CN103773357B - A kind of method removing glass dregs and sieve and silica-sesquioxide in waste and old fluorescent RE powder - Google Patents

Abstract

The invention belongs to the field of resource recycling, and in particular relates to a method for removing silicon-aluminum impurities from waste rare earth fluorescent powder. The waste rare earth phosphors are pre-roasted, acidolyzed and filtered to obtain acidolysis slag; the acidolysis slag is hydrolyzed to remove coarse glass slag, then wet sieved to remove medium particle glass slag, and finally hot alkali dissolves fine particle glass slag and Silicon aluminum oxide. The method of the present invention can efficiently remove coarse, medium and fine particle glass slag and other silicon-aluminum oxide impurities in waste rare earth phosphors, avoiding the influence of rare earth element leaching and extraction separation due to the formation of silicon-aluminum colloid in the subsequent recovery of rare earth elements . The invention has the characteristics of efficiently removing the silicon-aluminum impurities in the waste rare earth fluorescent powder, significantly improving the recovery rate of the rare earth, reducing the production cost, being suitable for industrial production and the like.

Description

A method for removing glass slag and silicon aluminum oxide in waste rare earth fluorescent powder

technical field

The invention belongs to the field of resource recycling, and in particular relates to a method for removing glass slag and silicon-aluminum oxide in waste rare earth fluorescent powder.

Background technique

The collected waste rare earth phosphor generally contains about 25% of glass slag (calculated as silicon dioxide) and about 15% of silicon-aluminum oxide (calculated as aluminum oxide) powder in the isolation layer. Si-alumina impurity elements form silica-alumina colloids during acidolysis after alkali fusion of waste rare earth phosphors, which not only reduces the leaching rate of rare earth elements, but also leads to low extraction efficiency of rare earths, resulting in low recovery rates of rare earths and high recovery costs.

The existing literature on recycling waste rare earth phosphors mainly focuses on the recovery of rare earth elements, and there are not many literatures related to the removal of silicon and aluminum impurity elements. For example, Chinese invention patent CN101150032 discloses a method for recycling waste fluorescent lamps, including cutting of fluorescent lamps, recycling of mercury, recycling of lamp base metals, and fire separation of rare earth elements in system phosphors. CN100577830C discloses a method for recovering rare earth elements in waste fluorescent lamps, which is characterized in that phosphor powder is melted with strong alkali, insolubles are dissolved with acid, and various valuable metal elements are recovered by extraction and precipitation. CN101942298A discloses a method for regenerating rare-earth trichromatic phosphors for lamps. After sieving and removing the phosphors of magnetic substance impurities, the regenerated phosphors obtained by reducing in a reducing atmosphere during washing and drying are directly applied to lamp remanufacturing. Japanese patents JP2005096821-A and JP2005132551-A respectively research crushing equipment for waste fluorescent lamps; JP2004238526-A recycles phosphors in waste light sources, but mainly involves the recovery of halogen phosphate phosphors.

Contents of the invention

The object of the present invention is to solve the problem of separating silicon-aluminum impurities in waste rare earth phosphors, provide a method for removing granular glass slag and silicon-aluminum oxides in waste rare earth phosphors, and use a combination of physical and chemical methods to remove glass slag and silicon-aluminum oxides in phosphors. Silicon-aluminum oxide impurities improve the phosphor alkali fusion, acid hydrolysis and extraction effects, and greatly increase the recovery rate of rare earths. The process has remarkable effect of energy saving and emission reduction, and the production cost is low.

The principle of the invention can be illustrated by the following chemical reaction.

When the lye is NaOH solution:

Al ₂ O ₃ (s)+2NaOH(aq)+3H ₂ O=2Al(OH) ₄ ^- (aq)+2Na ⁺ (aq), (1)

SiO ₂ (s)+NaOH(aq)+2H ₂ O=Na ⁺ (aq)+ Si(OH) ₅ ^- (aq), (2)

Al ₂ O ₃ ?2SiO ₂ ?2H ₂ O(s)+2NaOH(aq)+5H ₂ O=2Al(OH) ₄ ^- (aq)+2Si(OH) ₄ (aq)+2Na ⁺ (aq), ( 3)

When the lye is KOH solution:

