CN111646440A - Efficient drying method of ground phosphate rock pellets - Google Patents

Abstract

The invention discloses a high-efficiency drying method for phosphate rock powder pellets, which comprises the steps of primary heating, secondary heating, tertiary heating and air cooling. On the premise of ensuring the quality of phosphate rock powder pellets, the heating and drying time is shortened as much as possible, the drying efficiency of phosphate rock powder pellets is greatly improved, and the waste heat generated in the production process of yellow phosphorus is fully utilized for heating, which can save energy. The effect of reducing consumption is beneficial to the improvement of economic benefits of yellow phosphorus production. The invention has good drying effect, low energy consumption, low processing cost, high drying efficiency and high social and economic benefits.

Description

A kind of efficient drying method of phosphate rock powder pellets

technical field

The invention belongs to the technical field of phosphate rock processing, and in particular relates to an efficient drying method for phosphate rock powder pellets.

Background technique

Yellow phosphorus is an important chemical raw material, which can be used to produce various phosphides and phosphates, and has a wide range of uses. The production of yellow phosphorus in my country mainly adopts the electric furnace process, and the raw material usually used is phosphate rock lump. However, the lump ore in my country's phosphate rock only accounts for one-fifth of the total phosphorus reserves, and most of it is phosphate rock powder. In the process of crushing and processing, a large amount of phosphate rock powder will be produced, especially when using weathered phosphate rock powder, the generated fine powder ore usually reaches more than 20%. This part of the fine powder ore needs to be processed before it can enter the yellow phosphorus. Electric furnace technology, so most enterprises are unwilling to increase investment and cost, resulting in these phosphate rock fine powder materials cannot be reasonably used. However, with the rapid development of my country's phosphorus industry, there are not many high-quality lumps left for the production of yellow phosphorus, and it is difficult to meet the needs of yellow phosphorus production. Facing the current situation, processing phosphate rock powder into pellets and putting them into use is a solution to the waste of rock phosphate rock powder.

The process of processing phosphate rock powder into pellets is as follows: adding some specific ingredients to the phosphate rock powder and fully mixing, then adding a binder to obtain a mixed material, and pressing the mixed material uniformly into pellets. The strength of the pellets makes it difficult for the pellets to disperse. The pressed pellets need to be dried and consolidated, and finally sent to the yellow phosphorus electric furnace to obtain yellow phosphorus. At present, in the drying process of phosphate rock pellets, there are many problems such as long drying time, low fuel utilization rate, large consumption, and high processing cost. Secondly, because the pellets are heated externally, the drying speed is strictly controlled. If the drying speed is too fast and the temperature rises sharply, it is easy to cause the fragmentation of the pellets, and the drying effect is not good, which restricts the development of the processing and utilization of phosphate rock pellets. Therefore, it is an objective need to develop a high-efficiency drying method for phosphate rock pellets with good drying effect, low energy consumption and low processing cost.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a high-efficiency drying method for phosphate rock powder pellets with good drying effect, low energy consumption and low processing cost.

An efficient drying method for phosphate rock powder pellets, comprising the following steps:

①First-level heating: put the pressed phosphate rock powder pellets into the drying furnace, and pass through the drying hot air of 100-200℃ for preheating, and the preheating time is 10-15min;

②Secondary heating: add the phosphate rock powder pellets preheated in step ① into a microwave heating furnace for microwave heating. The power of the microwave heating furnace is 40-50kw, the heating time is 10-20min, and the heating temperature is controlled at 600 ~700℃;

③Three-stage heating: add the phosphate rock powder pellets heated in step ② into the chain grate roaster, feed the phosphorus furnace tail gas, and roast at a temperature of 800-900 °C for 15-25 min;

④Air cooling: Put the phosphate rock powder pellets after heating in step ③ into the grate cooler, and cool them down to below 100 ℃ by air cooling, to make phosphate rock pellets for yellow phosphorus production.

In step ②, before the microwave heating of the phosphate rock powder pellets, vacuum treatment is performed on the microwave heating furnace, and the vacuum degree is controlled below 500Pa.

In step ②, an infrared thermal imager is arranged on the top of the microwave heating furnace.

In step ①, the drying furnace is a rotary cylindrical heating furnace, and the drying hot air and the phosphate rock powder pellets adopt a counter-current heating method.

In step ②, the microwave heating is carried out in two stages. The first stage: the heating temperature is controlled at 400-500°C, and the heating time is 5-10min; the second stage: the heating temperature is controlled at 600-700°C, and the heating The time is 5 to 10 minutes.

In step ①, the drying hot air is the hot air discharged from the microwave heating furnace in step ②.

