阅读说明：本技术 一种采用几内亚铝土矿生产氧化铝中除磷的方法 (Method for removing phosphorus in production of alumina by adopting Guinea bauxite ) 是由 程涛 芦东 王顺祥 杨群太 丁星阳 尹海军 张大为 刘永红 梁鑫 于 2021-09-26 设计创作，主要内容包括：本发明提供一种采用几内亚铝土矿生产氧化铝中除磷的方法,属于氧化铝冶金技术领域,包括以下步骤：S1.将几内亚铝土矿破碎磨细成矿粉,然后制备原料矿浆；S2.将原料矿浆进行碱热溶出反应,反应结束后得到溶出矿浆；S3.将溶出矿浆进行稀释得到稀释液,向稀释液中加入石灰乳,然后再将稀释液进行分离得到铝酸钠溶液和赤泥；以溶出矿浆质量计,石灰乳加入量为2～5‰。该方法在拜耳法流程中的稀释槽添加石灰乳,使之与铝酸钠溶液中的磷反应生成磷酸钙进入赤泥,然后通过赤泥沉降排出。(The invention provides a method for removing phosphorus in alumina production by adopting Guinea bauxite, which belongs to the technical field of alumina metallurgy and comprises the following steps: s1, crushing and grinding Guinea bauxite into mineral powder, and then preparing raw material ore pulp; s2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished; s3, diluting the dissolved ore pulp to obtain a diluent, adding lime milk into the diluent, and then separating the diluent to obtain a sodium aluminate solution and red mud; the adding amount of the lime milk is 2-5 per mill based on the mass of the dissolved ore pulp. The method comprises the steps of adding lime milk into a dilution tank in a Bayer process flow, reacting the lime milk with phosphorus in a sodium aluminate solution to generate calcium phosphate, allowing the calcium phosphate to enter red mud, and then settling and discharging the calcium phosphate through the red mud.)

1. A method for removing phosphorus in the production of alumina by adopting Guinea bauxite is characterized by comprising the following steps:

s1, crushing and grinding Guinea bauxite into mineral powder, and then preparing raw material ore pulp;

s2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished;

and S3, diluting the dissolved ore pulp to obtain a diluent, adding lime milk into the diluent, and then separating the diluent to obtain sodium aluminate solution and red mud, wherein the adding amount of the lime milk is 2-5 per mill based on the mass of the dissolved ore pulp.

2. The method for removing phosphorus in the production of aluminum oxide by using Guinea bauxite according to claim 1, wherein the concentration of the diluent Nk is 140-145 g/l.

3. The method for removing phosphorus in aluminum oxide production by using Guinea bauxite according to claim 1, wherein lime milk is introduced when the temperature of the diluent reaches 100-110 ℃.

4. The method for removing phosphorus in the production of aluminum oxide by using Guinea bauxite according to claim 1, wherein the solid content of lime milk is 150-190 g/l.

5. The method for removing phosphorus in the production of aluminum oxide by using Guinea bauxite according to claim 1, wherein the introduction amount of the lime milk is 10-20 m³And h, reacting for 1-3 h.

Technical Field

The invention relates to the technical field of alumina metallurgy, in particular to a method for removing phosphorus in alumina production by adopting Guinea bauxite.

Background

Bauxite is the main raw material for producing alumina, and is an ore mainly composed of gibbsite, boehmite and diaspore. The Guinea bauxite is an excellent gibbsite type bauxite, the advantages of simple processing method, low consumption cost and good product quality in the process of producing alumina by a Bayer process are commonly recognized, and lime is not required to be added in the dissolution process to improve the dissolution reaction speed and reduce the alkali consumption, so the Guinea bauxite becomes the imported bauxite which is most used in China.