Al ₂ O ₃ (s)+2KOH(aq)+3H ₂ O=2Al(OH) ₄ ^- (aq)+2K ⁺ (aq), (4)

SiO ₂ (s)+KOH(aq)+2H ₂ O=K ⁺ (aq)+ Si(OH) ₅ ^- (aq), (5)

Al ₂ O ₃ ?2SiO ₂ ?2H ₂ O(s)+2NaOH(aq)+5H ₂ O=2Al(OH) ₄ ^- (aq)+2Si(OH) ₄ (aq)+2Na ⁺ (aq), ( 6)

The complex silicate and aluminate system also undergoes the following chemical reactions:

xNaAlO ₂ (aq)+yNa ₂ SiO ₃ (aq)+(y+z)H ₂ O=Na _x [(AlO ₂ ) _x (SiO ₂ ) _y ]?zH ₂ O+2yNaOH(aq). (7)

xKAlO ₂ (aq)+yK ₂ SiO ₃ (aq)+(y+z)H ₂ O=K _x [(AlO ₂ ) _x (SiO ₂ ) _y ]?zH ₂ O+2yKOH(aq). (8)

A method for removing particle glass slag and silicon-aluminum oxide in waste rare earth fluorescent powder according to the present invention is as follows:

(1) Pre-calcine the collected waste rare earth phosphors at a temperature of 300-800°C and a processing time of 0.5-4 hours to remove organic impurities mixed in it, promote the effective separation of glass slag and phosphors, and obtain roasted slag;

(2) The roasted slag is subjected to acidolysis and pressure filtration to obtain acidolysis slag and rare earth solution. The acidolysis slag needs to be washed with water during pressure filtration so that the acidolysis slag does not contain rare earth acidic solution. The acidolysis slag is separated by hydraulic separation and wet screening. Combined with sedimentation process, the coarse glass slag (>0.5mm) is removed by hydraulic separation, wherein hydraulic separation is one of cyclone separation, shaking table separation or spiral classification separation, sand settling and then passed through wet Sieve to remove the medium-sized glass slag (0.05~0.5mm), and the undersize obtained after overflow and wet sieving is subjected to sedimentation and filtration to obtain acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities. The size is 300~600 mesh, and the settled water returns to the hydraulic separation process;

(3) For the acid hydrolysis slag containing fine glass slag (<0.05mm) and silicon-aluminum impurities, the fine glass slag and silicon-aluminum oxide impurities are leached with hot alkali, the leaching temperature is 60~100°C, and the leaching time is 0.5~ 4h, the solid-to-liquid ratio is 1:10~1:3, the alkali solution is one or a mixed solution of NaOH and KOH solution, the alkali concentration is 30~60 wt %, and the silicon-alumina alkali liquor and alkali washing residue are obtained after pressure filtration;

(4) After hot alkali leaching and alkali melting, the silicon-aluminum alkali fusion and the waste acid after rare earth recovery are neutralized to recover silicon-aluminum elements.

The invention discloses a combination process of pre-roasting, hydraulic separation, wet screening and hot alkali to remove silicon-aluminum impurities. Pre-roasting removes organic inclusions in waste rare earth phosphors, which is beneficial to improving the effect of hydraulic separation. After acid hydrolysis, the acid hydrolysis slag is subjected to hydraulic separation to remove coarse glass slag in waste rare earth phosphors, wet sieving mainly removes medium glass slag, and hot alkali dissolves fine glass slag and silicon-aluminum oxide impurities. The method of the present invention can efficiently remove coarse, medium and fine particle glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors, avoiding the problem of low rare earth leaching and extraction efficiency caused by the formation of silicon-aluminum colloids in the subsequent recovery of rare earth elements . The invention has the advantages of efficiently removing glass slag and silicon-aluminum oxide impurities in waste rare earth fluorescent powder, significantly improving the recovery rate of rare earth, reducing the amount of materials used, reducing production costs, having significant energy saving and emission reduction, no secondary pollution, and improving the working environment And suitable for industrial production and other characteristics.

Description of drawings

Accompanying drawing 1 is process flow chart of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the examples, but the present invention is not limited only to the following examples.

