Freeze crystallisation and separation method

Abstract

The invention discloses a freeze crystallisation and separation method including arrangement therefore which includes the steps of selective temperature regulation to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and of multi-function tank (MFT) separation incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption. Inlet brine flow is controlled by measurement of Low TDS water extraction quality to control the Low TDS water floating level and subsequent brine layers. The outlet brine or concentrate and solid slurry discharge is controlled based on the fraction of the Low TDS water outlet volume.

Description

[0001] FREEZE CRYSTALLISATION AND SEPARATION METHOD FIELD OF INVENTION The present invention relates to a freeze crystallisation and separation method. More particularly, the present invention relates to a freeze crystallisation and separation method for hypersaline solutions, sugar juice and fruit juice concentration and is applicable in the fields of water treatment, brine concentration, mineral and salt harvesting, water recovery from brine or waste streams, wastewater treatment, sugar juice concentration, and fruit juice concentration. BACKGROUND TO INVENTION There are substantial challenges in mine water waste streams and the storage and processing of such streams. There are further brine mining processes that require managing geological water resources and currency losing water through evaporation ponds. The evaporation ponds consist of large areas and take time to reach commercial viability. Processing hyper-saline solutions presents substantial technological and environmental challenges. Traditional methods, including sun and forced evaporation technologies, are not only energy-intensive but also vulnerable to the environmental unpredictability. These methods frequently result in inconsistent production outputs and significant water loss, posing major sustainability and efficiency issues, particularly in open pond systems vulnerable to contamination. Moreover, the environmental impact assessment (EIA) process complicates implementation across jurisdictions. Existing freeze concentration processes in the sugar and fruit juice industries also lack scalability for large-scale applications, which are predominantly managed through evaporation technologies. High energy cost and associated product quality reductions due to heat process effecting colour and taste are all disadvantages of existing technologies. Traditional evaporation technologies necessitate considerable energy inputs and frequent maintenance, especially under the corrosive conditions typical of hyper-saline solutions. Their dependency on natural environmental conditions often causes severe production delays during adverse weather conditions. Furthermore, the high temperatures used in thermal evaporation processes can degrade the quality of sensitive products such as sugar and fruit juices, adversely affecting their colour and taste. It is an object of the invention to suggest a novel freeze crystallisation and separation method which will assist in overcoming the aforementioned obstacles. SUMMARY OF INVENTION According to the invention, A freeze crystallisation and separation method which includes the steps of selective temperature regulation to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and of multi-function tank (MFT) separation incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption. Also, according to the invention, a freeze crystallisation and separation arrangement for operating the method as described herein. Also, according to the invention, a freeze crystallisation and separation arrangement which includes selective temperature regulation to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and of multi-function tank (MFT) separation incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption. Inlet brine flow may be controlled by measurement of Low TDS water extraction quality to control the Low TDS water floating level and subsequent brine layers. The outlet brine or concentrate and solid slurry discharge may be controlled based on the fraction of the Low TDS water outlet volume. The method and arrangement may be adjustable, targeting water extraction, salt or mineral extraction, or both, depending on specific solution outcomes. For sugar juice, the focus shifts to sugar concentration and ash removal and the method and arrangement may employ a multi-stage in series reducing the extraction temperature at every stage to withdraw water from the juice and concentrate sugar juice. The method and arrangement may incorporate the following components: (a) industrial scraped surface heat exchanger adapted to acts as the ammonia evaporator using a scarped surface heat exchanger and being adapted for multi-purpose applications from highly saline brine solution to highly viscous sugar juice solutions; (b) compressor unit adapted to employs ammonia or other suitable refrigerants to drive the essential refrigeration cycle for the freeze crystallisation process; (c) de-superheater and oil cooler adapted to dissipate heat of compression and may be air cooled or water cooled, depending on system specific requirements; (d) refrigeration cycle components which include suction accumulators, expansion devices, valves and controls for ammonia or another suitable refrigerant; (e) multi-function tank adapted to separate ice crystals, purify ice, melt ice to deliver low total dissolved solids (TDS) purified water, and separate salt crystals or minerals, as necessary. The multi-function tank may also facilitate the extraction of high TDS concentrated solutions. The multi-function tank may be configurable for both modular small-scale operations and scalable large-scale industrial applications. The multi-function tank may eliminate the need for a mechanical scraper process by conducting all operations within a single tank, including crystal