REDUDUST
A SYSTEM FOR BYPASS DUST RECOVERY
BY:
ING. JONATHAN FORINTON
ING. PEDRO MONTES DE OCA
2012
REDUDUST
Agenda:
Introduction
Basic Concept
Products
Application
Pilot Plant
Industrial Installation
Summary
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INTRODUCTION
Many plants have implemented a bypass for removing
chlorine from the pyrosystem
Main Advantage:
– Stable operation despite Cl input
Main challenges today:
– Clean disposal of bypass dust
– Recuperation of raw material
– Winning of byproducts
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INTRODUCTION
Properties of Bypass dust:
– Very poisonous for the ambient in contact with water
–
–
–
–
Alkalis (K2O, Na2O),
Chlorine (Cl)
Sulfur (SO3)
Mercury, heavy Metals
Use today:
– Limited addition to cement
– Rest landfilled
Use with REDUDUST:
– Economically friendly solution: conversion to marketable
products: salts + clean raw meal
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BASIC CONCEPT
Before leaching – particles covered
with Micro Crystals of Chlorine based
salts
Water dissolves the Micro Crystals uncovered particles are now able to
react with water
Blue areas indicate free lime
Free lime reacts to Lime Hydrate
(orange)
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PRINCIPLE PROCESS DIAGRAM
Chemicals
Bypass-DustSeparation of Brine
Silo
and Filter Cake
Brine
Treatment
& Conditioning
Mixing
Filter Cake
Waste Heat
Crystallization
Source
Heat Supply
Salt Products
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MASS BALANCE OVERVIEW
DATA GIVEN FOR TYPICAL EGYPT BYPASS DUST
Sewage
water
Chemicals
Cement
Waste Heat
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5,0 t/h
6,0 t/h
1,0 t/h
10 MW
ReduDust Process Plant
Bypass
Dust
6,0 t/h
Product
Material
4,0 t/h
Potable
Water
2,0 t/h
Salts
INTERMEDIATE PRODUCTS
Limestone slurry
– collected sediments from
CO2 precipitation
Heavy metal sludge
– collected sediments from
heavy metal treatment
process
Limestone slurry (dry)
Both are usually not leaving
the process !!
Heavy metals sludge (dry)
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FINAL PRODUCTS
Lime hydrate filter cake
– Desalted bypass dust
released from filter press
Salt
– Crystallized mixture of all
salt contained in brine
– Separation and purification
of main elements possible
e.g. Potassium chloride
(KCl)
Filter cake
Salt
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PRODUCT APPLICATIONS
Filter cake (low chlorine) –approximately 35%
of residual moisture
– Reintroduce back to process into cement mill due to
low Cl content (<1%)
– SO2 Trap Preheater Tower and/or Filter Equipment
– Recycling as Raw Material: Calcining at 580°C, Energy
1.99MJ/kg CaO instead of 3.17 MJ/kg CaO
– Additive for Cement Blends
– No need for new material licenses,
because it is considered as bypass dust
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PRODUCT APPLICATIONS
Salts
– Valuable product on market (e.g. fertilizer production at
around 300 €/t market price)
– Valuable Raw Material for various processes in the
chemical Industry
– Meets all European laws for
chemical products
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PILOT INSTALLATION
Pilot Plant
ATEC Technical Center
(AUT)
2012
PILOT INSTALLATION
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PILOT INSTALLATION
Drying
Crystallizing
Mixing
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Chemical Treatment
Filtration
Mixing
PILOT INSTALLATION
Bypass dust storage
Slurry rapid mixer
Peristaltic pump
Filter press
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PILOT INSTALLATION
Chemical dozing
Crystallizer
Sedimentation tank
Process analytics
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Dryer
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INDUSTRIAL INSTALLATION
First Industrial-Sized
Plant
Holcim Rohoznik
2012
INDUSTRIAL INSTALLATION
DATA GIVEN FOR TYPICAL EUROPEAN BYPASS DUST
Basic design principles
– Utilization of waste heat from the cement plant
– Installation must follow chemical installation
requirements especially for environmental and safety
reasons
– Automatic operation
– Reception of Bypass dust from different plants is
considered
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INDUSTRIAL INSTALLATION
DATA GIVEN FOR TYPICAL EUROPEAN BYPASS DUST
Plant capacity
– Standard design capacity of 20.000 tpy of Bypass dust
– 4.000 tons of salts per year (approx. 3.000 tons of KCl)
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PLANT ARRANGEMENT
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KCl
silo
NaCl bags
Crystallization
Tanks
storage
Filter cake
outlet
Mixing &
Chemical treatment
• Respecting optimal
flow
– Bypass dust
– Filter cake
– Brine
– Salt
– Chemicals
• Dimensions of
footprint
– 24 m x 36 m
Filtration
Bypass dust storage,
dosing and transport
Chemicals
MATERIAL OVERVIEW
• Bypass dust 20k t/y
– CKD 8 – 15 % of Chlorine
• Filter cake 16k t/y
– Washed bypass dust <1% of Chloride
– moisture <30%
• Brine 20k t/y
– Saturated salty water >10% of Chlorine
• Chemicals used
– 4 common industrial chemicals available on the market
• Salt
– KCl >95% purity
– NaCl salt >98% purity
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INDUSTRIAL INSTALLATION
DATA GIVEN FOR TYPICAL EUROPEAN BYPASS DUST
Operational data
– 3 operators full time operation in 3 shifts working days
– depending on kiln operation due to its heat demand
(important for design of the storage capacity)
– Heat need for crystallization and drying is around 1.4 MW
– Designed to handle 5-15% chlorine content bypass dust
– Overall Cl-extraction efficiency >90%
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INDUSTRIAL INSTALLATION
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SUMMARY
Zero waste
Recycling of raw meal
Production of a saleable Product
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THANK YOU FOR YOUR ATTENTION
Please visit www.atec-ltd.com
2012