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General
Q: What is the shelf life of PQ products?
A: Our products have a long shelf life, however, we strongly recommend that the product be used within a year after the date of manufacture. For proper storage conditions, refer to the literature Storing and Handling PQ Liquid Sodium and Potassium Silicates.
Q: What kind of material is used for a storage tank for sodium or potassium silicate?
A: Storage tanks should be of carbon steel, stainless steel, or fiberglass reinforced plastic. Refer to the literature Storing and Handling PQ Liquid Sodium and Potassium Silicates.
Q: What is the best way to heat a sodium silicate tank?
A: Indirect or low-density heating is best with sodium silicate, to prevent hot spots from developing. Refer to the literature Storing and Handling PQ Liquid Sodium and Potassium Silicates.
Q: Can a drum of sodium silicate that has been frozen still be used?
A: It is best to prevent sodium silicate solutions from freezing. Once a drum of sodium silicate has been frozen, it can sometimes be thawed. Please contact Technical Service for recommended thawing procedures.
Q: Can sodium or potassium silicate be colored?
A: Dyes that are stable in alkaline solutions are usually suitable for use in sodium or potassium silicate solutions. Typically, dyes used for detergents can be used with sodium or potassium silicates.
Silicate Chemistry
Q: Why would potassium silicate be used instead of sodium silicate?
A: Although sodium and potassium silicates behave similarly, there are some important differences. Potassium silicates are more soluble, have higher rinseability, are less corrosive, have lower metal impurities, and don’t effloresce (that is, bloom) as much as sodium silicate. Also, potassium silicates are available at higher molar ratios than sodium silicates.
Q: Can liquid silicates be blended with other chemicals?
A: Yes, but blends can be very tricky. Because of the high alkalinity of our products, the silica (SiO2) component is soluble. That is, it stays in solution. If a lower pH chemical is added to silicate, a gel may form.
Q: How can sodium silicate powders be dissolved faster?
A: Use hydrous powders (for example, G® or GD®), which dissolve faster than glass powders. Metasilicates (Metso Pentabead® 20 or Metso Beads® 2048) dissolve the fastest because of their higher alkalinity. Potassium silicate also dissolves faster than sodium silicate. Warming the solution or adding some alkali to the water may help to dissolve the material faster.
Q: What does °Baume’ mean?
A: °Baumé (abbreviated °Bé) is an arbitrary scale used to define the density of a silicate solution. °Baumé can be converted to specific gravity by a mathematical equation. Specific gravity = 145/(145-°B')
Sales
Q: Is silicate available in smaller quantities than 55 gallon drums?
A: Some distributors may sell 5 gallon pails, however, sample sizes are available through the sample program for research and development.
Q: What volumes are available for liquid silicate, powdered silicates, and magnesium sulfate products?
A: Liquids: Tank truck (3500-3800 gallons), 55 gallon drum (in some cases,
drum quantities may be available only through one of our chemical
distributors);
Powdered silicate: 50 lb. or 100 lb. bags, some products are available
in supersacks;
Epsom Salt: 50 lb. bags, 2000 lb. semi-bulk bags;
Magnesium Sulfate Solutions: Tank truck
Q: Can smaller amounts of products be purchased through chemical distributors?
A: Yes, PQ products can be purchased through a number of different distributors. To find the distributor who can serve you best, please contact Customer Service.
Service
Q: Does PQ help to develop their customers’ products?
A: Yes, PQ provides technical advice, samples, and literature to help our customers in developing new products and new markets.
Q: Can PQ analyze my sample?
A: While we generally do not analyze samples, we have the capabilities. Please contact Technical Service for further information.
Detergents
Q: What is the DOT Shipping Classification for METSO PENTABEAD® 20 and METSOBEADS® 2048?
A: Please see the MSDS' for Metso Pentabead 20 and Metsobeads 2048
Q: What level of sodium metasilicate can be used in a formulation without labeling it a DOT Corrosive?
A: The corrosive nature of a formulated product is affected by the concentration as well as interaction of the ingredients in the formula. PQ recommends that formulators have their most concentrated products tested to ascertain their corrosivity.
Q: When I make up my detergent formulation it develops a white precipitate after a day or two. How can I prevent this?
A: In many cases, soluble calcium or magnesium may cause this precipitate. Sodium or potassium silicate formulations should be made up with softened water or with a chelating agent, such as polyphosphate or EDTA, to sequester the calcium and magnesium in hard water. Please contact Technical Service for other suggested solutions to this problem.
Films and Coatings
Q: How can sodium or potassium silicate films be made water resistant?
A: All the water must be removed from the film. This usually requires heat curing. Increase the temperature slowly to 200-210°F to slowly remove water and prevent bubbling of the film. Final curing can be done at 300-400°F. Refer to the literature Bonding and Coating Applications of PQ Soluble Silicates.
Q: Why does a silicate film blister when it is heated?
A: When a silicate film is heated quickly, water in the film turns to steam and causes the film to blister. Blistering can be prevented by first heating slowly to 200-210°F. Refer to the literature Bonding and Coating Applications of PQ Soluble Silicates.
Q: Is there a way to chemically set a silicate film?
A: Multivalent cationic metal compounds, such as calcium ions, react with silicate to form an insoluble silicate compound. A 5-10% calcium chloride solution can be used as an after-treatment to a silicate coating. Refer to the literature Bonding and Coating Applications of PQ Soluble Silicates.
Q: Can silicate films be made more flexible?
A: Higher ratio liquids (for example, SiO2/Na2O = 3.22) form a brittle film when dried at room temperature. However, lower ratio liquids (for example, 2.00) dry into more flexible films because they retain more water. One trick to making a flexible film using a high ratio liquid is to add materials such as sugar, glycerine or sorbitol. These compounds help by retaining the water needed for flexibility. Note that if a flexible film is heated to the point at which it loses more water, it will become brittle. Refer to the literature Bonding and Coating Applications of PQ Soluble Silicates.
Q: Why does a sodium silicate film or coating develop a white appearance?
A: The whitening is called efflorescence or blooming. Carbon dioxide in the atmosphere reacts with the sodium in the sodium silicate coating to form sodium carbonate on the surface of the coating. Efflorescence occurs especially in hot, humid conditions. Because potassium carbonate has a higher solubility (that is, it is more difficult for it to precipitate), potassium silicate tends to effloresce less than sodium silicate,
Q: Are silicate films stable at high temperatures?
A: Silicate films that are completely dehydrated have excellent resistance to high temperatures. Typical softening points of 1200°F and flow points of 1500°F are seen with films made from high ratio sodium silicates.
Q: Do you manufacture Epsom Salt with low chlorides and low Fe?
A: Yes. Chloride content is less than 50 ppm and Fe is less than 0.5 ppm.
Q: Is potassium silicate more expensive than sodium silicate?
A: Yes, due to higher cost of raw materials and processing.
Q: Can potassium silicate be substituted for sodium silicate in general applications?
A: In many cases, yes, but sodium silicate should not be substituted for potassium silicate.
Q: Is Caustic (NaOH) compatible with sodium silicate?
A: Yes, in all combinations except a 1:1 ratio and solids >35%, Caustic can precipitate a crystalline metasilicate.
Q: Are concentrated mineral acids compatible with sodium silicate?
A: No.
Q: Do you have a Drug Master File (DMF) for your Magnesium Sulfate Heptahydrate(Epsom) ?
A: Yes.
Q: Do you (PQ) allow Independent Quality Audits of your facilities?
A: Your sales representative will be glad to discuss any audit requirements you may have.
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