However, in the using process, compared with other bauxite, the Guinea bauxite has the defects of large fluctuation of ore components, fine granularity, easy hydrolysis, poor compression performance and the like. Meanwhile, the phosphorus content of the Guinea bauxite is high, so that the phosphorus accumulation in the process can be caused in the process of producing the aluminum oxide by the Bayer process, and the damage to the production can be caused to a certain extent, so that the normal operation of the production is influenced. The phosphorus content of the ore reaches more than 0.12 percent by adopting single Guinea bauxite ore, the harm of phosphorus is gradually reflected after the ore is put into production and used for half a year, the harm is mainly reflected by the fact that hydroxyapatite is generated by reaction with lime milk, hard scabs are formed on filter cloth of a leaf filter, the hard scabs cannot be removed by a traditional alkali washing method, the capacity of the leaf filter is seriously reduced, and the production organization is difficult.

Disclosure of Invention

The invention aims to solve the problems and provide a method for removing phosphorus in alumina production by adopting the Guinea bauxite.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for removing phosphorus in the production of alumina by adopting Guinea bauxite comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, adding lime milk into the diluent, and then separating the diluent to obtain a sodium aluminate solution and red mud; the adding amount of the lime milk is 2-5 per mill based on the mass of the dissolved ore pulp.

Preferably, the Nk concentration of the diluent is 140-145 g/l.

Preferably, when the temperature of the diluent reaches 100-110 ℃, lime milk is introduced.

Preferably, the solid content of the lime milk is 150-190 g/l.

Preferably, the introduction amount of the lime milk is 10-20 m³And h, reacting for 1-3 h.

The lime milk reacts with the diluted ore pulp to generate calcium phosphate precipitate, then the calcium phosphate precipitate enters the red mud, then the red mud enters a red mud sedimentation system, and finally the calcium phosphate precipitate is discharged to a red mud dam plant.

The reaction equation is:

PO₄ ^3-+Ca(OH)₂→Ca₃(PO₄)₂↓

the majority of domestic bauxite is diaspore ore, is difficult to dissolve out, needs higher mother liquor concentration and higher dissolving-out temperature, can completely react under the condition of adding lime, and the aim of adding lime under the dissolving-out condition is mainly to eliminate TiO₂The harm of the active ingredients and the reduction of the dissolved N/S are realized, and the adding mode is before the dissolution. The gibbsite bauxite introduced from abroad is easy to dissolve out in TiThe reaction is completed before the reaction of O2, and inert silicon is not converted into active silicon at a lower mother liquor concentration and a lower dissolution temperature, so lime is not added in the dissolution process to eliminate the harm of TiO2 and reduce the dissolved N/S. However, the phosphorus content in the Guinea bauxite is high, the phosphorus accumulation in the process can be caused in the process of producing the aluminum oxide by the Bayer process, and the damage to the production can be caused to a certain extent, and the normal operation of the production is influenced, so that the lime milk is added into the dilution tank for dephosphorization, the process is simple, and the effect is obvious.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

according to the method for removing phosphorus in the alumina produced by adopting the Guinea bauxite, as the leaf filter needs to be added with lime milk for filtration assistance, in order to avoid introducing other impurities and increase the cost for processing the impurities, the lime milk is added into the dilution tank in the Bayer process flow, so that the lime milk reacts with phosphorus in the sodium aluminate solution to generate calcium phosphate, the calcium phosphate enters the red mud, and then the red mud is settled and discharged, so that the problem of reduction of the yield of the leaf filter caused by separation of the phosphorus in the subsequent fine filtration process is solved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A method for removing phosphorus in the production of alumina by adopting Guinea bauxite comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 140 g/l. When the temperature of the diluent reaches 100 ℃, adding lime milk into the diluent, and then separating the diluent to obtain sodium aluminate solution and red mud; to dissolve out oreThe addition amount of the lime milk is 2 per mill based on the mass of the slurry. The solid content of the lime milk is 150 g/l. The introduction amount of the lime milk is 20m³And h, reacting for 3 h.

