Replacing Sand

Sandvik rock processing is offering a natural solution for tackling the problem of replacing natural sand with manufactured sand for concrete applications.

According to the company, practical experience has shown it is hard to replace natural gravel with conventionally crushed ballast. Problems arise in the filler parts of the sand - particles under 2 mm. It has therefore developed an analysis method that quantifies the ‘desirable properties’for a manufactured material to be able to replace natural gravel.

“In the production of concrete sand, Sandvik uses the Merlin-VSI autogenous crusher, with the Hurricane rotor. This combination provides the unique properties that very closely replicate the natural method of sand production,”said a company spokesman.

“Impact, cleavage and attrition of the stone particles produce good shaped grains right down to the mineral grain level. The Bi-Flow system also gives variable control of the product gradation, combined with higher crusher throughputs resulting in the lowest operating cost per tonne,”he added.

The directional Bi-Flow material, independent of the Hurricane rotor, is controlled via adjustment gates in a large hexagonal feed hopper and improves the grain shape by directing the Bi-Flow material into specific areas within the crushing chamber. This increases energised particle density and results in improved particle shape and production.

“Analyses of sand manufactured with the Merlin-VSI and Hurricane rotor shows it is possible to produce a material equivalent to natural gravel. This has been confirmed through grain shape analysis and tests of fresh concrete with manufactured sand,”said the spokesman.