A three-stage salt washing method

Abstract

The application discloses a three-stage salt washing method, which comprises the following steps: step one, raw material treatment: screening the obtained salt mixture; step two, first-stage salt washing: fully mixing the salt with brine, and washing the brine and the salt to fully mix; step three, preliminary salt washing, so as to obtain first-stage salt slurry, second-stage salt slurry and third-stage salt slurry, and the obtained three-stage salt slurries are respectively filled into corresponding buffer barrels, and waste liquid generated in the washing process is collected into a washing barrel; step four, mixing and circulating treatment of the waste liquid in the washing barrel, washing liquid and the three-stage salt slurries in the three-stage salt slurry buffer barrels in a reaction barrel, so as to obtain a collection liquid; and step five, heating the first-stage salt slurry buffer barrel and the second-stage salt slurry buffer barrel, and conveying the layered liquid therein to a deposition barrel for storage, so that the first-stage salt slurry, the second-stage salt slurry and the third-stage salt slurry are added, and subsequent treatment according to different salt slurry grades is facilitated, and the salt washing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of salt washing, in particular to a three-stage salt washing method. BACKGROUND

[0002] Salt refers to a class of metal ions or ammonium ions (NH4+) combined with acid ions or non-metal ions, such as sodium chloride, calcium nitrate, ferrous sulfate, and ammonium sulfate calcium chloride, copper chloride, sodium acetate, etc. Generally, salt is the product of double decomposition reaction, salt and salt reaction to generate new salt and new salt, salt and base reaction to generate new salt and new base, salt and acid reaction to generate new salt and new acid, such as sulfuric acid and sodium hydroxide to generate sodium sulfate and water, sodium chloride and silver nitrate to generate silver chloride and sodium nitrate, etc.

[0003] After searching, the invention patent with Chinese patent number CN109607569A discloses a three-stage salt washing method, which specifically includes the following steps: step one: five-effect salt slurry is added to a five-effect salt slurry buffer tank, and then the processed salt slurry is transported to a salt collection tank, step two: the salt slurry in the three-stage salt washing cylinder is transported to a transition salt slurry tank, a centrifuge is used for centrifugal treatment, then the centrifuge top flow liquid is transported back to the transition salt slurry tank, and the centrifuge after-liquid is transported to a sedimentation tank, step three: three-effect mother liquor, four-effect mother liquor and five-effect mother liquor are transported to a mother liquor buffer tank.

[0004] Compared with the prior art, the invention patent with Chinese patent number CN109607569A buffers and stirs the five-effect salt slurry through the five-effect salt slurry buffer tank, reduces the impurity content, and at the same time, carries out denitration treatment on the reused liquid, solving the problem that the existing five-effect evaporation salt making method directly adds the five-effect salt slurry to the salt collection tank for evaporation salt making in the processing process, which is easy to produce more impurities and increases the difficulty of the later purification work.

[0005] However, the above device still has the problem that the waste liquid generated in the initial washing process is difficult to effectively recycle and utilize, and the concentration of the washed salt is low, so a three-stage salt washing method is needed. SUMMARY

[0006] The purpose of the present application is to solve the problem in the prior art that the waste liquid generated in the initial washing process is difficult to effectively recycle and utilize, and the concentration of the washed salt is low, and a three-stage salt washing method is proposed.

[0007] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0008] A three-stage salt washing method, comprising the following steps:

[0009] Step one: raw material treatment: first screen the obtained salt mixture;

[0010] Step two: primary salt washing: the salt is mixed with brine, and the washing is brine and salt mixed washing;

[0011] Step three: after the preliminary salt washing, the first-stage salt slurry, the second-stage salt slurry and the third-stage salt slurry are obtained, and the obtained third-stage salt slurry is respectively poured into the corresponding buffer cylinder, and the waste liquid generated in the washing process is collected in the washing barrel;

[0012] Step four: the waste liquid in the washing barrel, the washing liquid and the third-stage salt slurry in the third-stage salt slurry buffer cylinder are mixed and circulated in the reaction cylinder to obtain a collection liquid;

[0013] Step five: the first-stage salt slurry buffer cylinder and the second-stage salt slurry buffer cylinder are heated, and the layered liquid therein is transported to the deposition cylinder for storage

[0014] The above technical scheme further comprises:

[0015] Preferably, in the raw material treatment process, the salt mixed mixture is filtered with a 200-mesh screen to remove the particulate matter therein.

[0016] Preferably, in the primary salt washing process, brine is first added for preliminary flotation, and the particles generated therein are filtered, and the above step is repeated three times to realize the preliminary salt washing.

