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Home /Our Solutions/Industrial/Metal Cleaning and Treating

Metal Cleaning and Treating

Metal cleaning solutions provide optimal conditions for post-treatment applications.

Cleaning
During post-metal treatment operations, metal surfaces must be thoroughly cleaned before a finish can be applied successfully. All foreign matter must be removed prior to painting or other surface preparation for acceptable adhesion to occur. Foreign matter includes:

  • Grease
  • Oil
  • Particulates
  • Corrosion oxides
  • Scale
  • Stencil markings

Effective surface cleaning is achieved through a combination of detergency, chemical reaction, solvent dissolution and mechanical action. Principal methods employed in cleaning metal parts include spray, soak and electrolytic.

ICL phosphates and phosphoric acids are used extensively in formulating both alkaline and acid cleaners. Alkaline cleaners are more effective in removing grease, oils, fatty soils and solid soils. Alkaline cleaners primarily contain water, builders and surfactants. Builders provide alkalinity and soften the water used in the cleaning process. Typical phosphate builders include:

  • Sodium tripolyphosphate (STPP)
  • Tetrasodium pyrophosphate (TSPP)
  • Tetrapotassium pyrophosphate (TKPP)
  • Trisodium phosphate (TSP)
  • Potassium tri-polyphosphate (KTPP)

Acid cleaners are more effective on scale, smut, lime and milkstone. They are typically composed of mineral acids, organic acids or acid salts, in combination with a wetting agent and detergent. Inhibitors and solvents may also be added for specific applications. ICL phosphoric acid, monosodium phosphate (MSP) and sodium acid pyrophosphate (SAPP) are commonly used ingredients in acid cleaning formulations. Acid pickling refers to a relatively more severe treatment for the removal of scale from semi-finished mill products such as forgings or castings. Commonly used acids for pickling stainless steels include nitric, sulfuric, hydrochloric and phosphoric. Phosphoric acid/ethylene glycol monobutyl ether mixtures are widely used for cleaning grease, oil, light rust and scale from iron and steel.

Treating
Phosphoric acid or phosphate salts are typically used to enhance corrosion resistance and improve the adhesion properties of metal surfaces before additional coating operations occur. They provide a base for oils or other rust preventive treatments that lubricate and resist wear and provide a base for adhesives in plastic-metal laminations, resulting in a surface on steel that facilitates forming operations. The phosphating process is of major industrial importance for protecting iron and steel surfaces, and may also be applied as a protective treatment for zinc, aluminum, cadmium and magnesium-based metals.

Typical phosphating solutions contain phosphoric acid, a phosphate salt (MSP, DSP, or SAPP) and a variety of accelerators such as nitrates, nitrites, chlorates, peroxides, sulfites, molybdates, borates or citrates. Iron and zinc phosphate coatings are the most commonly used. Manganese phosphates are used as a base for oil or lubricants, which represents the balance of the phosphating market. Phosphate coating solutions can be applied either by spray or immersion, depending on the application and coating weight desired.

The chemical polishing of aluminum, often called bright-dipping, is a popular means for obtaining a specular or bright finish on many types of aluminum fabrications and extrusions. Bright-dipping consists of immersing pre-cleaned aluminum parts into a phosphoric-nitric acid bath held at an elevated temperature. This process involves the selective attack on the aluminum surface protrusions, resulting in the leveling of the overall surface. A very smooth, specular finish can be obtained, which is then anodized, dyed and sealed. Examples of items with bright-dip finishes include lighting fixtures and reflectors, shower door frames, window frames, picture frames, lawn furniture and trim for automotive, luggage and appliance applications. Phosphoric acid is widely used in this application, together with fume suppressant and copper, which helps improve the specularity of the finish.

Chemical polishing of metals is often done electrolytically. This process involves removal of the metal at the high spots of irregularities with little or no dissolution of metal in the low spots or “valleys.” The base metal must be reasonably smooth to produce a satisfactory finish. Stainless steel, steel, brass, aluminum, nickel, copper and zinc are among the metal surfaces that can be electropolished. Highly concentrated solutions of phosphoric and/or sulfuric acids are frequently used for electropolishing. Chromic acid also finds some use in this application.

Products in

Product Info
Disodium Phosphate Anhydrous Softens boiler water, potable water treatment, phosphatizing metal cleaner, textile dye baths buffering agent.
Hemipotassium Phosphate Solid acid, fertilizer, acid cleaning, rust removal, milkstone removal, bonding agent in ceramics.
Makrophos® 5050 Preparation of potassium phosphates as solution for metal cleaning and treating.
Monosodium Phosphate Used in a wide range of industrial applications, including: water conditioner, acid cleaner, metal phosphatizing, cotton sulfur dyeing, electroplating buffer, dairy cleaner and feed supplement. Stabilization and process additive for toothpastes.
Phosphoric Acid (35-85%) Phosphoric Acid (35 – 85) refers to phosphoric acid at various concentrations between 35 and 85% can be used. We offer specific grades of 35%, 36%, 50%, 70%, 75%, 80% and 85%.
Potassium Tripolyphosphate Potassium tripolyphosphate (KTPP) is a dispersant and sequestrant of very high solubility. Some of its applications inclde: pigment dispersion in latex emulsion paints and builder in liquid detergents.
Potassium Tripolyphosphate 50% Solution Used in Pigment dispersion in latex emulsion paints, builder in liquid detergents, suspending agent, specialty boiler water compounds.
Sodium Acid Pyrophosphate Sequestration, deflocculation, corrosion inhibitor, chelation of calcium and iron.
Sodium Hexametaphosphate Attributes: sequestration, deflocculation, infinitely soluble, corrosion inhibitor, and the chelation of calcium and iron.
Sodium Tripolyphosphate Sodium Tripolyphosphate (STPP) is a very effective sequestering and dispersing agent. It finds application in many industrial applications, including cleaning, water treatment, and many others.
Tetrapotassium Phosphate 60% Solution Buffering Agent, corrosion & scale control, dispersing agent, water softening, metal chelation, liquid detergent builder, metals control in water treatment.
Tetrasodium Pyrophosphate Tetrasodium pyrophosphate (TSPP) is an effective sequestrant and dispersing agent used in detergents, clay processing, drilling muds, cements, water conditioning, textile processing, paper manufacturing, bleach bath stabilizer and metal cleaners.
Trisodium Phosphate Trisodium Phsophate (TSP) is used in most dry alkaline formulations, aiding in the removal of fat and protein deposits and keeping all soils suspended to prevent redeposition.