Non-ferrous MetallurgyCooling of hot and sticky dust-loaded process gases

Waste heat boilers in the non-ferrousindustry are usually designed as evaporationsystems based on the wide range of technicalstandards valid on a worldwide scale.

Oschatz designs waste heat boilers withtwo types of water-circulation systems:

■ combined natural and forced circulation (e.g. two-pass vertical boiler with convection pass),

■ forced circulation only (e.g. horizontal boiler).

The choice of the waste heat boiler type andwater circulation system depends on geometryand location of the process furnace outlet.

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Our Market is the World

At home in the worldOschatz – best technology backed by experience

Processes and solutionsWaste heat boilers for the non-ferrous metallurgical industry

Transport of a pre-fabricated waste heat boiler downstream flash smelting furnace in South Australia

Transport of two evaporatorbundles for horizontal wasteheat boiler section

Oschatz is a globally operating plantconstructor with over 160 years‘ experience,more than 1,400 employees as well as subsidia-ries, representative offices and branches aroundthe world. Our plants for cooling waste gasesand converting recovered heat into industriallyutilizable steam are used throughout the worldin the following industries:

■ Iron and Steel Metallurgy■ Non-ferrous Metallurgy ■ Chemical Industry ■ Power Plant Technology

Solutions for the non-ferrous industryFor decades, Oschatz waste heat boilers havebeen used worldwide for all production processesof non-ferrous metals such as copper, zinc, lead,nickel or tin. We develop tailor-made solutionsfor our customers based on the specific processdemands and needs for every plant and process,fully in line with the overall objective of maximiz -ing productivity and profitability.The hot and sticky dust-loaded process gases

and the various processes in the non-ferrousmetallurgy present a challenge for our gas cool -ing and heat recovery technology. But thanks tomost advanced production practices for wasteheat boilers combined with innovative cleaningsystems for effective heat transfer, safe and reli-able process waste heat boilers are produced.

Due to future-oriented solutions for the differ -ent processes, our customers have the opportu-nity – even after decades of operation – to in-crease the process capacity after simple andquick modifications at the boiler. All Oschatzplants are produced with most advanced technol -ogy so that they run optimally and very reliablyeven after thousands of operation hours.Depending on their destination, systems and

components are fabricated in our two modernproduction facilities in Kocaeli, Turkey, andNanjing, China. Needless to say, we comply withall quality standards, such as ISO 9001, the ASMEstandard, the Pressure Equipment Direc tive, AD,EU standards, etc.

On the basis of many years of develop-ment and experience Oschatz designsand manufactures:

■ membrane wall elements,■ evaporator/super-heater screens,■ evaporator/super-heater bundles/systems,■ wall, screen and bundle hammering systems,■ soot blowers for special cases.

The wide range of products available fromOschatz meets process requirements of thenon-ferrous industry all over the world. Oschatzcan ensure gas cooling parameters to meet thecustomers' demands, based on given gas inletconditions.

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Our Market is the World

Waste heat boilers downstream flash smeltingClean solutions for flash smelting of copper and nickel

Design range

Offgas rate 15,000 - 140,000 m3(STP)/hOffgas temperature at boiler inlet 1,250 - 1,400 °COffgas temperature at radiation chamber end 600 - 800 °CSulphation air 2,300 - 21,000 m3(STP)/hOffgas temperature at convection section end 350 - 400 °CFeed water temperature 105 - 140 °CSteam pressure 40 - 70 barSteam temperature 250 - 285 °CSteam rate 10 - 90 t/h

Waste heat boiler downstreamflash smelting furnace inOlympic Dam, Australia

Here the process gases are cooled with twowaste heat boilers. One boiler is installed down -stream the smelting furnace, the other boiler isinstalled downstream the electric furnace. The waste heat boilers are equipped with

mem brane walls, screens and bundles. To avoidcorrosion in the waste heat boilers the water/steam-side operating pressure is typically chosenbetween 40 and 70 bar. Depending on the SO2/SO3 concentration in the process gas it is thenassured that the temperature of the boilers'surfaces lies significantly above the sulphuric

Flash smelting of copper and nickel con-centrates takes place in a furnace with reactionshaft (Outokumpu flash smelting process). Theprocess gases are cooled in a special waste heatboiler. The products are traditionally processedfurther on in a converter. Another flash smeltingprocess is the Kivcet process for lead smelting.

