Frequently Asked Questions
Water
Q: What is the shelf life of liquid alum? show answer
A: General Chemical states that the liquid alum (aluminum sulfate) “shelf life” is one year from the date of manufacture. This is a standard time frame, but can be extended well beyond the listed shelf life under certain circumstances. Under normal storage conditions, the actual assay of the product (strength expressed as % Al2O3) is relatively stable. If conditions minimize evaporation of water such that crystallization is prevented through over-saturation, or if contamination of the product is prevented, then the physical shelf life of the liquid product can also be extended for several years. However, General Chemical does not guarantee the product past one year from the date of manufacture, the “shelf life”.
Q: Why are there different values for the strength of liquid alum? show answer
A: There are various ways that liquid alum can be expressed for concentration and dosage. Typically a Certificate of Analysis for liquid alum will provide the assay of the product expressed as the aluminum oxide equivalent, or Al2O3, typically ranging from 8.0 to 8.4%. Also liquid alum dosage is commonly expressed as the dry alum equivalent, where dry alum will have the formula of Al2(SO4)3•14H2O. A common value used for expressing liquid alum strength is as a 48.5% dry alum equivalent by weight. The real form of aluminum in liquid alum is as aluminum hexahydrate,
Al(H2O)63+. A Material Safety Data Sheet may use one of the CAS formulas for alum (aluminum sulfate), 10043-01-3, which is represented by “anhydrous” aluminum sulfate or Al2(SO4)3, where liquid alum has an approximate equivalent weight of 27.9%. These weight equivalents for the various molecular formulae are determined through stoichiometric mathematical conversions.
Q: What are the recommendations for making a solution of alum from the dry product? show answer
A: Commercial liquid alum (aluminum sulfate) is typically a solution near its saturation point, where the “Dry Alum” equivalent is approximately 48.5% on a weight/weight basis. Dry alum can be expressed as Al2(SO4)3•14H2O. The 14 waters of crystallization are included in the formula for Dry Alum. Because of the difficulty of creating a solution of liquid alum at 48.5% dry alum equivalent strength starting from a dry product, it is usually recommended that batches of alum solution are created, targeting 10 - 25 % by weight as dry alum equivalent (too dilute - hydrolysis takes place; too concentrated - takes too long to dissolve). Typically, it is recommended to follow a procedure using a 50 lb. bag of dry alum, made up to 55 gallons in a standard drum (lined/poly) with water. Warm water dissolves dry alum faster than cool water. The resulting alum solution will be 10.3 % dry alum solution by weight with the following properties: Specific Gravity = 1.062; Liquid Density = 8.86 lbs./US gallon. The 55 gallon drum is usually filled up half-way with water, and the alum is added slowly under mixing conditions. After the alum is added, the drum is brought up to the 55 gallon volume level with water, and mixing is continued until the dry alum is completely dissolved.
Q: If a dilute solution of liquid alum is desired for an application, what critical guidelines should be followed? show answer
A: The main objective is to obtain a concentration of alum solution where the pH of the alum and water solution does not go above 3.5. Once you get in the pH range above 4, then hydrolysis could begin, creating flocs in the solution similar to what happens in water treatment, forming aluminum hydroxide. If the water used for dilution of liquid alum is to be set at a constant rate with variable liquid alum flow rate, it should be important that the lowest potential liquid alum flow rate used in conjunction with the constant dilution water flow creates a solution that does not exceed a pH of 3.5. Higher flow rates of liquid alum will produce solutions lower than 3.5 if this criteria is followed.
Q: What temperatures cover the delivery of liquid alum and the minimum recommended storage temperature? show answer
A: The delivery temperature can be as high as 52 °C (125 °F). The minimum temperature should be 7.2 °C (45 °F) at its lowest, but can be set anywhere between 7.2 °C (45 °F) and 15.6 °C (60 °F) as a minimum temperature set point. The actual freezing point of liquid alum is approximately -15 °C (5 °F).
