CA3053055C

CA3053055C - Method and system for producing potassium chloride by recycling byproducts

Info

Publication number: CA3053055C
Application number: CA3053055A
Authority: CA
Inventors: Xiaosong LI; Xingfu WANG; Kangmin XIE; Shijun Wang; Long Huang; Qiuping YU; Yuanhai ZHAO; Zhenjie Zhang; Hongbin TIAN; Shengtai ZHANG; Hongwei Ren; Jianguo Yu; Xingfu Song; Jizhong HAI; Xuefeng Yu; Zhonglu SHI; Xiaorong Qu; Jianye Li; Qingfeng REN; Hongjun HAO
Original assignee: Qinghai Salt Lake Industry Group Co Ltd
Current assignee: Qinghai Salt Lake Industry Group Co Ltd
Priority date: 2019-03-06
Filing date: 2019-08-26
Publication date: 2022-08-30
Anticipated expiration: 2039-08-26
Also published as: CN111661855A; CN111661855B; BR112021009024A2; EA202191773A1; WO2020177159A1; CA3053055A1

Abstract

Disclosed are a system and a method for producing potassium chloride by recycling byproducts. The system comprises: a run-of-mine treatment system, a pulp conditioning system, a flotation system, a low-sodium concentration and brine removal system , a cold crystallization and crude potassium screening system , a crude potassium concentration and brine removal system, a refined potassium washing and brine removal system, and an overflow liquid and filtrate treatment system. The overflow liquid and filtrate treatment system is configured to recover and treat a first overflow liquid, a third overflow liquid, a fifth overflow liquid, and a first filtrate. By parallel connecting the devices such as a run-of-mine concentrator, a flotation machine, and a low-sodium concentrator, and by uniform pulp conditioning with a pulp conditioning tank, and a scattered distribution, the treated concentration of the material is made uniform.

Description

METHOD AND SYSTEM FOR PRODUCING POTASSIUM CHLORIDE
BY RECYCLING BYPRODUCTS
FIELD
[0001] Embodiments of the present disclosure generally relate to field of producing potassium chloride, and more particularly relate to a method and system for producing potassium chloride by recycling byproducts.
BACKGROUND

[0002]
Conventional potassium chloride producing methods using salt lake brine mainly include: a cold crystallization - direct flotation process, a hot soluble-crystallization process, a reverse flotation - cold crystallization process, and a brine mixing process and the like, or a combination of any of the processes above. The reverse flotation-cold crystallization process is applied relatively extensively. However, this process has a quality requirement on the raw carnallite and prefers using the salt pan carnallite ore, thereby requiring a large investment and a high energy consumption. However, the grade of final potassium chloride product using this process can only reach about 95%.

[0003] Meanwhile, during the whole production process, the potassium chloride contained in byproducts fails to be well recycled. This causes a large amount of potassium chloride to be discharged with tailings, thereby wasting potassium resources.

[0004] Further, if one device in the whole production line fails, material accumulation can occur. A more serious consequence is a full line shut-down and overhaul. This can reduce the line's productivity.

[0005] Therefore, it is desirable to further improve relevant production systems and process methods so as to extract potassium chloride from the byproducts of potash fertilizer production by combining an intra-system utilization approach and an outside-of-system utilization approach, thereby increasing the yield and efficiency of potash fertilizer production, and additionally, by improving connection manners and combination manners of various devices, a continuous production is easy to maintain, such that the overall process will not be Date Recue/Date Received 2021-04-14 affected by failure of any individual devices.
SUMMARY

[0006] A technical problem to be solved by the present disclosure is to provide a method and system for producing potassium chloride by recycling byproducts.

[0007] The present disclosure provides a system for producing potassium chloride by recycling byproducts. The system comprises: a run-of-mine treatment system 1, a pulp conditioning system 2, a flotation system 3, a low sodium concentration and brine removal system 4, a cold crystallization and crude potassium screening system 5, a crude potassium concentration and brine removal system 6, a refined potassium washing and brine removal system 7, and an overflow liquid and filtrate treatment system 8. The run-of-mine treatment system 1 is configured to screen and concentrate a carnallite pulp to obtain a first undertlow slurry and a first overflow liquid; the pulp conditioning system 2, which is connected to the run-of-mine treatment system 1, is configured to mix a flotation reagent with the first undertlow slurry to obtain a pulp conditioned slurry; the flotation system 3 is configured to perform a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry, the low-sodium concentration and brine removal system 4, which is connected to the flotation system 3, is configured to concentrate and remove brine from the low-sodium carnallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium carnallite ore with a <10% content of moisture; the cold crystallization and crude potassium screening system 5, which is connected to the low-sodium concentration and brine removal system 4, is configured to decompose crystallize, and screen the low-sodium carnallite ore with a <10% content of moisture to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen undertlow; the crude potassium concentration and brine removal system 6, which is connected to the cold crystallization and crude potassium screening system 5, is configured to concentrate and remove brine from the crude potassium screen underflow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore with a <10% content of moisture; the refined potassium washing and brine removal system 7, which is connected to the crude potassium concentration and brine removal system 6, is configured to wash and remove brine from the crude potassium ore with a <10% content of moisture to obtain a third filtrate and a refined potassium ore; and the overflow liquid and filtrate treatment system 8 is configured to recover and treat the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.

[0008] According to an embodiment of the present disclosure, the overflow liquid and filtrate treatment system 8 comprises a first treatment system 81, a second treatment system 82, and a third treatment system 83, wherein the first treatment system 81, which is respectively connected to the run-of-mine treatment system 1 and the flotation system 3, is configured to receive the first overflow liquid from the run-of-mine treatment system 1 and receive the floatation tailings from the flotation system 3, wherein the first overflow liquid and the flotation tailings are subjected to pulp conditioning and then discharged; the second treatment system 82, which is respectively connected to the cold crystallization and crude potassium screening system 5 and the refined potassium washing and brine removal system 7.
is configured to receive the third overflow liquid from the cold crystallization and crude potassium screening system 5 and receive the fifth overflow liquid from the refined potassium washing and brine removal system 7, wherein the third overflow liquid and the fifth overflow liquid, after being conditioned with fresh water, are transferred to the cold crystallization and crude potassium screening system 5 as a decomposing mother liquor; and the third treatment system 83, which is connected to the low-sodium concentration and brine removal system 4, is configured to receive, concentrate, and filter the first filtrate to recover the carnallite.

[0009] According to an embodiment of the present disclosure, the first treatment system 81 further comprises a primary scavenging cell 811, a secondary scavenging cell 812, and a storage tank 813, wherein the primary scavenging cell 811, when connected to the flotation system, is configured to receive the floatation tailings and perform primary scavenging to obtain a primarily scavenged froth and a primarily scavenged underflow; the secondary scavenging cell 812, when connected to the primary scavenging cell 811, is configured to receive the primarily scavenged underflow and performing secondary scavenging to obtain a secondarily scavenged froth and a secondarily scavenged undertlow; the primary scavenged cell 811, when connected to a tailing pond, is configured tor transfer the primary scavenged froth to the tailing pond; the secondary scavenging cell 812, when connected to the storage tank 813, is configured to transfer the secondarily scavenged underflow to the storage tank 813; and the secondary scavenging cell 812, when connected to the low sodium concentration and brine removal system 4, is configured to transfer the secondarily scavenged underflow to the low sodium concentration and brine removal system 4.

[0010] According to an embodiment of the present disclosure, the low sodium concentration and brine removal system 4, which is connected to the flotation system 3, is configured totransfer the second overflow liquid to the flotation system 3 so as to adjust a concentration of the pulp conditioned slurry.

[0011] According to an embodiment of the present disclosure, the crude potassium concentration and brine removal system 6, which is connected to the run-of-mine treatment system 1, is configured to transfer the fourth overflow liquid to the run-of-mine treatment system 1 so as to be concentrated for utilization.

