The REFRAJET® Addmix system injects a liquid binder into dry refractory materials during spraying to improve bonding and mechanical properties. It centrally injects a reactive aerosol into the dry material flow before adding a liquid binder via nozzle. This pre-wetting process reduces dust, rebound, and improves strength, density, and reduces porosity compared to traditional dry spraying. The system works with standard spraying equipment and improves properties of cement-free refractory concretes like REFRAJET® Nanobond types.

1. REFRAJET® Addmix technology
The innovative injection system for
Nanobond dry gunning concretes.

2. REFRAJET® Nanobond accelerator
Pump
Pump
Gunning nozzle
Dry material without
binding additive
Air
Air
Must be used
without water!
Gunning unit
Liquid binder No. 1
Pre-wetted material
REFRAJET®
Addmix nozzle
Dry material without
binding additive
­REFRAJET® Addmix
Innovative injection system for cement-free dry gunning concretes
Principle of the injection system
REFRAJET® Addmix is an innovative
injection system from Refratechnik
that optimizes the conventional dry
gunning procedure. REFRAJET®
Addmix was developed specifically
for the installation of cement-free
sol-gel bonded refractory con-
cretes of the type REFRAJET®
Nanobond.
The dry component REFRAJET®
Nanobond contains neither binding
agents nor any other chemically re-
active components, and therefore
consists exclusively of refractory
aggregates.TheREFRAJET®Addmix
injection system is positioned
immediately downstream of the
gunning unit.
It creates a reactive aerosol that is
injected centrally into the flow of
dry material. Hereby, the aerosol's
volume and concentration are
pre-defined. At the end of the con-
veying pipe, a liquid binder – e.g. a
silica sol – is added to this pre-wet-
ted and now reactive dry material
by means of a conventional nozzle
system.
Pre-wetting the concrete ensures
simpler final homogenization with
many advantages such as e.g. less
material rebound and significantly
reduced dust problems in the
nozzle. Moreover, REFRAJET®
Addmix improves the mechanical
properties of the cement-free
concretes involved.
Cold crushing strength and cold
modulus of rupture are increased,
and porosity is reduced. In
­addition, this injection system
permits denser processing.
Apart from the cement-free
gunning mixes of the REFRAJET®
Nanobond types – for which the in-
jection system provides significant
property optimizations compared
with the standard procedure –
­REFRAJET®Addmixcanalsobeused
for other Refratechnik concretes,
if the injection method is suitably
adapted.
REFRAJET® Addmix injection system for cement-free gunning mixes of the REFRAJET® Nanobond type.
3©Refratechnik Steel GmbH

3. CMR[N/mm2
]
25
30
20
15
10
5
0
Cold modulus of rupture
REFRAJET® Addmix conventional system: with binding additive in the dry material
Firing temperature [°C]
110 800 1000 1200 1300 1400 1500 1600
CCS[N/mm2
]
Firing temperature [°C]
120
140
100
80
60
40
20
0
110 800 1000 1200 1300 1400 1500 1600
Cold crushing strength
REFRAJET® Addmix
Properties and application
The material
• The dry material has a practi-
cally unlimited storage life, and
requires no special marking,
as it is manufactured without
chemical additives or binders
• Bonding strength and layer
thickness on refractory surfaces
can be adjusted and varied
without any problems
• Product properties are signifi-
cantly improved:
• Bonding on worn refractory
surfaces is greatly improved
• Pre-wetting the concrete
results in a denser concrete
structure with reduced
porosity
• Compared with the standard
procedure, cold crushing
strength and cold modulus
of rupture can be increased
significantly
Processing
• Pre-wetting by means of a
centrally injected aerosol
greatly reduces the risk of hose
blockages
• Dust generation is also reduced
noticeably – particularly during
overhead work
• Material rebound is also reduced
clearly
• Fine particle activation is more
intense than with the standard
procedure
• The gunning operator is not
hampered additionally:
• He simply works as accustomed
with his standard equipment,
because the injection parame-
ters are adjusted by the injection
machine operator via the system's
control unit.
REFRAJET® Addmix nozzle
• The nozzle can be used with
practically every conventional
rotor injection machine
• All parts of the REFRAJET® Addmix
nozzle are easy to replace
• The injection of other liquids or
powders is possible
• In order to reduce dust gene-
ration and material rebound,
REFRAJET® Addmix can also be
used with hydraulically bonding
refractory concretes
REFRAJET® Addmix rig:
All operating elements are
mounted on a central control panel
The advantages of REFRAJET® Addmix at a glance:
With the REFRAJET® Addmix injection system, marked improvements in cold crushing strength
and cold modulus of rupture across the entire temperature range are achieved.
Comparison of strength development as a function of pre-firing
temperature using REFRAJET® Nanobond F-58 R as an example:
4©Refratechnik Steel GmbH

4. St1-047-09/2017
Refratechnik Steel GmbH
Schiessstrasse 58
40549 Düsseldorf
Germany
Phone +49 211 5858 0
Fax +49 211 5858 49
steel@refra.com
www.refra.com
St1-047-09/2017