Phosphate cleaning systems

Antiflutter adhesives are used to adhere and isolate outer body panels (i.e., hoods, doors and deck lids) from inner reinforcements. They need to adhere to steel contaminated with stamping lubricants and be resistant to washont from phosphate cleaning systems. Many of these adhesives are designed to expand during the paint-bake process. Heat-cnrable rubber formnlations are used commonly, inclnding SBR and polybntadiene. 

Figure 6.21 Flow schematic of an electrocoat paint ultrafiltration system. The ultra-filtration system removes ionic impurities from the paint tank carried over from the chromate/phosphate cleaning steps and provides clean rinse water for the counter-current rinsing operation...

Addition of isopropylene, low-molecular-weight glycol ethers, cyclohexanol, certain amine compounds, fatty acids, and phosphate esters as cosolvents to a detergent blend is necessary to incorporate water in water-containing detergent blends. It is particularly important if water is added to the dry cleaning system with the detergent to facilitate the removal of water-soluble soils. 

The most effective way to prevent SCC in both stainless steel and brass systems is to keep the system clean and free of deposits. An effective deposit control treatment is imperative. A good corrosion inhibitor is also beneficial. Chromate and phosphate have each been used successfully to prevent the SCC of stainless steel in chloride solutions. 

These materials are now widely used for coating both steel and concrete surfaces that are subject to a particularly aggressive environment (e.g. North Sea oil platforms). There is less validity for their use under normal atmospheric conditions since they are relatively expensive and tend to chalk on exposure to sunlight. However, their use as zinc phosphate, pretreatment or blast primers for blast-cleaned steel which is subsequently overcoated by any other paint system is an extremely valuable contribution to the painting of new steel work. 

A 200-mL water sample is adjusted to pH 6-8 using 1 M NaOH followed by the addition of 2mL of methanol. The sample is concentrated and cleaned up using two consecutive cartridges, a 2-g Cig cartridge followed by a 1-g Cig cartridge. The residue is reconstituted in 4mL of water-phosphate buffer (pH 7)-ACN-TBABr (90 5 5 0.3) for analysis using HPLC/UV with a two-column switching system. 

Sample preparation is rather involved. A sample of urine or fecal matter is obtained and treated with calcium phosphate to precipitate the plutonium from solution. This mixture is then centrifuged, and the solids that separate are dissolved in 8 M nitric acid and heated to convert the plutonium to the +4 oxidation state. This nitric acid solution is passed through an anion exchange column, and the plutonium is eluted from the column with a hydrochloric-hydroiodic acid solution. The solution is evaporated to dryness, and the sample is redissolved in a sodium sulfate solution and electroplated onto a stainless steel planchette. The alpha particles emitted from this electroplated material are measured by the alpha spectroscopy system, and the quantity of radioactive plutonium ingested is calculated. Approximately 2000 samples per year are prepared for alpha spectroscopy analysis. The work is performed in a clean room environment like that described in Workplace Scene 1.2. 

Suds suppressors (LD, DW, ADW, HC) Limit suds amount when suds will interfere with cleaning Sensitivity to wash temperature, water hardness, and builder system Efficiency on the surfactant system Alkyl phosphates Silicones Soap 0-5% 0-5%... 

Sulfate - pRUG DELIVERY SYSTEMS] (Vol 8) - [FIBERS-ACRYLIC] (Vol 10) - [CELLULOSE] (Vol 5) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COAL] (Vol 6) - [FILTRATION] (Vol 10) - [FINE ARTEXAMINATION AND CONSERVATION] (Vol 10) -in geothermal resources [GEOTHERMAL ENERGY] (Vol 12) -m phosphoric acids [PHOSPHORIC ACID AND PHOSPHATES] (Vol 18) -in steam [STEAM] (Vol 22)... 

The column-switching system was applied to the determination of STR and DIHS in pork and bovine muscle and kidney. Perchloric acid was used to precipitate proteins and extract analytes from the tissue. The clear supernatant was further cleaned up by an offline SPE on a cation-exchange SPE column. After the washing of the cartridge with water, the analytes were eluted with phosphate buffer (pH 8.0) and diluted with HSA, perchloric acid, and water. The enrichment was achieved in the online mode. After loading the sample, the enrichment precolumn was flushed with HSA at pH 3.3 for 5 min. Using the ratio of MeCN to aqueous component of 83 17... 

Offline passivation involves treatment of equipment currently out of service. Treatment levels are typically higher consequently, passivation is completed more quickly. Passivation of nonchromate treatment generally uses either a polyphosphate, zinc, molybdate or other nonchromate-based inhibitor in combination with various surface-active cleaning agents. The passivation solution should be disposed of after the pretreatment stage, rather than dumped back into the cooling system where the potential for fouling can exist due to the precipitation of pretreatment compounds such as zinc or phosphate. Table 8.1 outlines both online and offline pretreatment procedures. 

Any proposal for a future chemical inhibitor program needs to employ an alkaline zinc/stabilized phosphate base, similar to that currently used, as required by the customer. However, as noted previously, the inhibitor needs improved deposit control agent (DCA) performance. This is especially important, as a new program would not start with a properly cleaned cooling system (an on-line clean will be recommended, but is likely to have only limited effect). Thus the inhibitor would include better/more polymers. 

The cooling system underwent a simple cleaning procedure, but the passivation and initial inhibitor dose stages were rolled into one. The plan was to maintain 250 ppm of inhibitor in the system for a 3-day period (typical inhibitor dose would be 100 to 120 ppm). However, almost no stabilizer dispersant was added and the cooling water was persistently cloudy. Thus the passivation program was of little value, and the turbidity indicated phosphate precipitation. 

Most cleaning/passivation formulations tend to be fairly simple and low cost, especially when large cooling systems are involved, although more complex, multifunctional formulations do exist. The products are added to the system water at 0.5 to 2.5% v/v, depending on system size, with the amount of phosphate initially present usually held to around 500 to 1000 ppm PO4. 

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