Extracting corrosive salt in large quantities

Customer:	Esco
Extracted material:	Salt
Industry:	Food
Vacuum cleaner:	DS 4150 with 200 l-pre-separator

White is the dominant colour at the production facilities of the esco Group. The abbreviation stands for “European salt company”. The company, which mines around 5 million tons of rock and evaporated salts annually, merged with its co-owner K+S in 2019 to form K+S Minerals and Agriculture GmbH.

Problem

Around 400 employees of esco, now K+S Steinsalz, mine rock salt in Bernburg / Saxony-Anhalt. In total the site produces around 2 million tonnes of solid salt last year. Since it deals with such large quantities, there is no way to prevent salt from collecting on the floors of the multi-story processing system where the raw materials are crushed and classified.

To clean the facility efficiently, the effects of gravity are put to good use: waste material from the production area is swept through "brush chutes" installed on each floor and collects in a large-capacity container on the ground floor of the building. To collect the sale on the individual levels of the wide-ranging production facility, a powerful industrial vacuum cleaner was essential. It also needed to be able to deliver a long service life, since salt is so highly corrosive.

Solution

After testing different vacuum cleaners, the managers chose a device from Ruwac. Because a single vacuum cleaner could not handle the large quantities of relatively heavy extracted material alone, Ruwac suggested combining a pre-separator silo with a very powerful type DS 4150 industrial vacuum cleaner.

The material is initially collected in the pre-separator made from strong but lightweight glass fibre-reinforced plastic (GRP), which traps the larger particles. The pre-separator has a capacity of around 200 litres and is fitted with a level sensor as well as a customised discharge tube to allow the existing brush chutes to be used. This allows the operator to vacuum the majority of the salt without using the filter of the actual vacuum cleaner itself.

In addition, this efficient two-stage process makes handling easier, because the operator only needs to move the GRP pre-separator, while the vacuum cleaner itself, which because of the two 7.5 kW drive units is much heavier, can remain more or less in one position. The “two-piece” system can be transported from floor to floor using the cargo elevator without requiring much strength, and the rust-resistant GRP construction of the pre-separator and vacuum cleaner allow them to be used daily in salt production.