CA1075559A - Method of producing phosphate removing materials - Google Patents
Method of producing phosphate removing materialsInfo
- Publication number
- CA1075559A CA1075559A CA294,822A CA294822A CA1075559A CA 1075559 A CA1075559 A CA 1075559A CA 294822 A CA294822 A CA 294822A CA 1075559 A CA1075559 A CA 1075559A
- Authority
- CA
- Canada
- Prior art keywords
- phosphate
- calcined
- wastewater
- media
- filter
- 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.)
- Expired
Links
Classifications
-
- 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
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
-
- 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
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
Abstract
ABSTRACT OF THE INVENTION
The present invention describes a method of producing phosphate-removing filter media and dusting agents. The method involves cac-cining a raw material aggregate containing therein a high percentage of the compounds of calcium, alumina and iron, by the use of a sufficient amount of heat to to cause the calcium, alumina and iron compounds to become concentrated within the calcined aggregate.
And then crushing, grinding and screening the calcined materials to a desired sizing.
The present invention describes a method of producing phosphate-removing filter media and dusting agents. The method involves cac-cining a raw material aggregate containing therein a high percentage of the compounds of calcium, alumina and iron, by the use of a sufficient amount of heat to to cause the calcium, alumina and iron compounds to become concentrated within the calcined aggregate.
And then crushing, grinding and screening the calcined materials to a desired sizing.
Description
The present invention relates to the production of phosphate removal agents; more particularly it relates to the production of an expanded porous calcium, aluminous-iron material for such a purpose.
In the treatment of municipal, domestic, industrial, manufacturing and agricultural wastewater effluents, it is common to convey such effluents to a treatment plant such as a primary sewage treatment plant, or a Primar then secondary ~ewage treatment plant,or a septic tank for the purpose of removing the pollutants therefrom.
Tertiary sewage treatment is ~ometimes added for the removal of phosphates from the wastewater but it suffers from the disadvantage in that its phosphate removal effect-lveness i8 not as high as other materials which might be used as for example, calcium, aluminous and iron compounds.
It i6 an object of the present invention to provide a method of producing an expanded porous product containing therein in concentrated form the compounds of calcium, alumina and iron suitable as a phosphate removal agent which when u9ed as a phosphate removal agent in the treat-- ment of wastewa~ers tends to overcome the aforementioned disadvantages associated with conventional wastewater treatment systems.
According to one asPect of the present invention there is provided a method of producing an expanded porous cal-cium, aluminous, iron material suitable as a phosphate . ' :
.,~ ~ .
:
` 1~)755S9 removal agent in the treatment of phosphate containing-wastewater, which method comprises calcining an aggregate containing therein a high proportion of the compounds of calcium, aluminum and iron at a temperature of from between 600 to 1400 degrees Fahrenheit until the organic matter and volatiles in the aggregate are driven off, the chem-ical and mineralogical composition of the aggregate is changed, the calcium, aluminous and iron content of the aggregate in changed and concentrated form ~i8 held within the calcined aggregate material, the external and inter-nal structure of the calcined aggregate opened up and made more porous, and also a greatly increased surface area~ developed therein.
The raw material aggregates ~table for use in the production of phosphate-removing agents are chosen from the group of aggregates consisting of clays, rock, shales, mineral wastes, industrial wastes, coal or burnt coal was- -tes, coal slag wastes or any form of wastes, containing therein the compounds of calcium, aluminum or iron in which they form a major part of the aggregate either as individual parts thereof or in combination.
It has been found that the temperature of calcination of the aggregate is a very important factor with the optimum temperature of calcination being that which will produce a product therefrom having the de~ired soft-burned ; porous physical characteristics and a desired concentration of the phosphate removing agents calcium, alumina and iron retained therein.
In the treatment of municipal, domestic, industrial, manufacturing and agricultural wastewater effluents, it is common to convey such effluents to a treatment plant such as a primary sewage treatment plant, or a Primar then secondary ~ewage treatment plant,or a septic tank for the purpose of removing the pollutants therefrom.
Tertiary sewage treatment is ~ometimes added for the removal of phosphates from the wastewater but it suffers from the disadvantage in that its phosphate removal effect-lveness i8 not as high as other materials which might be used as for example, calcium, aluminous and iron compounds.
