Stone, Sand and Gravel REVIEW - May/June 2018 - 38
AGLIME MATERIALS, CHEMICAL COMPOSITION,
AND CALCIUM CARBONATE EQUIVALENT (CCE)
Burned or Quick lime
Hydrated or Slaked lime
Ground Oyster Shells
Cement kiln dusts
Power plant ashes
Byproducts & Biosolids
CaO (calcium oxide)
Ca(OH)2 (calcium hydroxide)
Ca, Mg & K Oxides
Ca, Mg & K Oxides
Particles between the 10 mesh X
50 mesh sizes are 50-percent effective
over a three-year period. Materials
larger than 10 mesh are considered
too large to dissolve within a three- to
four- year time period. The decision
of what mesh size to use depends on
how rapidly the farmer wants the full
value of Aglime to be realized.
Aglime Materials, Chemical
Composition, and Calcium
Carbonate Equivalent (CCE)
The second major factor that determines Aglime quality is chemical
composition. Chemical composition
determines an Aglime material's
amount of acid it can neutralize. Pure
calcium carbonate (CaCO3) has an acid
neutralizing value of 100 percent.
When an Aglime material is evaluated, it is compared to calcium carbonate, and its neutralizing value
is called the Calcium Carbonate
Equivalent (CCE) value or percent CCE.
To sell Aglime to different regions, review the state
requirements for percentages
passing the different mesh sizes
and the calculation required to
provide the required Calcium
pin spacing and cage speeds. Cage
mills have lower maintenance than
a hammer mill. HP/ton ratio is
approximately 7:1 and produces a
Particle Size Distribution (PSD) that
passes most state specs without
screening. Cage mills handle moisture
well because there are no screens or
Hammer Mills. Final product size
is typically controlled by grate bars or
perforated screens, which can be high
maintenance because of the many
hammers and grate bars or screens to
replace. The highest HP/ton ratio is
approximately 10:1. It doesn't handle
moisture well due to blinding of the
screen/grates and it cannot handle
Types of crushing
methods used for Aglime
The primary crushing method
used is impact with Cage Mills,
Hammer Mills, and Vertical
Shaft Impactors (VSI).
Cage Mills. Final product size is controlled by
38 STONE, SAND & GRAVEL REVIEW, May/June 2018
Vertical Shaft Impactors (VSI).
Final size is controlled by rotor speed,
but a VSI can't grind fine enough to
pass some state Aglime specs and
requires screening after crushing.
HP/ton ratio is approximately 3:1 with
high throughput. Moisture can cause
Where should I start?
Determining the chemistry of your
material's Calcium Carbonate Equivalent
(CCE) is the place to start. You will need
to determine the amount of Aglime
material required to equal one ton of
pure calcium carbonate. For example;
if your material is Dolomitic Limestone,
with a CCE of 95, the rate per acre
equivalent to Calcitic Limestone, with
a CCE of 100, would be 1.05.
Testing your feed material is the next
step and should determine the following: feed size (PSD), energy consumption (horsepower per ton per hour or kW
per ton at the target PSD), wear metal
estimate per ton of throughput and finished product particle size distribution.
In conclusion, the production of
Aglime can be achieved in many ways,
and each operation will have its own
set of specific requirements that influence final production. When deciding
what crusher type is best for a specific
operation, it is important to consider
the following: local market conditions, state specifications, existing
equipment and facilities, maintenance
requirements, total power consumption and existing capacity, and auxiliary capital equipment.
Agronomists in many states can
help evaluate the economics of soil
chemistry and how Aglime can be used
to reduce fertilizer use, improve crop
yields and lower costs. Some states
may subsidize the use of Aglime.
Contact a local university extension
to learn about the use and incentives
in your region.
Eric Marcotte is the Inside Sales
Manager of Stedman Machine
Company, based in Aurora, Ind.
Stedman Machine Company,