Method of dewatering a waste stream containing entrained particles

Abstract

A method is provided for dewatering a water stream containing entrained particles. The water stream may be wastewater from a papermaking process. The separation of entrained particles from water is achieved using a clarifying composition comprising an ethyleneamine polymer or a precursor thereof. The ethyleneamine polymer acts as a flocculant to achieve the separation. The mixture is then separated in a clarifier unit to produce a clarified water stream and a clarifier underflow.

Description

Technical Field

[0001] This disclosure generally relates to methods for dewatering waste streams containing entrained particles, and more specifically to methods for dewatering waste streams under harsh conditions such as high temperature and alkaline conditions. Background Technology

[0002] In many industrial processes, separating entrained particles from water streams is an important unit operation to ensure product quality, protect equipment, comply with environmental regulations, and meet health and safety standards. For example, methods for separating particles from water are widely used in the paper and pulp industry, mining, textiles, and wastewater treatment industries.

[0003] Various techniques are employed to separate entrained particles from water streams, such as sedimentation, filtration, centrifugation, and flocculation. Flocculation, in particular, involves adding a flocculant or clarifying composition to the water stream, which causes the entrained particles to agglomerate or form "flocculations." The flocculants can then be separated from the water by sedimentation.

[0004] Flocculation can be a time-consuming process, typically requiring a residence time of up to 12 hours to reduce the concentration of entrained particles to target levels. Furthermore, the conditions within the water flow can be challenging, as temperature, pressure, pH, and other factors can affect the effectiveness of flocculants. Therefore, selecting appropriate chemicals that can withstand the potentially harsh conditions associated with the various water flows being treated and effectively flocculate particles from the flow within a reasonable timeframe can be challenging. In addition, there is a constant need to minimize the amount of flocculant required to achieve the desired performance.

[0005] Various water streams in papermaking require flocculation treatment. Examples of such streams include green liquor, green liquor residue, white liquor, white liquor sludge, bleaching workshop wastewater, and coating and sizing wastewater. Green liquor and green liquor residue, in particular, typically have high temperatures and alkaline pH during flocculation. To form green liquor, a smelt from the kraft paper process is dissolved in water, and the resulting green liquor is transferred to a clarifier unit for flocculation. After an appropriate residence time, the green liquor residue is removed as underflow from the clarifier unit for further treatment, while the clarified water is further treated with quicklime in a causticizing tank to convert the solution back into white liquor for return to the digester system of the kraft paper process. The treatment of green liquor residue is notoriously difficult due to its high alkalinity, high water content (the green liquor residue still contains a significant amount of water, e.g., at least 10% by weight), and the presence of calcium-based compounds (which often lead to scaling and clogging of equipment surfaces).

[0006] Therefore, it is desirable to provide a method for dewatering water streams containing entrained particles, particularly for water streams subjected to harsh conditions such as high temperature and alkalinity. Furthermore, it is desirable to provide a method for dewatering water streams using flocculant chemicals that may exhibit enhanced performance under the aforementioned harsh conditions. Moreover, it is desirable to maximize particle separation while minimizing residence time to achieve the desired particle separation. Furthermore, other desirable features and characteristics of this disclosure will become apparent from the following detailed description and the appended claims, in conjunction with the accompanying drawings and background information. Summary of the Invention

[0007] This overview is intended to introduce the selection of concepts in a simplified form, which will be further described in the detailed embodiments below. This overview is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0008] This document provides a method for dewatering a stream of water containing entrained particles. In an embodiment, the method for dewatering a stream of water containing entrained particles includes providing a stream of water containing water and entrained particles, having a pH of at least about 8 and a temperature of at least about 50°C. The method includes combining the water stream with a clarifying composition comprising a clarifying composition containing an ethyleneamine polymer or a precursor thereof (one or more). The method further includes separating the entrained particles from the water after combining the water stream with the clarifying composition.