Q: What is the difference between free alumina (Al2O3) and assay as total alumina (Al2O3) for alum? show answer
A: Aluminum sulfate is produced through an exothermic reaction between an aluminum source, such as alumina trihydrate or bauxite, and sulfuric acid with water used in the process. It has been commonplace to express the metal equivalent content of metal based compounds as the metal oxide. For aluminum sulfate, the total strength of the product is usually expressed as % aluminum oxide (Al2O3), or “alumina”. Even though there may be minimal to no alumina in the product, the assay as alumina is a mathematical stoichiometric conversion of the strength expressed as aluminum metal (Al). “Free alumina” is the measured excess aluminum metal in the finished product as compared to the balance of aluminum that has consumed all of the sulfuric acid during the digestion process. If excess sulfuric acid existed, where the entire aluminum source had been consumed by the acid, then there would be “free acid”.
Q: Are General Chemical’s products NSF/ANSI Standard 60 certified? show answer
A: General Chemical has over 40 manufacturing facilities that have trade names listed in accordance with NSF/ANSI Standard 60: Drinking Water Treatment Chemicals - Health Effects. The most direct method for searching for listed product trade names is through NSF’s search page at http://www.nsf.org/Certified/PwsChemicals/.
Q: What are the feed system requirements for polyaluminum (hydroxy)chloride (PACl) based products? show answer
A: Diaphragm and centrifugal pumps should have wetted parts of Hastelloy-C276 or a suitable plastic material and TFE diaphragms, in the case of diaphragm pumps, and TFE packing for centrifugal transfer pumps. PVC or CPVC are most commonly used for plastic material of construction for strainers, piping, and valves, with CPVC recommended for the unloading line to the storage tank. Natural gum rubber hose and semi-flexible polyethylene pipe with PVC inserts can be used if they are suitable for the pressures involved. More detailed information for specific system devices can be obtained by contacting General Chemical Technical Service for the Water Chemicals Group.
Oil Refining
Q: How is sulfuric acid used in the Oil or Oil Refining industry? show answer
A: Sulfuric acid is used by oil refineries in the alkylation process as a catalyst to produce gasoline.
Q: What is sulfuric acid re-generation? show answer
A: The sulfuric acid re-generation process involves taking a weak spent sulfuric acid stream from a commercial application (80-90% acid) and thermally decomposing it along with sulfur to generate fresh sulfuric acid (93-99% acid) that is recycled back to the commercial application to be used again.
Q: Is General Chemical interested in developing new partnerships in the sulfuric acid business by providing production, logistics, and market knowledge? show answer
A: Yes we would be interested in discussing these opportunities. We have extensive experience at several locations with multiple regeneration customers to serve as background to help potential new customers.
Pharmaceutical
Q: Do all of your vaccine adjuvant products have the same isoelectric point (IEP)? show answer
A: No, we specialize in providing a range of products for different applications and have the ability to customize products as well.
Q: Is your product sterilized? show answer
A: All of our products except Rehydragel CG are sterilized via gamma irradiation. We also offer non-sterilized products upon request.
Food/Beverage
Q: What anticaking agents and blends do you offer with potassium chloride? show answer
A: We offer magnesium carbonate, magnesium stearate, tricalcium phosphate, and silicon dioxide as anti-caking agents. In addition, we offer 50% blends with sodium chloride (table salt).
Industrial Processing
Q: What are the recommendations for making a solution of sodium nitrite from the dry product? show answer
A: Sodium nitrite should readily dissolve in water, warm or cold. But if one needs to make a higher concentration solution such as in the 38-40% range, then it may be desired to use the following guidelines. Sodium nitrite has a negative heat of solution of 91.6 Btu per pound. Dissolving the solid material will produce a cooling effect, so water used for dissolving should be fairly warm to get to the higher concentrations. It has a eutectic point at 39% concentration that has a crystallization temperature of -26 °C (-14.8 °F). The cooling effect of dissolving the sodium nitrite will lower the temperature of the mixture by about 65°F when trying to make a ~40% solution. In order to avoid lumping or caking, the water should be preheated as hot as may be practicable, 150 °F or higher.