Example 1

The collected waste rare earth phosphors were pre-calcined and roasted at 300°C for 3 hours. The roasted slag was subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue was sorted by hydrocyclone, wet sieving and sedimentation combined process , hydrocyclone sorting to remove coarse glass slag, sand settling through wet sieve for re-sorting to remove medium particle glass slag, the wet sieve mesh is 400 mesh, and the undersize after overflow and wet sieving is obtained by sedimentation and filtration The acid hydrolysis slag containing fine glass slag and silicon-aluminum impurities, and the settled water are returned to the hydrocyclone separation process. For the acid hydrolysis slag containing fine glass slag and silicon-aluminum impurities, 30 wt % NaOH solution was used to leach residual fine glass slag and silicon oxide, the solid-liquid ratio was 1:4, the leaching temperature was 90°C, and the leaching time was 1 h. Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 2

The collected waste rare earth phosphors were pre-calcined and roasted at 400°C for 3.5 hours. The roasted residue was subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue was separated by shaking table, wet sieving and sedimentation. The hydrocyclone sorts and removes the coarse glass slag, and the sand settling passes through the wet sieve for re-sorting to remove the medium-sized glass slag. The wet sieve has a sieve of 300 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 30 wt % KOH solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:5, the leaching temperature is 100°C, and the leaching time is 1.5h . Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 3

The collected waste rare earth phosphors are pre-roasted and roasted at 500°C for 4 hours. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The hydrocyclone sorts to remove the coarse glass slag, and the sand settling is re-sorted through the wet sieve to remove the medium-sized glass slag. The mesh of the wet sieve is 300 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, using a mixture of 50 wt % NaOH solution and KOH solution, leaching residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:6, and the leaching temperature is 60 ℃, leaching time 2h. Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 4

The collected waste rare earth phosphors are pre-roasted and roasted at 600°C for 0.5h. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue is separated by shaking table, wet sieving and sedimentation. The hydrocyclone sorts to remove the coarse glass slag, and the sand settling is re-sorted through the wet sieve to remove the medium-sized glass slag. The mesh of the wet sieve is 300 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 30 wt % KOH solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:7, the leaching temperature is 70°C, and the leaching time is 2.5h . Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 5

The collected waste rare earth phosphors are pre-roasted and roasted at 700°C for 1 hour. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The hydrocyclone sorts and removes the coarse glass slag, and the sand settling goes through the wet sieve for re-sorting to remove the medium-sized glass slag. The wet sieve has a sieve of 400 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. For the acid hydrolysis slag containing fine glass slag and silicon-aluminum impurities, 30 wt % NaOH solution was used to leach residual fine glass slag and silicon oxide, the solid-liquid ratio was 1:8, the leaching temperature was 80°C, and the leaching time was 3h. Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 6

The collected waste rare earth phosphors are pre-roasted and roasted at 800°C for 1.5 hours. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue is sorted by hydrocyclone, wet screening and sedimentation combination Process, hydrocyclone sorting to remove coarse particle glass slag, sand settling through wet sieve for re-sorting to remove medium particle glass slag, the wet sieve mesh is 500 mesh, and the undersize after overflow and wet sieving is filtered by sedimentation Acidolysis slag containing fine glass slag and silicon-aluminum impurities is obtained, and the settled water is returned to the hydrocyclone separation process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, using a mixture of 40 wt % NaOH solution and KOH solution, leaching residual fine-grained glass slag and silicon oxide, the solid-to-liquid ratio is 1:10, and the leaching temperature is 50 ℃, leaching time 4h. Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 7

The collected waste rare earth phosphors are pre-roasted and roasted at 300°C for 2 hours. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The hydrocyclone sorts and removes the coarse glass slag, and the sand settling goes through the wet sieve for re-sorting to remove the medium-sized glass slag. The wet sieve has a sieve of 400 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 50 wt % NaOH solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:9, the leaching temperature is 100°C, and the leaching time is 0.5h . Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 8

The collected waste rare earth phosphors were pre-calcined and roasted at 400°C for 2.5 hours. The roasted residue was subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue was separated by shaking table, wet sieving and sedimentation. The hydrocyclone sorts to remove the coarse glass slag, and the sand settling is re-sorted through the wet sieve to remove the medium-sized glass slag. The mesh of the wet sieve is 300 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 60 wt % K5OH solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:9, the leaching temperature is 80°C, and the leaching time is 0.5h . Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 9

