Organics USA Inc

Ammonium Hydroxide

Ammonium hydroxide, also known as ammonia water, ammonia solution, aqua ammonia, or aqueous ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq).


After sulphuric acid, ammonia is the second most commonly produced chemical globally. In 2018 around 200 million tonnes were produced, with 85% of that going towards the production of fertilizer. This provides agriculture with an efficient mechanism of transferring nitrogen to the soil. Apart from agriculture, ammonia and its byproducts have many uses ranging from its use as a coolant and as a dyeing agent in the textile industry, and around the home, there is a multitude of products that are based on ammonia.

Ammonia is a compound of nitrogen and hydrogen with the formula NH3. In its simplest form ammonia is a colorless gas with a characteristically pungent smell.

Ammonia can also be a significant headache in the control of wastewater and we now know that it can be recovered to be reinjected into the cycle of use. Ammonia recovery, therefore, has the potential to be a major pillar in the cycle of recovery and reuse that has been labeled the circular economy.

Schematic representation NH4OH
Schematic representation NH4OH

Heated air is introduced into the bottom of the stripping column while wastewater is fed into the top. The liquid percolates down through a packed bed and the ammonia is removed into the gaseous phase. From the top of the stripping column, the gas is fed into the scrubber column where the ammonia is once again removed from the gaseous phase, back into solution.

From the stripping column, the ammoniated air is doused with cold water to remove gaseous ammonia back into the liquid phase. It is then pumped through a heat exchanger, processed in the rectifier and condensed into the ammonia product ready for shipping or on site use.

What is ammonium hydroxide?

Ammonium hydroxide, also known as ammonia water, ammonia solution, aqua ammonia, or aqueous ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests an alkali with composition [NH4+][OH−], it is actually impossible to isolate samples of NH4OH.

What concentration of ammonium hydroxide can be achieved?

At 15.6°C, a saturated solution contains 35.6% ammonia by mass, 308 grams of ammonia per liter of solution, and has a molarity of approximately 18 mol/L. As the temperature increases the ammonia content decreases.

What is ammonium hydroxide used for?

Ammonium hydroxide is a chemical widely used in the electronics industry for etching circuit boards. It is also used as a cleaning agent and sanitizer in many household and industrial cleaners. In industries such as the manufacture of products such as fertilizer, plastic, rayon and rubber, ammonium hydroxide is a common ingredient.

Aqueous ammonia is corrosive to aluminum alloys, copper, copper alloys, and galvanized surfaces and is an excellent acid neutralizer.

What is the value-range of ammonium hydroxide?

The retail price of super reagent grade ammonium hydroxide, as a 28% to 30% solution, is typically to the order of $50 US per liter. The wholesale price is within the region of $200 US per ton.

How is ammonium hydroxide stored and transported?

Ammonium hydroxide has a shelf-life of around two years if stored at room temperature but should be stored tightly sealed in a vented cabinet away from acids. Over time, the concentration may decrease due to evaporation of the gas from the solution.

Would the ammonium hydroxide produced from wastewater be contaminated with other compounds?

Ammonia solutions may be transported in rigid or plastic JBCs that have successfully passed, without leakage or deformation, an appropriate hydrostatic pressure test with a test pressure of not less than 1.5 times the vapour pressure at 55°C. This latter is a function of the percentage of ammonia in solution. A minimum pressure vessel rating of 2 bar is standard, fitted with pressure relief valves.

What information is required to obtain a quotation?

The basic information required to assess a specific duty is: (1) flow rate, (2) influent ammonia concentration, (3) influent pH and alkalinity, (4) effluent ammonia concentration required, (5) form of product required, e.g. 25% solution of ammonium hydroxide, (6) source of waste heat. To provide a detailed quotation will require a site visit and all relevant site-specific information.

The Organics Ammonia Recovery Solution

Thermally-driven ammonia stripping was developed by Organics to offer an alternative route to that of pH adjustment for continuous-process ammonia stripping. With a thermally-driven stripper, no chemical additions are required.

The single important input is waste-heat with which to drive the chemical reactions. If waste-heat is not available, the fuel cost can be as prohibitive as that of chemical additions or carbon source requirements. Where waste-heat is available, from an engine-exhaust or unwanted biogas, the long-term operating cost can be confined to plant Operation and Maintenance, as well as electricity costs.

The preferred option within the Organics process is to use the ammonia-laden air as combustion air in the heat-raising process. By this means ammonia gas is destroyed as a part of the process of thermally powering the system.

Investigation and Analysis

Critical in the pathway towards a bespoke solution for the treatment of ammonia in wastewater is an analysis of the project and a simulation of the potential for ammonia recovery.

Organics provides a comprehensive service to ensure that our clients are supported throughout the entire process. The first step is to complete the questionnaire that is attached to this section. Once we have received the document, we will recommend whether or not it would be useful to undertake laboratory trials on a representative sample of the wastewater.

Once the samples are received, they are normally subjected to a treatability study in which the ammonia recovery process and subsequent conversion to a useful product are simulated. Essential in this process is an evaluation of the quality of the final product.

This, in turn, will provide a basis to ensure that any recommendation Organics may make is optimized to ensure that the most commercially viable recovery option is proposed.

Download our Questionnaire

As the first step in deciding analysis of whether a particular project has the potential for yielding a concentration of recoverable ammonia is to pull together all the information and undertake a desk study. If you are interested in investigating the potential of your project, please download our questionnaire and return it to the email address supplied.   


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