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CN-121976064-A - Method for stably producing high-solubility molybdenum calcine

CN121976064ACN 121976064 ACN121976064 ACN 121976064ACN-121976064-A

Abstract

The application relates to a method for stably producing high-solubility molybdenum calcine, belonging to the technical field of oxidizing roasting process of molybdenum concentrate. The application discloses a method for stably producing high-solubility molybdenum calcine, which utilizes a device for stably producing high-solubility molybdenum calcine, and comprises the following steps of (1) feeding and exhausting control based on the concentration and flow of flue gas SO 2 , (2) rotary kiln rotating speed control based on the temperature of a kiln head key point SO as to stabilize an oxidation zone, and (3) on-line thermal crushing treatment of screen materials SO as to solve the problem of low solubility of caking materials. The method has the effect of stably producing the high-solubility molybdenum calcine by adjusting key process parameters in real time to offset the influence of the fluctuation of raw material components.

Inventors

  • YI JIAN
  • LIU JINRUI
  • ZHAO ZHENGANG
  • LI XUAN
  • Ge Huagui

Assignees

  • 成都鼎泰新材料有限责任公司
  • 成都虹波实业股份有限公司

Dates

Publication Date
20260505
Application Date
20260203

Claims (10)

  1. 1. A method for stably producing high-solubility molybdenum calcine, characterized in that an apparatus for stably producing high-solubility molybdenum calcine is used, comprising the steps of: (1) The control logic comprises the steps of taking the flue gas flow 1960-2960 m 3 /h as a set median, automatically adjusting the running frequency of a kiln tail fan through a controller to keep the flue gas flow stable, taking the SO 2 concentration 1.5-5.0% as the set median, interlocking a SO 2 concentration detection signal with the frequency of a feeding motor, when the SO 2 concentration is reduced, indicating that the sulfur content entering the kiln in unit time is reduced, automatically increasing the feeding frequency by a control system, increasing the feeding amount to keep the reaction intensity, and automatically reducing the feeding frequency when the SO 2 concentration is increased, wherein the control target is to keep the kiln tail flue gas flow stable between 1960-2960 m 3 /h,SO 2 concentration and 1.5-5.0%; (2) The control logic comprises a monitoring point temperature which is a key index for judging the position and the condition of an oxidation reaction zone, a stage in which the temperature is 480-650 ℃ and indicates that the material desulfurization is basically completed and molybdenum dioxide is further oxidized into molybdenum trioxide, a step of interlocking a temperature signal of the monitoring point with the rotating speed of a driving motor of a furnace tube of the rotary kiln, a step of automatically reducing the kiln speed by a control system when the monitoring point temperature is higher than 650 ℃, and a step of prolonging the residence time of the material in the kiln to ensure that the desulfurization and the oxidation reaction are more sufficient, a step of automatically reducing the kiln speed by the control system when the temperature is lower than 480 ℃, wherein the reaction zone is backwards moved, the length of the oxidation zone is increased, the position interval between concentrate desulfurization and oxidation is relatively close, the molybdenum dioxide after the desulfurization is easily converted into the molybdenum trioxide at a higher temperature, the molybdenum trioxide is easily melted and sublimated at the higher temperature, the molybdenum dioxide is adhered to the formed dense oxide film, the inner molybdenum is prevented from contacting with oxygen, and the dissolution rate can be reduced, and particularly, the kiln head is remarkably increased to be higher than the temperature of a stable grade of a kiln head of the kiln at a temperature of between 45 ℃ and a temperature of more than 700 ℃, and a temperature of a kiln head is controlled at a temperature of a stable end of the kiln; (3) The method comprises the steps of carrying out on-line thermal crushing treatment on the oversize materials to solve the problem of low solubility rate of caking materials, screening the oversize materials which are partially sintered into blocks in calcine discharged from a kiln head of a rotary kiln by arranging an inclined grate at an outlet of the kiln head, directly feeding the fine powder materials into a cooling cylinder, immediately introducing the blocky oversize materials into a jaw crusher for on-line thermal crushing, and returning small particles formed after crushing into the cooling cylinder together with the fine powder materials.
  2. 2. The method for stably producing high-soluble molybdenum calcine according to claim 1, characterized in that the apparatus for stably producing high-soluble molybdenum calcine comprises: the feeding unit comprises a feeding bin and a feeder connected with the feeding bin, and the feeder is provided with a feeding motor; The roasting reaction unit comprises a rotary kiln body and a kiln head box, wherein a driving motor is arranged on the rotary kiln body, the discharge end of the feeder is connected with the feed end of the rotary kiln body, and a fan is arranged at the kiln tail of the rotary kiln; the flue gas monitoring unit comprises a dust collector rear air pipe arranged at the kiln tail of the rotary kiln, a gas flowmeter and an SO 2 concentration detector which are arranged on the dust collector rear air pipe; The furnace temperature monitoring unit comprises a bicolor pyrometer which is arranged at the position of the kiln head box, which is opposite to the rotary kiln body, and the monitoring point of the bicolor pyrometer is positioned in the rotary kiln body; the discharging screening and crushing unit is positioned below the kiln head box outlet and comprises a grate net, a jaw crusher and a cooling cylinder, wherein the grate net is obliquely arranged, the cooling cylinder is positioned below the grate net and is communicated with a fine particle material discharging end below the grate net, a feeding end of the jaw crusher is positioned at the lower end of the grate net, and a discharging end of the jaw crusher is connected to the cooling cylinder; The control system is used for receiving signals of the flue gas monitoring unit and the temperature monitoring unit in the furnace and executing closed-loop control on the feeding unit and the roasting reaction unit.
  3. 3. The method for stably producing high-soluble molybdenum calcine according to claim 2, wherein the closed-loop control comprises adjusting the frequency of the feed motor according to the SO 2 concentration signal, adjusting the frequency of the fan according to the gas flow signal, and adjusting the rotation speed of the drive motor according to the kiln head monitoring point temperature signal.
  4. 4. The method for stably producing high-solubility molybdenum calcine according to claim 2, wherein the control system takes the flue gas flow 2460m 3 /h as a set median value, automatically adjusts the operating frequency of the fan, and maintains the flue gas flow to be stable in 1960-2960m 3 /h.
  5. 5. The method for stably producing high-soluble molybdenum calcine according to claim 2, wherein the control system uses the concentration of SO 2 to 3.25% as a set median value, interlocks the SO 2 concentration detection signal with the frequency of the feeding motor, automatically increases the feeding frequency when the concentration of SO 2 is reduced, automatically decreases the feeding frequency when the concentration of SO 2 is increased, and maintains the concentration of SO 2 to be stable between 1.5 and 5.0%.
  6. 6. The method for stably producing high-soluble molybdenum calcine according to claim 2, wherein the control system uses 565 ℃ as a set median value, interlocks the kiln head monitoring point temperature signal with the rotation speed of the driving motor, automatically reduces the kiln speed when the temperature is higher than 650 ℃, automatically increases the kiln speed when the temperature is lower than 480 ℃, and maintains the temperature stable between 480 ℃ and 650 ℃.
  7. 7. The method for the stable production of highly soluble molybdenum calcine according to claim 2, characterized in that the inclination of the grate is 5-15 °.
  8. 8. The method for stably producing highly soluble molybdenum calcine according to claim 2, characterized in that the rotary kiln body has a size Φ2.5x42 m.
  9. 9. The method for stably producing high-soluble molybdenum calcine according to claim 2, characterized in that the monitoring point of the bicolor pyrometer is located 5 meters from the edge of the rotary kiln body end.
  10. 10. The method for stably producing high-soluble molybdenum calcine of claim 2, wherein the control system is electrically connected to the feed motor, the drive motor, the blower, the gas flow meter, the SO 2 concentration detector, the bicolor pyrometer.

