31 March 2006
Further German comments
on the
General technical guidelines for the environmentally sound management of wastes
consisting of, containing or contaminated with persistent organic pollutants (POPs)
At OEWG4, comments on the updating of the general technical guidelines on POPs were
invited.
Para. 118: Insert the following at the end:
“R4 Recycling/reclamation of metals and metal compounds, but restricted to
activities of primary and secondary metallurgy”
Rationale: The operation R4, but restricted to activities of primary and secondary metallurgy,
should be listed because it is possible that the POP content of wastes is destroyed or
irreversibly transformed according to Article 6 of the Stockholm Convention. Accordingly, the
R4 process “Thermal and metallurgical production of metals” is suggested below. In
particular, according to the European Reference Document on Best Available Techniques in
the Non Ferrous Metals Industries of December 2001, the Reference Document on Best
Available Techniques on the Production of Iron and Steel of December 2001 (currently under
revision) and the Draft Guidelines on best available techniques and provisional guidance on
best environmental practices relevant to Article 5 and Annex C of the Stockholm Convention
on Persistent Organic Pollutants of December 2004 metals may be recycled environmentally
sound. POPs contained in the feed materials are destroyed, the de-novo-formation is
restricted, the flue gas may be cleaned and the emissions are comparable with that of modern
incineration plants.
After para. 269, insert the following:
“(j bis) Thermal and metallurgical production of metals
269a. Process description: Non ferrous metals (NFM), e.g. aluminium, copper, zinc, lead
and nickel, are produced from ore concentrates as well as from secondary raw materials
(intermediates, wastes). There are lots of different production processes, which use
either thermal or hydrometallurgical technologies. Usual smelters in thermal production
are rotary furnaces, flash smelting furnaces, electric or electric arc furnaces, shaft
furnaces, hearth furnaces, converters, bath smelting furnaces, etc. In any case the
thermal production of NFM needs temperatures of about 1200 °C to smelt not only the
metal but also the mineral constituents of the raw materials. By this means, the molten
material separates into a metal phase (or in the case of sulfidic ores a matte) and a
mineral phase (slag). Details are described in the Reference Document on Best Available
Techniques in the Non Ferrous Metals Industry1 and in the Draft Guidelines on Best
Available Techniques and Provisional Guidance on Best Available Practices in the
Framework of the Stockholm Convention on Persistent Organic Pollutants2.
Ferrous containing wastes are charged to a blast furnace, a shaft furnace or the so called
PRIMUS production. All these processes are reduction processes at high temperatures.
The molten iron has a temperature of about 1450 °C. The high temperature is
destroying PCDDs and PCDFs and together with the reducing conditions in the process
there are no PCDD/PCDF creating conditions. The blast furnace process is described in
1
BREF Document (December 2001), various chapters
2 See Draft guidelines (31 January 2005) Section V, Chapters V.D. and VI.B.
...
-2the Reference Document on Best Available Techniques on the Production of Iron and
Steel3.
The blast furnace and the shaft furnace reduce the Fe-containing input by coke or small
amounts of other reducing agents to cast iron. The process gas is used as secondary fuel
in production combustions or in power plants. Therefore the process gas is de-dusted.
The settled out dust is recovered in the non-ferrous metal production. Direct gas
emissions of blast furnace or shaft furnace processes do not appear.
In the PRIMUS process the pelletised Fe-containing material is charged to a multi
hearth furnace together with coal as reduction carbon. The iron oxide is directly
reduced in the solid pellets. In a second step the reduced iron is molten in an electric arc
furnace to produce the cast iron. The off-gas of the multi hearth furnace is de-dusted by
a cyclone, underlies a post-combustion, is quenched and cleaned by addition of
adsorbant and a bag filter. The off-gas of the melting furnace also underlies a postcombustion and is quenched before it is mixed up with the off-gas of the multi hearth
furnace for the joint adsorbance step.
269b. Efficiency: Due to the conditions described above POPs entering the process with
feed material or fuels will be efficiently destroyed. Nevertheless data on DE or DRE are
not available.
269c. Waste types: Zinc containing filter dusts from steelworks, dusts from gas cleaning
systems of copper smelters etc. may contain PCDDs and PCDFs and are valuable
secondary raw materials for the production of waeltz oxide (crude zinc oxide) and
copper. Mineral oil containing PCB may also be used in special cases.
Wastes from iron and steel making processes as dusts or sludges from gas treatments or
other Fe-containing wastes as mill scale may contain PCDDs and PCDFs and are
recycled to iron making processes if the Fe-content is high enough and no other contents
disturbing the production facilities are included.
269d. Pre-treatment: Special pre-treatment of POP containing materials is commonly not
necessary for non- ferrous metals.
