Compositions and methods for dewatering aqueous suspensions

Abstract

The present application provides compositions and methods for recovering minerals, such as lime produced in a Kraft pulping process, from a mineral suspension. More specifically, the compositions comprise a polyalkoxylate copolymer, an alkylene amine alkoxylate, and optionally an anionic surfactant, which facilitate recovery of the mineral when the composition is added to a mineral dewatering process.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 022,602, filed May 11, 2020, the disclosure of which is incorporated herein by reference. Technical Field

[0003] Generally, this disclosure relates to the recovery of minerals from aqueous suspensions containing minerals (aqueous suspensions), such as the recovery of lime from lime produced in the Kraft pulping process. More specifically, this disclosure relates to methods for recovering minerals from suspensions, and compositions comprising polyalkoxylated copolymers, alkylamine alkoxylated compounds, and anionic surfactants, which, when added to a mineral suspension prior to any filtration step, facilitate the recovery of minerals from the mineral suspension with less water. Background Technology

[0004] Mineral recovery is an important task when minerals are present in aqueous suspensions such as Kraft pulping suspension. Compositions are added at different points in the Kraft pulping process to help recover lime associated with the process. The Kraft pulping process involves cooking wood chips in a “white liquor”—an aqueous solution of sodium sulfide and sodium hydroxide—under high temperature and pressure. The white liquor chemically dissolves lignin, which binds the cellulose fibers together, at elevated temperatures. There are two types of cooking systems: batch cooking systems and continuous cooking systems. Most Kraft pulping is done in batch digesters. In batch digesters, when cooking is complete, the contents of the digester are transferred to an atmospheric pressure tank, commonly called a blower. The entire contents of the blower are then sent to a pulp washer, where the used cooking liquor is separated from the pulp. The pulp then undergoes various washing stages, and possibly bleaching, before being squeezed and dried into the finished product. The “blowering” of the digester is not suitable for continuous cooking systems.

[0005] The Kraft process is designed to recover cooking chemicals. Used cooking liquor and pulp wash water are combined to form a diluted black liquor, which is concentrated to approximately 55% solids in a multi-effect evaporator system. The black liquor is then further concentrated to approximately 65% ​​solids in a direct contact evaporator by contacting it with flue gas from the recovery furnace, or in an indirect contact concentrator. The concentrated black liquor is then burned in the recovery furnace. The combustion of organic matter dissolved in the black liquor generates process steam and provides heat for the conversion of sodium sulfate to sodium sulfide. Inorganic chemicals present in the black liquor are collected at the bottom of the furnace as molten melt.

[0006] The smelt is dissolved in water to form green liquor which is transferred to a causticizing tank where lime (calcium oxide) is added to convert the solution back to white liquor to be returned to the digester system. The lime mud precipitates from the causticizing tank and is then calcined in a lime kiln to regenerate the lime. The lime is then reused to convert the green liquor to white liquor. The heat generated from the combustion of the black liquor is used for process heating, to drive equipment, to provide electricity, etc. However, many mills require more steam than the recovery boiler alone can provide. Therefore, conventional industrial boilers that burn coal, oil, natural gas, or bark and wood are commonly used.

[0007] An important step in the treatment of lime mud is to separate the lime from the water. This is typically done using a suitable filtration device such as a rotary vacuum drum filter. Typically, this type of filter is used to dewater and wash the lime mud before it enters the lime kiln. The drum is covered with a screen made of stainless steel or plastic fibers (typically 150 mesh) and as the drum rotates, a cake of lime mud builds up on the screen. A doctor blade is fixed at a fixed distance from the screen. Thus, a certain amount of lime mud is removed with the doctor blade leaving a layer of lime mud on the screen that acts as a filter medium for the lime mud. During filtration, as the lime mud builds up and is removed with the doctor blade, the dewatered lime mud falls onto a screw feeder which transports it to the feed end of the lime kiln. The dewatered lime mud is typically about 65-75% solids which requires that the temperature of this "pre-coat" filter be at least about 50°C, more typically about 70°C. Temperatures lower than these can reduce the filter capacity by 10% or more. Thus, it is important that any dewatering aids remain stable or do not phase separate at temperatures above 50°C.