[0009] This document also provides an exemplary papermaking method. In one embodiment, the papermaking method includes cooking a fibrous material in white liquor to produce kraft pulp. Then, after cooking, the method includes separating the kraft pulp from black liquor and processing the black liquor to produce a combustible melt product. The combustible melt product is then dissolved in water to produce a green liquor containing water and entrained particles, having a pH of at least about 8 and a temperature of at least about 50°C. The method includes combining the green liquor with a clarifying composition containing an ethyleneamine polymer or one or more precursors thereof, and then separating the entrained particles from the water. Attached Figure Description

[0010] The present disclosure will be described below in conjunction with the accompanying drawings, wherein like reference numerals denote like elements, and wherein: Figure 1 A method for dewatering water streams containing entrained particles is shown.

[0011] Figure 2 An exemplary papermaking method is shown. Detailed Implementation

[0012] The following specific embodiments are merely exemplary in nature and are not intended to limit this disclosure or its application and use. Furthermore, they are not intended to be limited to the foregoing background information or any theories presented in the following specific embodiments.

[0013] This document provides a method for dewatering water streams containing entrained particles. The method described herein is specifically designed for dewatering water streams exhibiting harsh conditions, such as high temperatures of at least about 50°C and alkaline conditions of at least about 8 pH, which can typically present flocculation challenges. However, according to the method of this disclosure, the water stream is combined with a clarifying composition comprising an ethyleneamine-containing polymer or a precursor thereof. The ethyleneamine-containing polymer may comprise a polyethyleneamine (PVAm) homopolymer or a copolymer comprising an ethyleneamine group and at least one other group derived from a comonomer. The precursors of the ethyleneamine-containing polymer (one or more) comprise a vinylcarboxamide-containing polymer. The vinylcarboxamide-containing polymer may be a poly(N-vinylcarboxamide) homopolymer, such as a polyvinylformamide (PVFA) homopolymer. Alternatively, the vinylcarboxamide-containing polymer may be a copolymer comprising two or more different carboxamide groups, or a copolymer comprising a carboxamide group and at least one other group derived from a comonomer having a structural formula different from the carboxamide group. Polymers containing vinyl carboxamides may exhibit enhanced performance under the aforementioned harsh conditions because the hydrolysis of carboxamide groups (e.g., formamide groups) to highly cationic primary amines is promoted under such conditions. Consequently, the cationic charge of vinylamine-containing polymers and / or vinyl carboxamide-containing polymers can be maximized by utilizing the in-situ hydrolysis of carboxamide groups that may be present in the vinyl carboxamide-containing polymers, thereby achieving maximized flocculation performance while potentially avoiding the processing and stability challenges that may be associated with pre-hydrolyzing vinyl carboxamide-containing polymers prior to combination with water flow.

[0014] Unless otherwise specified or apparent from the context, the term “about” as used herein is understood to mean within normal tolerances as measured using standard measuring equipment in the art, such as within two standard deviations of the average value of a particular measuring device. “About” can be understood as within 10%, 5%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. “About” may also be understood to imply an exact numerical value stated. All numerical values ​​provided herein are modified by the term “about” unless the context clearly indicates otherwise.

[0015] As used herein, the term “dry” or the phrase “in dry form” means, based on the total weight of the clarified composition, that the clarified composition contains less than about 10 wt% of water, or less than about 5 wt% of water, or less than about 1 wt% of water, or about 0 wt% to about 1 wt% of water.

[0016] As used herein, the term "water flow" refers to a flow containing a continuous liquid phase of water and entrained particles within the water. "Entrained particles" refers to materials that are solid at ambient temperature and pressure and are present in the water flow prior to its combination with the clarifying composition. In embodiments, the entrained particles are combustion products such as ash, which may be derived from cellulose fibers or other organic materials.

[0017] As used herein, the term "homogeneous polymer" refers to a polymer containing only repeating units of a single type of monomer. The term "copolymer" refers to a polymer containing repeating units of multiple different types of monomers. This means that the polymer consists of two or more monomeric substances.