Pulp/Paper
Q: What method would be recommended to determine the level of alum in either the thin or thick stock, or even the finished paper product? show answer
A: Over the years, General Chemical has developed an analytical method which allows for the determination of the concentration of aluminum originating from the application of liquid aluminum sulfate (alum) within the papermaking system. Known as “Alum Op” or optimization, the procedure utilizes a specific fluoride ion electrode to measure available soluble fluoride, which is used as a titrant against soluble trivalent aluminum. The thick stock, thin stock, tray water or paper sample off the wire is diluted to a recommended concentration, if required, and adjusted to a pH of 3.8 with a buffer solution. At this pH, all of the aluminum is changed to a soluble trivalent specie, which can complex with the sodium fluoride solution used in the titration process under procedural guidelines. An endpoint of an excess of sodium fluoride allows for the determination of alum in the original sample through calculations. Comparing various sample results from specific locations within the papermaking process will assist in evaluating the efficiency of alum usage in the process. General Chemical can provide the procedure for your reference and usage.
Q: Can alum be used in an alkaline papermaking process? show answer
A: The initial belief was that at alkaline pH levels, aluminum sulfate (alum) applied to paper stock would only produce insoluble aluminum hydroxide or even aluminum anion as aluminate through hydrolysis. Forms of aluminum hydroxide along with other multivalent and polynuclear cationic species formed can provide benefits from alum application. These may include improved retention, sizing, and anionic trash control. Some of the primary criteria for alum addition under these conditions include application of a dilute liquid alum to a point close to the headbox or in the tray under thorough mixing at the point of application. The relatively high dilution of alum, where the dilution takes place relatively close to the actual application point at approximately a 100:1 ratio by volume, will minimize any pH shock that could result in aluminum hydroxide deposition. It is important to use alum efficiently as not to provide excess alum to the system that will not be utilized for its intended application.
Q: We currently have a separate acid feed system for pH control and a liquid alum system for our application. Can a single product be provided, where both the acid and alum can be applied, removing the acid feed system entirely? show answer
A: General Chemical has a line of acidified alum products available which have a set ratio of alum and sulfuric acid for each product. If the alum and acid dosage levels are applied at a ratio which does not have much variation, then an acidified liquid alum product may be an option. What is needed, to determine the specific product to be substituted for the liquid alum and acid, are any of the following parameters: volumetric flow rate, dry equivalent dosage by weight, liquid equivalent dosage by weight, or any other method of expressing the application of the two separate products, by weight or by volume, with or without a time component.
Agriculture
Q: Can I apply Al+Clear® Liquid A7 with a fertilizer spray rig? show answer
A. Only custom applicators are allowed to apply Al+Clear® Liquid A7. It requires specialized equipment and training to apply Al+Clear® Liquid A7.
Q: Why does Al+Clear® Poultry Grade Alum and Al+Clear® Liquid A7 last longer than other litter amendments? show answer
A. Aluminum sulfate based litter amendments are referred to as Lewis Acids. Lewis Acids are unique in that they form buffered intermediates that meter out acid when exposed to moisture, prolonging acidification of litter and conversion of volatilized ammonia [NH3] to litter bound ammonium [NH4+]. Only Al+Clear® products contain Lewis Acid.
Q: Do you get immediate ammonia knock down with Al+Clear® Liquid A7? show answer
A. An important component of the Al+Clear® Liquid A7 formula is sulfuric acid that when applied to the litter immediately reacts with volatilized ammonia [NH3] converting it to litter bound ammonium [NH4+]. The aluminum sulfate part of the formulation [Lewis Acid] provides extended ammonia control.
Q: Will Al+Clear® Liquid A7 or Al+Clear® Poultry Grade Alum improve the nitrogen content of my litter? show answer
A. By converting volatilized ammonia [NH3] to litter bound ammonium [NH4+] when using Al+Clear® products as litter amendments, nitrogen is retained rather than being lost to the atmosphere, increasing the nitrogen content of the litter, and consequently improving the value of spent litter as fertilizer.
Q: Do Al+Clear® products add sodium to the litter and house floor (pad)? show answer
A. No Al+Clear® products do not add sodium to litter or house floors (pads). Long term studies with Al+Clear® have shown actual increased plant yields compared to test plots receiving non-treated chicken litter fertilizer.
