A practical guide to ammonium chloride, why it appears in feedlot rations and soldering fluxes alike, and how the grades differ, from a US-based distributor.
Ammonium chloride (NH4Cl, CAS 12125-02-9) is a white, water-soluble salt supplying roughly 25% nitrogen. Its uses span markets that look unrelated but share one root cause: it is acidic in solution and it decomposes on heating into ammonia and hydrogen chloride. That makes it a feed acidifier, a metal-cleaning flux, a battery electrolyte, and a fertilizer. Stratus Chemical supplies feed, agricultural, and technical grades across the United States.
| Property | Value |
|---|---|
| Chemical name | Ammonium chloride |
| Synonyms | Sal ammoniac, salmiac, ammonium muriate |
| CAS number | 12125-02-9 |
| Molecular formula | NH4Cl |
| Molecular weight | 53.49 g/mol |
| EC / EINECS | 235-186-4 |
| Appearance | White powder or crystals |
| Nitrogen content | Approximately 25% N |
| Water solubility | Readily soluble; approximately 383 g/L at 25 °C |
| Grades supplied | Feed, agricultural, technical; granular and powder |
| Packaging | Bags, supersacks |
| Documentation | COA & SDS provided on request |
The figures below are representative of feed grade ammonium chloride. They are indicative rather than guaranteed: specifications vary by source and by lot, and the certificate of analysis for your material governs.
| Parameter | Standard |
|---|---|
| NH4Cl, dry basis | 99.5% min |
| Loss on drying | 0.5% max |
| Ignition residue | 0.2% max |
| Heavy metals as lead (Pb) | 0.0005% max |
| Arsenic (As) | 0.0002% max |
| Cadmium (Cd) | 0.0001% max |
| Iron (Fe) | 0.0007% max |
| pH, 200 g/L at 25 °C | 4.0 – 5.8 |
| Appearance | White powder |
Ammonium chloride is the ammonium salt of hydrochloric acid, produced largely as a co-product of the Solvay soda ash process. It is a white, odorless, readily soluble crystalline solid, and it has been in industrial use long enough to have acquired a mineral name, sal ammoniac.
Two properties explain a product range that otherwise looks scattered. In solution it is mildly acidic, because the ammonium ion gives up a proton while the chloride does nothing to buffer it. And on heating it does not melt but dissociates into ammonia and hydrogen chloride gas, recombining as a white smoke on cooling.
Nearly every commercial use of ammonium chloride traces to one of those two facts.
Feed grade ammonium chloride is used as a urinary acidifier in male ruminants, principally feedlot cattle, sheep, and goats. High-concentrate rations tend to raise urine pH, and in alkaline urine phosphate salts crystallise and form calculi that can block the urinary tract, a condition stockmen call water belly and one that is frequently fatal in males. Acidifying the urine keeps those salts dissolved. Inclusion rates belong with a nutritionist working from the specific ration rather than a standing figure.
Molten zinc and solder will not wet an oxidised surface. On heating, ammonium chloride releases hydrogen chloride that strips the oxide film and leaves clean metal, while the evolving gas helps keep air off the surface until the coating takes. It is a component of the flux blankets used in hot-dip galvanizing and of traditional soldering fluxes and tinning blocks.
Ammonium chloride is the electrolyte in zinc-carbon cells, the original commercial dry cell. Volumes here have declined as alkaline chemistry took over the consumer market, but the application persists.
At roughly 25% nitrogen, ammonium chloride is used as a nitrogen fertilizer where the accompanying chloride is acceptable or beneficial. It is common on rice and coconut in Asia. On chloride-sensitive crops it is the wrong choice, and urea or ammonium sulfate is generally preferred where chloride is a concern.
Municipal systems that disinfect with chloramine rather than free chlorine need an ammonia source to react with the chlorine. Ammonium chloride serves that purpose, and chloramine's advantage is that the residual persists further into the distribution system than free chlorine does. See the full water treatment range.