[0017] Preferably, in the process of preliminary salt washing, the first brine is added in an amount of 40% of the total amount, the reaction time is 15-20 min, the second brine is added in an amount of 35% of the total amount, the reaction time is 12-17 min, and the third brine is added in an amount of 25% of the total amount, and the reaction time is 20-28 min.

[0018] Preferably, the mixing time between the third-stage salt slurry, the washing liquid and the waste liquid is 10 min, and the stirring device is used for stirring at a speed of 120 r / min to obtain a recovery liquid.

[0019] Preferably, the recovery liquid is transported to the piston type centrifuge by the centrifugal pump for centrifugation, and the recovery liquid generated by centrifugation is transported to the reaction cylinder to add the washing liquid for mixing again, and the mixed liquid is transported to the piston type centrifuge by the centrifugal pump for centrifugation, so as to realize the reciprocating operation to obtain the collection liquid.

[0020] The present application has the following advantages:

[0021] 1、In the present application, by adding the first-stage salt slurry, the second-stage salt slurry and the third-stage salt slurry, the classification of the salt slurry of different grades in the salt washing process is realized, which facilitates the subsequent treatment according to the different grades of the salt slurry and increases the efficiency of the salt washing.

[0022] 2. In this invention, by mixing the waste liquid, triple-effect salt slurry and washing liquid generated in the initial washing process and then centrifuging them, the residual salt slurry in the waste liquid can be collected, and the circulation effect is increased, which greatly increases the effect of the three-stage salt washing and avoids the waste of salt liquid. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] Step 1: Raw material processing: First, the obtained salt mixture is screened. The salt mixture is filtered through a 200-mesh sieve to remove particulate matter.

[0026] Step 2: First salt washing: Mix the salt and brine thoroughly. The washing process involves thoroughly mixing the brine and salt. During the first salt washing process, add brine first for preliminary flotation and filter out the particles produced. Repeat the above steps three times to achieve preliminary salt washing.

[0027] The first brine accounts for 40% of the total amount, and the reaction time is 15-20 minutes; the second brine accounts for 35% of the total amount, and the reaction time is 12-17 minutes; the third brine accounts for 25% of the total amount, and the reaction time is 20-28 minutes.

[0028] Step 3: After preliminary salt washing, first-effect salt slurry, second-effect salt slurry and third-effect salt slurry are obtained, and the obtained three-stage salt slurry are poured into the corresponding buffer tanks respectively. Waste liquid generated during the washing process is collected into the washing tank.

[0029] Step 4: The waste liquid and washing liquid in the washing tank are mixed with the tertiary salt slurry in the tertiary salt slurry buffer tank in the reaction tank. The mixing time between the tertiary salt slurry, washing liquid and waste liquid is 10 minutes. The mixture is stirred by a stirring device at a speed of 120 r / min to obtain the recovered liquid.

[0030] The recovered liquid is pumped to a piston centrifuge for centrifugation, while the recovered liquid produced by centrifugation is pumped to a reaction vessel where washing liquid is added and mixed again. The mixed liquid is pumped to a piston centrifuge for centrifugation, and the process is repeated to obtain the collected liquid.

[0031] Step 5: Heat the obtained primary and secondary brine buffer tanks and transfer the stratified liquids therein to the sedimentation tank for storage.

[0032] Example 2

[0033] Step 1: Raw material processing: First, the obtained salt mixture is screened. The salt mixture is filtered through a 200-mesh sieve to remove particulate matter.

[0034] Step 2: First salt washing: Mix the salt and brine thoroughly. The washing process involves thoroughly mixing the brine and salt. During the first salt washing process, add brine first for preliminary flotation and filter out the particles produced. Repeat the above steps three times to achieve preliminary salt washing.

[0035] The first brine accounts for 40% of the total amount, and the reaction time is 15-20 minutes; the second brine accounts for 35% of the total amount, and the reaction time is 12-17 minutes; the third brine accounts for 25% of the total amount, and the reaction time is 20-28 minutes.

[0036] Step 3: After preliminary salt washing, primary salt slurry, secondary salt slurry and tertiary salt slurry are obtained, and the three-stage salt slurry is poured into the corresponding buffer tanks respectively;

[0037] Step 4: The washing liquid in the washing tank and the tertiary salt slurry in the tertiary salt slurry buffer tank are mixed in the reaction tank. The mixing time between the tertiary salt slurry and the washing liquid is 10 minutes, and the mixture is stirred by a stirring device at a speed of 120 r / min to obtain the recovery liquid.

