Method for controlling crystal performance by changing stirring rotating speed in different time periods in intermittent crystallization process

Abstract

The invention discloses a method for controlling the performance of crystals by changing the stirring rotating speed in different periods in the intermittent crystallization process. The method comprises the following four stages of initial concentration, crystal nucleus separation, crystal growth and crystal aging. Solution specific gravities, solution volumes and solid-liquid proportions of the four stages are different, different stirring rotating speeds are adopted in different time periods of the crystallization process, and the number of crystal nucleuses generated in the solution in each time period, the growth speed of crystals in each time period and the number of crystal nucleuses of final crystals can be controlled. In the crystallization process of the solution in the intermittent crystallizer, different crystal nucleus or crystal production environments are manufactured by adopting a method of controlling the stirring rotating speed in a time division manner or a stepless speed change manner so as to control the growth process of the crystal nucleus or the crystal, and the purpose of controlling the performance of the final crystal is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of crystallization, and in particular to a method for controlling crystal performance by changing stirring speed in time periods during intermittent crystallization. Background Art

[0002] Crystallizers and crystallization technology are widely used in the crystallization process of water or organic solvent solutions in the pharmaceutical, food, chemical, metallurgical, light industry and other industries, especially in using crystallization methods to precipitate crystals in solid form.

[0003] The existing development of crystallization technology focuses more on reducing energy consumption in the crystallization process, process automation control and the impact of stirring speed on crystals, but does not pay attention to the changes in the performance of crystals precipitated from the solution in the intermittent crystallizer after changing the stirring speed in different time periods during the entire crystallization process.

[0004] With the rapid advancement of science and technology, various mechanical devices have put forward various incredible requirements for various materials. The performance of various materials is often genetically affected by the performance of upstream raw materials. Only by changing conventional thinking can we produce new materials with outstanding performance. Therefore, it is very necessary to improve the crystallization method of intermittent crystallizer in order to obtain crystals with obvious performance differences. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to provide a method for controlling the performance of crystals by changing the stirring speed in time periods during the intermittent crystallization process, so as to solve the problems raised in the above background technology.

[0006] The present invention solves the technical problem by adopting the following technical solution:

[0007] The present invention provides a method for controlling the performance of crystals by changing the stirring speed in different time periods during intermittent crystallization, comprising the following steps: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging;

[0008] The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

[0009] Preferably, when the stirring speed is controlled from slow to fast by time-division or stepless speed change, the crystals in the solution grow independently into single crystals without colliding with each other.

[0010] Preferably, under the control of the stirring speed from fast to slow to fast by time division or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that adhere to each other.

[0011] Preferably, the stirring speed in each time period is 15-45 r / min for 0-2 h, 30-45 r / min for 2-4 h, and 15-45 r / min for 4-6 h.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The present invention uses a method of time-dividing or steplessly changing the speed of stirring to control the crystallization process of a solution in an intermittent crystallizer to create different crystal nuclei or crystal production environments to control the growth process of the crystal nuclei or crystals, thereby achieving the purpose of controlling the performance of the final crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram of an intermittent crystallizer of the present invention;

[0015] Figure 2 This is a crystal diagram of ammonium paratungstate according to Example 1 of the present invention;

[0016] Figure 3 This is a crystal diagram of ammonium paratungstate according to Example 2 of the present invention;

[0017] Figure 4 This is a crystal diagram of ammonium paratungstate according to Example 3 of the present invention;

[0018] 1. Motor, 2. Reducer, 3. Intermittent crystallizer barrel, 4. Stirring paddle, 5. Cable, 6. Control cabinet. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] A method of controlling the performance of a crystal by changing the stirring speed in different time periods during an intermittent crystallization process in this embodiment includes the following steps: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging;

[0021] The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

[0022] In this embodiment, when the stirring speed is controlled from slow to fast by time division or stepless speed change, the crystals in the solution do not collide with each other during the growth process and become independent single crystals.

[0023] In this embodiment, when the stirring speed is controlled from fast to slow to fast by time division or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that adhere to each other.

[0024] The stirring speed in each time period of this embodiment is 15-45 r / min for 0-2h, 30-45 r / min for 2-4h, and 15-45 r / min for 4-6h.

[0025] Example 1

[0026] 8m 3 Add 10 ml of ammonium tungstate solution 3 In the intermittent crystallizer, the crystallization was carried out under the following conditions for 6 hours, and the crystallized ammonium paratungstate was dried and sieved through an 80-mesh stainless steel screen. The physical properties of the final ammonium paratungstate crystals are shown in the following table:

[0027] A method of controlling the performance of a crystal by changing the stirring speed in different time periods during an intermittent crystallization process in this embodiment includes the following steps: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging;

[0028] The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

[0029] In this embodiment, when the stirring speed is controlled from slow to fast by time division or stepless speed change, the crystals in the solution do not collide with each other during the growth process and become independent single crystals.

[0030] In this embodiment, when the stirring speed is controlled from fast to slow to fast by time division or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that adhere to each other.

[0031]

[0032] Example 2

[0033] 8m 3 Add 10 ml of ammonium tungstate solution 3 In the intermittent crystallizer, the crystallization was carried out under the following conditions for 6 hours, and the crystallized ammonium paratungstate was dried and sieved through an 80-mesh stainless steel screen. The physical properties of the final ammonium paratungstate crystals are shown in the following table:

[0034] A method of controlling the performance of a crystal by changing the stirring speed in different time periods during an intermittent crystallization process in this embodiment includes the following steps: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging;

[0035] The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

[0036] In this embodiment, when the stirring speed is controlled from slow to fast by time division or stepless speed change, the crystals in the solution do not collide with each other during the growth process and become independent single crystals.

[0037] In this embodiment, when the stirring speed is controlled from fast to slow to fast by time division or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that adhere to each other.

[0038]

[0039] Example 3

[0040] 8m 3 Add 10 ml of ammonium tungstate solution 3 In the intermittent crystallizer, the crystallization was carried out under the following conditions for 6 hours, and the crystallized ammonium paratungstate was dried and sieved through an 80-mesh stainless steel screen. The physical properties of the final ammonium paratungstate crystals are shown in the following table:

[0041] A method of controlling the performance of a crystal by changing the stirring speed in different time periods during an intermittent crystallization process in this embodiment includes the following steps: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging;

[0042] The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

[0043] In this embodiment, when the stirring speed is controlled from slow to fast by time division or stepless speed change, the crystals in the solution do not collide with each other during the growth process and become independent single crystals.

[0044] In this embodiment, when the stirring speed is controlled from fast to slow to fast by time division or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that adhere to each other.

[0045]

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for controlling the properties of crystals by changing the stirring speed in different time periods during intermittent crystallization. It is characterized in that The following steps are involved: There are four stages: initial concentration, crystal nucleus precipitation, crystal growth, and crystal aging; The specific gravity, volume and solid-liquid ratio of the solutions in the four specific stages are different. Using different stirring speeds at different times during the crystallization process can control the number of crystal nuclei generated in the solution at each time period, the growth rate of the crystals at each time period, and the number of crystal nuclei in the final crystal.

2. A method for controlling the properties of crystals by changing the stirring speed in different time periods during an intermittent crystallization process according to claim 1, It is characterized in that When the stirring speed is controlled from slow to fast by time-division or stepless speed change, the crystals in the solution grow independently into single crystals without colliding with each other.

3. A method for controlling the properties of crystals by changing the stirring speed in different time periods during an intermittent crystallization process according to claim 1, It is characterized in that When the stirring speed is controlled from fast to slow to fast by time-sharing or stepless speed change, the crystals in the solution slightly collide with each other to form complex crystals that stick to each other.

4. A method for controlling the properties of crystals by changing the stirring speed in different time periods during an intermittent crystallization process according to claim 2, It is characterized in that The stirring speed in each time period is 15-45r / min for 0-2h, 30-45r / min for 2-4h and 15-45r / min for 4-6h.

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