Lignosulfonates applications

Stabilizing agents are used to maintain drilling fluid rheological properties at highly elevated downhole temperatures. Chromium and chromium-free lignosulfonates, polyglycol ethers, sodium polystyrene sulfonate-co-maleic anhydride), and a melanin polymer have been used in this application. Additives such as sodium diethyldi-thiocarbamate have been used to stabilize aqueous polysaccharides such as xanthan gum (18). 

The application of lignosulfonate-chromium derivatives in oil well drilling mud has already been mentioned as a typical example of the above effects in combination with crosslinking. The use of lignosulfonates as active extenders in concretes is a further example of the applicability of the above effects (61). Another is the use of lignins as extenders for asphalt cement (70). 

Although developed originally and used principally for the determination of lignosulfonates in sea water, the applicability of the Pearl-Benson method has been widened to include the determination of not only lignosulfonates but of other lignins as well in fresh water. In its present form the sensitivity of the method is such that, in the absence of any extraneous absorbance, lignosulfonate concentrations as low as 0.2 to 0.5 ppm can be determined (Goldschmid 1971). 

It is available at essentially no cost, and by being fi eed of the xylose, the sulfite waste liquor becomes more suitable for making lignosulfonate (waste liquor concentrate) since in the latter the presence of pentose is detrimental for most applications. 

Applications. Experience. Ultrafiltration of SSL. This processing has been going on on a regular commercial basis since 1974 for manufacture of lignosulfonate products with a lignosulfonate content in the 90%+ range O). Not only the lignosulfonate content of the product is of importance, often also the molecular... 

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