JPS63104605A - Production of large crystal in crystallizer with crystal growth device - Google Patents

Abstract

PURPOSE:To efficiently obtain a large-diameter crystal by circulating and supplying a supernatant mother liquor at the upper part of a crystal growth device to the bottom of said device. CONSTITUTION:The supernatant mother liquor at the upper part of the crystal growth device 3 is circulated and supplied to the bottom of the device 3 to form a uniform fluidized bed of crystals. For example, the supernatant mother liquor at the upper part of the device 3 is drawn off from a supernatant mother liquor outlet 13 and circulated by a swirling pump 15 to the bottom of the device 3 from a swirling liquor injection port 16 through a swirling liquor pipe 14, and the crystal is grown while keeping the crystals at the bottom of the device 3 in a fluidized state. As a result, a large-diameter crystal can be efficiently obtained while preventing the deposition and caking of the crystals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing large crystals of common salt, ammonium sulfate, etc. in a crystallizer with a crystal grower.

[Conventional technology and its problems]

In conventional crystallizers with a crystallizer, crystals accumulate and solidify at the bottom of the crystallizer, which inhibits crystal growth, reduces yield, and interferes with continuous operation. ing.

Therefore, in order to prevent the crystals from accumulating and solidifying, a stirrer is installed at the bottom of the crystal grower to stir and fluidize the crystals, and to prevent the crystals from accumulating and solidifying at the bottom, while increasing the size of the crystals. I came here with the aim of

This conventional method will be explained based on FIG.

In FIG. 3, the saturated solution is drawn out from the upper part of the crystal grower 5 by the circulating pump 7), heated by the steam supplied from the heater steam inlet 9 in the heater 1, and then heated by the circulating vibro. The vapor is led to the evaporator 2 via I and is evaporated to become a supersaturated liquid.

The supersaturated liquid is then led to the fluid crystal growth zone at the bottom of the crystal growth device 3, and the solute corresponding to the supersaturation is crystallized on the crystals in the fluid crystal growth zone, and the supersaturated liquid is transformed into a clear saturated mother liquor 5 again. It is circulated to the heater 1 via a circulation vibro and a circulation bonder 7.

A solution in which a solute is dissolved is supplied from a liquid supply port 12, and the generated large crystals are discharged from a crystal discharge port 8.

Conventionally, a stirrer 1 is installed at the bottom of the crystal grower to prevent crystals from accumulating and solidifying at the bottom of the crystal grower and to produce large crystals.
7, a method is adopted in which the crystals are made to flow, but in this case, when producing crystals with a large grain size of 150,071 to 3,000μ, a large horsepower is required to prevent the crystals from accumulating at the bottom of the crystal grower. On the other hand, stirring with a stirrer with high horsepower causes the crystals to break due to stirring in the crystal zone, and these broken crystals become crystal nuclei and become an obstacle to the production of large-sized crystals. Ta.

[Purpose of the invention]

The present invention provides a method for efficiently producing large-sized crystals (by circulating and supplying clear mother liquor from the top of the crystal grower to the bottom of the crystal grower to form a uniform fluidized bed of crystals). The purpose is to

[Structure of the invention]

The present invention provides a method for growing crystals using a crystallizer equipped with a crystal grower, in which a clear mother liquor at the top of the crystal grower is circulated and supplied to the bottom of the crystal grower, and in particular, υ is
This method prevents the accumulation of crystals at the bottom of the crystal grower and produces crystals with large grain size.

The inventors of the present invention have conducted various studies in order to solve the drawbacks of the conventional technology, and have decided to circulate the clarified mother liquor at the top of the crystal grower to the bottom of the crystal grower to fluidize the crystals at the bottom of the crystal grower. The present invention was accomplished by discovering that it is possible to efficiently obtain uniformly shaped, large-sized crystals without the crystals accumulating, solidifying, or breaking.

The method of the present invention will be explained based on FIG. 1. In FIG. 1, the same symbols as in FIG. 3 have the same meanings as explained in FIG. A pipe, 15 is a swirling flow pump, and 16 is a swirling flow injection port.

In the present invention, the clarified mother liquor from the upper part of the crystal grower 3 is extracted from the clarified mother liquor outlet 13 and circulated through the swirl flow pipe 14, the swirl flow pump 15, the swirl flow injection port 16, and the bottom of the crystal grower 5. Crystal growth is performed while keeping the crystals at the bottom of the crystal grower in a fluid state.

As shown in FIG. 2, the swirling flow injection port 16 is preferably injected in a tangential direction in order to increase the effect of stirring the crystals.The amount of clarified mother liquor jetted from the swirling flow injection port 16 depends on the size of the device and the desired amount. Although it depends on the size of the crystal and the specific gravity of the crystal, the flow rate of the upward flow of the liquid at the bottom of the crystal grower is smaller than that of the crystal of the desired size. It is preferable to circulate and eject clear mother liquor.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a crystallizer with a crystal grower for explaining the method of the present invention, Fig. 2 is a cross-sectional view of the swirling flow injection port shown in Fig. 1, and Fig. 3 is a cross-sectional view of a conventional method. A cross-sectional view of a crystallizer with a crystal grower is shown for explanation.

Claims (1)

[Claims] 1. In a method of growing crystals using a crystallizer with a crystal grower, the clear mother liquor in the upper part of the crystal grower is circulated and supplied to the bottom of the crystal grower to prevent the accumulation and solidification of crystals. A method for producing large crystals. 2. The method for producing large grain crystals according to claim 1, wherein the clarified mother liquor at the top of the crystal grower is supplied to the bottom of the crystal grower by rotating.