CN1254437C - Method of refining salt solution - Google Patents

Abstract

The present invention relates to a method for refining salt water by removing calcium ions and magnesium ions in crude salt water, which has the steps: removing magnesium from crude salt water, (a), the crude salt water is placed in a magnesium removing reactor, a prepared settling agent of PAM and lime milk are added in the reactor, the reaction is kept for half an hour, and primary mixed liquid is obtained; (b), the primary mixed liquid is put in a primary salt water clarifying tank for clarification, primary salt water is prepared, and residual primary mud at the inner part of the tank bottom is put in a No. 1 mud washing tank for washing mud; removing calcium from the primary salt water, (a), the primary salt water is added in a calcium removing reactor, carbonization neutralizing water containing carbonic acid radicals is added in the calcium removing reactor, the concentration of the neutralizing water is 55 to 65 tt, the humidity is 35 to 40 DEG C., the reaction is kept for half an hour, and secondary mixed liquid is prepared; (b), the secondary mixed liquid is put in a secondary salt water clarifying tank for clarification for two to three hours, refined salt water is made, and residual secondary mud is put in a No. 2 mud washing tank for washing mud. The present invention has the advantages of simple process and high content of salt of the refined salt water.

Description

The method of refined brine

Technical field

The present invention relates to a kind of method of refined brine, specifically a kind of method of removing calcium in the crude brine, magnesium ion acquisition refined brine.

Background technology

Along with the increase day by day of soda ash output, crude salt supply day is becoming tight, and price one rises and rises again, and the rising range of soda ash price is difficult to catch up with the rising range of crude salt price, and is limited by the control of import urao price, and is therefore energy-saving and cost-reducing, imperative.And regrettably, though the many alkali factories of order China can not use extra large hydratable salt near the sea, the method for salt refining is to adopt lime-soda method and lime-carbonic acid ammonia process.Lime-soda method consumes finished product soda ash, and refining expense height is uneconomical with extra large hydratable salt, so can not use extra large hydratable salt.Lime-carbonic acid ammonia process cost is low, but need build the deliming tower, and the cleaning work amount is big, and the wasting manpower and material resources, and prepared refined brine salt content is low, influences the carbonization transformation efficiency, and this method is also uneconomical.

Summary of the invention

The purpose of this invention is to provide the method for the refined brine of the available extra large hydratable salt that a kind of economy saves trouble, it does not establish the deliming tower, with in milk of lime and the carbonization and water directly crude brine is made with extra care, with the refined brine salt content height that this method makes, production cost is low.

The technical scheme of realization foregoing invention purpose is undertaken by following step:

(1), gives the crude brine demagging

A, crude brine is placed in the demagging reactor, adds in the reactor and configure settling agent polyacrylamide and milk of lime, reacted 0.5 hour, make distiller liquor one time;

B, a distiller liquor put into the primary brine settling tank clarify, make primary brine, bucket at the end a last mud go into No. 1 mud cleaning bucket and wash mud;

(2), give the primary brine deliming

A, primary brine is added in the calcium-removing reactor, adds in the carbonization that contains carbonate toward calcium-removing reactor and water, in and the concentration of water be 55-65tt, humidity is 35-40 ℃, reacts 0.5 hour, makes the secondary distiller liquor;

B, the secondary distiller liquor was put into secondary brine settling tank clarification 2-3 hour, make refined brine and go into the refined salt tank, remaining secondary mud is gone into No. 2 mud cleaning buckets and is washed mud.

Compare with background technology, it is thorough to have a deliming demagging, is applicable to that the high crude brine of magnesium calcium impurities is refining.Produce 1 ton of soda ash than lime-soda process and can reduce by 30 yuan of/ton alkali of manufacturing cost, economic benefit is considerable.Technical process is simpler than carbonic acid ammonia process, because present method need not be provided with the deliming tower, has removed the workload that clear tower brings from, uses manpower and material resources sparingly.Be cost saving with extra large hydratable salt in addition, can obtain the high refined brine of salt content again, its refined brine salt content can reach more than the 106.0tt, and this is that the carbonic acid ammonia process is incomparable.

The present invention will be further described below in conjunction with embodiment.

