Sinter machine

A typical up-draft sinter machine (Fig. 2) has an endless belt of malleable iron pallets with grate bottoms upon which the charge is evenly spread. Beneath the pallets, wind boxes produce an up-draft of air through the charge. At the feed end, an ignition box starts the roasting. The combustion products, mostly SO2 and SO, are collected, usually for sulfuric acid production (see Sulfuric acid and sulfur trioxide). 

Another preparation method is a sintering process where phosphate ore, sand, and coal are blended together and ignited on the grates of a sintering machine. Air is pulled through the blend, and the entire mass is allowed to bum. The resulting fused bed of material is then cmshed and screened to the appropriate size distribution, and the undersized material is reprocessed. 

Typical applications in the chemical field (Beaver, op. cit.) include detarring of manufactured gas, removal of acid mist and impurities in contact sulfuric acid plants, recovery of phosphoric acid mists, removal of dusts in gases from roasters, sintering machines, calciners, cement and lime Idlns, blast furnaces, carbon-black furnaces, regenerators on fluid-catalyst units, chemical-recoveiy furnaces in soda and sulfate pulp mills, and gypsum kettles. Figure 17-74 shows a vertical-flow steel-plate-type precipitator similar to a type used for catalyst-dust collection in certain fluid-catalyst plants. 

The machine most commonly used for sintering iron ores is a traveling grate, which is a modification of the Dwight-Lloyd continuous sintering machine formerly used only in the lead and zinc industries. Modern sintering machines may be 4 m (13 ft) wide by 60 m (200 ft) long and have capacities of 7200 Mg/day (8000 tons/day). 

Sinter machine discharge Particulate matter Multiple cyclones, baghouse, or low-energy wet scrubber... 

The waste must have demonstrated recoverable levels of metals. Units that may be covered by this exemption include pyrometallurgical devices such as cupolas, sintering machines, roasters, and foundry furnaces, but do not include cement kilns or halogen acid furnaces. 

Duty heat transfer coefficients, 13 203-204 Duvadilan, molecular formula and structure, 5 11 It Dwight-Lloyd continuous sintering machine, 16 141... 

Sintering machines, 26 565 molybdenum, 17 9-10 of polytetrafluoroethylene, 18 300-301 phosphate ore, 19 7 Sintering process, 10 41, 94, 95 for ceramic membranes, 15 814, 815 sulfur recovery from, 23 772 with tin powder, 24 798-799 Sinter processes... 

The lead concentrate must he roasted for effective removal of sulfur and then smelted in a blast furnace. Sulfur is mostly removed hy a sinter process. The galena concentrate or the ore itself, if its impurity content is low, is mixed with silica and other slag-forming reagents and roasted in sinter machines to produce lead oxide, lead silicate, and some metallic lead. The principal reactions are ... 

Zinc concentrate sinter mix Micropelletized sinter machine feed... 

The ISP evolved to fill a very special niche in nonferrous metallurgy because of its capability of treating Lead-zinc concentrates which may also contain appredable amounts of copper. The concentrate is normally-oxidized in a sintering machine to produce a feed for the blast furnace where the zinc oxide is reduced with coke. Some effort has been underway to develop a hot briquetting operation to produce a suitable feed without sintering. Other efforts to improve the economic competitiveness of the process include air preheat and the use of an oxygen-enriched blast to reduce coke consumption. 

The sintering machine is a relatively small part of the equipment needed for a complex sintering plant. Auxiliary devices include conveying and storage equipment, mixing and proportioning equipment, fans, dust collectors, etc. 

Details of a number of ferrous sintering machines are found in Table 6.2. A typical modern machine may be 13 ft (4 m) wide by 200 ft (61 m) long with a capacity of 8000 t/day (7200 Mg/day). Included in Table 6.2 are particulars on a large Japanese sinter plant. Such large machines have grate surfaces 16.4 ft (5 m) wide by 394 ft (120 m) long and a production capacity of over 20,000 tons (18,000 Mg) of sinter per day. 

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