The beneficial effects that the present invention produces:

1. The present invention adopts multi-stage heating and gradually heating up to heat and dry the phosphate rock pellets, which can effectively prevent the cracking problem of the phosphate rock pellets caused by excessive temperature rise, and ensure that the phosphate rock pellets are dried after drying. The group has good quality;

2. In the present invention, the method of microwave heating is used to rapidly heat the phosphate rock powder pellets. Since microwave heating is heated by molecular vibration, when microwaves are used to rapidly heat the phosphate rock powder pellets, the pellets are also heated. There is no problem of cracking, and the drying time of the pellets can be greatly shortened and the drying efficiency can be improved on the premise of ensuring better pellet quality;

3. When the chain grate roaster is used for drying, the exhaust gas of the phosphorus furnace is introduced, which effectively recycles the waste heat generated in the production process of yellow phosphorus, reduces the energy consumption when drying the phosphate rock pellets, and reduces the processing time. cost.

To sum up, when the method of the present invention is used to dry the phosphate rock powder pellets, since the method of multi-stage heating, gradual heating, microwave heating and phosphorus furnace exhaust heating is adopted in the present invention, the phosphate rock powder pellets are guaranteed to be dry. On the premise of the quality of the pellets, the heating and drying time should be shortened as much as possible, the drying efficiency of the phosphate rock pellets should be greatly improved, and the waste heat generated in the production process of yellow phosphorus should be fully utilized for heating, which can save energy and reduce consumption, which is beneficial to yellow phosphorus. The economic benefits of phosphorus production are improved. The invention has good drying effect, low energy consumption, low processing cost, high drying efficiency and high social and economic benefits.

Detailed ways

The present invention is further described below in conjunction with the examples, but the present invention is not limited in any way, and any transformation or replacement made based on the teachings of the present invention belongs to the protection scope of the present invention.

Example 1:

The efficient drying method of the phosphate rock powder pellet described in the present embodiment 1, comprises the following steps:

①One-stage heating: put the pressed phosphate rock powder pellets into the drying furnace, and feed the drying hot air at 100°C for preheating, and the preheating time is 10min. Preferably, the drying furnace is a rotary cylindrical heating Furnace, drying hot air and phosphate rock pellets adopt counter-flow heating method. The counter-current heating method is conducive to the contact and heat exchange between the hot air and the phosphate rock pellets. At the same time, the phosphate rock pellets rotate with the rotary cylinder. In addition, the heating efficiency is high. In order to further save energy consumption, the drying hot air is the hot air discharged from the microwave heating furnace.

②Secondary heating: The phosphate rock powder pellets preheated in step ① are added to a microwave heating furnace for microwave heating. The power of the microwave heating furnace is 40kw, the heating time is 10min, and the heating temperature is controlled at 600℃. In order to obtain For better heating effect, vacuum the microwave heating furnace before microwave heating the phosphate rock pellets, and the vacuum degree is controlled below 500Pa. The top of the microwave heating furnace is provided with an infrared thermal imager. The temperature image of the phosphate rock pellets in the microwave heating furnace can be collected in real time, so that the operator can grasp the heating temperature in the microwave heating furnace in real time. Preferably, the microwave heating is carried out in two stages. The first stage is to control the heating temperature first. At 400°C, the heating time is 5 minutes; the second stage: the heating temperature is controlled at 600°C, and the heating time is 5 minutes.

③Three-stage heating: add the phosphate rock powder pellets heated in step ② into the chain grate roaster, feed the phosphorus furnace tail gas, and roast at a temperature of 800 ° C for 15 minutes;

④Air cooling: Put the phosphate rock powder pellets after heating in step ③ into the grate cooler, and cool them down to below 100 ℃ by air cooling, to make phosphate rock pellets for yellow phosphorus production.

Example 2:

The efficient drying method of the phosphate rock powder pellet described in the present embodiment 2 comprises the following steps:

①First-level heating: put the pressed phosphate rock powder pellets into the drying furnace, and pass in the drying hot air of 150℃ for preheating, and the preheating time is 12min. Preferably, the drying furnace is a rotary cylindrical heating Furnace, drying hot air and phosphate rock pellets adopt counter-flow heating method. The counter-current heating method is conducive to the contact and heat exchange between the hot air and the phosphate rock pellets. At the same time, the phosphate rock pellets rotate with the rotary cylinder. In addition, the heating efficiency is high. In order to further save energy consumption, the drying hot air is the hot air discharged from the microwave heating furnace.

②Secondary heating: The phosphate rock powder pellets preheated in step ① are added to a microwave heating furnace for microwave heating. The power of the microwave heating furnace is 45kw, the heating time is 15min, and the heating temperature is controlled at 650 ° C. In order to obtain For better heating effect, vacuum the microwave heating furnace before microwave heating the phosphate rock pellets, and the vacuum degree is controlled below 500Pa. The top of the microwave heating furnace is provided with an infrared thermal imager. The temperature image of the phosphate rock pellets in the microwave heating furnace can be collected in real time, so that the operator can grasp the heating temperature in the microwave heating furnace in real time. Preferably, the microwave heating is carried out in two stages. The first stage is to control the heating temperature first. At 450°C, the heating time is 7 minutes; the second stage: the heating temperature is controlled at 650°C, and the heating time is 8 minutes.