It i6 an object of the present invention to provide a method of producing an expanded porous product containing therein in concentrated form the compounds of calcium, alumina and iron suitable as a phosphate removal agent which when u9ed as a phosphate removal agent in the treat-- ment of wastewa~ers tends to overcome the aforementioned disadvantages associated with conventional wastewater treatment systems.
According to one asPect of the present invention there is provided a method of producing an expanded porous cal-cium, aluminous, iron material suitable as a phosphate . ' :
.,~ ~ .
:
` 1~)755S9 removal agent in the treatment of phosphate containing-wastewater, which method comprises calcining an aggregate containing therein a high proportion of the compounds of calcium, aluminum and iron at a temperature of from between 600 to 1400 degrees Fahrenheit until the organic matter and volatiles in the aggregate are driven off, the chem-ical and mineralogical composition of the aggregate is changed, the calcium, aluminous and iron content of the aggregate in changed and concentrated form ~i8 held within the calcined aggregate material, the external and inter-nal structure of the calcined aggregate opened up and made more porous, and also a greatly increased surface area~ developed therein.
The raw material aggregates ~table for use in the production of phosphate-removing agents are chosen from the group of aggregates consisting of clays, rock, shales, mineral wastes, industrial wastes, coal or burnt coal was- -tes, coal slag wastes or any form of wastes, containing therein the compounds of calcium, aluminum or iron in which they form a major part of the aggregate either as individual parts thereof or in combination.
It has been found that the temperature of calcination of the aggregate is a very important factor with the optimum temperature of calcination being that which will produce a product therefrom having the de~ired soft-burned ; porous physical characteristics and a desired concentration of the phosphate removing agents calcium, alumina and iron retained therein.
- 2 -:1075559 As the physical, chemical and mineralogical composition of the raw aggregate may vary considerably from one recovery site to another, the exact temperature of calcin-ation should be determined for aggregates from each part-icular site-Because of the aforementioned variations in calcin-ation temperatures which may range from a low of 600 F., to a high of 1400 degrees Fahrenheit, it should be noted that the temperature of calcination of the aggregate 10 should be that from which a soft-burned product having a porous structure may be produced while at the same :
time leaving therein the greater portion of its original calcium, alumina and iron content in more concentrated form~ It should also be noted that the temperature of cal-conation should be below that which would be classed as hard burned in `a. brick works and should be at least 50 degrees Fahrenheit below the melting point of the aggregate U8 ed -m e calcium-aluminous-iron material ofthe.invention 20 i8 also formed to expand on heating to give a product with an expandPd porous structure- Thi~ expansion is advantag-eous because after crushing and grinding the product obt-ained is in the form of particles with a desirable ang-ularity sufficient to interlock one with the other to form . therefrom an extremely effective filter media having a very large surface area as compared to normally u6ed filt~r media and sufficiently large numbers of angles to Provide maximum micro-straining filter-efffctivene8s. Thus in carrying out .
~" 1075559 calcining it is essential to calcine below the afore-mentioned "hard burned" formation temperature ~or a time sufficient to impart a "soft burned" expanded porous structure to the product of calcining.
According to another aspect of the present invention there is provided a method of preparing phosphate remov-ing compounds contained in a wastewater treatment material, which method consists of incorporating in, concentrated phosphate-removing compounds or a phosphate-removing compound contained in a wastewater treatment material, an expanded porous calcium-aluminous-iron material prod-uced by the above method.
For the purpose of this specification the term calcium-aluminous-iron aggregate is intended to cover calcium-aluminous-iron materials known to form light weight agg-regates by expanæion on calcining.
..
The calcium, aluminum and iron raw material aggregatesmay be calcined by the application of heat under cont-rolled conditions of firing in a kiln, open pit, under-ground ~iring or other suitable means, and thereafter thecalcined materials are crushed, ground and screened to provide therefrom the desired range of phosphate-removing wastewater treatment sizings.
It has been found that the phosphate-removing capab-: ility and the micro-straining capability as well as the backwashing capability of a filter medium and filter can be increased without alteration or impairment of the other qualities demanded of the filter medium or filter, 1075Ci59 by substituting, for preference, a specified amount or all of the calcium-aluminous-iron materia~ produced in - the method of the invention for an equal weight or all of the filter sand or other conventional types of filter medium in the filter.
:: .