Example 2

A method for removing phosphorus in the production of alumina by adopting Guinea bauxite comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 145 g/l. When the temperature of the diluent reaches 110 ℃, adding lime milk into the diluent, and then separating the diluent to obtain sodium aluminate solution and red mud; the adding amount of the lime milk is 5 per mill based on the mass of the dissolved ore pulp. The solid content of the lime milk is 190 g/l. The introduction amount of the lime milk is 10m³And h, reacting for 1 h.

Example 3

A method for removing phosphorus in the production of alumina by adopting Guinea bauxite comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 142 g/l. When the temperature of the diluent reaches 115 ℃, adding lime milk into the diluent, and then separating the diluent to obtain sodium aluminate solution and red mud; the adding amount of the lime milk is 3 per mill based on the mass of the dissolved ore pulp. The solid content of the lime milk is 160 g/l. The introduction amount of the lime milk is 15m³And h, reacting for 2 h.

Comparative example 1

A method for removing phosphorus in alumina production by adopting Guinei bauxite, which adds lime milk in a dissolving process, comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

S2, adding lime milk into the raw material ore pulp when the temperature of the raw material ore pulp reaches 115 ℃, wherein the adding amount of the lime milk is 3 per mill based on the mass of the raw material ore pulp. The solid content of the lime milk is 160 g/l. The introduction amount of the lime milk is 15m³And h, reacting for 2h, then carrying out alkali heat dissolution reaction, and obtaining dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 142 g/l. Then separating to obtain sodium aluminate solution and red mud.

Comparative example 2

A method for removing phosphorus in alumina production by adopting Guinei bauxite, which adds lime milk before dilution, specifically comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

And S3, adding lime milk into the dissolved ore pulp, wherein the adding amount of the lime milk is 3 per mill based on the mass of the raw ore pulp. The solid content of the lime milk is 160 g/l. The introduction amount of the lime milk is 15m³And h, reacting for 2 h. Then, the diluted solution was obtained, and the Nk concentration of the diluted solution was 142 g/l. And finally, separating to obtain sodium aluminate solution and red mud.

Comparative example 3

A method for removing phosphorus in the production of alumina by adopting Guinea bauxite comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 142 g/l. When the temperature of the diluent reaches 80 ℃, adding lime milk into the diluent, and then separating the diluent to obtain sodium aluminate solution and red mud; the adding amount of the lime milk is 3 per mill based on the mass of the dissolved ore pulp. The solid content of the lime milk is 160 g/l. The introduction amount of the lime milk is 15m³And h, reacting for 2 h.

Comparative example 4

A method for producing alumina by adopting Guinea bauxite does not comprise a dephosphorization step, and specifically comprises the following steps:

s1, crushing and grinding the Guinea bauxite into mineral powder, and then preparing raw material ore pulp.

And S2, carrying out alkali-heat dissolution reaction on the raw material ore pulp to obtain dissolved ore pulp after the reaction is finished.

S3, diluting the dissolved ore pulp to obtain a diluent, wherein the Nk concentration of the diluent is 142 g/l. And then separating the diluent to obtain sodium aluminate solution and red mud.

Experimental example:

experiment design: phosphorus was removed by the methods of examples 1 to 3 and comparative examples 1 to 4, wherein the composition of the guayule ore is as follows.

TABLE 1 composition table of Guinea bauxite

Detection indexes are as follows: and detecting the phosphorus content of the sodium aluminate solution, wherein when the phosphorus content is less than 0.8g/l, the subsequent production is not influenced.

And (3) detection results: see table 2 below.

TABLE 2 phosphorus content of sodium aluminate solution

As can be seen from Table 1, the method for removing phosphorus of the invention can solve the problem of low capacity of the leaf filter caused by the precipitation of phosphorus in the subsequent fine filtration process by adding lime milk in the dilution tank in the Bayer process flow.

The comparative examples 1-2 are added before the dissolution process and dilution, and the dephosphorization effect is slightly poor. Comparative example 3 the reaction temperature is too low and the phosphorus removal effect is not good.

The above description is intended to describe in detail the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the claims of the present invention, and all equivalent changes and modifications made within the technical spirit of the present invention should fall within the scope of the claims of the present invention.