growth, effective separation of ice, salt solutions, and removal of low TDS water and high-concentration solutions. The multi-function tank may have an ice melting coil where a refrigerant (such as ammonia) hot gas is condensed, therefore utilising the condenser to melt water ice and at the same time recover heat relating in higher energy efficiency to the refrigeration cycle. BRIEF DESCRIPTION OF DRAWINGS The invention will now be described by way of example with reference to the accompanying schematic drawings. In the drawings there is shown in Figures 1a, 1b, 1c, 1d: provide a general overview of how the refrigeration cycle and water treatment process of the method according to the invention interacts together, as well as how multiple stages can be added as required by the demand; Figure 2: shows a more detailed overview of the solution treatment process; and Figures 3a, 3b, 3c: show a more detailed overview of the refrigeration cycle. DETAILED DESCRIPTION OF DRAWINGS Referring to the drawings and according to the invention, a freeze crystallisation and separation method which includes the steps of selective temperature regulation to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and of multi-function tank (MFT) separation incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption. Inlet brine flow is controlled by measurement of Low TDS water extraction quality to control the Low TDS water floating level and subsequent brine layers. The outlet brine or concentrate and solid slurry discharge is controlled based on the fraction of the Low TDS water outlet volume. The method and arrangement are adjustable, targeting water extraction, salt or mineral extraction, or both, depending on specific solution outcomes. For sugar juice, the focus shifts to sugar concentration and ash removal and the method employs a multi-stage in series reducing the extraction temperature at every stage to withdraw water from the juice and concentrate sugar juice. The method and arrangement incorporate the following components: (a) industrial scraped surface heat exchanger adapted to acts as the ammonia evaporator using a scarped surface heat exchanger and being adapted for multi-purpose applications from highly saline brine solution to highly viscous sugar juice solutions; (b) compressor unit adapted to employs ammonia or other suitable refrigerants to drive the essential refrigeration cycle for the freeze crystallisation process; (c) de-superheater and oil cooler adapted to dissipate heat of compression and may be air cooled or water cooled, depending on system specific requirements; (d) refrigeration cycle components which include suction accumulators, expansion devices, valves and controls for ammonia or another suitable refrigerant; (e) multi-function tank adapted to separate ice crystals, purify ice, melt ice to deliver low total dissolved solids (TDS) purified water, and separate salt crystals or minerals, as necessary. The multi-function tank also facilitates the extraction of high TDS concentrated solutions. The multi-function tank is configurable for both modular small-scale operations and scalable large-scale industrial applications. The multi-function tank eliminates the need for a mechanical scraper process by conducting all operations within a single tank, including crystal growth, effective separation of ice, salt solutions, and removal of low TDS water and high-concentration solutions. The multi-function tank has an ice melting coil where a refrigerant (such as ammonia) hot gas is condensed, therefore utilising the condenser to melt water ice and at the same time recover heat relating in higher energy efficiency to the refrigeration cycle. This invention seeks to solve a common problem spreading over a wide field through the same system. This invention in essence remove water from sugar, saline or high total dissolved salt solutions. Depending on the application, the invention could target specific salts or minerals harvested from saline brine solutions for possible commercial exploitation. This commercial exploitation could be reached much faster through the invention and therefore not dependent on natural evaporation processes or rain filling the ponds and increase the harvest time. The invention further support processes where a concentrated solution is required to provide a commercially viable process to continue and exploit the value of the concentrated solution. The invention achieves all in the same system with minimal mechanical equipment and therefore a simplified solution to an industrial problem. The invention addresses the high energy intensive problem with current solutions in the market. Current solutions are not scalable, and this invention is the first to address the various challenges at scale. The new invention seeks to address and solve all these assisted problems with one single solution versatile to be employed in a broad range of applications in the technical field of application. Operational Efficiency and Environmental Impact: The process according to the invention significantly reduces energy consumption compared to traditional methods and is less affected by environmental variations, ensuring more stable and predictable production. It minimises environmental risks associated with open pond systems and significantly reduces water loss through its innovative water recovery process. The singular multi-function separation tank simplifies the operational process, eliminating mechanical equipment, enhancing reliability, and improving process control for higher quality products and operational efficiency. Product Quality and Compliance: By avoiding high temperatures, the technology preserves the natural characteristics of sugar and fruit juices, preventing discolouration and taste alteration, thereby ensuring compliance with food safety standards and meeting consumer preferences. The drawings provide an overview of the freeze crystallisation and separation method according to the invention. Figures 1a, 1b, 1c, 1d provide a general overview of how the refrigeration cycle and water treatment process interacts together, as well as how multiple stages can be added as required by the demand. Figure 2 shows a more detailed overview of the solution treatment process and Figures 3a, 3b, 3c show a more detailed overview of the refrigeration cycle. The three drawings are described in the sub section below in more detail. Figures 1a, 1b, 1c, 1d show two stages, with the first stage displayed in Figures 1a and 1b and the subsequent stage in Figures 1c and 1d. While only two stages are illustrated, additional stages can be seamlessly incorporated in a comparable manner as needed. The necessity for multiple stages depends on the specific solution at hand. For instance, when the objective is to produce a concentrate solution from an initial solution starting with a low concentration, multiple stages can efficiently separate and extract water to produce a concentrate solution. Conversely, when the starting solution is off a high concentration multiple stages can be utilised for the purpose of mineral and salt harvesting, as well as ice extraction at various temperatures, to achieve the desired outcome. Each stage consists of a refrigeration cycle machine room and a multi- functional tank (MFT) machine room. These machine rooms accommodate the refrigeration system equipment (including the water crystalliser) and solution treatment equipment, respectively. The refrigeration cycle machine room service two main function, the first is to provide the required cooling to the crystalliser and the second to provide the required heat to the MFT to melt the processed ice crystals. The MFT serves multiple purposes, including the separation of targeted solids from the solution and directing the solution to the next stage or to a specific process for additional treatment. These solids may consist of pure water with low Total Dissolved Solids (TDS) in the form of ice, which is melted and removed from the tank, or minerals settled at the bottom of the tank, which are extracted for further processing. As illustrated the two machine rooms interact via the crystalliser (CSR-1) located in the refrigeration machine room and the ice melter condenser (ICM-1) located in the MFT machine room. A simple description of the refrigerant flow (more detail in drawing C description below) is as follows, after compression the refrigerant is condensed in the ice melter condense (ICM-1), expanded and flows to the gravity suction discharge tank (T-1). From T-1, The saturated liquid refrigerant flows via gravity though the crystalliser (CSR-1) where it is evaporated, cooling the solution to form a solid / liquid slurry. The refrigerant then flows back to “T-1” and the compressor, and the process is repeated. The following paragraph provide a simple description of the flow process of the solution (more detail in drawing B description below). New feed water / solution is introduced to the system via inlet “D” in the first stage as shown on the drawing. The new feed water / solution then joins the outlet pipe work of the solution circulation system. The solution then exists the MFT machine room at outlet “F” where it enters the refrigeration cycle machine room and flows into the inner tubes of the crystalliser unit (CSR-1). In CSR-1 a solid / liquid slurry is generated as the solution flows through it. The slurry exists the machine room and enters MFT machine room again at inlet “G” where it is re-introduced into the lower bottom region of the tank. From here the solid Ice particles floats to the top of the tank where they are melted by the ice melter condenser (ICM-1) to produce low TDS water which exist the system via outlet “A”. Just above where the slurry is injected into the lower region of the tank; a take-off tube removes high TDS water from the tank that exist at outlet “E”. This high TDS water is used in as feed water / solution for the second (or next) stage or for the case where it is the last stage (or only one stage exists) removed from the system as required. The heavier solid particles (minerals / salts) that settles to the bottom of the tank from the injected slurry are remove via the solid waste removal screw (SCRW-1). This solid / liquid mixture then gets remove from the system via outlet “H”, where the mixture is passed through a salt separation screen to separate the solids and liquids. Additional separation and drying technology can be implemented in case where requirements for a drier product with no brine present. Figure 2 shows that the system consists of a refrigeration cycle (shown in Figures 3a, 3b, 3c) to provide low temperature refrigerant which is circulated through the jacket of the crystalliser (CSR-1; Industrial heat exchanger. Simultaneously, the brine is circulated through the inner shell of the crystallizer and subsequently directed back to the "Multi-Function Tank" (MTF) for further utilisation. As described above the MFT has several functions to separate targeted solids from the solution and forward the solution to next stage or to deliver to a certain process for further treatment. The solids could be pure water of low TDS water in the form of ice and melted to remove from the tank, or minerals from the bottom of the tank and removed for further processing. The crystallisation of ice and minerals or salts, also called eutectic freeze crystallisation achieved by the crystallisers (CSR-1; Industrial heat exchanger) and separated but the multifunction tank through gravity where the low TDS or pure water ice has a lower density than brine, resulting in floatation, and the minerals or salts with higher density drops to the bottom of the tank due to higher density. The velocity reduction with the tank surface and volume assisted with time allow for ice crystal growth and shape optimisation to expel the salts. The low TDS pure water will be formed through the