Embed Size (px)
Citation preview
AIB 011
Manufacturing Sand and Aggregates forConcrete in India
Historically, a large percentage of sand has beenproduced from alluvial deposits. However we are nowexperiencing a global shortage of natural sand, andenvironmental pressures, costs and a shortage of thistype of deposit has necessitated the manufacture of sandfrom quarried material.
One of the problems often experienced with naturalsand is the presence of contaminants, which can be verydifficult to remove.
These contaminants may be silt, organic matters andsometimes, harmful chemicals, such as sulphates andchlorides, all of which can have significant detrimentaleffects on the performance of structural concrete.
Manufactured sand, on the other hand, comes directlyfrom good quality virgin rock, and thus very few, ifany contaminants are present.
Case Study
An Indian company was designing a dry crushing plantto produce concrete aggregate and manufactured sandfrom basalt rock.
Their major concern was to find a crushing technologywhich would enable them to manufacture sand that wasof a high enough quality for use in concrete.
Proposal
Metso Minerals proposed the installation of a BarmacVSI crusher as a tertiary stage crusher, to process theproduct from the primary and secondary jaw crushers.
Solution
The Barmac crusher was installed in closed circuit witha screen to crush minus 25mm material, giving twoproducts; 12 - 4.75mm and 4.75 - 0 mm.
The plant has a capacity of 30-35 tph of sand and 15-20tph of minus 12mm aggregate.
ConclusionThe final sand product from this plant is of aconsistent high quality, has good equidimensionalshape, and falls well within specification. In fact,following test work, the producer has confirmed that:• Concrete made using Barmac sand is more
cohesive, has an increased density (making it moreresistant to chemical attack) and performs bettergenerally than an equivalent concrete made withnatural sand.
• The sand has been successfully tested for structuralconcrete, plaster first coat, mortar and concreteblocks.
• Water demand to get the equivalent workability toa natural sand concrete is lower.
• Cement consumption is reduced by 10-15%.• Barmac sand is, in fact, 17-18.5% less expensive to
produce than the local natural sand.
Further BusinessThis installation has created considerable interest inthe Barmac for manufacturing sand. In fact, it haspaved the way for some very significant Barmac salesinto the industry.
Major Benefits To The Concrete Industry
Natural sand is a product of many thousands of years of erosion. However, the Barmac VSI crushersimulates the particle size reduction and shaping that occurs in nature, using a unique rock-on-rockcrushing action. The Barmac grinds and mills the feed material to produce a fine product with nocontamination from wear parts. As the material fed into the Barmac grinds and impacts against itself,the typical wear cost per tonne of material processed is very low.
Manufactured, or Barmac Sand is being successfully used in the production of high quality concreteand asphalt around the world. Its superior shape puts it well within specifications imposed on sand foruse in concrete production.
Barmac Model Selected
• B6000 Barmac VSI• 110kW [150 hp]• Throughput: 93 tph• Material: Basalt• Work Index: 22• Feed: –25mm• Products: –12 +4.75mm and –4.75mm• Rotor tip speed: 62 m/s• Circulating load: 50 tph
0
10
20
30
40
50
60
70
80
90
100
0.01 0.1 1 10 100
Sieve Size (mm.)
Cum
% P
assi
ng
Barmac ProdScreen U/S
Barmac VSI crushers are also used in the industrial minerals, mining, recycling and general quarrying industries. A wide rangeof materials are processed through Barmac crushers worldwide. For more information on this or any other Barmac application,please contact your nearest Barmac representative.
AIB 011 – 1 – 4/99
Metso Minerals (Matamata) LimitedMangawhero Road, Private Bag 4071,Matamata, New ZealandTel. +64 7 881 9060, fax +64 7 888 [email protected]
������������� ��
������
��������������� ��
�������������������������������� ��
!������!"###��#�$�%� #� �&'����������������"���(�
))��� *��� ��
����� �����+���� ��� ��
#���
