GB2573320A - A method of producing an aluminium based coagulant - Google Patents
A method of producing an aluminium based coagulant Download PDFInfo
- Publication number
- GB2573320A GB2573320A GB1807285.0A GB201807285A GB2573320A GB 2573320 A GB2573320 A GB 2573320A GB 201807285 A GB201807285 A GB 201807285A GB 2573320 A GB2573320 A GB 2573320A
- Authority
- GB
- United Kingdom
- Prior art keywords
- aluminium
- coagulant
- membrane
- electrolysis
- anode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/24—Halogens or compounds thereof
- C25B1/26—Chlorine; Compounds thereof
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
- C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/14—Alkali metal compounds
- C25B1/16—Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
- C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B13/00—Diaphragms; Spacing elements
- C25B13/04—Diaphragms; Spacing elements characterised by the material
- C25B13/08—Diaphragms; Spacing elements characterised by the material based on organic materials
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
A method of producing an aluminium based coagulant including the process of dissolution of aluminum metal in sodium solution 2 through electrolysis 8. The anode 10 is made from aluminium metal, a membrane 12 is located between the anode 10 and cathode12, and a direct current is provided between the two electrodes. The cathode 12 may be formed from iron and the membrane 14 may also be non-porous material such as a pure cotton canvas material.
Description
A method of producing an aluminium based coagulant
Field of the Invention
The present invention relates to a method of producing an aluminium based coagulant. More especially the invention relates to a greener method of producing aluminium chlorohydrate coagulant, for example, that does not require an acidic environment and utilises less electricity than conventional and known methods.
Background of the Invention
A coagulant is a chemical agent that promotes the coagulation and flocculation effect of the colloidal particles in water and accelerates the formation of coarse particles, thus making it easier to be subject to fast sedimentation or filtration.
Commonly used coagulants include, without limitation, alum, polyaluminium chloride, activated silicic acid, polyacrylamide, magnesium alumina, ferrous sulphate and ferric chloride.
Reference is made below and in the detailed description to aluminium chlorohydrate coagulant. It is though clear that the method described may be used to make any aluminium based coagulant, typically in the form of aluminium oxychloride having the general formula AI2(OH)n Cl6-n.
Aluminium oxychloride is a modern generation coagulant that has properties that provide high quality water treatment even during the initial stages of purification.
Aluminium chlorohydrate is a group of specific aluminium salts having the general formula AlnCI(3n-m)(OH)m that are used as a coagulant in water purification, as well as in cosmetics as an antiperspirant and many other uses.
Aluminium chlorohydrate is the coagulant of choice for many industrial and sanitary wastewater treatment applications to remove dissolved organic matter and colloidal particles present in suspension, due to its high efficiency, effectiveness in clarification, and utility as a sludge dewatering agent. The chemical leaves no residual colour and offers very good turbidity and colour removal.
Known methods of producing aluminium chloride coagulant all include treatment under high pressure with acid or in an acidic environment, most notably with the presence of hydrochloric acid.
One such method includes preparation of the solution containing aluminium chloride by chemical dissolution of aluminium material in hydrochloric acid and subsequent hydrolysis of the obtained solution by its electrochemical treatment with alternating current. Aluminium is used as aluminium containing material and 5-10% hydrochloric acid is used for the preparation of the solution containing aluminium chloride. Electrochemical treatment is performed with alternating current with frequency of 50 Hz and current density of 0.5-5 A/dm2 during 5-30 hours and use of aluminium electrodes.
Russian patent application no. 2071941, for example, discloses a method of obtaining a chloroaluminium coagulant consists of the electrolytic dissolution of aluminium metal in a mixture of 5-10% solution of hydrochloric acid and natural bischofite (a hydrous magnesium chloride mineral) in the ratio (0.9 - 0.1): (0.1 - 0.9) part by volume, or pre-dissolving aluminium metal in 5-10% solution of hydrochloric acid, followed by mixing the obtained solution with natural bischofite in the ratio (0.9 - 0.1) : (0.1 - 0.9) part by volume and the subsequent electrolysis with alternating current at a frequency of 50 Hz and a current density of 0.5 to 5.0 A/dm. kV for 5-30 hours, during which electrolysis is not accompanied polarization processes.
Other methods, such as boiling pyrolysis, also require use of significant amounts of hydrochloric acid during the process.
The use of hydrochloric acid in known methods of producing aluminium chloride coagulant is hazardous and causes considerable logistical problems due to the complexity of its transportation and storage. Moreover, known methods are environmentally damaging due to the acidic conditions and high current required for the electrolysis, and the high temperature and pressure environment commonly required.
The present invention seeks to provide an improved method of producing aluminium chloride that is green and environmentally friendly and non-hazardous, due to the method not requiring the use of an acid or acidic conditions for its production. Furthermore the invention seeks to provide method that requires a minimal amount of current and provides a simplified process of manufacture.
To achieve these objectives, the present invention seeks to replace use of hydrochloric acid within the process with, non-hazardous, sodium chloride. The method of producing the coagulant includes the process of dissolution of aluminium metal in chloride solution through electrolysis wherein the chloride solution is sodium chloride, the anode is made from aluminium metal, a membrane is located between the anode and cathode, and a direct current is provided between the two electrodes.
Summary of the Invention
A method of producing an aluminium based coagulant comprising the step of using electrolysis to chemically dissolve aluminium material in sodium chloride solution.
Brief Description of the Drawings
The invention will now be described, by way of example only, with reference to the accompanying drawing which is a process flow diagram detailing, by way of example, a production process of the present invention.
Detailed Description of Preferred Embodiments
The process of producing aluminium chlorohydrate coagulant involves, primarily, the technique of electrolysis.
The chosen electrolyte 2 is a solution of sodium chloride (NaCI) commonly known as table salt, which is found in abundance in the world’s oceans, salt lakes, and underground deposits or in its natural form as a crystalline mineral known as rock salt or halite 4.
If collected in its sold form, the salt is first dissolved in water in a dissolution chamber 6.
The solution is pumped into an electrolysis chamber 8 having an anode 10 formed from an aluminium metal and a cathode 12 from iron.
A membrane 14 is located in the electrolysis chamber 8 and separates the anode 10 from the cathode 12. The electrolyte is pumped into the chamber 8 either side of the membrane 14. The membrane 12 is made from a non-porous material but is highly conductive. A suitable material for the membrane 14 would be, for example, a waterproof pure cotton canvas material. Each end of the membrane 14 is sealed to prevent leakage such that the liquids either side of the membrane 14 are kept separate and do not mix. The conductivity of the membrane 14 material allows electrons to pass through from one liquid to the other.
The anode 10 and cathode 12 are connected to a battery 16, or other electrical supply, to provide a constant direct current across the electrodes 10, 12. Preferably the electricity supply is portable to allow the entire apparatus to be portable so that the coagulant may be manufactured on site, if it is appropriate to do so.
The electrical current required for the electrolysis is very low compared to known techniques due to the coagulant being formed through a chemical reaction that takes place during the electrolysis. The applicant has found, for example, that 2g of aluminium can dissolved using only 1A of current.
The Applicant has found that the chemical reaction takes place once the temperature during electrolysis reaches around 70 to 80°C. The applicant has found this is the optimum temperature range for the required chemical reaction. Whilst the temperature will increase to within this range during exothermic reactions, additional heat could be provided to increase the temperature to the appropriate level quicker if necessary.
The Applicant has also found that the current required to produce the coagulant through electrolysis and chemical reactions can be reduced by reducing the distance between the electrodes.
The electrolysis and chemical reaction results in the aluminium hydrochlorate coagulant being formed in the first section 18 of the chamber 8, at the anode 10, and sodium hydroxide (NaOH), also known as caustic soda, being formed in the second section 20 of the chamber 8, at the cathode 12.
Sodium hydroxide is used in many industries, for example in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents, and as a drain cleaner. This “byproduct” adds further utility to the claimed process.
Once created, a secondary process could be included, to mix the aluminium chlorohydrate coagulant and sodium hydroxide to create sodium aluminate NaAIO2 which is also a recognised and desired coagulant. Sodium aluminate is traditionally produced under conditions of high pressure and temperature. The present method can be used to produce sodium aluminate (as a by-product in the process) without high pressure and temperature equipment by simple mixing.
The coagulant produced by this method is determined by a number of factors, including the amount of salt in the solution, the electricity (amperage) and the electrolysis/chemical reaction time. These factors can be varied to create different coagulants like for example, without limitation, PAC-10 (PAC with 10% basicity) or PAC-20 (PAC with 20% basicity).