Kivcet furnace withwaste heat boilers

Waste heat boiler assemblyin the workshop

Design range

Reaction shaft

Offgas rate 20,000 - 25,000 m3(STP)/hOffgas temperature at boiler inlet 1,200 - 1,300 °COffgas temperature at radiation chamber end 550 - 700 °COffgas temperature at convection section end 350 - 400 °CFeed water temperature 105 - 140 °CSteam pressure 40 - 70 barSteam temperature 250 - 285 °CSteam rate 20 - 40 t/h

acid dew point. It is imperative for the boilersurfaces to be kept as clean as possible in ordernot to exceed the maximum allowable gas tem-perature for the filter unit. Exactly for this pur-pose Oschatz has developed and patented ahighly efficient hammering system for the clean -ing of the boiler surfaces (see p. 10).The horizontal waste heat boiler downstream

Outokumpu flash smelting process consists ofa radiation chamber in which the gas is cooleddown to 600 °C – 800 °C and an adjacent con-vection part in which convection heating sur-faces are installed. For the Kivcet process eachradiation chamber of both boilers consits of twovertical shafts. Just like in the waste heat boilerdownstream Outokumpu flash smelting processthe convection part is horizontal, too. The typicalgas outlet temperature is approximately 350 °C.

The successful handling of the thermal expansionof the boilers in smelter conditions is an essentialfactor for maximum availability and avoidanceof leakages. This is achieved by flexible pendulumsupports that keep the boilers in position. Anadditional advantage of the pendulum supportsis that the boiler screens and bundles are essen-tially better accessible for maintenance works.

Flash smelting furnacewith waste heat boiler

Electric furnace

Offgas rate 5,000 - 10,000 m3(STP)/hOffgas temperature at boiler inlet 1,300 - 1,350 °COffgas temperature at radiation chamber end 550 - 700 °COffgas temperature at convection section end 350 - 550 °CFeed water temperature 105 - 140 °CSteam pressure 40 - 70 barSteam temperature 250 - 285 °CSteam rate 2 - 10 t/h

Originally, in the top submerged (TSL)lance smelting technology, the brick-linedfurnaces and hoods are surrounded by a watercooled jacket. Oschatz supplies a furnace shelland hood cooling that is integrated into theevaporation system of the waste heat boiler. These components are designed as gastight

welded membrane walls. In order to protect themembrane walls from excessive heat load, theyare equipped with studs on which a thin castablelayer is applied. The lifetime of these componentscomplies with the usual average lifetime of boilerpressure components. Compared to this, thebrickwork of an originally water cooled construc-tion needs to be relined at least once a year.In the top submerged (TSL) lance smelting

technology for the recovery of copper, nickel,lead, zinc and tin, the process gas has a temper -a ture range of 1,200 °C to 1,550 °C. The gas isdirected into a waste heat boiler to be cooled.During the cooling process dust propertieschange from the molten to the dry phase. De -pending on the concept of the whole plant, theprocess gas is cooled down to between 600 °Cand 900 °C in a two-pass vertical boiler or downto approx. 350 °C in a three-pass vertical/hori-zontal boiler. The dust is partly separated in thewaste heat boiler.

The further dust separation takes place in abaghouse or an electrostatic precipitator. When

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Our Market is the World

Waste heat boilers downstream ISASMELT processLance smelting and converting of copper, nickel, lead, zinc and tin

Waste heat boilers downstream Ausmelt processLeach residue smelting and fuming of zinc

saturated steam is not used, it iscondensed in an air cooled conden-sator which is installed above thesteam drum. While using recyclingmaterial, the acid dew point islower. Therefore a lower steam tem-perature can be chosen, too. The first part of the waste heat boiler uptake

is made even and smooth to prevent built-ups.This part can also be removed for access to thefurnace and boiler. An evaporation cooled furnaceroof operating above the acid dew point has alonger lifetime than water cooled roofs. A reliefdoor is arranged at the top of the furnace. It canalso be used as a pressure relief door to compen-sate small pressure fluctuations of the offgas.

Design range

Offgas rate 15,000 - 140,000 m3(STP)/hOffgas temperature at boiler inlet 1,200 - 1,550 °COffgas temperature at radiation chamber end 600 - 900 °COffgas temperature at convection section end 350 - 400 °CFeed water temperature 105 - 140 °CSteam pressure 40 - 70 barSteam temperature 250 - 285 °CSteam rate 10 - 90 t/h

Waste heat boiler downstream ISASMELT furnace in Mount Isa,

Australia

ISASMELT furnace with waste heat boiler

Design range

Smelting furnace

Offgas rate 15,000 - 120,000 m3(STP)/hOffgas temperature at boiler inlet 1,250 - 1,800 °COffgas temperature at boiler outlet 350 - 900 °CSteam pressure 30 - 70 barSteam rate 11 - 90 t/h

Fuming furnace

Offgas rate 5,000 - 80,000 m3(STP)/hOffgas temperature at boiler inlet 1,300 - 1,550 °COffgas temperature at boiler outlet 350 - 750 °CSteam pressure 30 - 70 barSteam rate 4 - 60 t/h

Two-pass vertical waste heat boiler

Ausmelt furnace with waste heat boiler

The engineering concept developed by Oschatzleads to significantly less shutdown intervalsresulting in significantly increased productioncapacity and therefore assures a better economicefficiency of the whole plant.

Our Market is the World8 9

Cyclone smelting and waste heat boilers for zinc residue and steel dust recycling

The metallurgical treatment of residues inthe non-ferrous metallurgical industry becomesmore and more important. Smelting in a cycloneis a future-oriented technology for the recoveryof metal contained in residues. This technologyhas been used for iron, lead, copper and zinc andis based on the CONTOP®-system. In the presentapplication the cyclone ser ves for recycling ofsteel flue dust and Zn re tort residues containingZnO and PbO.The steel mill dust and zinc retort residues

are wastes that contain Zn and Pb, other heavymetals, coal and slag formers (CaO, SiO2 andFeO). Dust and residues need to be cleaned anddeposited in an environmentally acceptable way.During the process the residues are melted toslag in a cyclone, Zn and Pb are fumed. Thefumed metals are post-combusted in a waste

Roasting of zinc, pyrite andcopper concentrates is carried outin fluidized beds. For this processOschatz supplies waste heat boilersincluding the coils for the fluidizedbeds. The hot roaster gases (800 to1,000 °C) with a high dust load (up to 400 g/Nm3)are cooled in Oschatz boilers to approximately350 °C.In general, these boilers are being equipped

with cooled tube walls, evaporation screens andsuper-heater screens. Because of the gas compo-sition of the process and the corresponding dustcharacteristics, a steady operation of the wasteheat boilers can only be achieved by highly effi-cient heating surface cleaning systems which donot require a shutdown of for the whole plant formaintenance purposes. Cleaning of boiler heatingsurfaces by the Oschatz hammering system hasbeen proven to be very successful. (see page 10)

heat boiler to oxides and recovered as dust fromthe gas flow. The gas cooling system for thesmelting and fuming cyclone and the waste heatboiler for this process have been supplied byOschatz. Only a small quantity of mechanicaldust results from cyclone smelting. As the cy-clones are connected to an evaporation system,the thermal load is better handled than with acooling water system, and the surface tempera-ture of the cooling tubes is always kept abovethe dew point of H2SO4 and HCI.

Benefits:

■ very high energy density,■ optimal reaction conditions and mass and heat exchange by high turbulence intensity,

■ reduced reactor dimensions with high throughput,

■ high smelting temperatures (> 2.000 °C) are possible, for instance in reactions with oxygen enrichment,

■ larger particle size than in comparable entrained flow reactors possible.

Smelting reactor, CONTOP®-system by Siemens VAI

Waste gas cooling systems downstream fluidized bed roastingfor zinc, pyrite (gold) and copper

Waste heat boiler downstreamroaster for gold recovery

in Newmont, USA

Fluidized bed roaster with waste heat boiler

Design range

Cyclone smelting

Cyclone diameter 1 - 3 mFeed rate of solids 10 - 100 t/hOffgas temperature at cyclone outlet 1,200 - 1,800 °CSteam pressure 30 - 70 barSteam rate 3 - 10 t/h

Waste heat boiler

Offgas rate 5,000 - 50,000 m3(STP)/hDust at boiler inlet 0.7 - 7 t/hOffgas temperature at boiler inlet 1,200 - 1,800 °CDust at boiler outlet 0.8 - 8 t/hOffgas temperature at boiler outlet 240 - 380 °CSteam pressure 30 - 70 barSteam rate 6 - 60 t/h

