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Re: INFOTERRA: HCl + H2SO4 pickle liquors waste mgmt with ze



     There can never be true "zero discharge" at a steel pickling operation 
     because the iron which is removed as scale from the pickled steel must 
     be rejected from the process.
     
     For spent sulphuric acid pickle liquors, the typical waste reduction 
     solution for a small pickler is to install an acid recovery system and 
     generate ferrous sulphate crystals for sale (or precipitate the iron 
     as a hydroxide sludge for disposal).
     
     For spent hydrochloric acid pickle liquors, some small pickling 
     operations neutralize the residual acid and send the solution to a 
     nearby sewage treatment plant where the iron chlorides are beneficial 
     for phosphate removal.  Others send the spent pickle liquor to larger 
     steel mills who have the roaster which can recover hydrochloric acid 
     and generate iron oxides for re-use.
     
     I did hear of one U.S. steel mill that ran a process which recovered 
     HCl from spent pickle liquors through the precipitation of first 
     ferrous hydroxide and then calcium sulphate.  Another tried a process 
     that recovered HCl through the addition of sulphuric acid and 
     evaporation of HCl gas, but it shut down because of extreme corrosion 
     problems.
     
     I hope this is helpful.
     
     Robert Michalowicz
     BOVAR Environmental
     2 Tippett Rd.
     Toronto, Ontario
     Canada
     M8Y 2K3
     (416) 630-6331
     robert_michalowicz@bovar.com


______________________________ Reply Separator _________________________________
Subject: INFOTERRA: HCl + H2SO4 pickle liquors waste mgmt with zero

Author:  p2tech@great-lakes.net
List-Name: P2Tech at INTERNET
Date:    8/28/97 6:06 PM


P2 Techers:  I am forwarding to you this request that was sent to the 
Infoterra listserv, along with my response, in case any one has some 
additional info they would like to pass on to the original sender.
     
     
>Date: Thu, 28 Aug 1997 15:02:58 -0500
>From: Alejandro Fernandez <alfernan@uniandes.edu.co> 
>Organization: Universidad de los Andes
>To: infoterra@cedar.univie.ac.at
>Subject: INFOTERRA: HCl + H2SO4 pickle liquors waste mgmt with zero 
discharge requirement
>Sender: owner-infoterra@cedar.univie.ac.at
>Reply-To: Alejandro Fernandez <alfernan@uniandes.edu.co> 
>Content-Length: 920
>
>Can someone help me? I am interested in options for management 
>(treatment, recovery) of pickling liquors wastes from wire 
>manufacturing. The tricky part is that a "zero-discharge" condition must 
>be contemplated in the analysis. A volume of up to 120 m3 must be 
>managed, 50% from HCl pickling liquor and 50% H2SO4 pickling liquor 
>(waste stream separation has not been implemented yet but is being 
>considered for the near future).
>Hydrolisis for HCl and Fe oxide recovery appers to be financially out of 
>range. 
>I would greatly appreciate any information that may assist to address 
>this challenge. Please send responses directly to sender. Thank you in 
>advance.
>
>Alejandro Fernandez, PE, QEP, CHMM
>e-mail: alfernan@uniandes.edu.co
>-
     
Mr. Fernandez:  
Several years ago I helped a company in Seattle prepare a pollution 
prevention and they had the same problem as you, and a very interesting 
solution.  The Davis Wire Company had to dispose of high volumes of acid 
from wire pickling.  Previously they had been neutralizing it for sewer 
disposal.  However they found out that sulfuric acid is a primary ingredient 
of certain kinds of fertilizer, and iron contamination of the fertilizer is 
not a problem since the stuff is applied to the soil from whence comes the 
minerals anyway.  So they purchased a small fertilizer production facility 
and put it at the end of the pickling liquor drain, and they sell the 
fertilizer they make to farmers in Eastern Washington.  Their engineer told 
me they seem to make more profits from fertilizer sales than from wire sales 
and he was wondering what industry he was in!  Hope this inspires some 
creative thinking for your clients.
     
Burt Hamner
Asian Institute of Management
Manila