Quicklime and dry mortar

In several countries high-quality lime is not available. Producers of AAC, sand lime brick, and other lime products are in urgent need for high-quality lime.

The ideal lime for AAC production is “hard burnt” or “middle burnt”. This lime has a low reactivity (slaking time of 4 - 7 (12) minutes to reach a temperature of 60 °C). The low reactivity facilitates consistent and slow rising of the AAC mix in the mould.

The ideal lime for sandlime brick and hydrated lime production is “soft burnt” or “middle burnt”. This lime has a higher reactivity (slaking time of 1- 4 minutes to reach a temperature of 60 °C). The higher reactivity facilitates quick slaking and reduces volume and through-put time in the reactor (sand lime) or slaking machine (hydrated lime).

Consistent burning of all lime stones in the shaft kiln, i.e. consistent distribution of heat inside the whole cross section of the kiln.
•    Complete calcination of all lime stones.
•    Combustion of sulphur particles (only possible at high temperatures).

Important features of the shaft kiln
•    lowest possible kiln volume
•    low investment for steel structures
•    low investment for refractory
•    low height
•    low area for installation
•    adjustable burning temperature allows customized burning to requirement
•    use of heated cooling air during burning
     (the ready burnt quicklime is cooled by air)
     = most effective energy use
     = lowest possible energy consumption (approx. 30 – 50 % less than rotary kiln)

Kiln sizes
The following sizes are available:
•    50 t/day quicklime
•    100 t/day quicklime
•    150 t/day quicklime
•    200 t/day quicklime
•    300 t/day quicklime

All shaft kilns can be operated at a minimum of 50 % of above mentioned capacity!

This is important when the consumption is calculated. During winter some countries need less quicklime.

Dry mix mortar is a well-mixed blend of various raw materials and is supplied as a ready mix in suitable packs avoiding unused remainders.

Wehrhahn has developed dry mortar plants suitable for practically all demands, such as:

• proprietary adhesive and mortars for aerated concrete

• glue mortar for ceramic wall tiles

• masonry mortar

• skim coat

• inside plaster

• outside stucco

• concrete

• floor screed

Benefits for the builder

• Usage for many kinds of construction material, such as autoclaved aerated concrete (AAC), rock, calcium silicate bricks, masonry blocks, tiles, joints, etc.

• Application manually or with rendering/ plastering machines

• Available in paper bags or in bulk

Main components

Dry sand preferred with wide particle size distribu- tion (silt < 5 %), limestone powder (fine crushed limestone CaCO₃), AAC hard scrap

Binders

Cement (Portland cement, various qualities), white cement, hydrated lime, gypsum (requires separate handling)

Additives

• methyl-cellulose

• air-entraining additives

• synthetic resin

• hydrophobing agents improve adhesion, workability, abrasion strength, water retention, bending tension strength, frost resistance, etc.