Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/16—Sintering; Agglomerating
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/34—Obtaining zinc oxide

Definitions

• the present invention relates to a process of making a Waelz oxide containing sinter for use in zinc smelting shaft furnaces.
• the initial material in this process must be present in lumpy form, which implies strict requirements regarding grain size and abrasion-resistance.
• Waelz oxide can be used in clinkered form without causing any diificulties during the sintering.
• the clinkering of the Waelz oxide requires a separate operation which increases the cost of the procedure.
• Waelz oxide in non-clinkered form in the sinter mixture of sulfidic raw material is possible only in minor amounts, since otherwise the quality of the sinter is impaired to an extent that the final sinter is no longer suitable for .the subsequent shaft furnace operation.
• the homogenizing, moistening and compacting of the Waelz oxide may be effected by pelletizing the same while simultaneously incorporating the fuel in it. According to a preferred embodiment, the percentage of the incorporated fuel is below the percentage of the fuel in the final sinter mixture.
• the fuel is incorporated in the form of a sulfur containing material.
• the pellets have a size up to 10 mm., and most preferably between 4 and 8 mm.
• the fuel can be in the form of coke fines, sulfidic concentrates or a mixture of these two materials. Preferably, sulfidic concentrates are employed.
• the percentage content of fuel in the pellets should be below the percentage of fuel in the final sinter mixture. In case of coke fines, the fuel percentage of the pellets may be higher, but it is preferred to keep it low even in this case. In calculating the amount of fuel it is assumed that 1% of coke corresponds to 1.8-2.0% sulfur in the sulfidic material.
• Waelz oxide is mixed with the required amount of fuel and is then moistened and pelletized in accordance with the invention.
• the pellets are then introduced into the sinter mixture and mixed with the latter prior to passing the mass into the sinter machine.
• the homogenizing, moistening and compacting are effected by moistening and intensively kneading the mixture so as to accomplish the completely uniform penetration by the moisture. Simultaneously an aging of the mixture is effected in this process, as distinguished from normal mixing.
• the mixing preferably is carried out in knife-edge screws (so called MAUK process).
• the mixing time in this embodiment is longer than the time of mixing of the final sinter mixture.
• the moisture content in this embodiment is between 3 and 20%, and most preferably between 5 and 10%.
• the advantage of the process of the invention is that the Waelz oxide can be used in making the sinter in amounts which could otherwise be employed only after a costly and laborious pretreatment such as clinkering.
• the process requires only a small amount of additional apparatus, as compared with the conventional process of making sinters from purely sulfidic raw materials.
• the sinter operations described in these examples were carried out on a stationary tray with an effective roasting surface of 0.09 m? by a pressure sinter process.
• the thickness of the layer of sinter mixture on the roastin surface was 20 cm., which included an ignition layer of 30 mm.
• the testing material comprised six diiferent sulfidic, lead, zinc and lead-zinc concentrates as well as limestone, sand, reused materials and lead oxide.
• Percent Zn 58-60 Pb 10-12 The amount of sinter mixture used in the different tests was about 17 kg. and consisted of concentrates, sand, limestone, coke and Waelz oxide. By adding the reused material to the sinter mixture, the fuel content of the sinter mixture was adjusted to about 7% sulfur. The total weight of the charge was about 45 kg.
• Rattler Index As the measure of the physical quality of the sinter product, the so-called Rattler Index was used. This test is based on employment of 1 kg. sinter product of a grain size of 25.4-50.8 mm. in a specific drum and testing therein for six minutes at a rotation speed of 72 r.p.m.
• the drum had a diameter of 165 mm. and a length of 228 mm. It was provided in its interior with two symmetrically arranged impact ledges of 25.4 mm. height and 228 mm. length.
• the portion of grain size below 12.7 mm. expressed in percentage of the total amount of sinter material is used as the measure for the abrasion-resistance and is designated as the Rattler Index.
• the Rattler Index ascertained after sintering was at 81.5.
• the moisture content of the sinter mixture was in each case adjusted to about 5%.
• Kneading and aging time Rattler Index 15 minutes 75.8 15 hours 78.2 63 hours 78.5 91 hours 79.2

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Manufacture And Refinement Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=5782035

Family Applications (1)

Country Status (8)

• 1971
  • 1971-03-26 PL PL1971146513A patent/PL70894B1/xx unknown
  • 1971-06-19 RO RO67375A patent/RO61780A/ro unknown
  • 1971-07-29 FR FR7127754A patent/FR2106410B1/fr not_active Expired
  • 1971-08-19 ZM ZM115/71A patent/ZM11571A1/xx unknown
  • 1971-08-27 GB GB4035471A patent/GB1342006A/en not_active Expired
  • 1971-08-28 JP JP6625571A patent/JPS5434688B1/ja active Pending
  • 1971-09-07 US US00178446A patent/US3748117A/en not_active Expired - Lifetime
  • 1971-09-09 CA CA122,425A patent/CA947090A/en not_active Expired

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