[0018] This article provides a method 10 for dewatering a water flow 12 containing entrained particles, and this method 10 is shown in... Figure 1 The present document also provides an exemplary papermaking method 110 incorporating dewatering method 10, and the method 110 is shown in... Figure 2 (Chinese) Reference Figure 1 An exemplary method for dehydrating a water stream 12 containing entrained particles is provided. The water stream 12 has a pH of at least about 8 and a temperature of at least about 50°C. In one embodiment, the temperature of the water stream 12 is from about 75°C to about 100°C, and the pH is from about 10 to about 13. The water stream 12 may have an initial suspended solids content of from about 100 to about 5000 ppm.

[0019] In the implementation plan, water flow 12 is a wastewater flow from the papermaking process. (Brief Reference) Figure 2 The water stream can be wastewater stream 112 from the papermaking process 110. For example, wastewater stream 112 can be wastewater stream 112 provided to clarifier unit 118, such as green liquor. Alternatively, the water stream can be residue stream 122. In other embodiments, although not shown, the water stream can be tailings stream from mining operations.

[0020] According to an exemplary method, and now referring to Figure 1The water flow 12 is combined with clarifying compositions 14 and 16. In one embodiment, clarifying composition 14 is combined with water flow 12 upstream of clarifier unit 18. In another embodiment, clarifying composition 16 is combined with water flow 12 within clarifier unit 18. Clarifying compositions 14 and 16 comprise an ethyleneamine-containing polymer or a precursor thereof. In one embodiment, the ethyleneamine-containing polymer may be a homopolymer containing only ethyleneamine groups, i.e., polyethyleneamine (PVAm). In other embodiments, the ethyleneamine-containing polymer may be a copolymer containing ethyleneamine groups and at least one other group derived from a comonomer. For example, the ethyleneamine-containing polymer may be poly(vinylformamide-co-ethyleneamine) or poly(ethyleneamine-co-vinylacetamide). In embodiments, the weight-average molecular weight of the ethyleneamine-containing polymer is greater than 50,000 Daltons.

[0021] In one embodiment, clarifying compositions 14, 16 comprise a vinylcarboxamide-containing polymer as a precursor to an vinylamine-containing polymer. As used herein, a vinylcarboxamide-containing polymer is defined as a polymer formed by polymerization of one or more N-vinylcarboxamide monomers of formula I. (I) Where R 1 and R 2 Each monomer is independently H or C1 to C6 alkyl. Examples of N-vinylcarboxamide monomers include N-vinylformamide, N-vinyl-N-methylacetamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-ethylacetamide, N-vinylpropionamide, N-vinyl-N-methylpropionamide, N-vinylbutyramide, or combinations thereof. Optionally, the polymerization may also include one or more vinyl monomers other than those of Formula I. “Vinyl monomer (one or more)” refers to a monomer (one or more) having a (H2C=C-) group in its structure. Vinyl monomers may alternatively be defined as olefinically unsaturated monomers. Suitable examples of vinyl monomers having a structure other than that of Formula I include, but are not limited to, N-vinylpyrrolidone, acrylamide, acrylic acid, vinyl acetate, methyl acrylate, or combinations thereof.

[0022] Polymers containing vinyl carboxamides can be homopolymers or copolymers. For example, if the N-vinyl carboxamide monomer used in the polymerization is an N-vinyl formamide monomer, the polymer containing vinyl carboxamides can be a polyvinyl formamide (PVFA) homopolymer or a copolymer including a formamide group and at least one other group derived from the comonomer.

[0023] In this embodiment, the vinyl carboxamide-containing polymer is combined with an aqueous stream without explicit hydrolysis of the vinyl carboxamide-containing polymer, wherein the carboxamide groups are hydrolyzed in situ in the aqueous stream to form an vinylamine-containing polymer having primary amine groups. In this embodiment, based on the total number of side groups in the vinyl carboxamide-containing polymer, the polymer may have carboxamide groups present in an amount of about 3 to about 99 mol%.

[0024] In some embodiments, based on the total weight of the clarifying composition, clarifying compositions 14, 16 may contain at least about 40 wt% of an ethyleneamine-containing polymer or a precursor thereof. In some embodiments, the clarifying composition may be combined with the water stream in an amount of about 2 to about 10 ppm based on the total weight of the water stream.