③Three-stage heating: add the phosphate rock powder pellets heated in step ② into the chain grate roaster, feed the phosphorus furnace tail gas, and roast at 850°C for 20 minutes;

④Air cooling: Put the phosphate rock powder pellets after heating in step ③ into the chain grate cooler, and cool them down to below 100 ℃ by air cooling, so as to make phosphate rock pellets for yellow phosphorus production.

Example 3:

The efficient drying method of the phosphate rock powder pellet described in the present embodiment 3 comprises the following steps:

①First-level heating: put the pressed phosphate rock powder pellets into a drying furnace, and feed hot drying air at 200°C for preheating. The preheating time is 15 minutes. Preferably, the drying furnace is heated by a rotary cylinder. Furnace, drying hot air and phosphate rock pellets adopt counter-flow heating method. The counter-current heating method is conducive to the contact and heat exchange between the hot air and the phosphate rock pellets. At the same time, the phosphate rock pellets rotate with the rotary cylinder. In addition, the heating efficiency is high. In order to further save energy consumption, the drying hot air is the hot air discharged from the microwave heating furnace.

②Secondary heating: The phosphate rock powder pellets preheated in step ① are added to a microwave heating furnace for microwave heating. The power of the microwave heating furnace is 50kw, the heating time is 20min, and the heating temperature is controlled at 700℃. In order to obtain For better heating effect, vacuum the microwave heating furnace before microwave heating the phosphate rock pellets, and the vacuum degree is controlled below 500Pa. The top of the microwave heating furnace is provided with an infrared thermal imager. The temperature image of the phosphate rock pellets in the microwave heating furnace can be collected in real time, so that the operator can grasp the heating temperature in the microwave heating furnace in real time. Preferably, the microwave heating is carried out in two stages. The first stage is to control the heating temperature first. At 500°C, the heating time is 10 minutes; the second stage: the heating temperature is controlled at 700°C, and the heating time is 10 minutes.

③Three-stage heating: add the phosphate rock powder pellets heated in step ② into the chain grate roaster, feed the phosphorus furnace tail gas, and roast at 900°C for 25 minutes;

④Air cooling: Put the phosphate rock powder pellets after heating in step ③ into the grate cooler, and cool them down to below 100 ℃ by air cooling, to make phosphate rock pellets for yellow phosphorus production.

It has been verified by actual production that when the present invention dries the phosphate rock powder pellets, the method of multi-stage heating, gradual heating, microwave heating and phosphorus furnace tail gas heating is adopted, and the waste heat in the production of yellow phosphorus is used for drying, which saves energy and reduces energy consumption. At the same time of consumption, it can ensure higher drying efficiency and better quality of phosphate rock pellets. The stable quality of phosphate rock powder pellets for the production of yellow phosphorus can be obtained, which realizes the efficient recovery and comprehensive utilization of phosphate rock powder resources, reduces the waste of yellow phosphorus rock, and improves the economy of yellow phosphorus production enterprises. It is beneficial to the long-term sustainable development of yellow phosphorus production enterprises.

Claims (6)

1. A high-efficiency drying method of ground phosphate rock pellets is characterized in that: the method comprises the following steps:

firstly, heating: putting the pressed and formed powdered rock phosphate pellets into a drying furnace, and introducing 100-200 ℃ dry hot air for preheating for 10-15 min;

secondly, heating: adding the ground phosphate rock pellets preheated in the step I into a microwave heating furnace for microwave heating, wherein the power of the microwave heating furnace is 40-50 kw, the heating time is 10-20 min, and the heating temperature is controlled at 600-700 ℃;

thirdly, three-stage heating: adding the powdered rock phosphate pellets heated in the second step into a grate type roasting machine, introducing phosphorus furnace tail gas, and roasting at the temperature of 800-900 ℃ for 15-25 min;

fourthly, air cooling: and (4) placing the powdered rock phosphate pellets heated in the step (III) into a grate cooler, and cooling to below 100 ℃ by air to obtain the powdered rock phosphate pellets for producing yellow phosphorus.

2. The method for efficiently drying the ground phosphate rock pellets according to claim 1, wherein in the second step, before the ground phosphate rock pellets are subjected to microwave heating, the microwave heating furnace is subjected to vacuum pumping treatment, and the vacuum degree is controlled to be below 500 Pa.

3. The method for efficiently drying the ground phosphate rock pellets according to claim 1, wherein in the second step, an infrared thermal imager is arranged at the top of the microwave heating furnace.

4. The method for efficiently drying the ground phosphate rock pellets according to claim 1, wherein in the step (i), the drying furnace is a rotary cylinder type heating furnace, and the drying hot air and the ground phosphate rock pellets are heated in a counter-flow manner.

5. The method for efficiently drying the ground phosphate rock pellets according to claim 1, wherein the microwave heating is performed in two stages, the first stage being: firstly, controlling the heating temperature to be 400-500 ℃ and the heating time to be 5-10 min; and a second stage: the heating temperature is controlled to be 600-700 ℃, and the heating time is 5-10 min.

6. The method for efficiently drying the ground phosphate rock pellets according to claim 1, wherein the hot drying air is hot air discharged from a microwave heating furnace in the step II.