Observation of the action of the calcined calcium-alum-inous-iron materials produced in the method of the inven-tion has disclosed that the angular calcium-aluminous-iron material after crushing, grinding and screening to the desired size wil~ interlock the various sized filter media particles together to provide desirable micro-straining effect in the filter media so that the resultant ~ilter media surface will offer a greater res-istance to wa5tewater pollutant passage through the filter media while still allowing for a desirable effluent flow rate therethrough and for maximum flexibility during backwashing.
I have found it best to crush, grind and screen the calcined phosphate-removing aggregate to produce there-from a coarsely granular down to a finely granular prod-uct and a finely ground product.wherein the maximum size of the coarsely crushed granular product is that size passing through a standard screen with a ~ 1/2 inch mesh size and the minimum size of the finely ground granular product is that retained on a standard screen with a 60 mesh size, and wherein the finely ground phosphate-removing product includes all those sizings pas~ing through a standard screen of 60 mesh size~ although it should be understood that the descrip~ion here is merely an optimum condition and other degrees of coarseness and fineness could be used.
I have also found it best to provide a wide range of phosphate-removing sizings from the coarsely-crushed, and finely-crushed and ground gran~lar sizings of the - calcined aggregates. This makes possible the Provision of filter-media having the property of phosphate rem-oval graduated according to the desired sizings ranging from coarsely granular down to finely granular in segreg-ated aggre~ations thereof when placed within pervious plastic bags or containers.
The aforementioned pervious bags may be made from plastic netting, waterPrOOfed woven material, polyprop-ylene or other suitable materials. The mesh size of the bags may be of any suitable size but the perforations in the pervious bags should have a smaller diameter sizing ; than the diameter of the phosphate-removing filter media.
Since most of the plastic or polypropylene netting used today for bag making is in tubular form it is essential tha~ a large enough diameter sizing be used. I have ; found it best to use a bag size of about 24 inches wide and 36 inches long. A narrower bag becomes to bulky and a longer bag to heavy to handle particularly when wet~ It should be understood that the description here is mere-ly an optimum sizing and other sizings or shapes could be used as may be required or be necessary to conform to the filter de~ign or configuration.
This artificially prepared product will in the presence of phosphate-containing wastewater react with its phosph-ate content to remove it therefrom by chemical precipitat-~75559 ion, sorptive processes or biological activity.
In the practice of the present invention, it is desir-able in most wastewater treatment applications such as domestic, industrial, manufacturing and agricultural wastewaters to pre-treat the wastes to remove solids, org-anics, toxic substances and heavy metals prior to treating the wastewater to remove phosphate sewage-fertilizer nutrients therefrom. This can be done by passing the wastewater through a conventional type primary, secondary and tertiary sewage treatment plant, or a septic tank sewage treatment system followed by a biological- oxid-ation bed containing granular adsorptive coal filter media therein, then Passing the effluent through the phosphate-removing filter media prepared by the method of the pres-ent invention prior to its discharge to surface waters.
` m e following tables are o~ ash analysis of typical raw material aggregates suitable for use in preparing the phosphate removing wastewater treatment materials of the invention.
Table 1 Aggregate in which calcium predominates.
Analysis of Ashs ~A12O3 Fe203 CaO (calcium) .. ,............. , l302 5.9 22.5 Table 2 Aggregate in which alumina predominates.
Analysis of Ash: ~1203 Fe203 CaO
%.................. 38.2 2.9 1.
Table 3 Aggregate in which Iron predominatess 30 Analysis of Ashs A12O3 Fe2O3 CaO
.................. 12.0 59.3 3.4 10~5559 The calcined materials of the invention after crushing, grinding and screening to a desired sizing are very porous and extremely abrasive with a desirable Particle angularity. They have a specific gravity of from between 1.80 to 3.5 and a grindability index of from between 30 to 50, with a hardness of from 2 to ~ on the Mohrs scale of hardness.
It has been found desirable to treat larger water areas such as lagoons, lakes and the like whose waters are loaded with phosphates and whose sediments are polluted with all manner of undesirable toxic substances, heavy metals and sewage fertilizer nutrient~. In treatment app-lications such as these it is not always possible to treat - the waters in filters or the like. I have found that the use of the finely ground phosphate removing materials when dusted over the water tend to cleanse the pollutants therefrom and on settling tend to bind the phosphates with-in the calcined phosphate removing treatment media.
