and this time also with a dual firing system for natural gas and petroleum coke.
But that is not all: in 2008, the last capacity expansion for the time being took place with the construction of a 600 t/d PFR kiln of the type R4S, which can also be operated either with natural gas or pulverised petroleum coke.
As a dynamic company, Calidra attaches great importance to technological leadership and economic efficiency: in the recent past, for example, a firing system for wood dust was installed in the oldest kilns and the kiln control system was upgraded to the latest state of the art - including a quality controller to support the kiln operators.
Recently, Calidra was also the first lime plant in the world to take a further step towards saving energy: the installation of a high-pressure fan instead of rotary piston blowers for the compression of combustion and cooling air recently went into operation successfully. The set target of saving 20% of electricity consumption was easily achieved.