Mixed Fertilizer Chemische Eigenschaften,Einsatz,Produktion Methoden
Landwirtschaftliche Anwendung
A mixed fertilizer is any homogeneous product
containing two or more plant nutrients. It usually
contains two or more major nutrients. It is made
chemically, or by blending, or by both methods. A mixed
fertilizer may include micronutrients and secondary
nutrients.
Mixed fertilizers, which are also called compound
fertilizers or complex fertilizers or fertilizer mixtures,
are generally granular, free flowing and easy to apply
uniformly. They have a relatively high nutrient content.
Among examples of mixed fertilizers are
nitrophosphates
Fertilizers may also be physically mixed, with or
without an inert material necessary to make up the
required grade, and without allowing a chemical
reaction.
The physical mixture of a fertilizer is generally
classified as homogeneous or heterogeneous. In
homogeneous mixtures, the molecules are interspersed,
as in a mixture of gases or in solution. Heterogeneous
mixtures have distinguishable phases, like in a mixture of
iron filings and sulphur. Unlike compounds, mixtures
can be separated by physical methods like distillation,
crystallization, etc.
Fertilizer solids of different densities and sizes are
mixed in a double-cone blender or with agitators for a
defined period; mixing for too long or too short a period
causes the components of the fertilizer mixture to
separate and this must be avoided.
Mixed salts production during ammonium
sulphate manufacture
Mixed salts of ammonium sulphate and ammonium
nitrate are made by ammoniating a mixture of sulphuric
acid and nitric acid or by combining these ammonium
salts in special ways to form three double salts identified
below:
NH
4)2SO
4.NH
4NO
3, (NH
4)
2SO
4.2NH
4NO
3,and (NH
4)2SO
4·3NH
4NO
3
One German process produces
containing 62% ammonium sulphate and 38%
ammonium nitrate, by ammoniating the requisite mixture
of sulphuric and nitric acids. The mixture is evaporated to
a moisture content of 3 % About 1 % ferrous sulphate is
added to prevent caking. The double salt is granulated
after spraying ammonia solution.
In a simpler process, ammonium nitrate solution is
evaporated to 95% concentration, cooled to 130°C and
reacted with solid ammonium sulphate in a pug mill
granulator until a pH of 4.0 is attained. The product is
then dried, cooled and bagged. Prilling can also be
adopted.
The TVA (Tennesse Valley Authority) produced
ammonium sulphate-ammonium nitrate contains 30 %
nitrogen. It is used mainly for sulphur-deficient soils.
This product is also made by ammoniation of a mixed
acid followed by pan granulation of the resulting slurry.
Its storage properties are superior to those of ammonium
nitrate or a mixture of solid ammonium nitrateammonium
sulphate since free ammonium nitrate is
absent.
When mixtures of sulphuric acid and phosphoric acid
are ammoniated, a variety of mixed and double-salt
products can be made. One of the popular compositions is
'ammophos' containing 16% nitrogen (N) and 20%
phosphorus (as P
2O
5). The ammoniated slurry is
granulated in a pug mill or a drum unit, dried and
screened. The mixed salt has good storage properties
under normal conditions.
Many methods have been developed to recover
sulphur from flue gas, involving scrubbing with
ammonia or injection of ammonia into flue gas. From
these reactions, ammonium sulphite, bisulphite, sulphate
and their mixtures result. Because the demand for
ammonium sulphate fertilizer is low, the sulphur from
the flue gases is disposed of as calcium sulphate.
Mixed Fertilizer Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte