CN103848453A

CN103848453A - Method for reducing periodic thinning of seeds decomposition process

Info

Publication number: CN103848453A
Application number: CN201210496388.XA
Authority: CN
Inventors: 李志国; 陈玉国
Original assignee: Shenyang Aluminum and Magnesium Engineering and Research Institute Co Ltd
Current assignee: Shenyang Aluminum and Magnesium Engineering and Research Institute Co Ltd
Priority date: 2012-11-28
Filing date: 2012-11-28
Publication date: 2014-06-11
Anticipated expiration: 2032-11-28
Also published as: CN103848453B

Abstract

The invention relates to a method for reducing periodic thinning of a seeds decomposition process, which comprises the following steps: grading products from a seeds decomposition final groove through a finished product cyclone, grading underflow to make the finished product, grading overflow and introducing into the seeds cyclone for grading, filtering the cyclone underflow through a filter, and taking the underflow as a seed added while the normal production, adding into the decomposition first groove, filtering the overflow through the filter and sending into a storage facility for individual preservation, and momentarily detecting the granularity of the finished products, and adding the seeds with fine grain in the decomposition first groove during a granularity curding process. According to the invention, the periodic thinning influence is reduced, the stabilization of the aluminum hydroxide granularity during the decomposition process is ensured, and the production operation is stable.

Description

A kind of method that reduces seed decomposition course periodic thinning

Technical field

The present invention relates to a kind of method that reduces seed decomposition course periodic thinning, belong to technical field of alumina production.

Background technology

In the seed decomposition course of alumina producing, there is aluminium hydroxide product granularity cyclic fluctuation phenomenon.Aluminum hydroxide particles " is constantly grown up " in whole decomposition course, in the time that these particles are grown up to critical granularity (+45 μ m approximately 90 ~ 95%), granule surface activity significantly reduces, particle surface adheres to, and ultra-fine (5 μ m) particle come off at short notice, and hydroxide particle-size state is undergone mutation.Once ultra-fine grain aluminium hydroxide produces, the corresponding generation of seed-coat " great-jump-forward " changes, but original thick (m) not minimizing of particle of 40-80 μ, now Two particle size relative volume has a long way to go, shared volume and the part by weight of the new ultra-fine grain aluminium hydroxide producing is very little, within for some time, affect little on decomposing the overall granular level of discharging aluminium hydroxide, but be accompanied by the continuous generation of ultra-fine grain aluminium hydroxide, grow up and coarse particles aluminium hydroxide as product discharge system, the granularity of discharging aluminium hydroxide starts to decline gradually, until former coarse particles aluminium hydroxide remains when little, discharging hydroxide particle-size touches the bottom, being accompanied by fine particle grows up gradually, the bottom out of coarse fodder hydroxide particle-size, form loop cycle.

In scientific worker's research, considered to delay to produce by rising temperature of initial decomposition the time of explosive refinement, weaken the amplitude of cyclic fluctuation, but temperature has dual function, reduce temperature and can improve rate of decomposition, but the degree of supersaturation of low temperature aluminium acid sodium solution is large, decomposition rate is fast, if do not have enough seed-coat for decomposing long-pending, secondary nucleation easily occur, thereby cause product granularity refinement; Rising temperature can suppress secondary nucleation, promotes the carrying out of agglomeration, but can make the degree of supersaturation of solution reduce, and slows down decomposition rate, reduces rate of decomposition.

Though through various countries scientific worker a large amount of research work for many years, fail to be so far well solved but the problem of periodic thinning appears in Bayer process For Aluminium Hydroxide Settling In The Process of Alumina Manufacture granularity, badly influence decomposition course quantity-produced and normally carry out.

Summary of the invention

The present invention is exactly a kind of method that reduces seed decomposition course periodic thinning providing in order to solve the problems of the technologies described above, and object is the impact in order to reduce periodic thinning, realizes decomposition course normal production continuously.

For reaching a kind of method that reduces seed decomposition course periodic thinning of above-mentioned purpose the present invention, it is characterized in that: seed decomposes last groove discharging through finished product cyclone classification, classification underflow is done finished product, Grading Overflow enters seed cyclone classification again, the seed that seed swirler underflow adds do normal production after filter filters time, join and decompose in first groove, the overflow of seed swirler is delivered in storage facility and is preserved separately as fine particle seed after filter filters, detect at any time product grading, run quickly in thick process in granularity, fine particle seed is supplemented to add to and decompose in first groove.

Described seed cyclone classification underflow, conduct after filtering adds unique source of seed decomposing system seed while normally production.

Described seed cyclone classification overflow, fine particle seed is preserved separately in storage facility as a supplement after filtering, does not add seed decomposing system in the time of normal production.

Described finished product cyclone classification underflow, regularly detects its product grading.

The fine particle seed of described independent preservation, changes according to product grading, runs quickly in thick process in granularity, adds to and decomposes in first groove.

By method described in this patent, can prevent that sodium aluminate solution self point from parsing superfine aluminum hydroxide particles, ensure enough fine particle seeds and add system in product granularity is run quickly thick process, all the time in decomposition course, maintain the aluminium hydroxide seed of various grades, realize fine particle seed and constantly add system, intermediate particle is by thin to slightly growing up continuously, and coarse particles is constantly grown up and discharged system as finished product, realizes decomposition course hydroxide particle-size stable.

Accompanying drawing explanation

Fig. 1 is process flow sheet of the present invention.

In figure: 1, decompose last groove; 2, decompose discharging; 3, become product swirler; 4, finished product; 5, Grading Overflow; 6, seed swirler; 7, swirler underflow; 8, filter; 9, seed; 10, decompose first groove; 11, swirler overflow; 12, fine particle seed; 13, storage facility.

Embodiment

Below in conjunction with accompanying drawing, the present invention will be further described, but protection scope of the present invention is not limit by embodiment.

As shown in Figure 1, the present invention is a kind of method that reduces seed decomposition course periodic thinning, comprise the steps: that seed decomposes last groove 1 discharging 2 through becoming product swirler 3 classifications, classification underflow is done finished product 4, Grading Overflow 5 enters 6 classifications of seed swirler again, the seed 9 that seed swirler 6 underflows 7 add do normal production after filter 8 filters time, add and decompose in

first groove

10, 6 overflows 11 of seed swirler are after filter 8 filters, the fine particle seed 12 obtaining is delivered in storage facility 13 and is preserved separately, detect at any time finished product 4 granularities, run quickly in thick process in granularity, fine particle seed 12 is supplemented to add to and decompose in first groove 10.

Claims

1. one kind is reduced the method for seed decomposition course periodic thinning, it is characterized in that: seed decomposes last groove discharging through finished product cyclone classification, classification underflow is done finished product, Grading Overflow enters seed cyclone classification again, the seed that seed swirler underflow adds do normal production after filter filters time, join and decompose in first groove, the overflow of seed swirler is delivered in storage facility and is preserved separately after filter filters, detect at any time product grading, run quickly in thick process in granularity, fine particle seed is supplemented to add to and decompose in first groove.

2. a kind of method that reduces seed decomposition course periodic thinning according to claim 1, is characterized in that described seed cyclone classification underflow, adds unique source of seed decomposing system seed during after filtering as normal production.

3. a kind of method that reduces seed decomposition course periodic thinning according to claim 1, it is characterized in that described seed cyclone classification overflow, fine particle seed is preserved separately in storage facility as a supplement after filtering, does not add seed decomposing system in the time of normal production.

4. a kind of method that reduces seed decomposition course periodic thinning according to claim 1, is characterized in that described finished product cyclone classification underflow, regularly detects its product grading.

5. a kind of method that reduces seed decomposition course periodic thinning according to claim 1, the fine particle seed of the independent preservation described in it is characterized in that, changes according to product grading, runs quickly in thick process in granularity, adds to and decomposes in first groove.