[0025] Clarifying compositions 14 and 16 can be provided in various different forms for combination with the water stream. For example, in one embodiment, clarifying compositions 14 and 16 are in a dry form and contain a vinyl carboxylamide-containing polymer as a precursor to an vinylamine-containing polymer. In this embodiment, the vinyl carboxylamide-containing polymer can be in particulate form, but other dry forms of the vinyl carboxylamide-containing polymer may also be provided. In other embodiments, clarifying compositions 14 and 16 are in the form of an aqueous solution, emulsion, or dispersion. In these embodiments, the dry form of the vinyl carboxylamide-containing polymer is immediately soluble in water before being combined with the water stream 12.

[0026] Providing clarifying compositions 14, 16 in granular form is advantageous because it allows for the transport and storage of larger quantities of active polymers within the clarifying composition compared to providing clarifying compositions in other forms, and provides a longer shelf life for the clarified composition. It also allows the clarifying composition to contain polymers with higher molecular weights than could be achieved with other forms of clarifying composition, thereby improving polymer performance during the dehydration process of water streams containing entrained particles.

[0027] If the vinylcarboxamide-containing polymer is in particulate form, it can be supplied as granular beads. In embodiments, the granular beads have a D50 particle size of about 50 micrometers to about 800 micrometers. Poly(N-vinylcarboxamide) or copolymers thereof can be produced in granular bead form by a reverse suspension polymerization method. Such polymerization methods include thermal polymerization using thermal initiators such as V-50 initiator (2,2'-azobis(2-methylpropanediamine) dihydrochloride) available from FUJIFILM Wako Chemicals USA, Corp. Alternatively, conventional free radical initiation systems can be used in polymerization methods (e.g., redox systems). An aqueous monomer is dispersed in a low-boiling-point hydrocarbon liquid, and a polymer stabilizer is added to aid in monomer droplet formation. The dispersion is deoxygenated. The contents are then heated to a suitable temperature. External heating is removed, a redox initiator is added, and adiabatic exothermic polymerization occurs. The product of the polymerization forms granular beads or microspheres, and water is removed from the resulting polymer, for example by azeotropic distillation. Once the water is removed, the resulting product precipitates and can be physically separated from any dispersion medium and dried using any conventional drying technique.

[0028] In embodiments where the clarifying composition comprises a vinyl carboxamide-containing polymer as a precursor to an vinylamine-containing polymer, the vinyl carboxamide-containing polymer is not explicitly hydrolyzed prior to combining the clarifying composition with a stream of water. Instead, the clarifying composition comprising the vinyl carboxamide-containing polymer is combined with a stream of water, and the conditions of the water stream enable in-situ hydrolysis of the carboxamide groups in the vinyl carboxamide-containing polymer to form the vinylamine-containing polymer. Specifically, the alkaline pH (at least about 8) and high temperature (at least about 50°C) of the water stream promote the hydrolysis of the carboxamide groups.

[0029] In-situ hydrolysis of the carboxamide groups present in vinyl carboxamide-containing polymers to form primary amine groups and generate vinylamine-containing polymers is advantageous because it maximizes the cationic charge of the vinylamine-containing polymers, thereby achieving maximized flocculation performance. Simultaneously, in-situ hydrolysis can potentially prevent processing and stability challenges that may be associated with explicitly pre-hydrolyzing the vinyl carboxamide-containing polymers to generate vinylamine-containing polymers before combining the clarifying composition with an aqueous stream.

[0030] In an embodiment, after combining the clarified composition comprising the vinyl carboxamide-containing polymer with a stream of water, when the pH of the stream is at least about 8 and the temperature is at least about 50°C, the degree of hydrolysis of the carboxamide groups in the vinyl carboxamide-containing polymer to form primary amine groups is about 2 mol% to about 98 mol%, or about 40 mol% to about 80 mol%, based on the total number of moles of carboxamide groups present in the vinyl carboxamide-containing polymer before combination with the stream of water. When the pH of the stream is about 10 to about 13 and the temperature is about 75°C to about 100°C, the degree of hydrolysis is about 60 mol% to about 70 mol%, or about 40 mol% to about 95 mol%, based on the total number of moles of carboxamide groups present in the vinyl carboxamide-containing polymer before combination with the stream of water.