It will be evident to those skilled in the art that it would be advantageous to form a treatment mixture of both the finely ground phosphate removing materials of the invention and the adsorptive coal in ~inely ground form where a complete form of wastewater trea~ment may be provided to serve the needs of larger water areas~ Such uses are intended to come within the scope of the present invention.
For the purpose of this invention micro-straining is intended to mean the removal from wastewater of extremely fine suspended mattex from water due to the porous9 rough and very abrasive nature of the phoæphate-removing filter medium and the ability of the filter medium to interlock one with the other due to the tr~mendou~ number of angles presented to -the incoming wastewater due to the angularity of the calcined phosphate-removing filter-medium Having described a pr0ferred embodiment of the invention, it should be apparent to those skilled in the art that the invention permit~ of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the aPPended claims.
.
No corresponding United States patent application has been filed.
time leaving therein the greater portion of its original calcium, alumina and iron content in more concentrated form~ It should also be noted that the temperature of cal-conation should be below that which would be classed as hard burned in `a. brick works and should be at least 50 degrees Fahrenheit below the melting point of the aggregate U8 ed -m e calcium-aluminous-iron material ofthe.invention 20 i8 also formed to expand on heating to give a product with an expandPd porous structure- Thi~ expansion is advantag-eous because after crushing and grinding the product obt-ained is in the form of particles with a desirable ang-ularity sufficient to interlock one with the other to form . therefrom an extremely effective filter media having a very large surface area as compared to normally u6ed filt~r media and sufficiently large numbers of angles to Provide maximum micro-straining filter-efffctivene8s. Thus in carrying out .
~" 1075559 calcining it is essential to calcine below the afore-mentioned "hard burned" formation temperature ~or a time sufficient to impart a "soft burned" expanded porous structure to the product of calcining.
According to another aspect of the present invention there is provided a method of preparing phosphate remov-ing compounds contained in a wastewater treatment material, which method consists of incorporating in, concentrated phosphate-removing compounds or a phosphate-removing compound contained in a wastewater treatment material, an expanded porous calcium-aluminous-iron material prod-uced by the above method.
For the purpose of this specification the term calcium-aluminous-iron aggregate is intended to cover calcium-aluminous-iron materials known to form light weight agg-regates by expanæion on calcining.
..
The calcium, aluminum and iron raw material aggregatesmay be calcined by the application of heat under cont-rolled conditions of firing in a kiln, open pit, under-ground ~iring or other suitable means, and thereafter thecalcined materials are crushed, ground and screened to provide therefrom the desired range of phosphate-removing wastewater treatment sizings.
It has been found that the phosphate-removing capab-: ility and the micro-straining capability as well as the backwashing capability of a filter medium and filter can be increased without alteration or impairment of the other qualities demanded of the filter medium or filter, 1075Ci59 by substituting, for preference, a specified amount or all of the calcium-aluminous-iron materia~ produced in - the method of the invention for an equal weight or all of the filter sand or other conventional types of filter medium in the filter.
:: .
Observation of the action of the calcined calcium-alum-inous-iron materials produced in the method of the inven-tion has disclosed that the angular calcium-aluminous-iron material after crushing, grinding and screening to the desired size wil~ interlock the various sized filter media particles together to provide desirable micro-straining effect in the filter media so that the resultant ~ilter media surface will offer a greater res-istance to wa5tewater pollutant passage through the filter media while still allowing for a desirable effluent flow rate therethrough and for maximum flexibility during backwashing.
I have found it best to crush, grind and screen the calcined phosphate-removing aggregate to produce there-from a coarsely granular down to a finely granular prod-uct and a finely ground product.wherein the maximum size of the coarsely crushed granular product is that size passing through a standard screen with a ~ 1/2 inch mesh size and the minimum size of the finely ground granular product is that retained on a standard screen with a 60 mesh size, and wherein the finely ground phosphate-removing product includes all those sizings pas~ing through a standard screen of 60 mesh size~ although it should be understood that the descrip~ion here is merely an optimum condition and other degrees of coarseness and fineness could be used.
