Acid Neutralization:  A Case Study 2022

Sofix, LLC Logo

Alkali Cost Savings & Reducted Health and Safety Concerns

Company: Sofix, LLC
Location: Chattanooga, Tennessee

Sofix LLC is an organic specialty chemical manufacturer, producing a range of color formers for the thermal paper industry. Their production plant utilizes magnesium hydroxide for pH and alkalinity control during the neutralization of excess sulfuric acid.

PROJECT SUMMARY

APPLICATION

Thermal paper color formers

PROCESS

Acid neutralization by means of AlkapHix® addition

CHALLENGE

The price of caustic soda reached an economically unfeasible point, which would lower profitability

GOAL

Find a replacement alkali source that produces the same desired results at a lower cost

SOLUTION

AlkapHix® provides desirable results at a fair price, with the perk of easing operations and reducing employee health & safety concerns

PROCESS:

Excess sulfuric acid is dispatched into a neutralization tank where magnesium hydroxide is introduced. While the dosing technique is temperature-dependent, the AlkapHix is pumped into the system until the pH reaches between 3 and 5. Once the pH increases to between 5 and 5.5, the batch is rinsed, which is enough to bring the pH between 6 and 8. The treated solution is then pumped out into a flume.

PROCESS CONDITIONS

AlkapHix® to Acid Ratio

~400 gal Mg(OH)₂ : 1500 gal H₂SO₄

Percent Solution of Acid

30%, by volume, H₂SO₄

pH, initial: 
≤1 | pH, line blow out: 5 - 5.5 | pH, final: 6 - 8 

AlkapHix® Slurry Storage

A 7,000-gal storage tank was installed with a centrifugal pump to pull directly from the bottom of the tank. Agitation is continuous in order to keep slurry in suspension.

CHALLENGE:

In 2011, Sofix concluded that the cost per pound of caustic soda was no longer economically feasible to utilize as an alkalinity source for pH control within their plant operations. If they were going to continue neutralizing excess sulfuric acid, an alternative material would be the optimal solution.

SOLUTION:

The replacement of caustic soda, NaOH, with magnesium hydroxide, Mg(OH), resulted in an average cost savings of 55%, per dry pound, while achieving the desired 6-8 pH range and alkaline stability.

a cost savings of 55%, per dry pound

BENEFITS:

  • A cost savings average of 55%, per dry pound

  • Provides a very similar process to that of caustic soda –making for an easy transition and ongoing operational process

  • Yields a large window to hit your neutralization point, resulting in little-to-no adjustments

  • Requires less raw water cooling due to the significant decrease in the heat of the reaction

  • The handling of magnesium hydroxide is much safer than that of sodium hydroxide

  • Alleviation from freezing and plugged-line problems due to magnesium hydroxide having a lower freezing point

  • Elimination of offset corrections in the event of an overdose. Mg(OH) is a low-soluble alkaline that peaks at a pH of 8, if overdosing occurs

comparison graphic of hazards between magnesium hydroxide and sodium hydroxide

AlkapHix® is a high purity magnesium hydroxide that is designed to support your application with the necessary pH control and additional alkalinity while providing consistent reactivity.

It is a nontoxic alternative for acid neutralization treatment and many other industrial processes.

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Technical Data Sheets

Safety Data Sheets

Applications

AlkapHix Infographic
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Hailee Wright, Technical Engineer, worked closely with the team at Sofix , LLC to develop this case study as a means of assisting other companies with similar challenges.  If you would like to participate in a Garrison Minerals case study, please reach out to info@garrisonminerals.com