[0031] When the degree of hydrolysis is within the above range, the hydrolysis of the carboxamide group to form a primary amine group is considered "complete". When the pH of the water stream is at least about 8 and the temperature is at least about 50°C, hydrolysis can be "complete" after about 10 minutes to about 600 minutes, or about 60 minutes to about 180 minutes, as defined herein. When the pH of the water stream is about 10 to about 13 and the temperature is about 75°C to about 100°C, hydrolysis can be "complete" within about 10 minutes to about 60 minutes, or about 15 minutes to about 30 minutes. After hydrolysis, when the pH of the water stream is at least about 8 and the temperature is at least about 50°C, the content of cationic groups in the resulting ethyleneamine-containing polymer can be about 2 mol% to about 98 mol%, or about 40 mol% to about 80 mol%, based on the total moles of the ethyleneamine-containing polymer. When the pH of the water flow is about 10 to about 13 and the temperature is about 75°C to about 100°C, the content of cationic groups in the resulting ethyleneamine polymer can be about 60 mol% to about 70 mol%, or about 40 mol% to about 95 mol%, based on the total number of moles of the ethyleneamine polymer.

[0032] Following in-situ hydrolysis, the resulting ethyleneamine-containing polymer contains primary amine groups, which are highly cationic. Due to the cationic nature of the primary amine functional groups in the ethyleneamine-containing polymer, the polymer readily couples with entrained particles in aqueous solutions, such as water streams. Specifically, the primary amine groups in the ethyleneamine-containing polymer undergo ionic interactions with entrained particles containing anionic groups. This ionic interaction leads to particle aggregation. The aggregated particles form concentrated regions in the water stream, which can then be separated from the water as described below.

[0033] According to the exemplary method, and continuing to refer to Figure 1After the water flow 12 is combined with the clarifying compositions 14 and 16, the entrained particles are separated from the water. For example, the entrained particles can be separated from the water in the clarifier unit 18. After the clarifying compositions 14 and 16 are combined with the water flow 12, the clarifying compositions 14 and 16 cause flocculation of the entrained particles in the water flow 12. The flocculated entrained particles are then separated, for example, by a sedimentation or filtration process within the clarifier unit 18.

[0034] The resulting streams from the separation include clarified water stream 20 and clarifier underflow 22. Clarified water stream 20 contains a lower concentration of entrained particles than water stream 12. In some embodiments, clarified water stream 20 may contain less than 100 ppm or less than 25 ppm of entrained particles. Clarifier underflow 22 contains ethyleneamine polymer and a higher concentration of entrained particles than water stream 12.

[0035] In one implementation scheme, and continuing to refer to Figure 1 Based on the total weight of the clarifier underflow 22, the clarifier underflow 22 may have a solids concentration of at least about 10 wt.%, or at least about 50 wt.%, or about 10 wt.% to about 90 wt.%, or about 30% to about 70%. In some embodiments, the clarifier underflow 22 may be further processed to further concentrate solid particles for disposal or remediation. In other embodiments, the clarified water stream 20 may be further processed to remove other residual entrained particles, which may allow the clarified water stream 20 to be recycled or used for another unit operation.

[0036] As envisioned in one specific embodiment herein, the water stream is a wastewater stream from a papermaking process, particularly a stream supplied to a clarifier unit. For example, the wastewater stream may be green liquor or green liquor residue. The clarifying composition is combined with the water stream, preferably upstream of or within the clarifier unit. The step of separating entrained particles from the water includes generating a clarifier underflow and a clarified water stream.

[0037] In one embodiment, the clarified water stream has less than 100 ppm, or less than 25 ppm, entrained particles. In another embodiment, the clarified water stream can be further processed to produce a stream such as white liquor, which can be returned to the papermaking process.