[0008] In the Kraft pulping process, lime is recovered from its pulp slurry by the process described above and then the lime cake is used as smelt for the re-caustic process. The % dry solids of the lime sludge that is produced and washed through the filter varies from mill to mill. Poor filter performance in the process can lead to serious operating problems in the lime kiln such as an increase in the amount of natural gas used by the kiln; an increase in the heat rate of the kiln; a decrease in the dry solids of the kiln feed mud; an increase in the water usage of the mud filter sprays; an increase in the kiln emissions of TRS (total residual sulfur) compounds; and more frequent cleaning of the mud filter sprays.

[0009] One negative effect of filter plugging is that the fuel consumption in the kiln is higher due to the smaller percentage of dry mud entering the kiln which results in more energy required to evaporate the water. This is followed by the formation of rings in the kiln due to the resistance of the soda and the increase in TRS gases through the kiln stack. These problems must be addressed by the mill with a certain amount or required fuel consumption as a priority.

[0010] The use of the compositions and methods described below results in a reduction in fuel consumption, wherein the compositions of the present invention promote an increase in water removal, providing the kiln with a drier sludge, which translates into a reduced need for higher heat and a reduction in fuel (natural gas) consumption.

[0011] Additionally, lime kilns are one of the places where the mineral dewatering and recovery process takes place, where, due to the presence of sodium sulfide (Na2S) in the mud, most of the TRS is discharged. With an increase in drainage, more water is removed and therefore more sodium sulfide is removed, resulting in a reduction in the TRS discharged.

[0012] Furthermore, the present method increases the drainage of lime mud or sludge, which translates into a better and faster washing of the mud, reducing the presence of sodium compounds and preventing the formation of stones and rings and the recovery of these compounds from the process.

[0013] Finally, the compositions and methods provide an increased stability of the disclosed suspensions to adapt to the harsh environment of a pulp mill, where temperatures vary from subzero to 50°C.

[0014] There is a continuous need to reduce the cost and / or environmental impact of the treatment chemicals used in the pulping process and to obtain maximum benefit and effort to reduce the water content in the lime cake resulting from the above-mentioned processes, which ultimately saves energy in the combustion or kiln process as described above. Therefore, it is desirable to find new and improved methods and formulations that meet the progress of technology and the changing economic criteria.

[0015] Further features and characteristics of the present disclosure, in connection with the background, will become apparent from the ensuing detailed description and the appended claims, in conjunction with the accompanying drawings. SUMMARY

[0016] A composition for enhancing the dewatering of mineral suspensions is provided. In particular, the composition comprises one or more polyoxyethylene-polyoxypropylene copolymers, one or more alkylene amine alkoxylates, and optionally one or more anionic surfactants. The composition can be added to the lime mud separation process prior to filtration of the lime.

[0017] Further, a method for improving the dewatering of an aqueous suspension containing minerals is provided, wherein a composition comprising one or more polyalkoxylate copolymers and one or more alkylene amine alkoxylates is added to the aqueous suspension prior to any filtration step; and the aqueous suspension is dewatered.

[0018] Finally, a method for dewatering lime mud suspensions in a Kraft pulping process is provided. A stabilizing composition comprising one or more polyalkoxylate copolymers and one or more alkylene amine alkoxylates is added to lime mud of a Kraft pulping process prior to any filtration step; and the lime mud is dewatered. The stabilizing composition is a formulation that does not phase separate at temperatures of about 50 °C or higher in the presence of water. BRIEF DESCRIPTION OF DRAWINGS

[0019] The present disclosure will be described below with reference to the following drawings, in which like numbers indicate like elements, and in which:

[0020] Figure 1 An apparatus for drainage performance testing is shown;

[0021] Figure 2 is a drainage performance test graph;

[0022] Figure 3 is a graph showing heat consumption of a plant furnace over time;

[0023] Figure 4 is a graph showing dry content or wet content of lime mud recovered in a plant over time;

[0024] Figure 5 is a graph showing water flow rate in a mud filter sprayer in a plant over time; and

[0025] Figure 6 is a graph showing residual sulfur content in a plant over time. DETAILED DESCRIPTION

[0026] The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of it. Furthermore, there is no intention to be bound by any theory of operation presented in the preceding background or the following detailed description.