[0038] The recovered liquid is pumped to a piston centrifuge for centrifugation, while the recovered liquid produced by centrifugation is pumped to a reaction vessel where washing liquid is added and mixed again. The mixed liquid is pumped to a piston centrifuge for centrifugation, and the process is repeated to obtain the collected liquid.

[0039] Step 5: Heat the obtained primary and secondary brine buffer tanks and transfer the stratified liquids therein to the sedimentation tank for storage.

[0040] Example 3

[0041] Step 1: Raw material processing: First, the obtained salt mixture is screened. The salt mixture is filtered through a 200-mesh sieve to remove particulate matter.

[0042] Step 2: First salt washing: Mix the salt and brine thoroughly. The washing process involves thoroughly mixing the brine and salt. During the first salt washing process, add brine first for preliminary flotation and filter out the particles produced. Repeat the above steps three times to achieve preliminary salt washing.

[0043] The first brine accounts for 40% of the total amount, and the reaction time is 15-20 minutes; the second brine accounts for 35% of the total amount, and the reaction time is 12-17 minutes; the third brine accounts for 25% of the total amount, and the reaction time is 20-28 minutes.

[0044] Step 3: After preliminary salt washing, first-effect salt slurry, second-effect salt slurry and third-effect salt slurry are obtained, and the obtained three-stage salt slurry are poured into the corresponding buffer tanks respectively. Waste liquid generated during the washing process is collected into the washing tank.

[0045] Step 4: The waste liquid and washing liquid in the washing tank are mixed with the tertiary salt slurry in the tertiary salt slurry buffer tank in the reaction tank. The mixing time between the tertiary salt slurry, washing liquid and waste liquid is 10 minutes. The mixture is stirred by a stirring device at a speed of 120 r / min to obtain the recovered liquid.

[0046] The recovered liquid is pumped to a piston centrifuge for centrifugation to obtain the collected liquid;

[0047] Step 5: Heat the obtained primary and secondary brine buffer tanks and transfer the stratified liquids therein to the sedimentation tank for storage.

[0048] 1000 kg of brine was treated and washed using the methods described in Examples 1, 2, and 3. After three stages of washing, the NaCl content was 92.31% in Example 1, 87.16% in Example 2, and 90.47% in Example 3.

[0049] By adding first-effect, second-effect, and third-effect salt slurries, the salt slurries of different grades can be classified during the salt washing process, which facilitates subsequent processing according to the different grades of salt slurries and increases the efficiency of salt washing.

[0050] By mixing the waste liquid, triple-effect salt slurry, and washing liquid generated in the initial washing process with subsequent centrifugal separation, the residual salt slurry in the waste liquid can be collected, and the circulation effect is increased, which greatly enhances the effect of the three-stage salt washing and avoids the waste of salt liquid.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A three-stage salt washing method, characterized in that, Includes the following steps; Step 1: Raw material processing: First, screen the obtained salt mixture; Step 2: First salt washing: Mix the salt and brine thoroughly, and wash until the brine and salt are fully mixed. Step 3: After preliminary salt washing, first-effect salt slurry, second-effect salt slurry and third-effect salt slurry are obtained, and the obtained three-stage salt slurry are poured into the corresponding buffer tanks respectively, and the waste liquid generated during the washing process is collected into the washing tank; Step 4: The waste liquid and washing liquid in the washing tank are mixed and circulated with the tertiary salt slurry in the tertiary salt slurry buffer tank in the reaction tank to obtain the collected liquid; Step 5: Heat the obtained primary and secondary brine buffer tanks and transfer the stratified liquids therein to the sedimentation tank for storage; In the first salt washing process, brine is added for preliminary flotation, and the particles produced are filtered out. The above steps are repeated three times to achieve preliminary salt washing. During the initial salt washing process, the first brine accounts for 40% of the total amount and the reaction time is 15-20 minutes; the second brine accounts for 35% of the total amount and the reaction time is 12-17 minutes; and the third brine accounts for 25% of the total amount and the reaction time is 20-28 minutes. The mixing time between the three-stage salt slurry, washing liquid and waste liquid is 10 minutes, and the mixture is stirred by a stirring device at a speed of 120 r / min to obtain the recovered liquid; The recovered liquid is pumped to a piston centrifuge for centrifugation, while the recovered liquid produced by centrifugation is pumped to a reaction vessel where washing liquid is added and mixed again. The mixed liquid is then pumped to a piston centrifuge for centrifugation, and the process is repeated to obtain the collected liquid.

2. The three-stage salt washing method according to claim 1, characterized in that, During the raw material processing, the salt mixture is filtered through a 200-mesh sieve to remove particulate matter.