[0038] The clarifier underflow contains a polyethyleneamine-containing polymer and entrained particles. In one embodiment, the clarifier underflow has a solids concentration of at least 10 wt.%, or at least 50 wt.%, or about 10 wt.% to about 90 wt.%, or about 30 wt.% to about 70 wt.%, based on the total weight of the clarifier underflow. In one embodiment, the clarifier underflow is collected after a residence time of less than 4 hours in the clarifier unit. The method contemplated herein allows the production of clarifier underflow with a solids concentration of at least 10 wt.%, or at least 50 wt.%, or about 10 wt% to about 90 wt%, or about 30 wt% to about 70 wt% (based on the total weight of the clarifier underflow) and a residence time of less than 4 hours. Achieving such a high clarifier underflow solids concentration at such a low residence time was previously unattainable.

[0039] In one embodiment, after separating the entrained particles from the water to produce a clarifier underflow and a water flow, the clarifier underflow can be further concentrated to produce a washed clarifier underflow composition having a solids content of at least 50 wt.%, or about 10 wt% to about 90 wt%, or about 30 wt% to about 70 wt% (based on the total weight of the washed clarifier underflow composition).

[0040] As envisioned in this document, and with reference to a particularly specific implementation scheme, and referring to Figure 2 The water stream is green liquor 112 from papermaking method 110. According to the exemplary papermaking method 110, fibrous material 124 is combined with white liquor 126 in a digester 128. The white liquor may contain sodium hydroxide, sodium sulfide, or a combination thereof. The fibrous material 124 is cooked in the white liquor 126 to produce kraft pulp 130. After cooking, the kraft pulp 130 is separated from the black liquor 136 in a separator 132. The black liquor 136 is then processed to produce a combusted melt product 140. For example, the black liquor 136 may be combusted in a recycling boiler 138. The combusted melt product 140 is dissolved in water 142 to produce green liquor 112. Green liquor 112 contains water and entrained particles. The pH of green liquor 112 is at least about 8 and the temperature is at least about 50°C. In this embodiment, the entrained particles in green liquor 112 include calcium or iron compounds, or combinations thereof. Clarifying compositions 114 and 116 are combined with green liquid 112. In one variation of this embodiment, clarifying composition 114 is combined with green liquid 112 upstream of clarifier unit 118. In another variation of this embodiment, clarifying composition 116 is combined with green liquid 112 within clarifier unit 118. In this embodiment, residue stream 122 is separated from liquid recovery stream 120. Residue stream 122 contains ethyleneamine-containing polymer and entrained particles.

[0041] The liquid recovery stream 120 can be further processed. In one embodiment, the liquid recovery stream 120 can be processed to produce white liquor. The white liquor can then be returned to the papermaking process 110 and reused.

[0042] The residue stream 122 can be further processed and improved. For example, in one embodiment, the residue stream 122 can be further concentrated to produce a washed residue stream having a solids content of at least 10 wt.%, or at least 50 wt.%, or about 10 wt.% to about 90 wt.%, or about 30 wt% to about 70 wt%, based on the total weight of the washed residue stream. In another embodiment, a clarifying composition can be combined with the residue stream 122, preferably upstream or inside a downstream clarifier unit. Further separation of entrained particles from the residue stream occurs in the downstream clarifier unit. In this embodiment, the residue stream is separated to produce a further clarified water stream and a clarifier underflow containing an ethyleneamine polymer and entrained particles.

[0043] It should be understood that any or all of the aforementioned components (e.g., monomers, modifiers, etc.) can be prepared or otherwise obtained (e.g., from commercial sources). Furthermore, such components and / or reagents used to prepare them can be derived from conventional (e.g., fossil-based) sources, or can be bio-based, i.e., prepared using biological methods and / or products derived from such methods. In some embodiments, the method uses all bio-based components in the preparation of the ethyleneamine-containing polymer. In other embodiments, at least a portion of the components is bio-based.

[0044] While at least one exemplary embodiment has been presented in the foregoing detailed descriptions, it should be understood that numerous variations exist. It should also be understood that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed descriptions will provide those skilled in the art with a convenient roadmap for implementing exemplary embodiments of this disclosure. It should be understood that various changes can be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of this disclosure as set forth in the appended claims.