[0027] In one aspect, a composition for dewatering an aqueous suspension of a mineral and water is provided. The composition improves dewatering of aqueous suspensions having mineral precipitates, such as dewatering of aluminum trihydrate, lime mud, and cellulose pulp. In particular, the composition comprises one or more polyalkoxylate copolymers, one or more alkylene amine alkoxylates, and optionally an anionic surfactant, wherein the composition is added to the aqueous suspension in mineral dewatering, such as occurs in pulp and papermaking processes, prior to any dewatering or filtration step of the aqueous suspension.

[0028] In another aspect of the composition, the polyalkoxylate copolymer comprises from about 5% to about 99% by weight of the total composition of active material and can be from about 10% to about 95% by weight of the total composition of active material and the one or more alkylene amine alkoxylates comprise from about 1% to about 95% by weight of the total composition of active material and can be from about 5% to about 50% by weight of the total composition of active material, the total composition not including water. It can be considered that the term "active material" or "active" is the active ingredient of the two or three component composition of the present invention, i.e., the copolymer and the alkoxylate. The amounts of these ingredients together are referred to as "active agent" or "active material", which does not include any water in the composition. Thus, the concentrations and amounts of the polymers and anionic surfactants used herein are based on "active solids".

[0029] In some aspects of the present invention, the alkylene amine alkoxylate is selected from the group consisting of alkoxylated ethylenediamine, diethylenetriamine, polyethylene polyamine, propylene diamine, butylene diamine, hexamethylene diamine, and combinations thereof. Examples of acceptable alkylene amines are those found in WO 01 / 07712. The amines can be substituted with other alkyl functional groups other than alkoxylates. The alkoxylates can be polyoxyethylene, polyoxypropylene, polyoxybutylene, or copolymers thereof chains, such as those commercially available as Tetronics (BASF), some of which are trademarked as Tetronics. Tetronics are sequential addition products of propylene oxide and ethylene oxide with ethylenediamine, such as those found in U.S. Patent No. 2,979,528, which is incorporated herein by reference. Other alkoxylated ethylenediamines include Tetronic TM 701, 702, 901, 1101, 1102, 1301, 1302, 1501, and 1502.

[0030] The polyalkoxylate copolymer can be a combination of two or more of polyoxyethylene, polyoxypropylene, and polyoxybutylene. The polyalkoxylate can be capped with an alkyl group selected from C1 to C 20 such as polyoxyethylene-polyoxypropylene block copolymers, such as those sold by BASF under the trademark "Pluronic" or other equivalent commercially available brands. Polyoxyethylene-polyoxypropylene copolymers useful in the composition include Pluronic L61, L62, L81, L101, and L121. TM L61, L62, L81, L101, and L121.

[0031] In another aspect of the inventive composition, the composition further comprises one or more anionic surfactants. The anionic surfactant can be from about 0.5% to about 30% by weight of the total composition active, can be from about 0.5% to about 10% by weight of the total composition active, can be from about 1% to about 8% by weight of the total composition active, and can be from about 2% to about 5% by weight of the total composition active. In some aspects of the inventive composition, the anionic surfactant is selected from the group consisting of fatty acids, such as tall oil fatty acid, oleic acid, alkyl ether carboxylate, sulfonate, sulfate, phosphate, sulfosuccinate, and combinations thereof. Preferably, the anionic surfactant is a sulfosuccinate.

[0032] In another aspect, the inventive composition is stable and does not undergo any phase separation at temperatures above room temperature, and can be stable at temperatures of about 50°C or higher when in solution.

[0033] In yet another aspect, a method of dewatering an aqueous suspension comprising mineral particles and water, such as a lime mud suspension in a Kraft pulping process, is provided. The method comprises adding a composition comprising one or more polyoxyethylene-polyoxypropylene copolymers and one or more alkylene amine alkoxylates and optionally one or more anionic surfactants to the aqueous suspension prior to any dewatering or filtering step of the aqueous suspension.

[0034] In some aspects of the inventive method, the composition comprising one or more polyoxyethylene-polyoxypropylene copolymers, one or more alkylene amine alkoxylates, and optionally an anionic surfactant can be added to the aqueous suspension in an amount of from about 10 ppm (parts per million) to about 10,000 ppm, and can be from 200 ppm to 1000 ppm.

[0035] In other aspects of the method, the one or more alkylene amine alkoxylates are selected from the group consisting of polyalkoxylated ethylene diamines, alkoxylated diethylene triamines, alkoxylated polyethylene polyamines, alkoxylated propylene diamines, alkoxylated butylene diamines, alkoxylated hexamethylene diamines, and combinations thereof. The amines can be substituted with other alkyl functional groups other than alkoxylates. The alkoxylates can be polyoxyethylene, polyoxypropylene, polyoxybutylene, or copolymers thereof chains, such as those commercially available under the "Tetronics" (BASF) trademark or other equivalent trade brands as Poloxamines. Poloxamines are sequential addition products of propylene oxide and ethylene oxide with ethylene diamine. Their preparation can be found in U.S. Patent 2,979,528, which is incorporated herein by reference. Such alkoxylated ethylene diamines include Tetronic TM 701, 702, 901, 1101, 1102, 1301, 1302, 1501, and 1502.

[0036] In some aspects of the inventive method, the polyalkoxylate can be selected from a polymer having a combination of two or more of polyethylene oxide, polypropylene oxide, and polybutylene oxide. The polyalkoxylate can be capped with a Ci to C 20 alkyl group. Preferred polyalkoxylates are polyethylene oxide-polypropylene oxide block copolymers sold under the trademark "Pluronic" (BASF) or other equivalent trade brands. Polyethylene oxide-polypropylene oxide copolymers useful in the inventive composition include Pluronic L31, L35, L42, L43, L62, L81, L81, L101, and L121, respectively. TM L61, L62, L81, L101, and L121.

[0037] In other aspects of the inventive method, the composition further comprises one or more anionic surfactants. The anionic surfactant can be selected from fatty acids, such as tall oil fatty acid or fatty acids derived from animal or vegetable oils, alkyl ether carboxylates, sulfonates, sulfates, phosphates, sulfosuccinates, fatty diacids, and combinations thereof. In some aspects, the anionic surfactant is a sulfosuccinate.

[0038] In some aspects of the inventive method, the anionic surfactant can comprise from about 0.1% to about 30% by weight of the total composition active and can comprise from about 0.5% to about 20% by weight of the total composition active.

[0039] Other aspects of the invention provide a method of dewatering a lime mud suspension, such as a lime mud suspension produced from a Kraft pulping process. The method comprises adding one or more polyethylene oxide-polypropylene oxide copolymers, one or more alkylene amine alkoxylates, and optionally one or more anionic surfactants to the lime mud suspension prior to any dewatering or filtering of the lime mud suspension.

[0040] Examples

[0041] Examples 1 to 5: Preparation of compositions for lime mud dewatering

[0042] The compositions of Examples 1 to 5 were prepared according to the feed specified in Table 1. The alkoxylated ethylenediamine Synperonic TM T701 was mixed with Genapol TM PF10 (copolymer of propylene oxide and ethylene oxide) or polyalkylene glycol polymer Tergitol TM L101 was mixed with tall oil fatty acid and anionic surfactant. Each sample was stored at 5°C, 25°C, 32°C, and 50°C. Examples 1 and 3-5 were found to be stable and no phase separation was observed at all temperatures, while Example 2, which had no glycol solvent, exhibited cloudiness and crystallization at 5°C.

