Pyrohydrolysis of Metal Chlorides Feasibility Study Oliver Gnotke, - - PowerPoint PPT Presentation

Pyrohydrolysis of Metal Chlorides Feasibility Study

Oliver Gnotke, Kronos International, Inc. & Jim Berthold, OLI (speaker) OLI Simulation Conference October 25, 2016

• Production titanium dioxide creates significant amounts of an aqueous

metal chloride solution as a by-product.

– Land filling of the solid residue is the normal waste removal process – pyrohydrolysis is a viable way to convert metal chlorides from TiO2 production into the valuable products hydrochloric acid and metal oxides with iron oxide as main component.

• The metal chloride solutions are complex highly concentrated aqueous

solutions of di- and trivalent iron chlorides, other metal chlorides and hydrochloric acid.

• Kronos followed a theoretical approach for a feasibility study to assess the

pyrohydrolysis process.

– As a first step it was essential to evaluate the applicability of OLI Stream Analyzer for metal chloride solutions. – For the simulation of a pyrohydrolysis process especially the prediction of solubility limits of salts and vapor pressures of HCl are important . – Available literature data was taken for the system FeCl2-HCl-Water and compared with OLI results. The deviation of OLI results and literature data were quite small. This qualified OLI as a valuable tool for the feasibility study.

Abstract

• Pyrohydrolysis: Convert metal chloride solution

into metal oxide and HCl

• Reaction is carried out in fluidized bed or spray

tower at temperature of 600-800°C

• HCl is recovered from gas stream by absorption

columns

Pyrohydrolysis Reaction 4 FeCl2 + 4 H2O + O2  2 Fe2O3 +8 HCl 2 FeCl3 + 3 H2O  Fe2O3 +6 HCl

Manufacturing of Titanium Dioxide & potential benefit of Pyrohydrolysis

Chloride Process Rutile HCl Leaching Ilmenite (High Iron content)

Neutralisation & Landfill

Metal Chloride

Pyrohydrolysis

Metal Chloride

Pyrohydrolysis

HCl Chlorine TiO2 Metal Oxide HCl for sale HCl Metal chloride solution Metal chloride solution

PROCESS

Steelworks Nickel Production Metal Separation Ore Processing Scrap Pickling Line Dissolving Station Extraction Liquid Extraction Liquid Dissolving Station Reactor Fuel Air Cyclone Venturi Separator Absorber Scrubber Fan Stack Off-Gas Regenerated Acid Treated Oxide Oxide

• Reactor, Cyclone,

Oxide Station

• Preconcentration
• HCl-Absorption
• Gas Cleaning

System Process Stages:

KRONOS project

• Feasibility Study for Pyrohydrolysis using

OLI

• No pilot unit available
• Economic assessment
• First step: Check OLI Stream Analyzer

results against available literature data

• 0,16 kg/kg HCl und 0,16 kg/kg FeCl2

Vapour Pressure as a function of temperature

0,1 0,2 0,3 0,4 0,5 0,6 40 50 60 70 80 90 100 Pressure [bar] Temperature [°C] Literature OLI

• Comparison OLI with literature data [Che70 ] @70°C, FeCl2-conc. 0,78

mol/l

• OLI Bubble point calculation, variable pressure

Gas phase composition in the system FeCl2-Water-HCl

0,0001 0,001 0,01 0,1 1 0,00 0,10 0,20 0,30 Mol% HCl in gas phase HCl liq. conc. [kg/kg] Literature OLI

• Comparison OLI with literature data [Che70 ] @70°C, FeCl2-conc.

0,78 mol/l

• Good prediction of azeotrope

System pressure

0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,00 0,05 0,10 0,15 0,20 0,25 0,30 Total pressure [bar] HCl-conc. liq.[kg/kg] Literature OLI

• HCl concentration in gas phase higher with addition of FeCl2
• Azeotrope shifted by FeCl2 addition
• Solutions with high salt concentrations could deliver over azeotropic hydrochloric acid

(i.e. > 20% HCl)

OLI prediction on influence of FeCl2

1,00E-04 1,00E-03 1,00E-02 1,00E-01 1,00E+00 0,1 0,2 0,3 Mol% HCl in gas phase HCl liq. conc. [kg/kg] OLI with FeCl2 OLI without FeCl2 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,1 0,2 0,3 Pressure [bar] HCl-conc. liq [kg/kg] OLI with FeCl2 OLI without FeCl2

FeCl2 /FeCl3 in HCl solubility data from OLI database

10 20 30 40 50 60 10 20 30 40 wt%-FeCl2 wt%-HCl

0C 20C 40C 60C 100C

FeCl2.2H2O FeCl2.4H2O FeCl2.6H2O FeCl2.4H2O FeCl2.2H2O

5 10 15 20 25 30 5 10 15 20 25 30 m-FeCl3 m-HCl t=25C

FeCl3.6H2O FeCl3.3.5H2O FeCl3.2.5H2O FeCl3.2H2O FeCl3.HCl

OLI comparison MgCl2 solubility in HCl

5 10 15 20 25 30 35 40 5 10 15 20 25 30 35 40 45 50 MgCl2, weight % HCl, weight %

Magnesium Chloride Solubility in Hydrochloric Acid

• 20C
• 8C

0C 25C 38C 48C 60C 70C

• Good prediction of OLI both in

– VLE – Solubility

• Valuable tool for the chloride system
• Next possible step

– Coupling of OLI with ASPEN for full flowsheet simulation of Pyrohydrolysis – Aspen needed for high temperature equipment

Conclusions

• [Che70]

Chen, McGuire, Lee: Vapor-Liquid Equilibria of the Hydrochloric Acid-Ferrous Chloride-Water System. Journal of Chemical and Engineering Data, Vol. 15, No.2, 1970

• [Sch52]

Schimmel, F.A.: The Ternary System Ferrous Chloride-Hydrogen Chloride- Water, Ferric Chloride-Ferrous Chloride-Water, 1952

• Pyrohydrolysis: Fundamentals and Applications for the Ferrous and Non-Ferrous Metallurgy,Dr.

Frank H. Baerhold, Dr. Albert Lebl, Rewas '99: Global Symposium on Recycling, Waste Treatment and Clean Technology by I. Gaballah (Editor), J. Hager (Editor), R. Solozabal (Editor)

Literature

• Dr.-Ing. Oliver Gnotke, born 1971 in Düsseldorf /Germany is the team

leader Chloride Process development for Kronos International, Inc., Leverkusen/Germany a leading producer of titanium dioxide with 6 production locations worldwide. He works for Kronos since 12 years having positions in different technical departments. His main responsibility is the

• ptimization of the production sites with respect to cost, quality and
• throughput. He has wide experience with CAE tools as for example

flowsheet simulation, CFD and thermodynamic properties estimation.

• Prior to his work for Kronos he worked from 1999-2004 as research

assistant at the Chair of Energy Technology, University of Darmstadt/Germany. His main research topics were experimental studies and simulation of multiphase flow in chemical and power plants. Graduated 2004 to PhD (Dr.-Ing.).

• He started his studies as Chemical Engineer at the University of Dortmund,
• Germany. During university studies he made several internships in the

chemical industry as Bayer, Henkel, CFPI (France) and Lurgi Engineering where he optimized polymerization reaction using numerical simulations.

Biography