Claims

1. A method for dewatering a water stream containing entrained particles, wherein the method comprises: The water flow is provided, wherein the water flow comprises water and the entrained particles, and wherein the water flow has a pH of at least about 8 and a temperature of at least about 50°C; Combining the water stream with a clarifying composition comprising a ethyleneamine polymer or one or more precursors thereof; and After combining the water stream with the clarifying composition, the entrained particles are separated from the water.

2. The method of claim 1, wherein combining the water stream with the clarifying composition comprises combining the water stream with a vinylcarboxamide-containing polymer as a precursor of the vinylamine-containing polymer, wherein the vinylcarboxamide-containing polymer is formed from one or more N-vinylcarboxamide monomers of formula I. (I) Where R 1 and R 2 Each is independently an H or C1 to C6 alkyl group. The carboxamide groups of the vinyl carboxamide-containing polymer are hydrolyzed in situ to form an vinylamine-containing polymer with primary amine groups.

3. The method of claim 2, wherein combining the water stream with the vinyl carboxamide-containing polymer comprises combining the water stream with a vinyl carboxamide-containing polymer having vinyl carboxamide groups present in an amount of about 3 to about 99 mol%, based on the total number of side groups of the vinyl carboxamide-containing polymer.

4. The method according to any one of claims 1 to 3, wherein combining the water stream with the clarifying composition comprises combining the water stream with a clarifying composition in a dry form, an aqueous solution form, an emulsion form, or a dispersion form.

5. The method of claim 4, wherein the clarifying composition is combined with the water stream in the form of dried particles.

6. The method according to any one of claims 1 to 5, wherein providing the water flow comprises providing the water flow at a temperature of about 75°C to about 100°C and a pH of about 10 to about 13.

7. The method according to any one of claims 1 to 6, wherein providing the water flow comprises providing a wastewater flow from the papermaking process.

8. The method of claim 7, wherein the water stream has an initial suspended solids content of 100 to about 5000 ppm.

9. The method of claim 8, wherein separating the entrained particles from the water comprises producing a clear water stream having less than 100 ppm of entrained particles.

10. The method of claim 9, wherein separating the entrained particles produces the clarified water stream having less than 25 ppm of entrained particles.

11. The method of claim 9, wherein separating the entrained particles from the water comprises generating a clarifier underflow having a solids concentration of at least 10 wt.% based on the total weight of the clarifier underflow.

12. The method of claim 11, further comprising concentrating the clarifier underflow to produce a washed clarifier underflow composition having a solids content of at least 50 wt.% solids based on the total weight of the washed clarifier underflow composition.

13. The method of claim 11, wherein generating the clarifier underflow comprises collecting the clarifier underflow after a residence time of less than 4 hours in the clarifier unit.

14. The method of claim 7, wherein providing the water flow comprises providing a green liquid, wherein the entrained particles comprise compounds containing calcium and / or iron.

15. The method of claim 14, wherein combining the green liquor with the clarifying composition includes combining the green liquor with the clarifying composition upstream of or inside the clarifier unit.

16. The method of claim 15, wherein separating the entrained particles comprises separating the residue stream from the liquid recovery stream, wherein the residue stream comprises the entrained particles and an ethyleneamine-containing polymer.

17. The method according to any one of claims 1 to 6, wherein providing the water flow comprises providing a tailings flow from a mining operation.

18. The method according to any one of claims 1 to 17, wherein the clarifying composition comprises the ethyleneamine polymer or one or more of its precursors in an amount of at least about 40% by weight, based on the total weight of the clarifying composition.

19. The method of claim 18, wherein the clarifying composition is added in an amount of about 2 to about 10 ppm based on the total volume of the water flow.

20. Papermaking methods, including: Cooking fibrous materials in white liquor to produce kraft pulp; After cooking, the kraft pulp is separated from the black liquor; The black liquor is processed to produce a combustible molten product; The combustion melt product is dissolved in water to produce a green liquid, wherein the green liquid contains water and entrained particles, and wherein the green liquid has a pH of at least about 8 and a temperature of at least about 50°C. Combining the green liquid with a clarifying composition comprising a polymer containing ethyleneamine polymer or one or more precursors thereof; and After combining the green liquid with the clarifying composition, the entrained particles are separated from the water.

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