[0043] Table 1. Compositions for lime mud dewatering (in parts by weight)

[0044] Example 1 2 3 4 5 Synperonic TM T701 (alkoxylated ethylenediamine) 15 70 28 Tergitol TM L101 (polyalkoxylate copolymer)] 30 12 Genapol TM PF10 (polyalkoxylate copolymer) 75 75 75 Tall oil fatty acid 25 10 20 Butylene glycol 5 10 Water 50

[0045] Example 6. Laboratory lime mud dewatering evaluation

[0046] Drainage performance testing, i.e. dewatering, was accomplished using the apparatus shown in Figure 1 To simulate the conditions of a lime mud filter, a 2-stage test was used. A 750 gram (g) sample of lime mud was diluted to 25% solids with water and heated to 85°C while mixing with a stirrer to form a suspension. The suspension was placed in the Britt jar (1) with the vacuum pump (5) and valve (2) closed. Once the mixture was in the Britt jar (1), the valve (2) was opened and the time to form a foot coat on the filter pad was determined by weighing the filter pad and mineral deposit. A stainless steel plate was placed on top of the foot coat. A top coat was then formed on the steel plate using 150 g of the 25% suspension to cover the foot coat. The top coat sample was recovered by lifting the stainless steel plate and the moisture content of the top sample layer could be determined. The formation time, i.e. the time required to form a 150 gram weight of top coat or top sample layer from the 25% suspension, was measured in a similar manner to the foot coat.

[0047] The drainage performance of the compositions of Examples 2-5 were evaluated using the procedure described above. The dosage was 300 g / ton.

[0048] The parameters used as performance indicators for the lime mud dewatering test were foot coat / top coat / washout time and solids content. In theory, the shorter the vacuum break time indicates a higher drainage rate.

[0049] Under the test conditions, there was little variation in time between the treatments, so the solids content of the dewatered lime mud was chosen as the parameter for comparing the products.

[0050] From Figure 2 It can be seen that Example 4, which had the highest content of polyethoxylated-polypropoxylated ethylene diamine of the 4 compositions tested, performed the best. Examples 2 and 3 also performed well in the presence of tall oil fatty acid. The poor performance exhibited by Example 5 was attributed to dilution of the composition, which, if concentration was taken into account, performed comparably to Example 4.

[0051] Examples 7-9: Aqueous compositions

[0052] Previous work has shown that formulating products in water without organic solvents and having a viscosity of about 10,000 centipoise (cP) or less is advantageous for dosing and application. The formulations of Examples 7-9 include an anionic surfactant, dioctyl sodium sulfosuccinate (DOSS), in addition to the polyethoxylated-polypropoxylated ethylenediamine (Tetronic TM 701) and the polyoxyethylene-co-polyoxypropylene (Pluronic TM L61). The chemical composition of the compositions can be found in Table 2. The cloud point was obtained by heating the clear composition to the temperature at which it became cloudy. This temperature was more or less the same as the temperature at which the cloudy composition became clear upon cooling.

[0053] Table 2. Aqueous compositions for lime mud dewatering (by weight)

[0054] Example 7 ]]> ​ 8 ]]> ​ <![CDATA[ 9 ]]> Tetronic TM 701 (polyethoxylated-polypropoxylated ethylene diamine) 300 250 200.4 Pluronic TM L61 2 (polyoxyethylene-co-polyoxypropylene) 50 46.3 DOSS, 70% by weight, in propylene glycol 45 45 39.2 Water 655 655 714.1 Cloud point, °C 40 39 40.5 pH @ 22°C 5.44 7.82 7.96

[0055] Examples 7-9 were found to have a cloud point of up to 40°C. These compositions phase separated at 50°C, but they recovered at room temperature after 6 weeks of storage at such temperature. The new formulations were found to become slightly cloudy and / or slightly viscous at 32°C, but remained stable and did not phase separate upon return to room temperature. No stability issues were observed at 4°C and room temperature for 6 weeks, including 3 freeze-thaw cycles.

