Production Process

Grinding the limestone and shale.

Grinding limestone and shale taken from the quarries is done next to the source, and then transported in trucks to the storage area.

Storage Area

The raw material’s Storage Area includes a single warehouse divided into two sections to store different materials (limestone, shale, sand, pyrite and calcium sulphate) in piles stretching lengthwise. It is covered to avoid emitting dust into the atmosphere and to protect the material from atmospheric conditions.

Milling the material

The purpose of milling is to reduce the size of raw material’s particles in order to properly execute the chemical reactions in the kiln. A conveyer belt gathers the materials once weighed, to be taken to the mill.
The plant has a vertical roller mill to mill, dry and separate the material.
The material leaving the mill is call "powder" which is stored in closed silos and later taken to a homogenising process which introduces air pressure through the base of the silo.

Producing clinker

The raw powder is entered into a heat exchanger where the progressive heating process takes place, reaching 1,000 ºC. The raw material is heated with kiln gases before actually entering it, this way it does not have to be inside so long, thus saving energy.
Inside the heat exchanger the gas transporting the raw material rises through a strong suction fan which simultaneous reduces the gases temperature and raises the materials.
With all of this inside the heat exchanger, the material’s limestone is 95% decarbonised.
Within the kiln, the material continues increasing in temperature until reaching 1,450 ºC, which is the necessary temperature to properly make cement.
The kiln output, clinker, looks like rounded granules and is cooled with air cooler than 120 ºC.
Clinker is the basic product for manufacturing cement. In some cements, clinker may make up to 95% of the product.

Storage and Delivery

From the cement mill circuit there is transport to any of the four silos for cement storage, each with a capacity of 7,500 each. The silos have an airing system that allows the cement to flow.
Under each silo a loading hose and scale has been installed for loading tank trucks in bulk.
Moreover, cement can be extracted from the central silos and transported through a system of transports and elevators, until being sacked.

Sacking

The sacking plant is a specially designed warehouse for storing and shipping. It has a 12-spout rotating sacker, with a 4,000 sacks per hour production capacity.

Between the sacker and the pallet loader, all within a sack transport circuit, there is a sack cleaning device and another scale which discards incorrect weights.

Once the material is stacked on a pallet, it is stored in the warehouse to be shipped.