[0012] According to an embodiment of the present disclosure, the run-of-mine treatment system 1 comprises a carnallite screening machine 11 and a run-of-mine concentrator 12, wherein the carnallite screening machine 11 is configured for screening off impurities and large-particle salt in the carnallite pulp to obtain a screen underflow product; and the run-of-mine concentrator 12, which is connected to the carnallite screening machine 11, is configured for concentration the screen underflow product to obtain the first overflow liquid and the first underflow slurry, causing a solid mass content of the first underflow slurry to be 30-45%, wherein the run-of-mine concentrator 12 is provided in one or in plurality.
100131 According to an embodiment of the present disclosure, the pulp conditioning system 2 comprises a slurry distribution tray 21 and a pulp conditioning tank 22, wherein the slurry distribution tray 21 comprises a plurality of interfaces for connecting with the plurality of run-of-mine concentrators 12, the slurry distribution tray 21 being configured to receive the first underflow slurry, mix the first undertlow slurry with the flotation reagent, and distribute the first underflow slurry and the flotation reagent to the pulp conditioning tank 22; and the pulp conditioning tank 22, which is connected to the slurry distribution tray 21, is configured to uniformly mix the first undertlow slurry and the flotation reagent to obtain the pulp conditioned slurry.
[0014] According to an embodiment of the present disclosure, the flotation system 3 comprises a flotation distribution tray 31 and a flotation machine 32, wherein the flotation distribution tray 31, which is connected to the pulp conditioning system 2, is configured to receive the pulp conditioned slurry, and perform concentration adjustment to the pulp conditioned slurry by adding an adjustment mother liquor to obtain an adjusted slurry, wherein a solid mass content of the adjusted slurry is 20 /0-25%, and the adjustment mother liquor refers to a liquid phase having same compositions as a slurry mother liquor; and the flotation machine 32, which is connected to the flotation distribution tray 31, is configured to perform roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry, wherein the flotation machine 32 is provided in one or in plurality.
[0015] According to an embodiment of the present disclosure, the low-sodium concentration and brine removal system 4 comprises a low-sodium concentrator 41, a low-sodium centrifugal machine distribution tank 42, and a low-sodium centrifugal machine 43, wherein the low-sodium concentrator 41 is configured to receive the low-sodium carnallite slurry and concentrate the low-sodium carnallite slurry to obtain the second undertlow slurry and the second overflow liquid, wherein a solid mass content of the second underflow slurry is 40%-45%; the low-sodium concentrator 41 is provided in one or in plurality:
the low-sodium centrifugal machine distribution tank 42, which is connected to the low-sodium concentrator 41. is configured to receive and distribute the second underflow slurry to the low-sodium centrifugal machine 43; the low-sodium centrifugal machine 43, which is provided in one or in plurality and connected to the low-sodium centrifugal machine distribution tank 42, is configured for remove brine from the second underflow slurry to obtain the first filtrate and the low-sodium carnallite ore with a <10% content of moisture.
[0016] According to an embodiment of the present disclosure, the cold crystallization and crude potassium screening system 5 comprises a crystallizer 51 and a crude potassium screening machine 52, wherein the crystallizer 51, which is provided in one or in plurality, is configured to receive, decompose, and crystallize the low-sodium carnallite ore with a <10%
content of moisture to obtain the third underflow slurry and the third overflow liquid, wherein a solid mass content of the third underflow slurry is 15% ¨ 30%; and the crude potassium screening machine 52, which is connected to the crystallizer 51, is configured to screen the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen undertlow.
[0017] According to an embodiment of the present disclosure, the crude potassium concentration and brine removal system 6 comprises a crude potassium concentrator 61, a crude potassium centrifugal machine distribution tank 62, and a crude potassium centrifugal machine 63, wherein the crude potassium concentrator 61, which is provided in one or in plurality, is configured to receive and concentrate the crude potassium screen undertlow to obtain the fourth overflow liquid and the fourth underflow slurry, wherein a solid mass content of the fourth undertlow slurry is 40%-45%; the crude potassium centrifugal machine distribution tank 62, which is connected to the crude potassium concentrator 61, is configured to receive and distribute the fourth undertlow slurry to respective crude potassium centrifugal machines 63; the crude potassium centrifugal machine 63, which is provided in one or in plurality and connected to the crude potassium centrifugal machine distribution tank 62, is configured to remove brine from the fourth underflow slurry to obtain the second filtrate and the crude potassium ore with a <10% content of moisture.
[0018] According to an embodiment of the present disclosure, the crude potassium centrifugal machine 63, which is connected to the crude potassium concentrator 61, is configured to transfer the second filtrate to the crude potassium concentrator 61 so as to be recycled.
[0019] According to an embodiment of the present disclosure, the refined potassium washing and brine removal system 7 comprises a repulp washing tank 71, a refined potassium concentrator 72, and a refined potassium centrifugal machine 73, wherein the repulp washing tank 71, which is provided in one or in plurality, is configured to receive and wash the crude potassium ore with a <10% content of moisture to obtain a repulpped slurry;
the refined potassium concentrator 72, which is provided in one or in plurality and corresponds to the repulp washing tank 71, is configured to concentrate the repulpped slurry to obtain the fifth undertlow slurry; the refined potassium centrifugal machine 73, which is provided in one or in plurality and matched to the refined potassium concentrator 72, is configured to remove brine from the fifth underflow slurry to obtain the refined potassium ore and the third filtrate, wherein the refined potassium ore has a <10% content of moisture.
[0020] According to an embodiment of the present disclosure, the refined potassium concentrator 72. which is connected to the repulp washing tank, is configured to condition a concentration of the crude potassium ore with a <10% content of moisture using the fifth underflow slurry. The refined potassium concentrator 72, which is connected to the refined potassium centrifugal machine 73, is configured to recover the third filtrate to the refined potassium concentrator 72 so as to be concentrated.
[0021] In another aspect of the present disclosure, a method for producing potassium chloride by recycling byproducts is provided. The method comprises: step SI:
screening and concentrating a carnallite pulp to obtain a first undertlow slurry and a first overflow liquid;
step S2: mixing a flotation reagent with the first undertlow slurry to obtain a pulp conditioned slurry; step S3: performing a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry; step S4: concentrating and removing brine from the low-sodium carnallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium carnallite ore with a <10% content of moisture; step S5:
decomposing, crystallizing, and screening the low-sodium carnallite ore with a <10% content of moisture to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen underflow; step S6: concentrating and removing brine from the crude potassium screen underflow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore with a <10% content of moisture; step S7: washing and removing brine from the crude potassium ore with a <10% content of moisture to obtain a third filtrate and a refined potassium ore; and step S8: recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.
100221 According to an embodiment of the present disclosure, the step S8 comprises:
performing pulp conditioning to the first overflow liquid and the flotation tailings and then discharging the pulp conditioned first overflow liquid and flotation tailings;
receiving the third overflow liquid and the fifth overflow liquid, which; after being conditioned by fresh water, are used as a decomposing mother liquor for a crystallization process;
receiving, concentrating, and filtering the first filtrate to recover carnallite.
[0023] According to an embodiment of the present disclosure, the method further comprises performing primary scavenging to the flotation tailings to obtain a primarily scavenged froth and a primarily scavenged undertlow; performing secondary scavenging to the primarily scavenged underflow to obtain a secondarily scavenged froth and a secondarily scavenged underflow; performing pulp conditioning to the primarily scavenged froth and the first overflow liquid and then transferring the pulp conditioned primarily scavenged froth and first overflow liquid to a tailing pond; and transferring the secondarily scavenged underflow to a low-sodium concentration and brine removal system.
[0024] According to an embodiment of the present disclosure, the second overflow liquid is used to adjust a concentration of the pulp conditioned slurry.
[0025] According to an embodiment of the present disclosure, the fourth overflow liquid is used to blend the carnallite pulp.
[0026] According to an embodiment of the present disclosure, the step SI
comprises:
screening off impurities and large-particle salt in the carnallite pulp to obtain a screen underflow product; and concentrating the screen underflow product to obtain the first overflow liquid and the first underflow slurry, wherein a solid mass content of the first undertlow slurry is 30-45%, and a solid mass content of the carnallite pulp is >25%.