Description

Method for stably producing high-solubility molybdenum calcine Technical Field The application relates to the technical field of oxidizing roasting processes of molybdenum concentrate, in particular to a method for stably producing high-solubility molybdenum calcine. Background Roasting of molybdenum concentrate is a key process for producing molybdenum oxide, and rotary kilns are commonly used in industry at present. In the roasting process, molybdenum concentrate is fed into a rotary kiln from the kiln tail through a screw feeder, and along with the rotation of a kiln body, materials move from the kiln tail to the kiln head, oxidation reaction occurs in the process, a large amount of heat is released, and the temperature in the kiln is maintained at 500-1000 ℃ through self-reaction. And cooling the flue gas containing SO 2 by a kiln tail sedimentation tank and a heat exchanger, then sending the flue gas to neutralize and absorb or prepare sulfuric acid, and enabling molybdenum oxide obtained after oxidation to flow out from the kiln head. However, the roasting by adopting the rotary kiln has the following technical problems that firstly, the ingredient fluctuation of the raw materials causes unstable solubility, firstly, the moisture control of molybdenum concentrate of different raw materials is inconsistent, the moisture is low by about 4 percent, and the moisture is high by 20 percent. Because the influence of moisture on the fluidity of the material is remarkable, when the material is fed by a screw, the fluctuation of the amount of the material entering the rotary kiln in unit time is large, so that the relative positions of a preheating zone, a desulfurization zone and an oxidation zone of the material in the rotary kiln are changed, and finally the solubility rate of molybdenum oxide is influenced, and secondly, the grade difference of molybdenum concentrate is large, the grade difference is about 15 percent, and the high grade can reach 55 percent. If the adjustment is not performed in time, the total sulfur amount entering the kiln changes, so that the reaction heat and the reaction zone in the kiln change rapidly, and the dissolubility is disqualified, and the molybdenum concentrate is gradually changed from low impurity to high impurity along with the reduction of the original mineral resources, such as a high copper raw material or concentrate containing molybdate. For high copper materials, molybdenum-copper alloy is easily generated due to the excessively high reaction temperature in the furnace, and for molybdate, the temperature in the furnace is easily reduced because the molybdate does not generate oxidation exothermic reaction, so that concentrate cannot be fully oxidized. If the reaction temperature in the furnace is not strictly controlled, the molybdenum oxide can be dissoluble and disqualified. Secondly, the oversize material treatment process has the defect that the roasted material contains agglomerated oversize materials which are in a ball-shaped state, so that the contact opportunity of the internal material with oxygen is reduced, more molybdenum dioxide is contained, and the solubility rate is lower. At present, the conventional method is to mix the cooled product with conventional products after manually raking out and cooling the product and then crushing the product by a crusher, and the treatment mode not only increases the labor intensity, but also indirectly reduces the overall solubility rate of the roasted product. Thirdly, the control mode relies on manual experience, the existing control mode has high requirement on experience of operators, technological parameters need to be adjusted in time according to raw material changes, hysteresis and inaccuracy often exist in manual adjustment, and therefore the molybdenum oxide solubility rate is often unqualified, and the product quality is unstable. Disclosure of Invention In view of the above, the present application provides a method for stably producing high-soluble molybdenum calcine, which adjusts key process parameters in real time by automatic detection and feedback control to counteract the influence of fluctuation of raw material components, thereby stably producing high-soluble molybdenum calcine, and effectively overcoming the defects of the prior art. The application provides a method for stably producing high-solubility molybdenum calcine, which comprises the following steps: (1) The control logic comprises the steps of taking the flue gas flow 1960-2960 m 3/h as a set median, automatically adjusting the running frequency of a kiln tail fan through a controller to keep the flue gas flow stable, taking the SO 2 concentration 1.5-5.0% as the set median, interlocking a SO 2 concentration detection signal with the frequency of a feeding motor, when the SO 2 concentration is reduced, indicating that the sulfur content entering the kiln in unit time is reduced, automatically increasing the feeding frequency by a co