condenser coil or heating coil fitted (ICM-1) in the top of the tank. The ice crystals reach a level where the melted water, floating at the top of the tank, aids in the melting process of the new crystals arriving at the uppermost level of the tank. The Low TDS water flows out from the top of the tank trough a filtration pipe to ensure no ice crystals are removed, but only pure low TDS water. The Low TDS water concentration (SM) and temperature is measured to control the “make up brine pump, P2 to ensure we have a suitable equilibrium between brine in feed and low TDS water harvested from the top of the “multi-function tank” MFT. The ice melting coil (ICM-1) positioned in the top of the MFT are designed and manufactured with finned coil. Refrigerant hot gas is condensed and cooled, in the low temperatures ice water just above 0 degrees C. The coil dissipates the net heat remaining after the heat of compression in the refrigeration cycle gas compressor process was removed via the de-superheater (DSH-1) and oil cooling heat exchangers (OGA). Figure shows the Refrigeration cycle, the compressor (CMP-1) discharging the compressed ammonia refrigerant gas to a suitable condensing pressure just above ice temperature in the tank. The hot superheated ammonia gas flows first through the air-cooled de-superheater (DSH-1) and then through the ice “melting coil” (IMC-1) fitted in the top of the MFT (multi-function tank). The “air cooled oil cooler” (OGA) also dissipate heat absorbed by the oil through the heat of compression process of the refrigeration cycle. Both de-superheating of ammonia gas and cooling oil through the ambient air removes heat of compression, leaving the net heat to be rejected in the refrigeration cycle to melt the ice. This process results in efficiency improvement due to low condensing pressures. Depending on specific climatic or operational conditions, we have the option to use the “optional Heat exchanger” (HE-3) possibly using cold brine or cold Low TDS water from the process to assist with cooling if required. After the condensation of ammonia gas to liquid ammonia in the refrigeration cycle, the ammonia would pass through an expansion devise, in this case a considerably basic float control valve (HP.V-1) feeding the “gravity accumulator” (T-1). This accumulator is positioned higher than the crystalliser industrial heat exchangers (CSR-1) to facilitate gravity circulation of the ammonia through the jackets of the crystallisers. The liquid ammonia evaporates by absorbing the heat from the brine and produce ice crystals and salt crystals, moved with the spiral auger toward the other end of the crystallisers and exit the refrigeration system to enter to MFT. The velocity of brine in the crystallisers is controlled to allow slow crystal growth for both ice and salts through eutectic freeze crystallisation (EFC). All crystallisers are independently fed with brine to allow controlled flow to facilitate suitable crystal growth. Multi-Functional Tank (MFT) Function and Control Description - referring back to Figure 2: The MFT is balanced with the control of two exit pumps namely P3 and P4. The high TDS water discharge pump P4 is controlled as a function of the Low TDS overflow water (FM-1). Furthermore, high TDS water feed pump is, P2, is also controlled as a function of FM-1. Therefore, the Low TDS flow meter (FM-1) control both P4 and P2, for instance if SM (salinity meter) measures that low TDS water outflow has a TDS measurement above a set level it will instruct the control system to reduce the pump speed of P2. This reduction in speed of P2 will then have a direct influence on the pump speed of P4. Pump P3, on the other hand, is configured to operate based on a percentage of P4's speed, ensuring balanced functionality within the system. Circulation Pump P1 speed is controlled as a function of the speed of Pump P2 to ensure that the flow rate into the crystalliser (CSR-1) is kept at the constant set flow rate. The solid waste screw (SCRW-1) removes solids slurry that separated through eutectic freeze crystallisation (EFC) and settled in the bottom of the tank and move this slurry towards the slurry pump, P3. The MFT is a central point for various factions to simplify the process and eliminate pure ice removal through mechanical means. The tank functions could be listed as follows: (1) Crystal growth tank to allow matured ice crystals to facilitate salt dissipation and improve Low TDS ice quality. (2) Allow ice to separate and float to the top of the tank. (3) Allow salt crystals to separate and migrate to the bottom of the tank. (4) Allow brine stratification and concentrated brine migrate to lower part of the tank. (5) Low TDS ice melted in top of the tank (6) Low TDS water remain in top of the tank in layers of Low to higher TDS. (7) Low TDS water is drained through measurement of Low TDS water quality and controlling the in feed of new brine with Pump P2. (8) The MFT store a buffer of concentrated bine to ensure circulation of brine mixed with new entering through pump P2 and FM-2. This process ensures one central control for all separation functions required to achieve the required outcome. The possible stream outcomes from the MFT: (1) brine concentration through removal for freshwater ice. (2) Harvesting of targeted salts or minerals at targeted temperatures. (3) recovering water from a high TDS solution (4) Multiple extraction at the same time through water recovery, salt separation and brine concentration in one single tank. This process uses all the benefits of crystal growth through time and conglomeration of ice crystals, bumping against each other and allow time to grow in a larger crystal necessary for effective water purification air low TSS. (4) Brine extracted at higher concentration and sent to the next stage or process. (5) At the same time, we recover heat through melting of the ice to ensure minimum energy consumption with refrigeration cycle.

[0002] Figures 1a, 1b, 1c, 1d List of References

[0003] Figure 2 List of References

[0004] Figures 3a, 3b, 3c List of References

Claims

PATENT CLAIMS 1. A freeze crystallisation and separation method which includes the steps of selective temperature regulation to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and of multi-function tank (MFT) separation incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption.

2. A method as claimed in claim 1, in which inlet brine flow is controlled by measurement of Low TDS water extraction quality to control the Low TDS water floating level and subsequent brine layers.

3. A method as claimed in claim 1 or claim 2, in which the outlet brine or concentrate and solid slurry discharge is controlled based on the fraction of the Low TDS water outlet volume.

4. A method as claimed in any one of the preceding claims, which is adjustable, targeting water extraction, salt or mineral extraction, or both, depending on specific solution outcomes.

5. A method as claimed in any one of the preceding claims, which, for sugar juice, the focus shifts to sugar concentration and ash removal and the method may employ a multi-stage in series reducing the extraction temperature at every stage to withdraw water from the juice and concentrate sugar juice.

6. A method as claimed in any one of the preceding claims, which incorporates the following components: (a) industrial scraped surface heat exchanger adapted to acts as the ammonia evaporator using a scarped surface heat exchanger and being adapted for multi-purpose applications from highly saline brine solution to highly viscous sugar juice solutions; (b) compressor unit adapted to employs ammonia or other suitable refrigerants to drive the essential refrigeration cycle for the freeze crystallisation process;(c) de-superheater and oil cooler adapted to dissipate heat of compression and may be air cooled or water cooled, depending on system specific requirements; (d) refrigeration cycle components which include suction accumulators, expansion devices, valves and controls for ammonia or another suitable refrigerant; (e) multi-function tank adapted to separate ice crystals, purify ice, melt ice to deliver low total dissolved solids (TDS) purified water, and separate salt crystals or minerals, as necessary.

7. A method as claimed in any one of the preceding claims, in which the multi-function tank facilitates the extraction of high TDS concentrated solutions.

8. A method as claimed in any one of the preceding claims, in which the multi-function tank is configurable for both modular small-scale operations and scalable large-scale industrial applications.

9. A method as claimed in any one of the preceding claims, in which the multi-function tank eliminates the need for a mechanical scraper process by conducting all operations within a single tank, including crystal growth, effective separation of ice, salt solutions, and removal of low TDS water and high-concentration solutions.

10. A method as claimed in any one of the preceding claims, in which the multi-function tank has an ice melting coil where a refrigerant (such as ammonia) hot gas is condensed, therefore utilising the condenser to melt water ice and at the same time recover heat relating in higher energy efficiency to the refrigeration cycle.

11. A freeze crystallisation and separation arrangement for operating the method as claimed above.

12. A freeze crystallisation and separation arrangement which includes selective temperature regulation means to foster the growth of water ice and salt crystals, segregated by their density and wherein ice crystals float, while salt / mineral crystals sink after mixed slurry was deposited at the lower end of the tank and internal filtration pipes places to filter brine and Low TDS (total dissolved solids) water preventing crystals entering the flow; and multi-function tank (MFT) separation means incorporating a heat recovery mechanism using compressor discharge gas to melt the ice, optimising energy efficiency and reducing overall power consumption.

13. An arrangement as claimed in claim 12, in which inlet brine flow is controlled by measurement of Low TDS water extraction quality to control the Low TDS water floating level and subsequent brine layers.

14. An arrangement as claimed in claim 12 or claim 13, in which the outlet brine or concentrate and solid slurry discharge is controlled based on the fraction of the Low TDS water outlet volume.

15. An arrangement as claimed in any one of claims 12 to 14, which incorporates the following components: (a) industrial scraped surface heat exchanger adapted to acts as the ammonia evaporator using a scarped surface heat exchanger and being adapted for multi-purpose applications from highly saline brine solution to highly viscous sugar juice solutions; (b) compressor unit adapted to employs ammonia or other suitable refrigerants to drive the essential refrigeration cycle for the freeze crystallisation process; (c) de-superheater and oil cooler adapted to dissipate heat of compression and may be air cooled or water cooled, depending on system specific requirements; (d) refrigeration cycle components which include suction accumulators, expansion devices, valves and controls for ammonia or another suitable refrigerant;(e) multi-function tank adapted to separate ice crystals, purify ice, melt ice to deliver low total dissolved solids (TDS) purified water, and separate salt crystals or minerals, as necessary.

16. An arrangement as claimed in any one of claims 12 to 15, in which the multi-function tank facilitates the extraction of high TDS concentrated solutions.

17. An arrangement as claimed in any one of claims 12 to 16, in which the multi-function tank is configurable for both modular small- scale operations and scalable large-scale industrial applications.

18. An arrangement as claimed in any one of claims 12 to 17, in which the multi-function tank eliminates the need for a mechanical scraper process by conducting all operations within a single tank, including crystal growth, effective separation of ice, salt solutions, and removal of low TDS water and high-concentration solutions.

19. An arrangement as claimed in any one of claims 12 to 18, in which the multi-function tank has an ice melting coil where a refrigerant (such as ammonia) hot gas is condensed, therefore utilising the condenser to melt water ice and at the same time recover heat relating in higher energy efficiency to the refrigeration cycle.

20. An arrangement as claimed in any one of claims 12 to 19, which is adjustable, targeting water extraction, salt or mineral extraction, or both, depending on specific solution outcomes.

21. An arrangement as claimed in any one of claims 12 to 20, which, for sugar juice, the focus shifts to sugar concentration and ash removal and the method may employ a multi-stage in series reducing the extraction temperature at every stage to withdraw water from the juice and concentrate sugar juice.

22. A freeze crystallisation and separation method substantially as hereinbefore described with reference to the accompanying drawings.

23. A freeze crystallisation and separation arrangement substantially as hereinbefore described with reference to the accompanying drawings.

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