Description
Cıtric Acid (C₆H₈O₇) is a weak organic acid.

Typical Properties
Appearance: White, crystalline powder
Specific Gravitiy: 1.54
pH (%1 solution): 2.1 – 2.2

Features and Benefits

Cıtric Acid reduces pH and removes soluble calcium ions by the reaction

Soluble iron ion content greater than 40 mg/l causes rapid and severe cross-linking of xanthan gum such as Kar-Zan D or Kar-Zan DS leading to excess gelation. Cıtric Acid is considered an excellent sequestering agent for iron complexing.  At pH values lower than 7, citric acid forms complex with iron (III) ions and consequently prevents fish eyes due to cross-linking of polymers.

Application
Cıtric Acid is used to treat cement contamination by removing soluble calcium and reducing pH.

Cıtric Acid is also utilized as iron sequestering agent to prevent polymer cross-linking particularly in non-dispersed polymer systems.

Limitations
Cıtrıc Acıd is more expensive and used at higher concentration levels than to alternative chemicals

Treatment
In removal of cement contamination amount of Cıtric Acid required is calculated as follows:

Where F_w is water fraction in the fluid.

One pound of citric acid removes 0.53 lb of excess lime which nearly equals 0.78 lb of cement. It is recommended to keep soluble iron content of 40 mg/l or less in polymer systems (KAR-PAY DRILL, KAR-POLY K+). Make-up water is pretreated with 0.25 to 0.5 lb/bbl of citric acid   to chelate iron and to reduce pH to 4.0 to 5.0 range. Pretreatment will prevent cross-linking, excess gelation and fish eyes. 35 ppm citric acid sequesters about 10 ppm iron (III).

Citric acid should be added slowly to the active system through hopper.

Packaging
Cıtric Acid is supplied in 25 kg (55 lb) moisture-proof, multiwall paper sacks