[0056] The compositions of Examples 7-9 were tested for lime mud dewatering using the same protocol described in Example 6. Example 2 was included in the sample group as a performance reference. The formulations containing the ethylenediamine block polymer, i.e., Examples 8 and 9, had improved dewatering properties compared to the formulation without the ethylenediamine block polymer, i.e., Example 7. Example 2 was found to perform better than the other examples, but it was 100% active without any dilution. By normalizing the performance to the active content (see Table 3), the performance of Examples 7-9 was better, indicating that the DOSS improved the performance. TM 701) and the polyoxyethylene-co-polyoxypropylene (Pluronic

[0057] Table 3. Lime mud dewatering increase relative to untreated

[0058] Example 2 ]]> ​ 7 ]]> ​ 8 ]]> ​ 9 ]]> ​ % solids increase over untreated 7.92 3.70 6.32 5.26 Performance normalized to actives 7.9 11.2 19.1 19.2

[0059] Examples 10 to 18 - Aqueous compositions with high cloud point

[0060] Examples 10-18 demonstrate that the inclusion of the polyoxyethylene-co-polyoxypropylene, i.e., Pluronic TM L61, Genapol TM PF10, SynperonicTM L61 and Chemal TM The compositions of BP-261 have sufficiently high cloud point temperatures that they can be used in higher temperature applications. Each composition was formulated at an elevated cloud point. In Examples 11-18, an anionic surfactant, Dowfax TM 2A1 (an alkyl diphenyl sulfonate, Dow, Inc.) or sodium xylene sulfonate with a small amount of glycol solvent added as a modifier (see Table 4).

[0061] Table 4. Compositions with high cloud points

[0062]

[0063] *Polyethoxylated-polypropoxylated ethylene diamine.

[0064] Example 19 - Potassium fatty dicarboxylate salt

[0065] The following mixture was used in Examples 20 and 21. 10.03 parts of 45% potassium hydroxide was diluted in 70.92 parts of water. To this solution was slowly added 20.17 parts of C 16-18 Alkenyl succinic anhydride Prequel TM 2000C and the mixture was heated at 70 to 80°C until the mixture became clear and uniform.

[0066] Examples 20 and 21 - Lime mud dewatering compositions

[0067] Compositions were prepared according to the feeds shown in Table 5. These compositions have cloud points higher than 50°C.

[0068] Table 5. Fatty acids for lime mud dewatering

[0069] Example 20 21 PLURONIC TM L61]]> 26.72 25 TETRONIC TM 701]]> 5.00 5 DOSS, 70%, in polyethylene glycol 400 2.32 2.0 Product from Example 19 ​ 10.14 10.0 Plain bulk water 60.12 655 Cloud point, °C 60 58 pH @ 22°C 8.12 8.11

[0070] Example 22 - Plant trial

[0071] A 9 month plant trial was conducted during which various variables such as fuel consumption, dry lime mud content, water flow rate in the mud filter sprayers, and residual sulfur content of the lime mud were monitored. The plant performance was as follows:

[0072] Mud filter - Andritz;

[0073] Disc filter (14 discs, 3.7 dm);

[0074] Nominal kiln production: 960 tons;

[0075] Fuel: primary natural gas and secondary methanol

[0076] During the trial, 170g of the composition from Example 2 was used per ton of lime produced. The composition was added to the process, with 90% added to the lime sludge filter sprayer and 10% added to the sludge feed, while the lime product was diluted with water. The heat consumption of the plant furnace was based on the reduction in natural gas calculated from the calorific value, i.e.:

[0077]

[0078] Using the above calculations, the reduction in natural gas was monitored throughout the entire test period and plotted against time (see [link]). Figure 3 For calculation purposes, a calorific value of 5,757 MJ / ton is determined to represent the dry content of the lime mud.

