Sounds like you need to give it a baking soda &amp; warm water bath first.  Also, 511 will work well on the slate as mentioned earlier, but there are some drawbacks on some applications, more so if this is exterior or has exposure to elements.  If this is the case I would use something more along the lines of what you are already considering, an impregnator.  You can use a regular paver enhancer for color and follow up with the matching solvent based impregnator, very effective and long lasting.<br>
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<div class="gmail_quote">On Sat, May 29, 2010 at 4:52 PM, Joe Smith <span dir="ltr">&lt;<a target="_top" href="mailto:joesmith@naturalstonecare.net">joesmith@naturalstonecare.net</a>&gt;</span> wrote:<br>
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<div>What, helping others? You are a real radical......</div>
<div>Have a great weekend and give Pam a hug. <br><br>Joe Smith 
<div>610 517 0653 cell</div>
<div>Sent from phone</div>
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<div><br>On May 29, 2010, at 2:53 PM, &quot;John Freitag&quot; &lt;<a target="_top" href="mailto:jfreitag@thestoneandtileschool.com" target="_blank">jfreitag@thestoneandtileschool.com</a>&gt; wrote:<br><br></div>
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<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">Walter ,</span></p>
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<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">The chalky residue is probably from the aggressiveness of the brush and the acid. I would use a honing powder to remove the chalky look you may need to start with a 200 grit powder then use a 400 powder, this should bring back most of the color then apply a water based color enhancing sealer.</span></p>

<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">If you’re looking to add some shine you could use Stone Lok from Richard James Chemical. If you need additional information call me.</span></p>
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<p class="MsoNormal"><span style="FONT-SIZE: 14pt; COLOR: #1f497d; FONT-FAMILY: &#39;Cataneo BT&#39;">John E. Freitag </span></p>
<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">President/Director</span></p>
<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">The Stone and Tile School</span></p>
<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d">Office 407-567-7652</span></p>
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<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d"><a target="_top" href="http://jfreitag@thestoneandtileschool.com" target="_blank"><span style="COLOR: blue">jfreitag@thestoneandtileschool.com</span></a></span></p>
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<p class="MsoNormal"><span style="FONT-SIZE: 11pt; COLOR: #1f497d"><a target="_top" href="http://www.thestoneandtileschool.com/" target="_blank"><span style="COLOR: blue">www.thestoneandtileschool.com</span></a></span></p>
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<p class="MsoNormal"><b><span style="FONT-SIZE: 10pt">From:</span></b><span style="FONT-SIZE: 10pt"> <a target="_top" href="mailto:wnartowicz@gmail.com" target="_blank">wnartowicz@gmail.com</a> [mailto:<a target="_top" href="mailto:wnartowicz@gmail.com" target="_blank">wnartowicz@gmail.com</a>] <b>On Behalf Of </b>Walter Nartowicz<br>
<b>Sent:</b> Friday, May 28, 2010 12:12 PM<br><b>To:</b> Restoration and Maintenance<br><b>Subject:</b> [sccpartners] slate dusting</span></p></div>
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<p class="MsoNormal">Hey guys,</p></div>
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<p class="MsoNormal">I am doing a clean and seal job on a slate floor- I&#39;m not exactly sure what type of slate it is, only that it is a blue/grey color with a little bit of texture to it. We&#39;ve acid washed it with a green nylon scrub brush. The cleaning process is causing quite a bit of slurry, I believe due to the aggressive brush. Normally I could put a nice solvent based color enhancing sealer on it and it would take the chaulky look away. In this case we are limited to using an immpregnator sealer which leaves the slate with the chaulky look which the customer is unhappy with. Any ideas on how to get rid of the chaulkyness?<br clear="all">
<br>-- <br>Jim Corron<br>Mid Atlantic Stone Solutions<br><a target="_top" href="http://www.midatlanticstonesolutions.com/" target="_blank"><a target="_top" href="http://www.midatlanticstonesolutions.com/" target="_blank">www.midatlanticstonesolutions.com</a></a><br>
4607 Fayetteville Road<br>Raleigh, NC 27603<br>919-772-2155 (Main Office)</p></div>
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Stone and Tile Pros<br>