Ammonium chloride is used as a nitrogen source in fermentation and yeast nutrition, in textile dyeing and leather tanning as a pH buffer, in the manufacture of other ammonium compounds, and in flame retardant formulations.
| Product | How it behaves | Trade-off |
|---|---|---|
| Ammonium chloride | Approximately 25% N, soluble, acidifying, supplies chloride | Strong urinary acidifier and flux, but chloride rules it out on sensitive crops and saline soils |
| Ammonium sulfate | Approximately 21% N plus 24% sulfur, acidifying, chloride-free | Adds sulfur where it is limiting, but lower nitrogen analysis and a weaker acidifier per unit |
| Urea | Approximately 46% N, the most concentrated dry nitrogen source | Cheapest nitrogen per unit, but not acidifying and subject to volatilisation losses on the surface |
| Zinc chloride flux | Aggressive oxide removal in soldering and galvanizing | More active than ammonium chloride, but corrosive residues must be cleaned off after the joint |
How to choose: for fertilizer, the question is chloride tolerance, exactly as it is with potassium chloride. Where chloride is fine, ammonium chloride competes on nitrogen cost; where it is not, use a sulfate or urea. For feed acidification, ammonium chloride is the standard because it acidifies harder per unit than ammonium sulfate, though palatability is a known issue and rations are often built around that. For fluxes, ammonium chloride and zinc chloride are frequently used together rather than as alternatives.
Store ammonium chloride dry in closed original packaging, off damp floors. It is hygroscopic and cakes readily, and caked material will not meter or blend evenly afterward, which is the routine practical complaint about the product.
Solutions are mildly acidic and corrosive to mild steel, copper, and galvanized surfaces over time. Specify appropriate materials for dissolving tanks, pumps, and lines rather than assuming a benign salt is benign to equipment.
Keep ammonium chloride away from strong alkalis, which liberate ammonia gas on contact, and from strong oxidizing agents. Heating releases ammonia and hydrogen chloride, so fluxing operations need ventilation appropriate to that. Use the dust and eye protection specified in the Safety Data Sheet.
Ammonium chloride is used as a urinary acidifier in ruminant feed, as a nitrogen fertilizer for chloride-tolerant crops such as rice and coconut, as a flux in galvanizing and soldering, as the electrolyte in zinc-carbon dry cells, as a nitrogen source in fermentation, and in water treatment as the ammonia source for chloramine disinfection. Stratus Chemical supplies feed, agricultural, and technical grades across the United States.
The CAS number for ammonium chloride is 12125-02-9. Its molecular formula is NH4Cl and its molecular weight is 53.49 g/mol. Its EC number is 235-186-4. It is also known as sal ammoniac, salmiac, and ammonium muriate.
As a urinary acidifier, to prevent urinary calculi, commonly called water belly, in male ruminants on high-concentrate rations. Feedlot diets tend to push urine pH upward, and at alkaline pH phosphate salts crystallise in the urinary tract, which in males can cause a blockage that is frequently fatal. Ammonium chloride lowers urine pH and keeps those salts in solution. This is a preventive nutritional measure, and inclusion rates should be set by a nutritionist against the specific ration.
On heating, ammonium chloride decomposes into ammonia and hydrogen chloride gas. The hydrogen chloride attacks and strips the oxide layer from the metal surface, leaving clean metal for the solder or molten zinc to wet, while the gas evolution helps shield the surface from re-oxidation. This is the reason a hot soldering iron cleaned on a block of sal ammoniac tins so readily.
A representative feed grade specification runs ammonium chloride at 99.5% minimum on a dry basis, loss on drying at 0.5% maximum, ignition residue at 0.2% maximum, lead at 0.0005% maximum, arsenic at 0.0002% maximum, cadmium at 0.0001% maximum, and iron at 0.0007% maximum, with a pH of 4.0 to 5.8 measured at 200 g/L and 25 °C, supplied as a white powder. Specifications vary by source and lot, so confirm against the certificate of analysis for the material you are quoted.
Store ammonium chloride dry in closed original packaging, off damp floors. It is hygroscopic and cakes readily, which is the routine practical complaint about the product. Its solutions are mildly acidic and corrosive to mild steel, copper, and galvanized surfaces over time, so use appropriate materials in dissolving and handling equipment. Keep it away from strong alkalis, which liberate ammonia gas, and from strong oxidizers. Follow the Safety Data Sheet for the specific grade.
Stratus Chemical supplies ammonium chloride in bags and supersacks, in feed, agricultural, and technical grades and in granular and powder forms, with a certificate of analysis provided for each shipment. Tell us the grade, particle size, and volume and we will confirm pricing and availability within one business day.
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