Using the conventional blast furnace for recycling, the Fe-containing materials have to
be sintered in a sinter plant. This process is described in the Reference Document on
Best Available Techniques on the Production of Iron and Steel as well as in the Draft
Guidelines on Best Available Techniques and Provisional Guidance on Best Available
Practices in the Framework of the Stockholm Convention on Persistent Organic
Pollutants.
For the shaft furnace (Oxycup furnace) the Fe-containing waste is briquetted. The
briquetting is a cold process in which a binder and water is added to the fines, they are
pressed to briquettes, dried and hardened. There is no PCDD/PCDF emission of this
process.
269e. Emissions and residues: In non-ferrous metal production emissions may include
inter alia sulfur dioxide, nitrogen oxides, metals and their compounds as well as PCDDs
and PCDFs which may be formed within the process or downstream in the waste gas
system under certain conditions (de-novo-synthesis). Application of BAT should,
however, take these factors into account and effectively prevent, minimise or render
them harmless. Emissions of PCDD and PCDF are between 0.1 – 0.5 ng TEQ/Nm3 and
3
BREF Document (December 2001), Chapter 7
...
-3often below 0.1 ng TEQ/Nm3. Residues include filter dusts and slimes from waste water
treatment. Slags are in many cases products for construction purposes.
For ferrous metal recycling emissions can occur from sinter plant. The achievable
emissions from sinter plants are between 0.1 to 0.5 ng TEQ/Nm³ for adsorbance addition
followed by an electrostatic precipitator or by a bag filter. The PCDD/PCDF reduction
efficiency of the waste gas treatment is given with 98 %. The off gas treatment of
PRIMUS process reduces PCDD/PCDF emissions below 0.1 ng TEQ/Nm³.
269f. Release control and post-treatment: Process gases require treatment to remove dust
which consists mainly of metals or metal oxides as well as sulfur dioxide when smelting
sulfidic materials. Consequently, treatment includes the use of fabric filters, electrostatic
precipitators or scrubbers, sulfuric acid plants in non ferrous metal production etc.
Sometimes adsorption techniques with activated carbon are applied, preferably using
the adsorption process in order to minimize PCDD and PCDF. Primary measures to
minimize PCDD and PCDF formation are controls of temperatures and cooling
conditions.
It has been reported that PCDD and PCDF concentrations of some metals production
filter dusts reach in average not more than 15 µg I-TEQ/kg4. If recovery is not possible,
the dusts may require disposal in a specially engineered landfill or permanent storage in
an underground mine/formation. Slags do not contain any PCDDs and PCDFs (due to
their production conditions), values of about 20 ng I-TEQ/kg being reported may come
from airborne dust.
269g. Energy requirements: Most thermal production processes for NFM are energyintensive with significant differences between different metals. The treatment of POPs
within these processes does not require additional energy.
There is no POP related energy demand for recycling of Fe-containing wastes. Only the
special off gas treatment requires for some additional energy.
269h. Material requirements: For the thermal production of metals raw materials (ores,
concentrates or secondary material) are used as well as additives (e.g. sand, limestone)
and fuels (oil, gas, coal or coke).
269i. Portability: Metal smelters are large and fixed installations.
269j. Health and safety: The treatment of wastes within thermal processes can be
regarded as safe if properly designed and operated.
269k. Capacity: Many metal smelters have capacities above 100,000 tons per year.
269l. Other practical issues: None
269m. State of commercialization: Waeltz furnaces are designed for the processing of
PCDD and PCDF containing steel dust for zinc recycling and are well established
processes covered by BAT (www.bus-steel.com/index.html). Some other NFM smelters,
e.g. the KRS (Kayser Recycling System) use secondary copper raw materials, which may
4 See Final Report on the Study to facilitate the implementation of certain waste related provisions of the
Regulation on Persistent Organic Pollutants (August 2005), delivered by BiPRO to the EU-Commission
(europa.eu.int/comm/environment/pops/index_en.htm), page 134 ff
...
-4partly contain PCDD and PCDF (www.na-ag.com). A primary copper smelter uses PCB
contaminated oil as fuel.
Cast iron production from Fe-containing materials of iron and steel production in
conventional blast furnace is operating for years at DK Recycling und Roheisen GmbH
in Duisburg (www.dk-duisburg.de). The shaft furnace (Oxycup furnace) is operating
since 2003 at ThyssenKrupp Steel AG in Duisburg (www.thyssenkrupp.com). Both
processes are the same as hot metal production for steel making which is used for many
decades. PRIMUS process is operating in industrial scale at Differdange, Luxembourg
since 2003 (www.paulwurth.com).
269n. Vendors: Patents for technologies are mostly owned by the companies themselves.”
Rationale: The described process is another commercially available operation for the
environmentally sound destruction or irreversible transformation of the POP content in
wastes.