Q: Is it safe to work in a poultry house treated with Al+Clear® Liquid A7? show answer
A. Exposure of Al+Clear® Liquid A7 to the grower, equipment and chickens can be eliminated following the applicators instructions. Equipment should be up and out of the way before the application takes place preventing exposure to Al+Clear® Liquid A7. During the application fans should be turned off to prevent turbulence. Following the application the grower should leave sufficient tunnel fans on to assist in the drying process. Depending on the moisture content of the litter drying can occur in a matter of minutes to overnight. For specific instructions on safe handling Al+Clear® products, refer to specific Material Safety Data Sheets (MSDS).
Q: Will an Al+Clear® Liquid A7 application have any effect on my equipment? show answer
A. Al+Clear® Liquid A7 is applied before equipment is set into place and it will not come in direct contact with Al+Clear® Liquid A7. The application equipment is designed to spray a coarse spray of Al+Clear® Liquid A7 that is applied directly to the litter without creating a mist or aerosol. No feed pans or feeder lids will be exposed to Al+Clear® Liquid A7 during the application process.
Q: Is there anything that a grower needs to do to make the Al+Clear® Liquid A7 application more effective? show answer
A. There are several things that are important in order to insure that an application is successful and effective:
Pre-Application
- Timing of application is important. Al+Clear® Liquid A7 should be applied 2-3 days prior to placement of baby chicks.
- Litter conditions should dictate application rates. Ask you regional technical sales representative for assistance in determining the proper application rate for differing litter conditions.
- The contract grower should be at the farm at the time of the application if at all possible.
- Lights should be on in the house during the application.
- End doors should be left open unless it is raining.
- Pre-ventilate prior to the application. Either turn fans on minimum ventilation in advance of the application to get ammonia levels to a safe level for the application [20 ppm] or turn on two tunnel fans for 10 minutes to purge the house of ammonia prior to the application.
- Cut fans off during the application to prevent the possibility of creating turbulence that might result in overspray.
Post-Application
- If the application is only performed in the brood chamber it is vitally important to drop the center curtain and equipment as soon as possible after the application to prevent ammonia from the off-end of the house rolling over onto the treated brood area. It is also important to go into minimum ventilation as soon as the application is performed. It is important to pull air from the brood end of the house to the off-end fans and exhaust. Not following this procedure can dramatically reduce the effectiveness of an Al+Clear® Liquid A7 application.
- Keep in mind that litter amendments are not a substitute for proper ventilation. It is recommended that the contract grower adhere to the integrators ventilation policies regardless of the effectiveness of the ammonia control. Moisture has to be eliminated from the broiler house and without adequate early ventilation, litter conditions can deteriorate rapidly causing a variety of husbandry problems.
Q: Who do I call if I have a problem with an application? show answer
A. The first person to call is the applicator. If there are additional questions or the problem is not resolved, contact your area technical sales representative.
Q: How long can I expect Al+Clear® Liquid A7 to control ammonia? show answer
A. Ammonia control is dependent on many factors (for example, application rate, house preparation, readiness for the application, properly conducted application, age and depth of litter, litter moisture, C:N ratio of litter, etc., but generally speaking, Al+Clear® Liquid A7 applications typically last anywhere from 10 – 21 days. The main objective is to get chicks out of the brood chamber with minimal exposure to volatilized ammonia and to maintain ammonia control as long as possible using customary application rates.
Q: Do you have to pre-heat a house when using Al+Clear® Liquid A7 or Al+Clear® Poultry Grade Alum? show answer
A. Not in the traditional sense. General Chemical recommends some form of in-house composting which is a more cost effective way to remove moisture and ammonia from built-up litter when done properly.
Q: Are Al+Clear® products eligible for EQIP? show answer
A. All Al+Clear® products (Al+Clear® Poultry Grade Alum (dry), Al+Clear® Liquid, and Al+Clear® Liquid A7) are approved for both Air and Water Quality Standard EQIP programs. Al+Clear® products are the only products approved for Water Quality Standard EQIP programs. Contact your regional technical sales representative for details.
Q: Where do I sign up for EQIP? show answer
A. To sign up for EQIP you will need to first contact your local NRCS office and they will provide instructions regarding documents that you will need for the application process.
Q: Are General Chemical products eligible for cost share? show answer
A. All General Chemical products are eligible for both Water and Air Quality Standards.
