CN102275953A

CN102275953A - Method for producing caustic soda by purified brine

Info

Publication number: CN102275953A
Application number: CN2011102010786A
Authority: CN
Inventors: 蒋远华; 杨晓勤; 张道红; 何原; 彭美凡
Original assignee: Hubei Shuanghuan Science and Technology Stock Co Ltd
Current assignee: Hubei Shuanghuan Science and Technology Stock Co Ltd
Priority date: 2011-07-19
Filing date: 2011-07-19
Publication date: 2011-12-14

Abstract

The invention relates to a method for producing caustic soda by purified brine. The method comprises the following steps: adding a collecting barrel, a vertical-type salt-washing device, a salt settler, an old brine barrel, and a cyclone on a pipeline for recovering salts precipitated in a caustic soda evaporation procedure, collecting salt slurry in the caustic soda evaporation procedure by the collecting barrel, allowing the collected salt slurry to enter the vertical-type salt-washing device, performing cooling, re-dissolving and flotation with purified brine entered from the lower part, discharging the salt slurry from a discharge valve at the lower part of the vertical-type salt-washing device, allowing the washed clear liquid to overflow from a overflow port of the vertical-type salt-washing device to the salt settler, discharging the salt slurry in the salt settler to a salt slurry barrel, allowing the clear liquid rich in sodium sulfate to flow into the old brine barrel, delivering the clear liquid to a salt and sodium sulfate co-production system by a pump, delivering the salt slurry in the salt slurry barrel to the cyclone by a salt slurry pump, allowing the clear liquid at the top of the cyclone to flow to the old brine barrel, and delivering the salt slurry thickened by the cyclone to a salt-dissolving pool for brine refining. The invention has the following beneficial effects: 1. mother liquor with high-content sodium sulfate is recovered, which is environment friendly; 2. power consumption and steam using amount are reduce, which saves resources and reduces production cost.

Description

A kind of method of utilizing purified brine to produce caustic soda

Technical field

The present invention relates to the brine rectification process technical field among the chlorination worker, specifically a kind of method of utilizing purified brine to produce caustic soda.

Background technology

Salt accounts for 17～20% in the production of caustic soda cost, and the change salt solution NaCl content that is used for dissolved solids salt approaches the NaCl content requirement into the electrolyzer refined brine more, and the solid salt of adding is just few more, is zero until the solid salt consumption.Enter the stable of stable more stable operation that just is beneficial to production system more of crude brine NaCl content, the foreign matter content of salt solution operation and quality product.And China's salt mine aboundresources, the mass concentration of the NaCl in the bittern can reach 290～310g/l, by optimizing technology, under the condition that does not add solid salt, can satisfy the production requirement of system alkali through refining.The difficulty of the perhalogeno system alkali of caustic soda industry is the denitrating technique in the salt refining at present, when the refined brine sulfate radical content is higher, can hinder the chlorion discharge, sulfate radical discharges at anode electrolytic cell, can produce oxygen, consumed power reduces current efficiency, and sodium sulfate and sodium-chlor all contain sodium ion simultaneously, because common-ion effcet, reduce the solubleness of sodium-chlor, influence the refined brine sodium chloride content, and the reduction that enters the electrolyzer brine concentration will directly affect the direct current consumption of production of caustic soda.Now adopt freezing denitration and inspissation technology to realize that brine denitration is refining.And the power consumption of freezing denitration, inspissation and steam consumption quantity account for 20% of total cost (folding 100%NaOH), therefore how to optimize brine rectification process, reduce the salt refining cost of enterprise, economize on resources, and reduce cost, and just become a urgent problem.

Summary of the invention

The technical problem to be solved in the present invention is exactly the defective at existing production of caustic soda technology, and a kind of method of utilizing purified brine to produce caustic soda is provided, and it has optimized brine rectification process, has reduced the salt refining cost, economizes on resources.

For solving the problems of the technologies described above, the technical scheme that the present invention takes is: it utilizes the halogen resources advantage, develops saline and alkaline associating, realizes perhalogeno system alkali.Its step comprises: increased gathering barrel, vertical desalinization of soil by flooding or leaching device, heavy salt device, old halogen bucket and swirler on the recovery salt pipeline that the evaporating caustic soda operation is separated out, the salt slurry of evaporating caustic soda operation enters vertical desalinization of soil by flooding or leaching device after collecting through gathering barrel, with the purified brine (Ca that enters from the bottom ²⁺+ Mg ²⁺≤ 5mg/L) through after cooling (to 32～35 ℃), Hui Rong, the flotation, the salt slurry is discharged to salt slurry bucket from vertical desalinization of soil by flooding or leaching device bottom bleeder valve, clear liquid after the washing overflows to heavy salt device from the overflow port of vertical desalinization of soil by flooding or leaching device, salt slurry in the heavy salt device enters salt slurry bucket, the clear liquid that wherein is rich in sodium sulfate flows back to old halogen bucket, be sent by pumping to the sal prunella co-generation system, the salt slurry of salt slurry bucket is delivered to swirler by brine pump, the clear liquid on swirler top flows back to old halogen bucket, carries out salt refining through being transported to of the slurry of the salt after swirler thickening salt pond.This process circulation is carried out, because waste liquid all returns mine and salt manufacturing, caustic soda system water system balancing realizes wastewater zero discharge and perhalogeno system alkali.

Beneficial effect of the present invention:

1, reclaimed high nitre mother liquor, with environmental friendliness;

2, reduce power consumption and steam consumption, saved resource, reduced production cost.

Description of drawings

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

Fig. 2 is a vertical desalinization of soil by flooding or leaching device process flow sheet of the present invention

Embodiment

Below in conjunction with process flow sheet the present invention is described further:

As shown in Figure 1 and Figure 2, the present invention has increased gathering barrel, vertical desalinization of soil by flooding or leaching device, heavy salt device, old halogen bucket and swirler on the recovery salt pipeline that the evaporating caustic soda operation is separated out, the salt slurry of evaporating caustic soda operation enters vertical desalinization of soil by flooding or leaching device after collecting through gathering barrel, with the purified brine (Ca that enters from the bottom ²⁺+ Mg ²⁺≤ 5mg/L) through after cooling (to 32～35 ℃), Hui Rong, the flotation, because the sodium sulfate that purifies in the halogen is undersaturated condition, and sodium-chlor is near saturated, therefore in the process of contact washing, contained sulfate radical will be dissolved in the smart halogen in the salt slurry, thereby reduced the sulfate radical in the salt slurry, reached the purpose that purifies salt matter.The salt slurry is discharged to salt slurry bucket from vertical desalinization of soil by flooding or leaching device bottom bleeder valve, clear liquid after the washing overflows to heavy salt device from the overflow port of vertical desalinization of soil by flooding or leaching device, salt slurry in the heavy salt device enters salt slurry bucket, the clear liquid that wherein is rich in sodium sulfate flows back to old halogen bucket, be sent by pumping to the sal prunella co-generation system, the salt slurry of salt slurry bucket is delivered to swirler by brine pump, and the clear liquid on swirler top flows back to old halogen bucket, carries out salt refining through being transported to of the slurry of the salt after swirler thickening salt pond.This process circulation is carried out, because waste liquid all returns mine and salt manufacturing, caustic soda system water system balancing realizes wastewater zero discharge and perhalogeno system alkali.

Claims

1. method of utilizing purified brine to produce caustic soda, it is to have increased gathering barrel on the recovery salt pipeline that the evaporating caustic soda operation is separated out, vertical desalinization of soil by flooding or leaching device, heavy salt device, old halogen bucket and swirler, the salt slurry of evaporating caustic soda operation enters vertical desalinization of soil by flooding or leaching device after collecting through gathering barrel, with the purified brine process cooling that enters from the bottom, Hui Rong, after the flotation, the salt slurry is discharged to salt slurry bucket from vertical desalinization of soil by flooding or leaching device bottom bleeder valve, clear liquid after the washing overflows to heavy salt device from the overflow port of vertical desalinization of soil by flooding or leaching device, salt slurry in the heavy salt device enters salt slurry bucket, the clear liquid that wherein is rich in sodium sulfate flows back to old halogen bucket, be sent by pumping to the sal prunella co-generation system, the salt slurry of salt slurry bucket is delivered to swirler by brine pump, the clear liquid on swirler top flows back to old halogen bucket, carries out salt refining through being transported to of the slurry of the salt after swirler thickening salt pond.