[mtaylor12]

Hi,

First of all, to get it out of the way: I'm not a chemist. 

Background (For the curious):  I'm a Mudman on an oil drilling rig.  Right now, I'm in the middle of a project that involves drilling a few dozen horizontal wells through a formation that contains heavy, thick, hard-to-produce oil contained in relatively unconsolidated sands.  In order to minimize damage to formation porosity, I'm using a purely-polymer based drilling fluid(think Xanthan gum).  Once the wells are drilled, I'm displacing the wellbores with a "breaker fluid" of 3% KCl (by weight, to prevent clay layers from swelling and collapsing) and 4 pounds per barrel (4 lbs / 42 gallons) of Lithium Hypochlorite.  This is to destroy the polymers and minimize plugging of pores in the sand.

My question is this:  What is the equivalent "strength" of this 4 lb/bbl (4 pounds per 42 gallons) Lithium Hypochlorite solution when compared to regular household bleach?  I've been giving safety briefs before pumping this stuff for a while now, and this is a question that has come up quite a few times, and I would really like to know the answer.  Thanks!

[Borek]

According to wikipedia typical bleach has a concentration of sodium hypochlorite between 3 and 6 %w/w. Convert 4 pounds per 42 gallons to %w/w and you will have an approximate answer.

[Arkcon]

Futhermore, a quick Google tells me that the LD50 for lithium hypochlorite is much higher than for sodium hypochlorite.  This means the lithium salt is much less toxic than sodium hypochlorite.  I figure the toxicity is based on oxidizing power, so lithium hypochlorite seems to be much weaker than the equivalent concentration of house hold bleach.  Seems that lithium hypochlorite is commonly used to sterilize spas.

[mtaylor12]

Thank you both for the helpful replies!

Sorry for the oilfield units I'm about to use, but does this seem about right?

4 lbs/bbl LiClO / (8.334 lbs/gal x 42 gal/bbl) = ~1.1% w/w

Given the lower level of toxicity of LiClO vs NaClO, and the normal concentration of 3-6% for household bleach, would I be in the ballpark by saying that what I'm using is about 25% as hazardous as household bleach?  Exact precision isn't necessary for this application; I would just like to give the roughnecks I work with a reference point without accidentally downplaying the hazards.

[opsomath]

LiClO is going to have a little bit higher chlorine percentage than NaClO due to smaller formula weight, (it's a factor of about 1.3) but your ballpark numbers are just fine. I'd say the stuff is something like half the strength of bleach.