The collected waste rare earth phosphors are pre-roasted and roasted at 400°C for 3 hours. The roasted residue is subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue is sorted by hydrocyclone, wet screening and sedimentation combined process , hydrocyclone sorting to remove coarse glass slag, sand settling through wet sieve for re-sorting to remove medium particle glass slag, the wet sieve mesh is 200 mesh, and the undersize after overflow and wet sieving is obtained by sedimentation and filtration The acid hydrolysis slag containing fine glass slag and silicon-aluminum impurities, and the settled water are returned to the hydrocyclone separation process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 30 wt % NaOH solution and KOH solution mixed solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:8, and the leaching temperature is 90°C , leaching time 1.5h. Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Example 10

The collected waste rare earth phosphors were pre-calcined and roasted at 600°C for 3.5 hours. The roasted residue was subjected to acid acid hydrolysis to obtain rare earth solution and acid hydrolysis residue. The acid hydrolysis residue was separated by shaking table, wet sieving and sedimentation. The hydrocyclone sorts to remove the coarse glass slag, and the sand settling is re-sorted through the wet sieve to remove the medium-sized glass slag. The mesh of the wet sieve is 300 mesh. Fine particle glass slag and acid hydrolysis slag of silicon-aluminum impurities, and settled water are returned to the hydrocyclone sorting process. Acid hydrolysis slag containing fine-grained glass slag and silicon-aluminum impurities, use 40 wt % NaOH solution to leach residual fine-grained glass slag and silicon oxide, the solid-liquid ratio is 1:7, the leaching temperature is 70°C, and the leaching time is 2.5h . Alkali washing slag can remove glass slag and silicon-aluminum oxide impurities in waste rare earth phosphors through alkali fusion and water washing processes.

Claims (4)

1. remove a method for glass dregs and sieve and silica-sesquioxide in waste and old fluorescent RE powder, it is characterized in that comprising the following steps:

(1) waste and old fluorescent RE powder carries out preroasting, obtains fired slags;

(2) fired slags obtains acidolysis slag and earth solution through acidolysis and press filtration, acidolysis slag adopts waterpower sorting, wet screening and sedimentation combination process to carry out sorting, sorting obtains raw glass slag, overflow and sand setting, the screen underflow of overflow and wet screening obtains through sedimentation the acidolysis slag containing fine particle glass dregs and sial impurity, and sedimentation water returns waterpower sorting operation;

(3) the acidolysis slag containing fine particle glass dregs and sial impurity adopts thermokalite to leach, and obtains sial alkali lye and alkali cleaning slag through press filtration;

(4) alkali cleaning slag obtains washed-residue and sial alkali lye through alkali fusion, washing and press filtration, and washed-residue obtains rare earth and raffinate through acidolysis, extraction;

(5) sial alkali lye and raffinate reclaim sial art breading reclaim sial element through neutralizing.

2. a kind of method removing glass dregs and sieve and silica-sesquioxide in waste and old fluorescent RE powder according to claim 1, it is characterized in that: described step (1) pre-calcination temperature is 300 ~ 800 DEG C, pre-firing times is 0.5 ~ 4h.

3. a kind of method removing glass dregs and sieve and silica-sesquioxide in waste and old fluorescent RE powder according to claim 1, it is characterized in that: the waterpower in described step (2) is divided and elected swirler sorting, separation by shaking table and screw classifying as and divide the one chosen, and wet screening size of mesh is 300 ~ 600 orders.

4. a kind of method removing glass dregs and sieve and silica-sesquioxide in waste and old fluorescent RE powder according to claim 1, it is characterized in that: the extraction temperature that described step (3) thermokalite leaches fine particle glass dregs and sieve and silica-sesquioxide impurity is 60 ~ 100 DEG C, extraction time is 0.5 ~ 4h, solid-to-liquid ratio is 1:10 ~ 1:3, wherein thermokalite is one in NaOH and KOH solution or mixing solutions, and alkali concn is 30 ~ 60 wt%.