[0079] The average heat consumption at the start of the experiment was determined to be 5,958 MJ / ton. After adding the composition to the process as described above and conducting the experiment for 9 months, the heat consumption decreased to an average of 5,732 MJ / ton. This resulted in a heat consumption reduction of approximately 226 MJ / ton CaO or approximately 5940 Nm³. 3 / Day, this is very important.

[0080] The dry content of the lime mud was also monitored throughout the experiment and shown in [the data]. Figure 4 Before adding the formulation of the present invention, the average dry content of the lime sludge was found to be approximately 76% solids. After adding the new composition, the average dry content of the lime sludge increased to 78.75% solids. Furthermore, the standard deviation of the dry content of the lime sludge was 2.81 before adding the new composition, while the standard deviation increased to 1.86 after adding the new composition, indicating that the composition has higher stability.

[0081] Another indicator of operational efficiency is the water flow rate in the lime sludge filter sprayer. Before the addition of the new composition, the average water flow rate in the sludge filter sprayer was 53 m / s. 3 / hour. However, after adding the new composition, the average water flow rate of the lime sludge filter sprayer was 45m. 3 / hour. This resulted in a 15% reduction in water consumption (196m³) compared to the water consumption before the addition of the new formulation. 3 / day)(see Figure 5 Finally, no clogging of the lime sludge filter occurred during the experiment, thus reducing the amount of water required in the process.

[0082] Finally, the residual sulfur content of the lime mud was determined throughout the experiment (see...). Figure 6 Before the addition of the new formulation, the average residual sulfur was 20.72 mg / Nm³. 3 After the addition of the new composition, the sulfur content was determined to be 14.06 mg / Nm³. 3Despite the reduction in water usage by the sprayers, this resulted in an average reduction of 32% in total residual sulphur (TRS).

[0083] In summary, the results of the plant trial have shown that the use of the composition of the present application comprising polyoxyethylene-polyoxypropylene copolymer and alkylene amine alkoxylate can provide a) reduction in the amount of natural gas used for lime kiln (about 5.940 Nm 3 / day of natural gas); b) reduction in heat consumption of the kiln (heat consumption of the kiln was about 226 MJ / ton CaO); and c) increase in dry solids in the kiln feed lime mud by 3.62%.

[0084] While at least one example embodiment has been presented in the foregoing detailed description, it should be appreciated that a wide variety of modifications exist. It should also be appreciated that the example embodiment or embodiments are only examples and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an example embodiment of the disclosure. It should be understood that various changes can be made in the function and arrangement of elements described in the example embodiment without departing from the scope of the disclosure as set forth in the appended claims.

Claims

1. A composition for dehydrating an aqueous suspension of minerals and water, comprising: One or more polyoxyethylene-polyoxypropylene copolymers, and One or more alkyleneamine alkoxylates, wherein the one or more alkyleneamine alkoxylates are selected from alkylated ethylenediamine, alkylated diethylenetriamine, alkylated polyethylenepolyamine, alkylated propylenediamine, alkylated butylenediamine, alkylated hexamethylenediamine, and combinations thereof; The one or more polyoxyethylene-polyoxypropylene copolymers comprise 5% to 99% by weight of the active material in the total composition; and the one or more alkylamine alkoxylates comprise 1% to 95% by weight of the active material in the total composition.

2. The composition according to claim 1, wherein the composition further comprises one or more anionic surfactants.

3. The composition according to claim 2, wherein the one or more anionic surfactants are selected from fatty acids, sulfonates, sulfates, phosphates, sulfosuccinates, fatty acids, and combinations thereof.

4. The composition according to claim 3, wherein the one or more anionic surfactants are sulfosuccinates.

5. The composition according to claim 2, wherein the anionic surfactant comprises 0.5% to 30% by weight of the active ingredient in the total composition excluding water.