I have also found it best to provide a wide range of phosphate-removing sizings from the coarsely-crushed, and finely-crushed and ground gran~lar sizings of the - calcined aggregates. This makes possible the Provision of filter-media having the property of phosphate rem-oval graduated according to the desired sizings ranging from coarsely granular down to finely granular in segreg-ated aggre~ations thereof when placed within pervious plastic bags or containers.
The aforementioned pervious bags may be made from plastic netting, waterPrOOfed woven material, polyprop-ylene or other suitable materials. The mesh size of the bags may be of any suitable size but the perforations in the pervious bags should have a smaller diameter sizing ; than the diameter of the phosphate-removing filter media.
Since most of the plastic or polypropylene netting used today for bag making is in tubular form it is essential tha~ a large enough diameter sizing be used. I have ; found it best to use a bag size of about 24 inches wide and 36 inches long. A narrower bag becomes to bulky and a longer bag to heavy to handle particularly when wet~ It should be understood that the description here is mere-ly an optimum sizing and other sizings or shapes could be used as may be required or be necessary to conform to the filter de~ign or configuration.
This artificially prepared product will in the presence of phosphate-containing wastewater react with its phosph-ate content to remove it therefrom by chemical precipitat-~75559 ion, sorptive processes or biological activity.
In the practice of the present invention, it is desir-able in most wastewater treatment applications such as domestic, industrial, manufacturing and agricultural wastewaters to pre-treat the wastes to remove solids, org-anics, toxic substances and heavy metals prior to treating the wastewater to remove phosphate sewage-fertilizer nutrients therefrom. This can be done by passing the wastewater through a conventional type primary, secondary and tertiary sewage treatment plant, or a septic tank sewage treatment system followed by a biological- oxid-ation bed containing granular adsorptive coal filter media therein, then Passing the effluent through the phosphate-removing filter media prepared by the method of the pres-ent invention prior to its discharge to surface waters.
` m e following tables are o~ ash analysis of typical raw material aggregates suitable for use in preparing the phosphate removing wastewater treatment materials of the invention.
Table 1 Aggregate in which calcium predominates.
Analysis of Ashs ~A12O3 Fe203 CaO (calcium) .. ,............. , l302 5.9 22.5 Table 2 Aggregate in which alumina predominates.
Analysis of Ash: ~1203 Fe203 CaO
%.................. 38.2 2.9 1.
Table 3 Aggregate in which Iron predominatess 30 Analysis of Ashs A12O3 Fe2O3 CaO
.................. 12.0 59.3 3.4 10~5559 The calcined materials of the invention after crushing, grinding and screening to a desired sizing are very porous and extremely abrasive with a desirable Particle angularity. They have a specific gravity of from between 1.80 to 3.5 and a grindability index of from between 30 to 50, with a hardness of from 2 to ~ on the Mohrs scale of hardness.
It has been found desirable to treat larger water areas such as lagoons, lakes and the like whose waters are loaded with phosphates and whose sediments are polluted with all manner of undesirable toxic substances, heavy metals and sewage fertilizer nutrient~. In treatment app-lications such as these it is not always possible to treat - the waters in filters or the like. I have found that the use of the finely ground phosphate removing materials when dusted over the water tend to cleanse the pollutants therefrom and on settling tend to bind the phosphates with-in the calcined phosphate removing treatment media.
It will be evident to those skilled in the art that it would be advantageous to form a treatment mixture of both the finely ground phosphate removing materials of the invention and the adsorptive coal in ~inely ground form where a complete form of wastewater trea~ment may be provided to serve the needs of larger water areas~ Such uses are intended to come within the scope of the present invention.
For the purpose of this invention micro-straining is intended to mean the removal from wastewater of extremely fine suspended mattex from water due to the porous9 rough and very abrasive nature of the phoæphate-removing filter medium and the ability of the filter medium to interlock one with the other due to the tr~mendou~ number of angles presented to -the incoming wastewater due to the angularity of the calcined phosphate-removing filter-medium Having described a pr0ferred embodiment of the invention, it should be apparent to those skilled in the art that the invention permit~ of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the aPPended claims.
.
No corresponding United States patent application has been filed.
