Brine Production by Solution Mining
In solution mining, salt is extracted by forcing water under pressure into a bore-hole drilled into an underground salt bed or dome.
The salt dissolves, turning the water into brine and creating a cavern in the salt-bed. The brine is then pumped back to the surface and on to the evaporation process.
The result of this process is a stable underground cavity in the diapir, the existence of which will not imply any significant practical consequences to the environment from the chemical, hydrogeological and mechanical point of view.
This process is by far the cleanest and less damaging procedure to obtain salt from the diapir. The impact in the environment can be considered non-existent.
The technique usually targets salts at depths greater than 400-500m and down to about 2000m. JUMSAL´s current salt solution operations range from 600m to 1000m depth.
Three concentric pipes are used to operate the cavity using the central pipe to inject fresh water into the well.The water dissolves the wall and roof of the cavity producing brine which is pumped out using the annulus. Finally through the third pipe an inert fluid blanket is pumped in to control the growth of the cavity and the roof stability.
Insoluble elements are not swept along by the brine current and settled down to the bottom of the cavity.
The concentration of the brine obtained depends on the size of the surface exposed to the fresh water. Normally after a few weeks after commencing the solution mining, the brine comes out saturated carrying about 300g of salt per litre of brine.
Salt production from brine
The next process brine goes through is the crystallization of the salt out of the brine by evaporation of the water. In order to do that, JUMSAL uses two methods:
The first method would be Vacuum Plant evaporation in a Thermo-compression forced crystallisation plant, and the natural solar evaporation in crystallisers to be processed in the plant afterwards.
The mechanical crystallisation method with simple effect or thermo-compression is used to make high-purity salts. The procedure consists of reducing the pressure to diminish the point of evaporation until sodium chloride is recrystallised with the highest concentration. This way other dissolved salts; especially calcium sulphate, potassium chloride and magnesium chloride are reduced to the minimum.
The second method would be the crystallization of salt by Solar evaporation in open to the atmosphere ponds.
The solar salt needs further treatment in a Washing plant.The salt so obtained is classified and dried to obtain high-quality products that can be used in the food and the industrial sector.