6. The composition according to claim 1, wherein the one or more polyoxyethylene-polyoxypropylene copolymers account for 20% to 50% by weight of the active ingredient in the total composition.

7. The composition according to claim 1, wherein the one or more alkylamine alkoxylates constitute 5% to 50% by weight of the active ingredient in the total composition.

8. The composition according to any one of claims 1-7, wherein the composition does not undergo phase separation at a temperature of 50°C or higher when water is present.

9. The composition according to any one of claims 1-7, wherein the composition is added to a lime mud suspension, said lime mud suspension comprising a mud suspension from the Kraft pulp process.

10. A method for dehydrating an aqueous suspension, comprising: Provide a dehydration composition; Add the composition to an aqueous suspension, the composition comprising a) one or more polyoxyethylene-polyoxypropylene copolymers and b) one or more alkylamine alkoxylates, wherein the one or more alkylamine alkoxylates are selected from alkoxylated ethylenediamine, alkoxylated diethylenetriamine, alkoxylated polyethylenepolyamine, alkoxylated propylenediamine, alkoxylated butylenediamine, alkoxylated hexamethylenediamine, and combinations thereof, wherein the one or more polyoxyethylene-polyoxypropylene copolymers constitute 5% to 99% by weight of the active ingredient in the total composition; and the one or more alkylamine alkoxylates constitute 1% to 95% by weight of the active ingredient in the total composition; and Filter aqueous suspensions.

11. The method of claim 10, wherein the composition is added in an amount of 10 ppm to 10,000 ppm of an aqueous suspension.

12. The method according to any one of claims 10-11, wherein the composition further comprises one or more anionic surfactants.

13. The method of claim 12, wherein the one or more anionic surfactants are selected from fatty acids, sulfonates, sulfates, phosphates, sulfosuccinates, fatty acids, and combinations thereof.

14. The method of claim 13, wherein the one or more anionic surfactants are sulfosuccinates.

15. The method of claim 10, wherein the one or more polyoxyethylene-polyoxypropylene copolymers comprise 20% to 50% by weight of the active ingredient in the total composition.

16. The method of claim 10, wherein the one or more alkylamine alkoxylates constitute 5% to 50% by weight of the active ingredient in the total composition.

17. The method of claim 11, wherein the composition is added in an amount of 200 ppm to 1,000 ppm of an aqueous suspension.

18. The method of claim 12, wherein the one or more anionic surfactants comprise 0.5% to 30% by weight of the active ingredient in the total composition.

19. The method of claim 18, wherein the one or more anionic surfactants comprise 1.0% to 5.0% by weight of the active ingredient in the total composition.

20. A method for dewatering a lime mud suspension, comprising: Provide lime sludge suspension; A composition comprising a) one or more polyoxyethylene-polyoxypropylene copolymers and b) one or more alkylamine alkoxylates, wherein the one or more alkylamine alkoxylates are selected from alkoxylated ethylenediamine, alkoxylated diethylenetriamine, alkoxylated polyethylenepolyamine, alkoxylated propylenediamine, alkoxylated butylenediamine, alkoxylated hexamethylenediamine, and combinations thereof, wherein the one or more polyoxyethylene-polyoxypropylene copolymers constitute 5% to 99% by weight of the active ingredient in the total composition; and the one or more alkylamine alkoxylates constitute 1% to 95% by weight of the active ingredient in the total composition; and To dehydrate the lime mud suspension.

21. The method of claim 20, wherein the composition further comprises one or more anionic surfactants.

22. The method according to claim 20 or 21, wherein the lime sludge suspension is derived from the Kraft pulping process.

23. The method of claim 20, wherein the one or more polyoxyethylene-polyoxypropylene copolymers comprise 20% to 50% by weight of the active ingredient in the total composition.

24. The method of claim 20, wherein the one or more alkylamine alkoxylates constitute 5% to 50% by weight of the active ingredient in the total composition.

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