WIRE INDUSTRYACID PURIFICATION

INTERWIRE 2015

DR. ROGER FRANCOIS – BEKAERT

TOM PHILIPP, P.E. – PRO-pHx, Inc.

THE CHEMISTRY

The catalyst changes the solubility of ferrous chloride and ferrous sulfate into insoluble iron precipitates. Organics are co-precipitated. Acids are purified and not regenerated.

Pickling Tanks

Drag-out Recovery

FILTRATION• In the past filtration was done with filter cartridges and filter

bags.

• Previous arrangement was not satisfactory due to its labour intensive nature.

• Recently, a Two Chamber Global Automatic Back Wash Filtration System was installed.

• Back washing of the chambers take place when back pressure reaches 1.38 bar (20 psi) or every 1.5 hours.

• The chambers are air purged before and after back washing to reduce acid loss and dilution.

• Filter medium is rated at 20 micron.

•FILTERS EVALUATED

2008 Global 1X PVC 2009 Westech gravity bag filter 2011 Siebec bag & cartridge filter 2012 Global 2X CPVC

Global 2X CPVC

Automatic Filter CyclesCycle Function

Service Filtered acid to pickle tank

Blowdown Unfiltered acid to pickle tank

Fill Cylinder fills with water

Backpulse Air & water discharge solids

Blowdown Cylinder emptied of fluid

Fill Cylinder fills with acid

Filter Connections

CHEMISTRY CONSUMPTION

•ACID USEAGE 6 LITERS/TON•CHEMISTRY USEAGE 0.06 LITERS/TON

Project Performance Before After

Bath Concentration g/l HCl 160 80

Bath Decants Yes No

Iron Concentration g/l 100 Max 40 -80

Virgin HCl Reduction None 30%

Lime Neutralization Reduction None 70%

Filter Cake Reduction None 65%

USA PROJECT ECONOMICSINSTALLED

• Previous Annual Costs• (Virgin acid + Wastewater treatment) $128,000.00• Filtration Equipment – Installed 49,000.00• Annual chemistry, utilities, labor 32,000.00• First Year Savings 47,000.00• Future Yearly Savings 96,000.00• Period to recover investment 6.8 months

SOUTH AFRICAN PROJECT

25,000 – 35,000 MT/YEARTWO LINES

USED 16% Regenerated Acid – off-site

Off-Site Regeneration

• Excessive recycle costs – ($ 0.65 /gal)• In and out hauling of dilute acids• Storage requirements for hazardous waste acid

Drawing of System Layout

Fouled Membrane Reason for having tanks

cleaned prior to use of chemistry

African Project Economics Historic annual cost for regenerated acid $ 116,800 Initial cost: equipment installed $ 43,950 Annual operating cost: chemistry/utilities $ 35,830 First year savings $ 37,030 Future yearly savings $ 80,970 Average monthly savings, first 5 years $ 6,015 Period to recover investment 6.5 months

Summary

Three wire plants have installed the precipitation chemistry and filtration for continuous acid purification. The technology accomplishes:• Lower acid pickling concentrations• Elimination of bath decants or dumps• Reduced virgin acid purchases• Reduced neutralizing chemical purchases• Reduced filter cake production• Improved process control