[0027] According to an embodiment of the present disclosure, the step S2 comprises: mixing the first undertlow slurry with the flotation reagent. and distributing the first undertlow slurry and the flotation reagent; and uniformly mixing the first underflow slurry and the flotation reagent to obtain a pulp conditioned slurry.
[0028] According to an embodiment of the present disclosure, the step S3 comprises:
performing concentration adjustment to the pulp conditioned slurry by adding an adjustment mother liquor to obtain an adjusted slurry, wherein a solid mass content of the adjusted slurry is 20%-25%, and the adjustment mother liquor refers to a liquid phase having same compositions as a slurry mother liquor; and performing roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry.
[0029] According to an embodiment of the present disclosure, the step S4 comprises:
concentrating the low-sodium carnallite slurry to obtain the second undertlow slurry and the second overflow liquid, wherein a solid mass content of the second underflow slurry is 40%-45%; distributing the second underflow slurry; removing brine from the second undertlow slurry to obtain the first filtrate and the low-sodium carnallite ore with a <10%
content of moisture.
[0030] According to an embodiment of the present disclosure, the step S5 comprises: mixing the low-sodium carnallite ore with a <10% content of moisture with a decomposing mother liquor to perform decomposition and crystallization under a controlled speed to thereby obtain the third undertlow slurry and the third overflow liquid, wherein a solid mass content of the third undertlow slurry is 15% ¨ 30%; and performing a screening operation on the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen undertlow.
[0031] According to an embodiment of the present disclosure, the step S6 comprises:
concentrating the crude potassium screen undertlow to obtain the fourth overflow liquid and the fourth underflow slurry, wherein a solid mass content of the fourth underflow slurry is 40%-45%; distributing the fourth underflow slurry; removing brine from the fourth underflow slurry to obtain the second filtrate and the crude potassium ore with a <10%
content of moisture.
[0032] According to an embodiment of the present disclosure, the second filtrate is transferred to a procedure of concentrating the crude potassium screen underflow to be recycled.
[0033] According to an embodiment of the present disclosure, the step S7 comprises:
washing the crude potassium ore with a <10% content of moisture to obtain a repulpped slurry;
concentrating the repulpped slurry to obtain the fifth underflow slurry;
removing brine from the fifth undertlow slurry to obtain the refined potassium ore and the third filtrate, wherein the refined potassium ore has a <10% content of moisture.
[00341] According to an embodiment of the present disclosure, in a repulp procedure, a concentration of the crude potassium ore with a <10% content of moisture is adjusted using the fifth underflow slurry; and the third filtrate is recovered to a repulpped slurry concentration procedure so as to be concentrated.
[0035] In the present disclosure, by recycling the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate to the system respectively, intra-system recovery of potassium chloride is implemented to replace adding external materials, which, on one hand, increases the yield of potassium chloride, and on the other hand, saves costs. In the present disclosure, by parallel connecting the devices such as the run-of-mine concentrator 12, the flotation machine 32, and the low-sodium concentrator 41 and by uniform pulp conditioning with the pulp conditioning tank 22 and scattered distribution, the treated concentration of the material is made uniform; besides, due to the mutual standby relationship among the parallel-connected devices, failure or overhaul of one device does not affect operation of the overall process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Fig. 1 is a schematic diagram of a system for producing potassium chloride by recycling byproducts according to one embodiment of the present disclosure;
100371 Fig. 2 is a schematic diagram of an overflow liquid and filtrate treatment system according to one embodiment of the present disclosure;
[0038] Fig. 3 is a schematic diagram of the first treatment system according to one embodiment of the present disclosure;
[0039] Fig. 4 is a schematic diagram of a run-of-mine treatment system according to one embodiment of the present disclosure;
100401 Fig. 5 is a schematic diagram of a pulp conditioning system according to one embodiment of the present disclosure;
[0041] Fig. 6 is a schematic diagram of a flotation system according to one embodiment of the present disclosure;
[0042] Fig. 7 is a schematic diagram of a low-sodium concentration and brine removal system according to one embodiment of the present disclosure;
[0043] Fig. 8 is a schematic diagram of a cold crystallization and crude potassium screening system according to one embodiment of the present disclosure;
[0044] Fig. 9 is a schematic diagram of a crude potassium concentration and brine removal system according to one embodiment of the present disclosure;
[0045] Fig. 10 is a schematic diagram of a refined potassium washing and brine removal system according to one embodiment of the present disclosure; and [0046] Fig. 11 is a schematic diagram showing steps of a method for producing potassium chloride by recycling byproducts according to one embodiment of the present disclosure.
DETAILED DESCRIPTION OF EMBODIMENTS
[0047] Hereinafter, preferred embodiments of the present disclosure will be illustrated in detail with reference to the accompanying drawings; the reference numerals represent compositions and technologies in the present disclosure, such that implementation of the advantages and features of the present disclosure is more easily understood in an appropriate environment. What will be described hereinafter are specific implementations of the claims of the present disclosure, and other specific implementations which are related to the claims but not explicitly described also fall into the scope of the claims.
[0048] Fig. 1 is a schematic diagram of a system for producing potassium chloride by recycling byproducts in accordance with one embodiment of the present disclosure.
[0049] As shown in Fig. I, a byproduct-recyclable system for producing potassium chloride comprises: a run-of-mine treatment system 1, a pulp conditioning system 2, a flotation system 3, a low-sodium concentration and brine removal system 4, a cold crystallization and crude potassium screening system 5, a crude potassium concentration and brine removal system 6, a refined potassium washing and brine removal system 7, and an overflow liquid and filtrate treatment system 8, wherein the run-of-mine treatment system 1 is configured to screen and concentrate a camallite pulp to obtain a first underflow slurry and a first overflow liquid; the pulp conditioning system 2, which is connected to the run-of-mine treatment system 1, is configured to mix a flotation reagent with the first underflow slurry to obtain a pulp conditioned slurry; the flotation system 3 is configured to perform a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry;
the low-sodium concentration and brine removal system 4, which is connected to the flotation system 3, is configured to concentrate and remove brine from the low-sodium carnallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium carnallite ore with a <10% content of moisture; the cold crystallization and crude potassium screening system 5, which is connected to the low-sodium concentration and brine removal system 4, is configured to decompose, crystallize, and screen the low-sodium carnallite ore with a <10% content of moisture to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen underflow; the crude potassium concentration and brine removal system 6, which is connected to the cold crystallization and crude potassium screening system 5, is configured to concentrate and remove brine from the crude potassium screen undertlow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore with a10%
content of moisture;
the refined potassium washing and brine removal system 7, which is connected to the crude potassium concentration and brine removal system 6, is configured to wash and remove brine from the crude potassium ore with a <10% content of moisture to obtain a third filtrate and a refined potassium ore; and the overflow liquid and filtrate treatment system 8 is configured to recover and treat the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.
100501 In the present disclosure, potassium chloride is produced with salt pan carnallite as the raw material. Main compositions of the collected salt pan carnallite include: potassium chloride, sodium chloride, and magnesium chloride. Concentration of carnallite pulp is adjusted to have a solid mass content >25%. Impurities, large-particle salt, etc., are screened off from the carnallite pulp by a carnallite screening machine 11; the screen underflow is transferred to the run-of-mine concentrator 12 to be concentrated to obtain the first underflow slurry and the first overflow liquid. By adjusting parameters of the concentration device, a solid mass content of the first undertlow slurry is adjusted to 30-45%.
100511 The first overflow liquid enters the overflow liquid and filtrate treatment system 8 to be treated.
100521 The first underflow slurry enters the pulp conditioning system 2, wherein the flotation reagent is added based on the solid mass content in the slurry; the two are uniformly mixed by agitating or other means known in the art to obtain a pulp conditioned slurry.
[0053] By sufficiently and uniformly mixing the first undertlow slurry and the flotation reagent, the sodium flotation reagent may sufficiently contact with the sodium chloride during the flotation process, which can enhance flotation efficiency.
[0054] The present disclosure adopts a reverse flotation - cold crystallization process, wherein the flotation reagent is a sodium chloride collector. Before the pulp conditioned slurry enters the flotation device, its concentration needs to be adjusted to yield a solid mass content of 20%-25%, thereby further controlling the flotation efficiency.
[0055] During the reverse flotation process, the sodium chloride solid is bonded with the flotation reagent to form a froth, and the froth is discharged from the flotation system 3 as tailings; the low-sodium carnallite slurry is also obtained. Main compositions of the low-sodium carnallite slurry include: potassium chloride, magnesium chloride, as well as a small amount of sodium chloride.
[0056] The low-sodium carnallite slurry is first concentrated in the low-sodium concentration and brine removal system 4 to cause its solid mass content to reach 40%-45%, obtaining the second overflow liquid. The second overflow liquid is a solution mainly including magnesium chloride; then, the low-sodium carnallite slurry is centrifuged to remove brine to finally obtain the first filtrate and the low-sodium carnallite ore with a <10% content of moisture.
[0057] Particularly, the second overflow liquid may be used by the flotation system 3 to adjust the concentration of the pulp conditioned slurry, and the first filtrate is recycled by the overflow liquid and filtrate treatment system 8; then, the low-sodium carnallite ore with a <10% content of moisture enters the next procedure.
[0058] The low-sodium carnallite ore with a <10% content of moisture is transferred to the cold crystallization and crude potassium screening system 5 where it is decomposed by a decomposing mother liquor and then crystallized to control supersaturation of the potassium chloride in the solution to thereby reduce the amount of potassium chloride crystals. which achieves the objective of causing the potassium chloride crystals to grow under a room temperature; further, as the sodium chloride cannot be separated out in an unsaturated state, the quality and granularity of the potassium chloride product is guaranteed.
Then, a screening operation is performed, where the screen overflow coarse-grained carnallite which has not been decomposed yet returns to the crystallizer 51 to be re-decomposed, and then the crude potassium screen undertow enters the next procedure.
[0059] The third overflow liquid and the third undertow slurry are produced in the decomposition and crystallization process, wherein the third overflow liquid is recycled by the overflow liquid and filtrate treatment system 8 for synthesizing the decomposing mother liquor. The solid mass content of the third undertow slurry is 17-27%, mainly including coarse-grained carnallite which has not been decomposed and fine-grained potassium chloride.
The third undertow slurry is screened to obtain the crude potassium screen overflow and the crude potassium screen undertlow, wherein the crude potassium screen overflow returns to the crystallizer 51 to be re-decomposed, and the crude potassium screen underflow enters the crude potassium concentration and brine removal system 6.
[0060] The crude potassium concentration and brine removal system 6 concentrates the crude potassium screen undertow to obtain the fourth undertow slurry and the fourth overflow liquid, wherein a solid mass content of the fourth underflow slurry is 40%-45%;
then, the fourth underflow slurry is subjected to brine removal to obtain the second filtrate and the crude potassium ore with a <10% content of moisture; the second filtrate returns to the concentration procedure to be recovered; the fourth overflow liquid is transferred to the run-of-mine screening system where brine is mixed to recover the carnallite in the liquid phase; and the crude potassium ore with a <10% content of moisture enters the next procedure.
[0061] The refined potassium washing and brine removal system 7 washes the crude potassium ore with a <10% content of moisture to further dissolve the magnesium chloride and the potassium chloride; fresh water is added based on a conductivity to adjust the slurry concentration to a 40%-45% solid mass content; the washed slurry is then concentrated to obtain the fifth overflow liquid and the fifth underflow slurry, wherein the fifth overflow liquid is used by the overflow liquid and filtrate treatment system 8 for blending the decomposing mother liquor, and the fifth undertow slurry partially returns to the washing procedure for adjusting the concentration of the washed slurry, but a large part enters the brine removal procedure to remove brine from the fifth undertow slurry to thereby obtain a refined potassium ore, which has a <10% content of moisture: during the brine removal process, the third filtrate is further obtained, wherein the third filtrate is available for being recycled during the internal concentration process of the refined potassium washing and brine removal system