The present invention is with the method for with water crude brine being carried out refined brine in milk of lime and the carbonization.It is undertaken by following step:

(1), give the crude brine demagging: its chemical equation is:

A, crude brine is placed in the demagging reactor, stir clarification 1 hour toward reactor interior adding settling agent polyacrylamide (PAM) and milk of lime, the adding capacity of settling agent PAM is 0.08% of a crude brine, the adding capacity of milk of lime is 34.5% of a crude brine, and the clear liquid that makes is a distiller liquor;

B, a distiller liquor is put into the primary brine settling tank, stirs clarification once more, make primary brine, bucket at the end a last mud go into No. 1 mud cleaning bucket and wash mud;

(2), give the primary brine deliming, its chemical equation is:

A, primary brine is added in the calcium-removing reactor, adds toward calcium-removing reactor and contain CO ₂Concentration be in the carbonization of 55-65tt and water 21.75Ml, stir clarification 0.5 hour, make the secondary distiller liquor;

B, the secondary distiller liquor is put into secondary brine settling tank secondary clearing again, make secondary brine, remaining secondary mud is gone into No. 2 mud cleaning buckets and is washed mud;

C, the secondary brine clear liquor is placed in the refined salt bucket, goes heavy alkali to absorb operation.

Mud and secondary mud are washed mud at 1, No. 2 mud cleaning bucket, reclaim salt and ammonia.Remaining useless mud is delivered to heavy alkali discharging, is placed on respectively in the light salt brine settling tank and clarifies by washing the light salt brine that makes behind the mud, makes light salt brine, and remaining useless mud is used for heavy alkali flow process.

EXPERIMENTAL EXAMPLE: see the following form

Table 1

Embodiment step: get crude brine 600ml, add milk of lime 2.07ml, add polyacrylamide (PAM) the settling agent 0.5ml that configures simultaneously, in the demagging reactor, make one time distiller liquor after the demagging, a distiller liquor is put into the primary brine settling tank to be clarified, take out clarifying primary brine 400ml after 1 hour, join deliming in the calcium-removing reactor, contain CO interior the adding toward calcium-removing reactor ₂, titre is in the carbonization of 55-65tt and water 21.75ml, stirs and enters settling tank after 0.5 hour, taking-up post-defecation liquid is refined brine 3000ml after 2-3 hour.The analytical results of refined brine such as following table:

Table 2

The controlling index of refined brine

	Index name	Unit	Span of control	Sample time	Remarks
						1	Crude brine	Titre	≥107.5	1 hour
2	Refined brine concentration	Titre	≥105	1 hour
						3	Refined brine magnesium	Mg/litre	≤15	8 hours
4	Refined brine calcium	Mg/litre	≤15	8 hours
						5	Refined brine FNH 3	Titre	5-9	At any time
6	The newborn concentration of ash	Titre	158-162	0.5 hour	Lime is analyzed
						7	In and water concentration	Titre	55-65	1 hour	Heavy alkali analysis
8	Crude brine magnesium	Titre		2 hours
						9	Crude brine calcium	Titre		2 hours
10	The primary brine turbidity	PPM	40-80	1 hour
						11	Refined brine concentration	PPM	＜30	1 hour
12	Useless mud FNH 3	Mg/litre	＜150		At any time
						13	Primary brine surplus [OH]	Titre	0.05-0.1	8 hours	The sea hydratable salt can be adjusted
14	The superfluous CO of secondary brine 3 2-	Titre	1-2	8 hours	Suitable clarifying effect adjustment
						15	Settling agent concentration	Weight %	0.04-0.05	4 hours
16	Crude brine humidity	℃	39±2	1 hour
						17	Light salt brine humidity	℃	42±2	1 hour
18	Primary brine humidity	℃	About 36 ℃	At any time
						19	In and water temp	℃	35-40℃	At any time	Heavy alkali control
20	The newborn temperature of ash	℃	≥93	At any time	Lime control
						21	Useless mud saliferous	Titre	≤6	3 hours
22	Useless mud rate of descent	％	≥90	2 hours	Heavy 30 minutes
						23	Salt mud rate of descent	％	≥60	1 hour	Heavy 5 minutes
24	Demagging, calcium reaction times	Minute	Less than 2 minutes		Experimental data
						25	The deliming churning time	Minute	≥30		Determine by actual

Claims (1)

1, a kind of method of refined brine is characterized in that, undertaken by following step,

(1), gives the crude brine demagging

A, crude brine is placed in the demagging reactor, adds in the reactor and configure settling agent polyacrylamide and milk of lime, reacted 0.5 hour, make distiller liquor one time;

B, a distiller liquor put into the primary brine settling tank clarify, make primary brine, bucket at the end a last mud go into No. 1 mud cleaning bucket and wash mud;

(2), give the primary brine deliming

A, primary brine is added in the calcium-removing reactor, adds in the carbonization that contains carbonate toward calcium-removing reactor and water, in and the concentration of water be 55-65tt, humidity is 35-40 ℃, reacts 0.5 hour, makes the secondary distiller liquor;

B, the secondary distiller liquor was put into secondary brine settling tank clarification 2-3 hour, make refined brine and go into the refined salt tank, remaining secondary mud is gone into No. 2 mud cleaning buckets and is washed mud.