Salinen Austria AG is one of Europe’s leading salt suppliers. The company’s most important products include brine for the chemical industry, food, industrial and melting salt, and chemically pure salt for pharmaceuticals. Three sites (Bad Ischl, Hallstatt, Altaussee) produce more than 3 million cubic meter of brine. Because of this, Austria is one of the most important salt producers in Europe. Salinen Austria AG contracted with Altmayer Anlagentechnik to construct a system that would be used to transfer tailing piles from the brine purification process used in the production of evaporated salt into the caverns. The tailing piles from the brine purification process are to be used to pack the salt cavities that have been created.
The method is, on the one hand, highly ecologically conscious in the sense of closed loop waste management, and, on the other hand, packing excavated caverns increases the stability of the underground works. The packing material is delivered by truck at a dry weight of approx. 70 % and unloaded into hoppers. Using walking floors and screw conveyors the packing material is conveyed into a mixing container. It is mixed with the brine removed from the mine to form a homogenous solution with approx. 30% dry matter.
A hydraulic, quadruple-action piston membrane pump (HMQ series- Fig. 1) pumps the packing material out of this hopper at an internal design pressure of 40 bar and a capacity of 6 to 45 m³/h into the mine via a pipeline that is about 2.5 km long. The mined caverns are then refilled with the packing material. Once the suspension has had time to settle in the caverns, the brine is pumped back up to the surface and is again used for mixing. In contrast to solids handling pumps, a piston membrane pump is ideally suited for abrasive, liquid media. For this reason, the HMQ is ideal for conveying the packing material in this application.
Due to the high salt content of the packing material, the suction and pressure lines, as well as the cone valve housing and pump housing, are made of stainless steel, so that the pump parts that come into contact with the product do not corrode.
The integrated reversing valves are suited for use with the pumped medium and the process pressure. The reversing valves are installed in such a way that the medium’s direction of flow through the pump is “reversed” (Fig. 2). The normal direction of flow for piston membrane pumps is from bottom to top; in this case, the medium flows from top to bottom. The advantage gained through reversing valves is that the medium is pumped in the same direction of flow in which sedimentation may take place. This means that larger particles cannot lodge in the product valves and the membrane housings, and possible damage to the membrane can be avoided.
The HMQ pump uses an intelligent membrane pulsation damper (Fig. 3). The iMPD damper automatically adapts to changing operating pressures, providing low residual pulsation over the entire pressure range. The iMPD automatically adapts to the actual operating conditions through the use of a piston compressor.
The performance range of Abel HMQ pumps goes up to 500 m³/h, for media up to 10.0 MPa. Main applications are
- Conveying suspensions
- Feeding filter presses
- Treating water
- Conveying ore and ash
- Desulphurisation of flue gas