13 7.
[0062] Fig. 2 is a schematic diagram of an overflow liquid and filtrate treatment system according to an embodiment of the present disclosure.
[0063] As shown in Fig. 2, the overflow liquid and filtrate treatment system 8 comprises a first treatment system 81, a second treatment system 82, and a third treatment system 83, wherein the first treatment system 81, which is respectively connected to the run-of-mine treatment system I and the flotation system 3, is configured to receive the first overflow liquid from the run-of-mine treatment system 1 and receive the floatation tailings from the flotation system 3, wherein the first overflow liquid and the flotation tailings are subjected to pulp conditioning and then discharged; the second treatment system 82, which is respectively connected to the cold crystallization and crude potassium screening system 5 and the refined potassium washing and brine removal system 7, is configured to receive the third overflow liquid from the cold crystallization and crude potassium screening system 5 and receive the fifth overflow liquid from the refined potassium washing and brine removal system 7, wherein the third overflow liquid and the fifth overflow liquid, after being conditioned by fresh water, are transferred to the cold crystallization and crude potassium screening system 5 as the decomposing mother liquor; and the third treatment system 83, which is connected to the low-sodium concentration and brine removal system 4, is configured to receive, concentrate, and filter the first filtrate to recover the carnallite.
[0064] The flotation tailings are froth with solid sodium chloride, which are not easy to be discharged; but by mixing it with the first overflow liquid, it becomes easier to transfer.
Additionally, the flotation tailings include a large amount of sodium chloride, which, after being dissolved using the first overflow liquid, may be further used as a raw material to recover the sodium chloride.
100651 The decomposing mother liquor is used in the cold crystallization and crude potassium screening system 5 for decomposing the slurry in the crystallization procedure.
[00661 The first filtrate includes fine-grained carnallite. In the present disclosure, the concentrated first filtrate is filtered by a horizontal belt filter to recover the fine-grained carnallite.
[0067] The first treatment system 81 may comprise a tailing settling pond, a tailing cell, and etc., wherein the tailing cell is used to receive the tailings and the first overflow liquid, such that the tailings may be transferred smoothly. The remainder of the first overflow liquid may

14 be discharged to the tailing settling pond, which, after being settled, is discharged to the carnallite salt pan to be recovered.
[0068] The second treatment system 82 may be a dissolving tank to receive the third overflow liquid and the fifth overflow liquid, wherein fresh water may be added to blend the decomposing mother liquor.
[0069] The third treatment system 83 comprises a concentrator and a centrifugal machine or comprises a concentrator and a belt filter.
[0070] According to an embodiment of the present disclosure, the low-sodium concentration and brine removal system 4, which is connected to the flotation system 3, is configured to transfer the second overflow liquid to the flotation system 3 to adjust a concentration of the pulp conditioned slurry.
[0071] The second overflow liquid is preferably transferred to the flotation system 3 to adjust the concentration of the pulp conditioned slurry, while the extra second overflow liquid may return to the carnallite salt pan to be recovered.
[0072] According to an embodiment of the present disclosure, the crude potassium concentration and brine removal system 6, which is connected to the run-of-mine treatment system 1, is configured to transfer the fourth overflow liquid to the run-of-mine treatment system 1 to blend the carnallite slurry.
[0073] Fig. 3 is a schematic diagram of the first treatment system according to an embodiment of the present disclosure.
[0074] As shown in Fig. 3, the first processing system 81 further comprises a primary scavenging cell 811, a secondary scavenging cell 812, and a storage tank 813, wherein the primary scavenging cell 811, when being connected to the flotation system, is configured to receive the floatation tailings and perform primary scavenging to obtain a primarily scavenged froth and a primarily scavenged underflow; the secondary scavenging cell 812, when being connected to the primary scavenging cell 811, is configured to receive the primarily scavenged underflow, and perform secondary scavenging to obtain a secondarily scavenged froth and a secondarily scavenged underflow; the primary scavenged cell 811, when being connected to the tailing pond, is configured to transfer the primarily scavenged froth to the tailing pond; the secondary scavenging cell 812, when being connected to the storage tank 813, is configured to transfer the secondarily scavenged undertlow to the storage tank 813; and the secondary scavenging cell 812, when being connected to the low-sodium concentration and brine removal system 4, is configured to transfer the secondarily scavenged undertlow to the low-sodium concentration and brine removal system 4.
[0075] The primary scavenging cell 811 performs primary scavenging to the flotation tailing froth to obtain the primarily scavenged froth and the primarily scavenged underflow. wherein a dominant portion of the flotation reagent in the primarily scavenged froth is bonded with the sodium chloride such that it is hard to be recycled. Meanwhile, the primarily scavenged froth has a relatively low content of potassium chloride, which can hardly be recovered in the prior known system to provide an economic benefit. The present disclosure adopts an approach of discharging the primarily scavenged froth and the first overflow liquid into the tailing pond for treatment. The secondary scavenging cell 812 is designed to be lower than the primary scavenging cell 811 such that the primarily scavenged underflow automatically flows into the secondary scavenging cell 812 to be subjected to the secondary scavenging to obtain the secondarily scavenged froth and the secondarily scavenged underflow. The secondarily scavenged underflow may also be transferred as the low-sodium slurry to the low-sodium concentrator to go through subsequent procedures. The secondarily scavenged froth includes a large amount of flotation reagent which is not bonded with the sodium chloride yet, as well as a portion of flotation reagent which has been bonded with the potassium chloride in the primary scavenging process and has released the potassium chloride during the second scavenging enters the froth. Such portions of flotation reagent are the target to be recycled in the present disclosure.
[0076] The secondarily scavenged froth is collected into the storage tank 813 and transferred, by a transfer pump, into the flotation distribution tray. On the one hand, the flotation reagent is recovered, and on the other hand, since the secondarily scavenged froth has a relatively high content of potassium chloride, it is also worthy of recovering. This setting significantly improves the flotation effect, saves the flotation reagent, and boosts the yield of potassium chloride.
[0077] Fig. 4 is a schematic diagram of the run-of-mine treatment system according to one embodiment of the present disclosure.
[0078] As shown in Fig. 4, the run-of-mine treatment system 1 comprises a carnallite screening machine 11 and a run-of-mine concentrator 12, wherein the carnallite screening machine 11 is configured to screen off impurities and large-particle salt in the carnallite pulp to obtain a screen underflow product; and the run-of-mine concentrator 12, which is connected to the carnallite screening machine 11, is configured to concentrate the screen undertlow product to obtain the first overflow liquid and the first underflow slurry, wherein a solid mass content of the first underflow slurry is 30-45%, and the run-of-mine concentrator 12 is provided in one or in plurality.
[0079] Impurities and large-particle salt and the like are screened off from the carnallite pulp by the carnallite screen machine 1 1 The screen underflow product enters the run-of-mine concentrator 12 to be concentrated. The first underflow slurry (with a 30%-35%
solid mass content) is transferred to the pulp conditioning system 2 by an underflow pump; part of the first overflow liquid is mixed with the tailings and then discharged, and the remainder of the first overflow liquid is discharged to the carnallite salt pan to be recycled.
[0080] The run-of-mine concentrator 12 may be provided in plurality, wherein the plurality of run-of-mine concentrators 12 are arranged in parallel, such that even a concentrator fails, the operation of the entire production line would not be affected. In the alternative, a plurality of active concentrators and standby concentrators may be arranged to maintain stability of the total processing capacity of the run-of-mine concentrators 12.
[0081] Fig. 5 is a schematic diagram of a pulp conditioning system according to one embodiment of the present disclosure.
[0082] As shown in Fig. 5, the pulp conditioning system 2 comprises a slurry distribution tray 21 and a pulp conditioning tank 22, wherein the slurry distribution tray 21 comprises a plurality of interfaces for connecting with the plurality of run-of-mine concentrators 12, the slurry distribution tray 21 being configured to receive the first underflow slurry, mix the first underilow slurry with the flotation reagent, and distribute the first undertlow slurry and the flotation reagent to the pulp conditioning tank 22; and the pulp conditioning tank 22, which is connected to the slurry distribution tray 21, is configured to uniformly mixing the first underflow slurry and the flotation reagent to obtain the pulp conditioned slurry.
100831 The slurry distribution tray 21 receives the first underflow slurry from the run-of-mine concentrator 12; the flotation reagent is added into the slurry distribution tray 21 based on the solid mass content of the first undertlow slurry, and then the slurry enters the pulp conditioning tank 22; meanwhile air of 0.5-0.7 Mpa is introduced via an air compressor into a ring pipeline at the bottom of the pulp conditioning tank 22, wherein a large amount of air bubbles with appropriate sizes pop out when the air passes through evenly arranged air holes on the ring-shaped pipeline; with mechanical agitation in the pulp conditioning tank 22, the sodium chloride is selectively attached to the air bubbles; finally, the slurry enters the flotation distribution tray 31, and after the concentration of the slurry is adjusted (to a solid mass content: 20%-25%) by adding a pulp conditioning mother liquor, enters the flotation system 3.
[0084] The slurry distribution tray 21, which is connected to a plurality of run-of-mine concentrators 12, mixes the underflow slurries from the plurality of concentrators as well as the flotation reagent, such that the compositions of the pulp conditioned slurries are uniform before the flotation procedure, and the flotation reagent is also uniformly distributed in the pulp conditioned slurries, thereby improving flotation efficiency.
[0085] Fig. 6 is a schematic diagram of a flotation system according an embodiment of the present disclosure.
[00861 As shown in Fig. 6, the flotation system 3 comprises a flotation distribution tray 31 and a flotation machine 32, wherein the flotation distribution tray 31, which is connected to the pulp conditioning system 2, is configured to receive the pulp conditioned slurry, and perform concentration adjustment to the pulp conditioned slurry by adding an adjustment mother liquor to obtain an adjusted slurry, wherein a solid mass content of the adjusted slurry is 20%-25%, and the adjustment mother liquor refers to a liquid phase having same compositions as a slurry mother liquor; and the flotation machine 32, which is connected to the flotation distribution tray 31, is configured to perform roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry, wherein the flotation machine 32 is provided in one or in plurality.
[0087] The flotation distribution tray 31 receives the pulp conditioned slurry, the concentration of which is adjusted using the adjustment mother liquor; then, the adjusted slurry is transferred to a plurality of flotation machines 32, which guarantees consistency of the material compositions in respective flotation machines 32 and facilitates uniform control of operation parameters of the flotation machines 32. The flotation includes the following steps: roughing, concentrating, and scavenging, thereby obtaining tailings and the low-sodium carnallite slurry.
[0088] Similar to the run-of-mine concentrator 12, the flotation machine 32 may also be provided in one or in plurality; when the flotation machines are provided in plurality, the flotation machines 32 are arranged in parallel, thereby boosting the treatment capacity of the present disclosure.
[0089] The flotation distribution tray 31 enables consistency of various properties of the materials in respective flotation machines 32, which facilitates uniformly setting flotation conditions.
[0090] Fig. 7 is a schematic diagram of a low-sodium concentration and brine removal system according to one embodiment of the present disclosure.
[0091] As shown in Fig. 7, the low-sodium concentration and brine removal system 4 comprises a low-sodium concentrator 41, a low-sodium centrifugal machine distribution tank 42, and a low-sodium centrifugal machine 43, wherein the low-sodium concentrator 41 is configured to receive the low-sodium carnallite slurry and concentrate the low-sodium carnallite slurry to obtain the second underflow slurry and the second overflow liquid, wherein a solid mass content of the second underflow slurry is 40%-45%; the low-sodium concentrator 41 is provided in one or in plurality; the low-sodium centrifugal machine distribution tank 42, which is connected to the low-sodium concentrator 41, is configured to receive the second underflow slurry and distribute the second underflow slurry to the low-sodium centrifugal machine 43; the low-sodium centrifugal machine 43, which is provided in one or in plurality and is connected to the low-sodium centrifugal machine distribution tank 42, is configured to remove brine from the second underflow slurry to obtain the first filtrate and the low-sodium carnallite ore with a <10% content of moisture.
[0092] The low-sodium concentrator 41 receives the low-sodium carnallite ore, which is concentrated to obtain the second underflow slurry and the second overflow liquid, wherein the low-sodium concentrator 41 is connected to the flotation distribution tray 31 to transfer the second overflow liquid to the flotation distribution tray 31 as the adjustment mother liquor.
By controlling the underflow flow rate and concentration, the low-sodium concentrator 41 causes the solid mass content of the second underflow slurry to be 40%-45%, thus improving the yield of centrifuged brine removal. Meanwhile, the low-sodium concentrator 41 may be provided in plurality, and the plurality of low-sodium concentrators 41 are connected in parallel with the flotation machine 32; as such, the treatment capacity of the low-sodium concentrator 41 may be enhanced.
[0093] The low-sodium centrifugal machine distribution tank 42 is connected to the low-sodium concentrator 41; when the current system has a plurality of low-sodium concentrators 41 connected in parallel, the second underflow slurrys discharged from respective low-sodium concentrators 41 are uniformly mixed in the low-sodium centrifugal machine distribution tank 42 and then distributed to the low-sodium centrifugal machine 43 for brine removal.
[0094] The low-sodium centrifugal machine 43 may be provided in one or in plurality.
When a plurality of low-sodium centrifuges 43 are provided, the overall treatment capacity may increase; besides, failure of a certain low-sodium centrifugal machine 43 does not affect the entire production line.
[0095] Fig. 8 is a schematic diagram of a cold crystallization and crude potassium screening system according to one embodiment of the present disclosure.
[0096] As shown in Fig. 8, the cold crystallization and crude potassium screening system 5 comprises a crystallizer 51 and a crude potassium screening machine 52, wherein the crystallizer 51, which is provided in one or in plurality, is configured to receive, decompose, and crystallize the low-sodium camallite ore with a <10% content of moisture to obtain the third underflow slurry and the third overflow liquid, wherein a solid mass content of the third undertlow slurry is 15% ¨ 30%; and the crude potassium screening machine 52, which is connected to the crystallizer 51, is configured to screen the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen underflow.
[0097] The crystallizer 51 is connected to the low-sodium centrifugal machine 43. The centrifuged low-sodium carnallite ore with a <10% content of moisture enters the crystallizer 51; meanwhile, the decomposing mother liquor is added to decompose and crystallize the low-sodium carnallite ore at a controlled rate, wherein by controlling a decomposition condition of the low-sodium carnallite ore, the supersaturation of the potassium chloride in the solution is controlled, which reduces the amount of potassium chloride crystals, thereby reaching the purpose of growing the potassium chloride crystals at a room temperature.
Further, the sodium chloride cannot be separated out when its liquid phase is in an unsaturated state, which guarantees the quality and granularity of the potassium chloride product. In this way, the third underflow slurry and the third overflow liquid are obtained.
The solid mass content of the third underflow slurry is 17%-27%. The third underflovv slurry is transferred to the crude potassium screen machine for being screened, wherein the screen overflow coarse-grained carnallite which has not been decomposed yet returns to the crystallizer 51 to be re-decomposed, and the crude potassium screen underflow enters the crude potassium concentrator 61. The third overflow liquid is treated by the overflow liquid and filtrate treatment system 8 for blending the decomposing mother liquor.
[0098] Fig. 9 is a schematic diagram of a crude potassium concentration and brine removal system according to one embodiment of the present disclosure.
[0099] As shown in Fig. 9, the crude potassium concentration and brine removal system 6 comprises a crude potassium concentrator 61, a crude potassium centrifugal machine distribution tank 62, and a crude potassium centrifugal machine 63, wherein the crude potassium concentrator 61, which is provided in one or in plurality, is configured to receive and concentrate the crude potassium screen underflow to obtain the fourth overflow liquid and the fourth undertlow slurry, wherein a solid mass content of the fourth undertlow slurry is 40%-45%; the crude potassium centrifugal machine distribution tank 62, which is connected to the crude potassium concentrator 61, is configured to receive the fourth underflow slurry and distribute the fourth underflow slurry to respective crude potassium centrifugal machines 63; the crude potassium centrifugal machine 63, which is provided in one or in plurality and connected to the crude potassium centrifugal machine distribution tank 62, is configured to remove brine from the fourth underflow slurry to obtain the second filtrate and the crude potassium ore with a <10% content of moisture.
[00100] The crude potassium concentrator 61 receives the crude potassium screen underflow, which is concentrated to obtain the fourth undertlow slurry and the fourth overflow liquid.
The solid mass content of the fourth undertlow slurry is 410%-45%, which is transferred to the crude potassium centrifugal machine distribution tank 62 to be uniformly distributed to the crude potassium centrifugal machine 63 for brine removal, thereby obtaining the second filtrate.
[001011 Particularly, the crude potassium concentrator 61 is connected to the run-of-mine concentrator 12 of the run-of-mine treatment system 1, configured to transfer the fourth overflow liquid to the run-of-mine concentrator 12 to recover the carnallite therein.
[00102] The crude potassium centrifugal machine 63 is connected to the crude potassium concentrator 61, and the second filtrate is transferred from the crude potassium centrifugal machine 63 to the crude potassium concentrator 61 to be recycled.
[00103] According to an embodiment of the present disclosure, the crude potassium centrifugal machine 63, which is connected to the crude potassium concentrator 61, is configured to transfer the second filtrate to the crude potassium concentrator 61 to be recycled.

[00104] Fig. 10 is a schematic diagram of a refined potassium washing and brine removal system according to one embodiment of the present disclosure.
[00105] As shown in Fig. 10, the refined potassium washing and brine removal system 7 comprises a repulp washing tank 71, a refined potassium concentrator 72, and a refined potassium centrifugal machine 73, wherein the repulp washing tank 71, which is provided in one or in plurality, is configured to receive and wash the crude potassium ore with a _<10%
content of moisture to obtain a repulpped slurry; the refined potassium concentrator 72, which is provided in one or in plurality and corresponds to the repulp washing tank 71, is configured to concentrate the repulpped slurry to obtain the fifth underflow slurry; the refined potassium centrifugal machine 73, which is provided in one or in plurality and matched to the refined potassium concentrator 72, is configured to remove brine from the fifth underflow slurry to obtain the refined potassium ore and the third filtrate, wherein the refined potassium ore has a l0% content of moisture.
[00106] According to an embodiment of the present disclosure, the refined potassium concentrator 72, which is connected to the repulp washing tank, is configured to adjust a concentration of the crude potassium ore with a <10% content of moisture using the fifth underflow slurry. The refined potassium concentrator 72, which is connected to the refined potassium centrifugal machine 73, is configured to recover the third filtrate to the refined potassium concentrator 72 to be concentrated.
[00107] The crude potassium ore with a <10% content moisture, after having been centrifuged by the crude potassium centrifugal machine 63, enters the repulp washing tank 71, where fresh water is added based on electrical conductivity and the slurry concentration in the repulp washing tank 71 is adjusted using the fifth underflow slurry from the refined potassium concentrator 72 to reach a 40%-45% solid mass content; the washed slurry enters the refined potassium concentrator 72 to be concentrated to obtain the fifth overflow liquid and the fifth underflow slurry. A large portion of the fifth underflow slurry enters the refined potassium centrifugal machine 73 for brine removal to obtain a potassium chloride wet feed (the refined potassium ore with a content of moisture <10%), while the remainder is used for adjusting the pulp concentration in the repulp washing tank 71.
[00108] The third filtrate returns to the refined potassium concentrator 72 to be recovered.
[00109] The fifth overflow liquid is recovered by the overflow liquid and filtrate treatment system 8 for blending the decomposing mother liquor to be used by the crystallizer 51.

[00110] Fig. 11 is a schematic diagram showing steps of a method for producing potassium chloride by recycling byproducts.
[00111] As shown in Fig. 11, a method for producing potassium chloride by recycling byproducts is provided, comprising: step SI: screening and concentration a carnallite pulp to obtain a first undertlow slurry and a first overflow liquid; step S2: mixing a flotation reagent with the first underflow slurry to obtain a pulp conditioned slurry; step S3:
performing a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry; step S4: concentrating and removing brine from the low-sodium carnallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium carnallite ore with a i<_10% content of moisture; step S5: decomposing, crystallizing, and screening the low-sodium carnallite ore with a <10% content of moisture to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen underflow; step S6:
concentrating and removing brine from the crude potassium screen undertiow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore with a <10% content of moisture; step S7: washing and removing brine from the crude potassium ore with a <10%
content of moisture to obtain a third filtrate and a refined potassium ore;
and step S8:
recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.
[00112] According to an embodiment of the present disclosure, the step S8 comprises:
performing pulp conditioning to the first overflow liquid and the flotation tailings and then discharging the pulp conditioned first overflow liquid and flotation tailings;
receiving the third overflow liquid and the fifth overflow liquid, which, after being conditioned by fresh water, are used as a decomposing mother liquor for a crystallization process;
receiving, concentration, and filtering the first filtrate to recover carnallite.
[00113] According to an embodiment of the present disclosure, the method further comprises performing primary scavenging to the flotation tailings to obtain a primarily scavenged froth and a primarily scavenged undertlow; performing secondary scavenging to the primarily scavenged underflow to obtain a secondarily scavenged froth arid a secondarily scavenged underflow; performing pulp conditioning to the primarily scavenged froth and the first overflow liquid and then transferring the pulp conditioned primarily scavenged froth and first overflow liquid to a tailing pond; and transferring the secondarily scavenged underflow to a low-sodium concentration and brine removal system.

[00114] According to an embodiment of the present disclosure, the second overflow liquid is used for adjusting a concentration of the pulp conditioned slurry.
[00115] According to an embodiment of the present disclosure, the fourth overflow liquid is used for blending the carnallite pulp.
[00116] According to an embodiment of the present disclosure, the step SI
comprises:
screening off impurities and large-particle salt in the carnallite pulp to obtain a screen underflow product; and concentrating the screen underflow product to obtain the first overflow liquid and the first underflow slurry, wherein a solid mass content of the first underflow slurry is 30-45%, and a solid mass content of the carnallite pulp is >25%.
[00117] According to an embodiment of the present disclosure, the step S2 comprises: mixing the first underflow slurry with the flotation reagent, and distributing the first underflow slurry and the flotation reagent; and uniformly mixing the first underflow slurry and the flotation reagent to obtain a pulp conditioned slurry.
[00118] According to an embodiment of the present disclosure, the step S3 comprises:
performing concentration adjustment to the pulp conditioned slurry by adding an adjustment mother liquor to obtain an adjusted slurry, wherein a solid mass content of the adjusted slurry is 20%-25%, and the adjustment mother liquor refers to a liquid phase having same compositions as a slurry mother liquor; and performing roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry.
[00119] According to an embodiment of the present disclosure, the step S4 comprises:
concentrating the low-sodium carnallite slurry to obtain the second underflow slurry and the second overflow liquid, wherein a solid mass content of the second undertlow slurry is 40%-45%; distributing the second underflow slurry; removing brine from the second underflow slurry to obtain the first filtrate and the low-sodium carnallite ore with a <10%
content of moisture.
[00120] According to an embodiment of the present disclosure, the step S5 comprises: mixing the low-sodium carnallite ore with a <10% content of moisture with a decomposing mother liquor to perform decomposition and crystallization under a controlled speed to thereby obtain the third underflow slurry and the third overflow liquid, wherein a solid mass content of the third underflow slurry is 15% ¨ 30%; and performing a screening operation on the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen underflow.
[00121] According to an embodiment of the present disclosure, the step S6 comprises:
concentrating the crude potassium screen undertlow to obtain the fourth overflow liquid and the fourth underflow slurry;, wherein a solid mass content of the fourth underflow slurry is 40%--45%; distributing the fourth underflow slurry; removing brine from the fourth underflow slurry to obtain the second filtrate and the crude potassium ore with a <10%
content of moisture.
[00122] According to an embodiment of the present disclosure, the second filtrate is transferred to a procedure of concentrating the crude potassium screen undertlow for being recycled.
[00123] According to an embodiment of the present disclosure, the step S7 comprises:
washing the crude potassium ore with a <10% content of moisture to obtain a repulpped slurry;
concentrating the repulpped slurry to obtain the fifth underflow slurry;
removing brine from the fifth underflow slurry to obtain the refined potassium ore and the third filtrate, wherein the refined potassium ore has a <10% content of moisture.
[00124] According to an embodiment of the present disclosure, in a repulp procedure, a concentration of the crude potassium ore with a <10% content of moisture is adjusted using the fifth underflow slurry; and the third filtrate is recovered to a repulpped slurry concentration procedure so as to be thickened.
[00125] In the present disclosure, by recycling the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate to the system respectively, intra-system recovery of potassium chloride is implemented to replace adding external materials, which, on one hand. increases the yield of potassium chloride, and on the other hand, saves costs. In the present disclosure, by parallel connecting the devices such as the run-of-mine concentrator 12, the flotation machine 32, and the low-sodium concentrator 41 and by uniform pulp conditioning with the pulp conditioning tank 22 and scattered distribution, the treated concentration of the material is made uniform; besides, due to the mutual standby relationship among the parallel-connected devices, failure or overhaul of one device does not affect operation of the overall process.
[00126] It should be noted that, the examples above are intended to illustrate the present disclosure, not to limit the present disclosure. Without departing from the scope of the claims, those skilled in the art may devise alternative examples. In the claims, no reference numerals placed in the parentheses should be construed as any limitation to the claims.

Claims

We Claim:

1. A system for producing potassium chloride by recycling byproducts, the system comprising:
a run-of-mine treatment system (1), a pulp conditioning system (2), a flotation system (3), a low sodium concentration and brine removal system (4), a cold crystallization and crude potassium screening system (5), a crude potassium concentration and brine removal system (6), a refined potassium washing and brine removal system (7), and an overflow liquid and filtrate treatment system (8), wherein the run-of-mine treatment system (1) is configured to screen and concentrate a carnallite pulp to obtain a first underflow slurry and a first overflow liquid;
the pulp conditioning system (2) is connected to the run-of-mine treatment system (1) and configured to mix a flotation reagent with the first underflow slurry to obtain a pulp conditioned slurry;
the flotation system (3) is configured to perform a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry;
the low sodium concentration and brine removal system (4) is connected to the flotation system (3) and configured to concentrate and remove brine from the low-sodium carnallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium carnallite ore having a moisture content of <10%;
the cold crystallization and crude potassium screening system (5), is connected to the low sodium concentration and brine removal system (4) and configured to decompose, crystalize, and screen the low-sodium carnallite ore having <10% moisture content to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen underflow;
the crude potassium concentration and brine removal system (6) is connected to the cold crystallization and crude potassium screening system (5) and configured to concentrate and remove brine from the crude potassium screen underflow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore having <10% moisture content;
the refined potassium washing and brine removal system (7) is connected to the crude Date recue / Date received 2021-12-01 potassium concentration and brine removal system (6) and configured to wash and remove brine from the crude potassium ore having <=10% moisture content to obtain a fifth overflow liquid ,a third filtrate and wet potassium chloride ; and the overflow liquid and filtrate treatment system (8) is configured to recover and treat the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate;
the overflow liquid and filtrate treatment system (8) comprises a first treatment system (81), a second treatment system (82), and a third treatment system (83), wherein the first treatment system (81) is respectively connected to the run-of-mine treatment system (1) and the flotation system (3), and configured to receive the first overflow liquid from the run-of-mine treatment system (1) and receive the floatation tailings from the flotation system (3), wherein the first overflow liquid and the flotation tailings are subject to pulp conditioning before being discharged;
the second treatment system (82) is respectively connected to the cold crystallization and crude potassium screening system (5) and the refined potassium washing and brine removal system (7), and configured to receive the third overflow liquid from the cold crystallization and crude potassium screening system (5) and receive the fifth overflow liquid from the refined potassium washing and brine removal system (7), wherein, the third overflow liquid and the fifth overflow liquid, after being conditioned with fresh water, are transferred to the cold crystallization and crude potassium screening system (5) as a decomposing mother liquor; and the third treatment system (83) is connected to the low-sodium concentration and brine removal system (4), and configured to receive, concentrate, and filter the first filtrate to recover a carnallite;
the first treatment system (81) further comprises a primary scavenging cell (811), a secondary scavenging cell (812), and a storage tank (813), the primary scavenging cell (811), when connected to the flotation system, is configured to receive the floatation tailings and perform a primary scavenging to obtain a primarily scavenged froth and a primarily scavenged underflow, the secondary scavenging cell (812), when connected to the primary scavenging cell (811), is configured to receive the primarily scavenged underflow and perform a secondary scavenging to obtain a secondarily scavenged froth and a secondarily scavenged underflow, the primary scavenging cell (811), when connected to a tailing pond, is configured to transfer the primarily scavenged froth to the tailing pond, the secondary scavenging cell (812), when connected to the storage tank (813), is configured to transfer the secondarily scavenged underflow to the storage tank (813); and the secondary scavenging cell (812), when connected to the low sodium concentration and brine removal system, is configured to transfer the secondarily scavenged underflow to the low sodium concentration and brine removal system;
wherein the pulp conditioning system (2) comprises a slurry distribution tray (21) and a pulp conditioning tank (22), wherein the slurry distribution tray (21) comprises a plurality of interfaces for connecting with a plurality of run-of-mine concentrators (12), the slurry distribution tray (21) being configured to receive the first underflow slurry, mix the first underflow slurry with the flotation reagent, and distribute the first underflow slurry and the flotation reagent to the pulp conditioning tank (22);
and the pulp conditioning tank (22) is connected to the slurry distribution tray (21) and is configured to uniformly mix the first underflow slurry and the flotation reagent to obtain the pulp conditioned slurry.

2. The system according to claim 1, wherein the low sodium concentration and brine removal system (4), which is connected to the flotation system (3), is configured to transfer the second overflow liquid to the flotation system (3) so as to adjust a concentration of the pulp conditioned slurry.

3. The system according to claim 1, wherein the crude potassium concentration and brine removal system (6), which is connected to the run-of-mine treatment system (1), is configured to transfer the fourth overflow liquid to the run-of-mine treatment system (1) to be concentrated.

4. The system according to claim 1, wherein the run-of-mine treatment system (1) Date recue / Date received 2021-12-01 comprises a carnallite screening machine (11) and the run-of-mine concentrator (12), wherein the carnallite screening machine (11) is configured to remove impurities and large salt particles in the carnallite pulp to obtain a screen underflow product;
the run-of-mine concentrator (12) is connected to the carnallite screening machine (11), and configured to concentrate the screen underflow product to obtain the first overflow liquid and the first underflow slurry, causing a solid mass content of the first underflow slurry to be 30-45%; and the run-of-mine concentrator (12) is provided in singular or in a plurality.

5. The system according to claim 1, wherein the flotation system (3) comprises a flotation distribution tray (31) and a flotation machine (32), wherein the flotation distribution tray (31) is connected to the pulp conditioning system (2) and is configured to receive the pulp conditioned slurry, and perform concentration adjustment to the pulp conditioned slurry by adding an adjustment mother liquor to obtain an adjusted slurry;
a solid rnass content of the adjusted slurry is 20%-25%;
the adjustment mother liquor refers to a liquid phase having same compositions as a slurry mother liquor;
the flotation machine (32) is connected to the flotation distribution tray (31) and is configured to perform roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry; and the flotation machine (32) is provided in singular or in a plurality.

6. The system according to claim 1, wherein the low sodium concentration and brine removal system (4) comprises a low sodium concentrator (41), a low sodium centrifugal machine distribution tank (42), and a low sodium centrifugal machine (43), wherein the low sodium concentrator (41) is configured to receive and concentrate the low-sodium carnallite slurry to obtain the second underflow slurry and the second overflow liquid;
a solid mass content of the second underflow slurry is 40 4-45%;
Date recue / Date received 2021-12-01 the low sodium concentrator (41) is provided in singular or in a plurality;
the low sodium centrifugal machine distribution tank (42) is connected to the low sodium concentrator (41), and is configured to receive and distribute the second underflow slurry to the low sodium centrifugal machine (43); and the low sodium centrifugal machine (43) is provided in singular or in a plurality and connected to the low sodium centrifugal machine distribution tank (42), and is configured to remove brine from the second underflow slurry to obtain the first filtrate and the low-sodium carnallite ore having a <10% moisture content.

7. The system according to claim 1, wherein the cold crystallization and crude potassium screening system (5) comprises a crystallizer (51) and a crude potassium screening machine (52), wherein the crystallizer (51) is provided in singular or in a plurality and is configured to receive, decompose, and crystallize the low-sodium camallite ore to obtain a third underflow slurry and the third overflow liquid;
a solid mass content of the third underflow slurry is 15% ¨ 30%; and the crude potassium screening machine (52) is connected to the crystallizer (51) and is configured to screen the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen underflow.

8. The system according to claim 1, wherein the crude potassium concentration and brine removal system (6) comprises a crude potassium concentrator (61), a crude potassium centrifugal machine distribution tank (62), and a crude potassium centrifugal machine (63), wherein:
the crude potassium concentrator (61) is provided in singular or in a plurality and is configured to receive and concentrate the crude potassium screen underflow to obtain the fourth overflow liquid and a fourth underflow slurry;
a solid rnass content of the fourth underflow slurry is 40 4-45%;

Date recue / Date received 2021-12-01 the crude potassium centrifugal machine distribution tank (62) is connected to the crude potassium concentrator (61), and is configured to receive and distribute the fourth underflow slurry to respective crude potassium centrifugal machines (63); and the crude potassium centrifugal machine (63) is provided in singular or in a plurality and connected to the crude potassium centrifugal machine distribution tank (62), and is configured to remove brine from the fourth underflow slurry to obtain the second filtrate and the crude potassium ore having a <10% moisture content.

9. The system according to claim 8, wherein the crude potassium centrifugal machine (63) is connected to the crude potassium concentrator (61), and is configured to transfer the second filtrate to the crude potassium concentrator (61) to be recycled.

10. The system according to claim 1, wherein the refined potassium washing and brine removal system (7) comprises a repulp washing tank (71), a refined potassium concentrator (72), and a refined potassium centrifugal machine (73), and wherein the repulp washing tank (71) is provided in singular or in a plurality and is configured to receive and wash the crude potassium ore to obtain a repulpped slurry;
the refined potassium concentrator (72) is provided in singular or in a plurality, corresponds to the repulp washing tank, and is configured to concentrate the repulpped slurry to obtain a fifth underflow slurry and the fifth overflow liquid;
the refined potassium centrifugal machine (73) is provided in singular or in a plurality, corresponds to the refined potassium concentrator (72), and is configured to remove brine from the fifth underflow slurry to obtain the wet potassium chloride and the third filtrate; and the wet potassium chloride has a <10% moisture content

11. The system according to claim 10, wherein the refined potassium concentrator (72), is connected to the repulp washing tank, and is configured to condition a concentration of the crude potassium ore using the fifth underflow slurry; and Date recue / Date received 2021-12-01 the refined potassium concentrator (72) is connected to the refined potassium centrifugal machine (73), and is configured to recover the third filtrate to the refined potassium concentrator (72) to be concentrated.

12. A method for producing potassium chloride by recycling byproducts, the method comprising:
step (S1): screening and concentrating a carnallite pulp to obtain a first underflow slurry and a first overflow liquid;
step (S2): mixing a flotation reagent with the first underflow slurry to obtain a pulp conditioned slurry;
step (S3): performing a flotation operation on the pulp conditioned slurry to obtain tailings and a low-sodium carnallite slurry;
step (S4): concentrating and removing brine from the low-sodium camallite slurry to obtain a second overflow liquid, a first filtrate, and a low-sodium camallite ore having a <10%
moisture content;
step (S5): decomposing, crystallizing, and screening the low-sodium camallite ore to obtain a third overflow liquid, a crude potassium screen overflow, and a crude potassium screen underflow;
step (S6): concentrating and removing brine from the crude potassium screen underflow to obtain a fourth overflow liquid, a second filtrate, and a crude potassium ore having a <10%
moisture content;
step (S7): washing and removing brine from the crude potassium ore to obtain a fifth overflow liquid, a third filtrate and a wet potassium chloride; and step (S8): recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate;
wherein the step (S8) comprises: performing pulp conditioning to the first overflow liquid and the flotation tailings and then discharging the pulp conditioned first overflow liquid and flotation tailings, receiving the third overflow liquid and the fifth overflow liquid, which, after Date recue / Date received 2021-12-01 being conditioned by fresh water, are used as a decomposing mother liquor for a crystallization process; and receiving, concentrating, and filtering the first filtrate to recover carnallite;
performing primary scavenging to the flotation tailings to obtain a primarily scavenged froth and a primarily scavenged underflow, performing a secondary scavenging to the primarily scavenged underflow to obtain a secondarily scavenged froth and a secondarily scavenged underflow, performing pulp conditioning to the primarily scavenged froth and the first overflow liquid and then transferring the pulp conditioned primarily scavenged froth and first overflow liquid to a tailing pond; and transferring the secondarily scavenged underflow to a low sodium concentration and brine removal system;
wherein the step (S2) comprises: unifoimly mixing the first underflow slurry and the flotation reagent to obtain the pulp conditioned slurry, and distributing the pulp conditioned slurry.

13. The method according to claim 12, wherein the second overflow liquid is used to adjust a concentration of the pulp conditioned slurry.

14. The method according to claim 12, wherein the fourth overflow liquid is used to blend the camallite pulp.

15. The method according to claim 12, wherein the step (S1) comprises:
screening off impurities and large-particle salt in the camallite pulp to obtain a screen underflow product; and concentrating the screen underflow product to obtain the first overflow liquid and the first underflow slurry, causing a solid mass content of the first underflow slurry to be 30-45%;
wherein a solid mass content of the camallite pulp is >25%.

16. The method according to claim 12, wherein the step (S3) comprises:
performing concentration adjustment to the pulp conditioned slurry by adding an Date recue / Date received 2021-12-01 adjustment mother liquor to obtain an adjusted slurry, wherein a solid mass content of the adjusted slurry is 20 4-25%, and the adjustment mother liquor refers to a liquid phase having the same compositions as a slurry mother liquor; and performing roughing, concentrating, and scavenging operations on the adjusted slurry to obtain the tailings and the low-sodium carnallite slurry.

17. The method according to claim 12, wherein the step (S4) comprises:
concentrating the low-sodium carnallite slurry to obtain a second underflow slurry and the second overflow liquid, wherein a solid mass content of the second underflow slurry is 40 4-45%;
distributing the second underflow slurry; and removing brine from the second underflow slurry to obtain the first filtrate and the low-sodium carnallite ore having a <10% moisture content.

18. The method according to claim 12, wherein the step (S5) comprises:
mixing the low-sodium carnallite ore with a decomposing mother liquor to perform decomposition and crystallization under a controlled speed to thereby obtain a third underflow slurry and the third overflow liquid, wherein a solid mass content of the third underflow slurry is 15% ¨ 300/; and performing a screening operation on the third underflow slurry to obtain the crude potassium screen overflow and the crude potassium screen underflow.

19. The method according to claim 12, wherein the step (S6) comprises:
concentrating the crude potassium screen underflow to obtain the fourth overflow liquid and a fourth underflow slurry, wherein a solid mass content of the fourth underflow slurry is 40 4-45%;
distributing the fourth underflow slurry; and removing brine from the fourth underflow slurry to obtain the second filtrate and the crude Date recue / Date received 2021-12-01 potassium ore having a <10% moisture content.

20. The method according to claim 12, wherein the second filtrate is transferred to a procedure of concentrating the crude potassium screen underflow to be recycled.

21. The method according to claim 12, wherein the step (S7) comprises:
washing the crude potassium ore to obtain a repulpped slurry;
concentrating the repulpped slurry to obtain a fifth underflow slurry and the fifth overflow liquid; and removing brine from the fifth underflow slurry to obtain the wet potassium chloride and the third filtrate, wherein the wet potassium chloride has a <10% moisture content.

22. The method according to claim 21, further comprising adjusting a concentration of the crude potassium ore using the fifth underflow slurry before washing the crude potassium ore;
and recovering the third filtrate to be concentrated in the step of the concentrating repulpped slurry.

Date recue / Date received 2021-12-01