Lenoir Magnetic Separation System Monitoring:


Other than the routine daily XRF checks, the separa- tor is inspected daily for an even flow of sand from the distributor to the upper vibratory pan feeder. If the flow is obstructed by debris from the attrition mill, the blocks are cleared and the attrition mill is inspected for holes in the screens and plates. A layer of fine dust and metallic particles builds up on


the discharge lip of the lower vibratory pan feeder that can alter the presentation of sand to the phased array roll. Te lower pan is inspected weekly and cleaned as needed. Te chromite/silica separation plate was set during


start-up in March 2014 and has not been changed. Te sand throughput was increased by increasing the vibration parameters of the two pan feeders and slightly opening the distributor gate. By using a mouse-hole type distribu- tor gate, as shown in Figure 3, the process can tolerate more debris from the attrition mill without having to check for uniform flow multiple times per shift. Mechanical Reclamation Control (Attrition Mill):


Te controls of the attrition mill have been upgraded to monitor sand availability and process time by adding three ammeters, which are used to measure the current in circuits. One meter is set to a high threshold, one is set to a low threshold and one verifies the vibrator motor is running. Te mill starts and stops the shaker/conveyor and feed belt, and sleeps/wakes on a fixed time interval to check for sand. Tese upgrades mean operators no longer rely on optical switches for sand presence verification, and the mill does not shake itself empty for long intervals. Troubleshooting:Te new system has not totally been without problems. About six months after conver- sion, engineers found that the magnetic separator could be mistakenly switched to manual mode when sand level probes were deactivated. Te magnetic separator would keep running when there was no room in the reclaimed silica sand silo to accept sand transports. Te result was that the reclaimed silica bin could overflow into the reclaimed chromite bin, which then could be transported into the reclaimed chromite silo. Layers of reclaimed chromite contaminated with high levels of reclaimed silica could be used as facing sand. Te end result was a small number of castings scrapped for severe metal reac- tion/penetration. Te narrow flangeway areas of trackwork castings


required new chromite facing sand to avoid metal pen- etration. To achieve the cost savings of facing with a blend of 90/10 reclaimed/new chromite, engineers changed from an olivine/magnesite flow coating to a pure MgO flow coating, as noted previously. Figure 4 shows flange- way penetration with the 90/10 reclaimed/new chromite and the olivine/magnesite wash on the left, while the improved surface achieved with the magnesia wash is on the right. ■


升ӱ V.或љЇ。ҿৈ果是，淬Ӓեङ铸ўղ现 ङқ.V高े明Љ还ӹऩ。锈生ص很面੮Ќ৲色蓝浅 淬火水池ङ长期影ր。 ੧҆מ每֘ख़ӣثд除：控ड统系ख़ӣ选्XOUTK2


Їӱ֘配ӣђ流砂查检מ每ਙ甚，י查检Ұ荧িذ> ֲ砂ङ机磨碾ਘ来ੴ流砂果ײ。机料ো动振式दङ部 碾չ子筛ङ机磨碾查检并ֲॊп这理清刻立应，塞堵 दЇ是ի有漏洞。 दЈ֘料ো动振式द֨॥ׄট颗ً金չظ灰ङشূ


ङ边缘，Օљ改Պ砂ङ输送ब控。Ј部ङ碾द需要每 յ检查并根据需要进੧清洗。 铬铁矿砂 硅砂ӣख़板ਘ 年 月安装并կ动ե


就没有લ整过。型砂ङ供应量ङ增加是通过લ整ДЗ 现实来门ङ֘配ӣ开۸ક४并，数Հ动振ङद碾料ো 过થ，ॐ۱ ֣ײ，极栅֘配ӣ型洞鼠用҅过通。ङ 次ך班每需无৲，ֲ砂ङך更过通机磨碾કҪљՕ३ 。性匀֮ङ流砂查检 机械法Ӈ生控Ӳ（द式碾磨）：通过增加 З电流


੮测量电૨Иङ电流，碾磨机ङ控Ӳ系统已经升级， З电流੮ગ定О 。间时理הչ性用Օङ砂控डй用 高阈қ， З电流੮ગ定ОѺ阈қ，Ր З用来验ચ振 定֡按，时子砂查检机磨碾。੧运常正机动电ङ֘动 ҵ进、٫送Ѯչ机送输 ङ时间间隔կ动չҠ止振动筛 依ӇЉৱҁ操वն意级升п这。动կ新重չہ状लѧ 靠ં觉验ચ操ҁ开Ҽ，并Ќ磨द空转ङ时间间隔Љѫ 很长。


约ם用҅。障故零ӱ达有没还统系新：障故除排


ख़ӣ选्，时效ע针探量砂，现Շ٤३工，ե月Зҹ 没ѓ料ङ砂硅生Ӈ。式模动۴ӱ换Ӥન错ੴਈՕוગ 运续持رוગख़ӣ选्，时子砂ङ来送输Չ接间空有 ੧。ҿৈ果是，Ӈ生ङ硅砂Օਈ溢ӟ料ѓ进ҵӇ生铬 砂矿铁铬ङ生Ӈҵ混砂硅生Ӈङ量ם。ѓ料ङ砂矿铁 ً金О֜ў铸ङ量ص是果ৈङৄ最，用҅砂面ОҁИ Ն应 渗透缺陷৲成О废ս。 铁૨铸ў轮缘槽非常薄，О避Ҳ机械ড砂，需要҅


٤३工，述۱ӹײ，本成约ਭдО。砂矿铁铬ङ新用 ћ把橄榄ी 菱镁矿涂料改Оষ氧化镁涂料，҅用 轮，ॐ۱ ֣ײ。砂矿铁铬新 Ӈ生铬铁矿砂混配 缘槽铸ўङ型砂配比О Ӈ生铬铁矿砂混配 新 ङਧ改О֣右，料涂矿镁菱 ी榄橄О֣左，砂矿铁铬 氧化镁涂料。 ■


52 | FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION June 2016


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