Figure 1 is a process flow diagram showing an example of how the process can be built and structured. The process includes an array of pumps 22 and storage tanks 24 between the creation of the coagulant and other chemical(s), and delivery of the coagulant and/or chemicals to a chosen site for an intended purpose. The process described is provided for example purposes only and the electrolysis element can incorporated in many other process formats and structures.
Claims (9)
1. A method of producing an aluminium based coagulant including the step of using electrolysis to chemically dissolve aluminium material in sodium chloride solution.
2. A method according to claim 1, wherein the sodium chloride is first collected in salt form and is dissolved in water in a dissolution chamber.
3. A method according to claim 1 or claim 2, wherein the solution is pumped into an electrolysis chamber having an anode formed from an aluminium metal and a cathode formed from iron.
4. A method according to claim 3, wherein the anode and cathode are separated by a membrane.
5. A method according to claim 4, wherein the membrane is non-porous.
6. A method according to claim 4 or claim 5, wherein the membrane is formed from a high conductive material.
7. A method according to claim 6, wherein the membrane is made from a pure cotton canvas material.
8. A method according to any one of claims 3 to 7, wherein the anode and cathode are connected to a battery, or other electrical supply, to provide a constant direct current across the electrodes.
9. A method according to claim 8, wherein the electricity supply is portable to allow the coagulant may be manufactured on site.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1807285.0A GB2573320A (en) | 2018-05-03 | 2018-05-03 | A method of producing an aluminium based coagulant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1807285.0A GB2573320A (en) | 2018-05-03 | 2018-05-03 | A method of producing an aluminium based coagulant |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201807285D0 GB201807285D0 (en) | 2018-06-20 |
| GB2573320A true GB2573320A (en) | 2019-11-06 |
Family
ID=62598207
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1807285.0A Withdrawn GB2573320A (en) | 2018-05-03 | 2018-05-03 | A method of producing an aluminium based coagulant |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2573320A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB509815A (en) * | 1937-05-15 | 1939-07-21 | Ig Farbenindustrie Ag | Improvements in the manufacture and production of water-soluble basic aluminium compounds |
| DE1964661A1 (en) * | 1969-09-11 | 1971-03-18 | Kurita Water Ind Ltd | Electrolysed coagulant contg. aluminium - for water treatment |
| US3715290A (en) * | 1969-09-11 | 1973-02-06 | Kurita Water Ind Ltd | Method and apparatus for preparation of aluminium coagulating agent |
| SU675089A1 (en) * | 1978-01-03 | 1979-07-25 | Вильнюсское Проектно-Конструкторское Бюро Механизации И Автоматизации | Method of obtaining coagulant for cleaning waste water |
| RU2081828C1 (en) * | 1994-05-13 | 1997-06-20 | Волгоградский государственный технический университет | Method for production of chlorine- and aluminium-containing coagulant |
| CN101609895A (en) * | 2009-07-07 | 2009-12-23 | 广东省生态环境与土壤研究所 | A kind of cloth cathode assembly that is used for microbiological fuel cell and preparation method thereof |
-
2018
- 2018-05-03 GB GB1807285.0A patent/GB2573320A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB509815A (en) * | 1937-05-15 | 1939-07-21 | Ig Farbenindustrie Ag | Improvements in the manufacture and production of water-soluble basic aluminium compounds |
| DE1964661A1 (en) * | 1969-09-11 | 1971-03-18 | Kurita Water Ind Ltd | Electrolysed coagulant contg. aluminium - for water treatment |
| US3715290A (en) * | 1969-09-11 | 1973-02-06 | Kurita Water Ind Ltd | Method and apparatus for preparation of aluminium coagulating agent |
| SU675089A1 (en) * | 1978-01-03 | 1979-07-25 | Вильнюсское Проектно-Конструкторское Бюро Механизации И Автоматизации | Method of obtaining coagulant for cleaning waste water |
| RU2081828C1 (en) * | 1994-05-13 | 1997-06-20 | Волгоградский государственный технический университет | Method for production of chlorine- and aluminium-containing coagulant |
| CN101609895A (en) * | 2009-07-07 | 2009-12-23 | 广东省生态环境与土壤研究所 | A kind of cloth cathode assembly that is used for microbiological fuel cell and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201807285D0 (en) | 2018-06-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |