Grading media filter

Half-burned dolomite (CaCOs MgO) is used in some treatment plants as a closely graded granular filter medium to raise the pH of water without the risk of over-dosing. 

The flotation unit maximum loading is 2.1 L/s/m2 (3.1 gal/min/ft2). The maximum filtration rate is 1.7 L/s/m2 (2.5 gal/min/ft2). Each filter compartment is backwashed at or more than 10.2 L/s/m2 (15 gal/min/ft2) during the backwash operation. The single-medium backwash filter consists of 28 mm (11 in.) high-grade silica sand. The effective size and uniformity coefficient for the sand are 0.35 mm and 1.55, respectively. 

Calcium hydroxide [1305-62-0] M 74.1. Heat analytical grade calcium carbonate at 1000° during Ih. Allow the resulting oxide to cool and add slowly to water. Heat the suspension to boiling, cool and filter through a sintered glass funnel of medium porosity (to remove soluble alkaline impurities). Dry the solid at 110° and crush to a uniformly fine powder. 

Cyanamide pigments are produced from industrial-grade calcium cyanamide which is first dissolved. Sulfide and phosphide impurities are precipitated as iron or lead salts [5.127]—[5.132] or oxidized [5.133] [5.135] and filtered off together with graphite impurities. The pure calcium cyanamide is reacted in an aqueous medium with soluble lead or zinc salts or with a slurry of lead oxide or zinc oxide [5.127], [5.129], [5.133], [5.136]—[5.138]. The pigments are filtered, washed, dried, and ground. Zinc cyanamide [5.139] and pure lead cyanamide are not explosive. An explosion reported during the production of lead cyanamide was caused by contamination with small amounts of acid or nitrates [5.140],... 

The compounds (2-5 mg) were dissolved in 2.5 mL of THF (Aldrich, spectrophotometric grade) and 0.25 mL of water. 2-Hydroxypropylcellulose (Hercules, Klucel E 60,000 200mg) was then added and the mixture was shaken until the HPC dissolved completely. The solution was then placed in a open quartz cell (1mm deep) and evaporated in a circulating air oven (35°C) to dryness leaving a transparent film suitable for absorption measurements. Irradiation of the films was performed with the set-up described previously [11] using a medium pressure mercury lamp and a borosilicate glass filter to eliminate wavelengths below 300 nm. 

The abdomen stratum corneum samples were homogenized in 1 2 0.8 (v/v/v) chloroform methanol deionized water (1 ml solvent mixture/ 10 mg tissue). Solvents (Baker HPLC grade) were distilled prior to use. Homogenized tissue was left overnight and then filtered through a fine mesh fritted glass filter. Lipid extraction media were separated into two phases with the addition of chloroform and water (7.6 2 2 (v/v/v) extraction medium chloroform water)... 

Many small-scale filters simply consist of a fixed, rigid medium, robust enough to withstand limited pressures, mounted in a suitable housing. These filters, which are also vacuum operated, are used to clarify by depth filtration. Media are composed of sintered metals, ceramics, plastics, or glass. Filters prepared from closely graded and sintered chemical powders are suitable for the sterilization of solutions by filtration on a manufacturing scale. 

A solution of 1.0 g (2.7 mmol) of 7.1b in 250 mL of spectral grade acetone was irradiated (immersion well apparatus, Pyrex filter sleeve, Hanovia 450 W medium-pressure mercury lamp) under a nitrogen atmosphere until capillary gas chromatography indicated little... 

How much faster is gravity filtering with medium-grade filter paper using good technique than poor technique ... 

UP FLOW FILTER - A unit containing a single filter medium, usually with graded sand. 

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