Primary collector

The functional group ia collectors for nonsulfide minerals is characterized by the presence of either a N (amines) or an O (carboxyUc acids, sulfonates, etc) as the donor atoms. In addition to these, straight hydrocarbons, such as fuel oil, diesel, kerosene, etc, are also used extensively either as auxiUary or secondary collectors, or as primary collectors for coal and molybdenite flotation. The chain length of the hydrocarbon group is generally short (2—8 C) for the sulfide collectors, and long (10—20 C) for nonsulfide collectors, because sulfides are generally more hydrophobic than most nonsulfide minerals (10). 

Primary collector An air-cleaning device that removes the larger particulate matter before a HEPA filter. 

Cyclone and high efficiency centrifugals often act as primary collectors followed by fabric or wet type. 

Dry centrifugals used as primary collectors, followed by final cleaner. 

Coarse abrasive particles readily removed in primary collector types. 

Primary collector invariably indicated with concentration and partial size range involved, wet or fabric collectors when used are employed as final collectors. 

The drilling operation, which provides a recess for the installation of a fuse in a 155mm shell, was performed in building 1619. An air driven drill is used to put a recess in the Composition B that has been encased in the nose. The dust generated from this operation is removed by suction through a 5.1 cm (2.0 in) line to a Hoffman primary dust collector. Downstream of the primary collector is a secondary collector used to take any excess not trapped in the primary collector. Two sample areas were selected for study as shown in Figure 5. 

Figure 18.1 shows the rate of flotation of different sulphides from operation A (UG2 Complex). In these experiments, xanthate was used as the primary collector with dithiopho-sphate as the secondary collector. 

The primary collector used in PGM flotation is xanthate. As a choice of secondary collectors, dithiophosphates and mercaptans are used in some operating plants. 

In plant practice, lead oxide minerals are recovered using a sulphidization method with xanthate as the primary collector and mercaptans as the secondary collector. 

In the cases where CuS04 is used as an activator, mercaptan is used as a primary collector. Typical amine consumptions ranged from 80 to 150 g/t. Amine is a fast-acting collector and does not require conditioning time. 

A number of different chromium collectors were also examined, including R84, which is a sulphonate collector as the primary collector, and amine acetate as the secondary collector was found to be effective for chromium flotation. The most critical parameter for selective chromium flotation was the pH. Selective chromium flotation occurs at a very narrow pH region, 1-2.5. Figure 25.12 shows the effect of pH on chromium flotation. 

A close look at the entire apparatus revealed that the surface area of the sample chamber was in excess of 300 cm2 whereas the surface area of 15 g of glass beads, approximately the amount that would usually be in a primary collector, was only 182 cm2. When the fact that the released pheromone had to travel a distance of nearly 20 cm from the point of release to the point of entrap-... 

Vatavuk (1990) pointed out that a key dimension in the sizing of a cyclone is the inlet area. Properly designed cyclones can remove nearly every particle in the 20-30 micron range. Typically, cyclone separators have efficiencies in the range of 70-90%. Because of the low efficiency of these units, they are often used as a first stage of dust collection, or are referred to as primary collectors. 

As previously mentioned, aluminum oxide is used as our primary collector, but other media have been used for special situations. For example, when the Hanford reactors were operating, quantities of hexa-valent Cr were discharged to the Columbia River and subsequently to the ocean, and we were interested in studying the dispersion rate of the Columbia River plume. Alumina did not collect the dichromate ion eflBciently. By using alumina saturated with stannous chloride, the chromium was reduced oa contact to the trivalent state, and this was very eflBciently retained on the bed. We also found that by saturating alumina with barium sulfate, we could collect radium isotopes, presumably by a replacement reaction with the barium on the matrix. For... 

The cyclone type is used as the primary collector and the backhouse type is used as the secondary collector. The fines collected in the primary collector are coarse dust, which returns to the hot aggregate. The fines collected in the secondary collector are fine dust, which, if suitable, is collected in the filler silo. 

The possible void formation in the SG primary collectors under natural circulation cooldown conditions was investigated. This phenomenon could be suppressed by using the degasifier lines. 

The steam generator denoted RGV-4E is a one-body SG [200-202]. The heat-exchange area is incorporated inside as the surface of the bundle of primary pipes, and has a U-shape. The ends of these pipes are fixed to the walls of the primary collector. Inside the SG body are several separators and a system for steam water distribution. The PGV-4E steam generator permits dry steam production with a pressure of about 4.61 MPa at a temperature of about 258 °C. 

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