Design range

Offgas rate 15,000 - 120,000 m3(STP)/hOffgas temperature at boiler inlet 800 - 1,000 °COffgas temperature at boiler outlet 350 - 400 °CFeed water temperature 105 - 140 °CSteam pressure 42 - 70 barSteam temperature 250 - 400 °CSteam rate of boiler 6 - 50 t/hFluidized bed cooling coils 3 - 50 t/h

Steel dust and zinc residue recycling with cyclone smelting and waste heat boiler

Even the best product can go wrong sometime; parts may need to be repaired or replaced.In such instances, our customers can rely on theexpert service provided by Oschatz. Our subsidi-ary Oschatz Services & Solutions s.r.o. (OSS)pulls out all the stops to keep downtimes at yourplant to an absolute minimum. The speedy avail -ability of spare parts, which can be installed onsite by our specialists if required, helps us ensurethat your plant can resume production as quicklyas possible. The components are built or repairedin the OSS manufacturing facility in Vysočany,Praha. Total floor space: 1,650 m2 (17,760 ft2).

What our service provides:■ The quickest possible plant availability in the event of breakdown or repair

■ Highly qualified repair personnel with plant-specific know-how

■ 24/7 emergency service

Consulting services from our team:■ Optimization of operating costs■ Improved technical and personnel planning of resources and costs

■ Planning of environmental protection measures

■ Conversion of furnaces■ Performance-enhancing adjustment of steam parameters

Our service team is ready to help you around the clock.

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Our Market is the World

Oschatz Services & Solutions s.r.o.Expert support around the clock

A waste heat boiler downstream ISASMELT process is manufactured.

The OSS manufacturing facility in Vysocany Praha ensures the speedy availability of spare parts.

Oschatz offers heating surface cleaningsystems for:

■ boiler walls,■ screens,■ evaporator bundles.

For the boiler wall cleaning system a hammer hitsan anvil that is directly mounted on the boilerwall. For a screen bundle each screen has its ownhammer positioned outside of the boiler at thetop. This hammer hits in the direction of the gasflow. The evaporator bundles are hammered atthe bottom with one hammer hitting twobundle layers. The Oschatz hammeringcleaning system is used successfullyfor the dust removal in wasteheat boilers downstreamflash smelting, ISA-SMELT, Ausmelt androasting processes.

Test unit of a coolingsurface cleaning system

The Oschatz boiler hammering cleaningsystem is the result of 50 years of developmentand experience. The special patented hammeringsystem provides an extraordinary cleaning effectfor slag and dust, without damaging the boiler.

Oschatz hammers hit the heating sur-faces of the boiler within the tensilestrength limits of the steel. Hammer,anvil, boiler and buckstays are notoverstressed and show no sign of

plastic deformation of the steel when subjectto high impacts. Oschatz hammers hit on well-defined points permitting maximum accelerationand have a variable cleaning vibration frequency.

Cleaning of waste heatboiler cooling surfacesInnovative hammering cleaning systems

Production plant in Kocaeli, TurkeyOschatz has been producing boilers and wasteheat systems in the Turkish region of Kocaeli,close to Istanbul, since 1997. In 2011, productionwas expanded and relocated to a new site:

■ Site area: 60,000 m² (646,000 ft²)■ Production area: 10,000 m² (108,000 ft²) ■ Four production workshops up to 22 metres high

■ Deep-water port close by■ Production in accordance with ASME standards, the Pressure Equipment Directive, AD standards and ISO 9001

■ Second stage of construction (four additional workshops /10,000 m²) in progress

Production plant in Nanjing, ChinaTo serve the markets in Asia, Australia andOceania quickly and cost-effectively, Oschatzhas operated a production plant in Nanjing,China, since 2005 (second stage of constructionin 2008):

■ Site area: 50,000 m² (538,000 ft²)■ Production area: 15,000 m² (161,000 ft²)■ Seven production workshops■ Link to the port of Changjian■ Production in accordance with Chinese GB standards, ASME standards, AD standards and ISO 9001

Production plant in Prague, Czech RepublicThe Oschatz production location in Prague was established in 2012 for the production of pipe work, smaller boiler components and spare parts:

■ Production area: 1,650 m² (17,760 ft²)■ Certified in accordance with SCC** 2006 and EN 3834-2■ Centrally located, and well connected to international highways

Oschatz GmbH Westendhof 10-12 45143 EssenGermany

Phone +49 201 1802-0Fax +49 201 1802-165info@oschatz.comwww.oschatz.com