Claims (8)
1. A method of producing phosphate-removing materials having micro-straining capabilities from highly miner-alized raw material which includes the steps of:
a. providing raw materials containing high percentages of the compounds of calcium, aluminum and iron therein, b. calcining said raw materials to produce therefrom expanded and porous wastewater treatment media having micro-straining capabilities, c. concentrating said mineral compounds of step (a) by said calcination of step (b) to produce therefrom highly mineralized calcined materials, d. leaching said calcined materials with an aqueous liquid to remove water-soluble and adhering substances therefrom, e. crushing, grinding and screening said product of calcination and mineral compound concentration to prod-uce a quantity of fine particulate material having a maximum particle diameter passing through a 60 mesh size screen, and a larger size calcined material in which the maximum particle diameter size is that passing through a 11/2 inch mesh size screen and the smallest particle diameter size is that retained on a 60 mesh size screen, f. calcining said raw materials of step (a) under controlled conditins at a temperature of from 600 to 1400 degrees Fahrenheit until the volatiles and carbonaceous matter in the raw materials are driven off and until the structural, chemical and mineral-ogical composition of said calcined raw materials is changed and the compounds of calcium, aluminum and iron are concentrated therein, g. segregating predetermined quantities of said screened calcined phosphate-removing filter media as separately sized aggregations thereof according to a predetermined specific range of filter-media sizings which may range from coarsely granular down to finely granular, h. providing a pervious flexible filter-media cont-ainer having perforations therein in which perforation diameter is smaller than the smallest diameter sizing of said phosphate-removing filter-media placed therein, i. incorporating a baffle in the pervious filter media container formed from non-pervious material, j. pre-treating wastewater to remove toxic substances, heavy metals and organics by passing said wastewater through granular sorptive coal filters, k. providing aid filter containers containing said highly mineralized granular phosphate-removing larger size calcined filter-media and directing a phosphate-containing effluent stream therethrough,
1. removing suspended matter from said wastewater by passing said wastewater through said expanded and porous calcined materials said calcined materials having micro-straining capabilities, m. providing said highly mineralized phosphate-removing smaller sizings from said fine particulate salcined materials, n. adding said highly mineralized phosphate-removing calcined fine particulate materials as additives to said filters and to said wastewater.
2. A method as claimed in Claim l, further comprising providing raw materials suitable for use in the prod-uction of highly mineralized phosphate removing filter media and wastewater treatment additives chosen from the group consisting of clays, rock, shales, mineral wastes, industrial wastes, coal or burnt coal wastes, coal slag wastes or any form of wastes what-soever containing therein the compounds of calcium, alum-inum or iron in which said compounds form a major part thereof.
3. A method as claimed in Claim l, further comprising soft-burning said raw materials to provide a calcined product having an expanded external and internal structure with an improved porous and roughly-textured surface area, and thereafter crushing,grinding and screening said calcined product to provide a material having a predet-mined and well defined angularity suitable for use in micro-straining applications in wastewater treatment.
4. A method as claimed in Claim 3, further comprising calcining said raw material with a sufficient amount of heat to provide a calcined product having a specific gravity of from 1.80 to 3.5, a hardness on the Mohrs scale of hardness of from 2.0 to 4, and a grindability index of from 30 to 50.
5. A method as claimed in Claim 1, in which wastewater-phosphates are removed therefrom in contact with the said phosphate-removing treatment media, by sorptive processes, biological activity, or precipitation there-from.
6. A method as claimed in Claim 5, in which the activating agents in the phosphate-removing treatment media are compounds of calcium, aluminum and iron.
7. A method as claimed in Claim 4, in which said calcined product when used as a phosphate-removing filter medium may be used to substitute for either part or all of the conventional sand or gravel filter medium or part of or all of the granulated sorptive coal treatment medium of a wastewater-treatment container or bed thereof.
8. A method as Claimed in Claim 7, in which said calcined finely ground product when used as a phosphate-removing filter-media or wastewater treatment additive may be used to substitute for conventional phosphate-removing agents such as aluminum sulphate, iron salts or lime.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA294,822A CA1075559A (en) | 1978-01-12 | 1978-01-12 | Method of producing phosphate removing materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA294,822A CA1075559A (en) | 1978-01-12 | 1978-01-12 | Method of producing phosphate removing materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075559A true CA1075559A (en) | 1980-04-15 |
Family
ID=4110522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA294,822A Expired CA1075559A (en) | 1978-01-12 | 1978-01-12 | Method of producing phosphate removing materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1075559A (en) |
-
1978
- 1978-01-12 CA CA294,822A patent/CA1075559A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |