CN1214030A

CN1214030A - Method of waste stabilization via chemically bonded phosphate ceramics, structural materials incorporating potassium phosphate ceramics

Info

Publication number: CN1214030A
Application number: CN97193157A
Authority: CN
Inventors: 阿伦·S·瓦格; 迪利浦·辛格; 郑圣勇
Original assignee: University of Chicago
Current assignee: University of Chicago
Priority date: 1996-03-18
Filing date: 1997-03-18
Publication date: 1999-04-14
Also published as: WO1997034848A1; AU2530897A

Abstract

A method for regulating the reaction temperature of a ceramic formulation process is provided comprising supplying a solution containing a monovalent alkali metal; mixing said solution with an oxide powder to create a binder; contacting said binder with bulk material to form a slurry; and allowing the slurry to cure. A highly crystalline waste form is also provided consisting of a binder containing potassium and waste substrate encapsulated by the binder. A structural product is provided comprising a phosphate-containing ceramic binder encapsulating bulk waste to confer strength and resistance against weathering and thermal and chemical attack.

Description

Method for waste stabilization using chemically bonded phosphate ceramics, potassium phosphate ceramics incorporating structural materials

Background of the invention

Technical Field

The present invention relates to a method for stabilizing loose waste and producing structural products from the waste, and more particularly to a ceramic material that stabilizes loose, low level radioactive and mixed waste, and a method for producing structural products from the ceramic material, and a method for producing the ceramic material.

Background

Low-level mixed waste contains hazardous chemicals and low-level radioactive materials. Generally, the mixed waste stream contains hydration liquid, heterogeneous debris, inorganic waste and particulates, organic liquids, and soil. The volume of mixed waste produced by the U.S. department of energy alone projected over the next five years is estimated to be about one hundred twenty million cubic meters.

Stabilizing these mixed wastes requires two phases that effectively stabilize the contaminants.

A common method of stabilizing and storing these mixed waste materials involves vitrification. For example, one method (crown, U.S.5302565) requires firing at a temperature of at least 1850 ℃ for at least 12 hours to form a ceramic mold body. However, this high temperature-related approach is costly. In addition, vitrification of the waste stream often results in combustion of the volatile components contained in the waste stream. Such combustion can produce undesirable secondary waste streams.

A system for producing cement with ceramic-like properties does not require high temperatures for final crystallization (US 4436555 to Sugama et al). However, this method results in the release of ammonia that corrodes the container during processing and storage, and also produces explosive components if the waste material contains nitrates.

The inventors have also developed ceramic processing methods to stabilize and encapsulate the waste material. These processes have many advantages over conventional portland cement, grout one, polymer-and ceramic encapsulation technologies. Ceramic encapsulation systems are particularly attractive in that the bonds formed in these systems are ionic or covalent and therefore stronger than the hydrated bonds in portland cement. Because waste stabilization using ceramics is based on chemical and physical stabilization, the leaching properties of these final waste objects are superior to those of the above-described waste objects that are primarily based on physical encapsulation. Unlike the previous vitrification requirements, the exothermic ceramic processing method does not require heat treatment or provision of heat, with the result that the stabilization of the waste is itself economical and does not have bulky equipment and transport steps.

However, exothermic ceramic processing methods are not suitable for low cost encapsulation of loose waste. The inventors have found that a large amount of heat generated during the reaction causes boiling of the reaction solution, resulting in defects (e.g., pores) in the final ceramic body, shortening workability and rapid non-uniform aging. When the reaction temperature is partially controlled by circulating cold water along the slurry container or mold in which the sample is solidified, sufficient heat is not generated as the sample volume increases.

Another disadvantage of conventional ceramic waste production processes is that such systems create low pH conditions. For example, acid-base ceramic encapsulation reactions begin under strongly acidic conditions with a pH close to 0. Such strong acid conditions are unstable to HgS, making it leachable prior to physical encapsulation. Low pH conditions also result in CaCO₃And (5) decomposing.

In addition to the mixed waste discussed above, the more common waste also presents disposal problems. For example, bulk materials such as lumber waste, polystyrene foam, cellulose, tires, dust, old carpet backing, mineral waste, and plastics exacerbate the problem of reducing landfill space. Some of these materials, such as polystyrene foam, are flammable.

Efforts to convert many of these waste materials into useful products have failed. For example, the use of polymeric binders comprising such organic compounds, such as formaldehyde, to encapsulate waste materials often leads to combustion problems and smoke emissions. The use of such polymers is costly. Thereby limiting architectural applications.

The process of using ceramic binders to encapsulate loose waste requires a high weight ratio of binder to waste material. The large amount of binder makes the process costly, exothermic, and hardening accelerated as a result of the exotherm. Thus, it is difficult to use ceramic binders to encapsulate loose waste materials for use as insulation, building materials and composites.

One method for encapsulating waste materials with phosphate-containing materials is disclosed in U.S. Pat. No. re.32329. However, this process is designed to facilitate rapid curing of the final product. Thus, the desired flow characteristics of the product (e.g., blow insulation) are not expected.

There is a need in the art for a method of bulk waste stabilization and curing that does not generate significant heat during the encapsulation process. The process must be operated under mild pH conditions in order to favour the stabilisation of waste which is unstable at low pH conditions. The final product must have low leaching and high durability in the hydration system.

There is also a need in the art for a method of utilizing or treating non-renewable and non-biodegradable benign waste without generating a secondary waste stream. The method must be economical in producing structural materials for construction. There is also a need for an inexpensive structural product that is partially comprised of benign waste.

Summary of the invention

The object of the present invention is to overcome the many disadvantages of the prior art in the encapsulation and stabilization of low-level radioactive, mixed with other waste materials.

It is another object of the present invention to provide a method of temperature controlled ceramic formation that encapsulates and stabilizes waste material. The invention is characterized by the use of readily available compounds to regulate acid-base reactions associated with the formation of ceramic waste objects. An advantage of the present invention is that low temperatures are maintained during the formation process.

It is another object of the present invention to provide a low temperature reaction liquid in a method for stabilizing mixed waste using chemically bonded ceramic phosphate. The present invention is characterized by adjusting the pH of the reaction liquid. One advantage of the present invention is that the reaction temperature is reduced to facilitate the formation of denser waste materials. Another advantage is that waste materials that decompose or are unstable in certain low pH environments are more stable.

It is yet another object of the present invention to provide a ceramic waste object rich in potassium. The invention is characterized by a high content of crystalline phases in the final waste body. One advantage of the present invention is a more dense, less porous waste object.

It is a further object of the present invention to provide a method for producing a structural material. The invention is characterized by the use of a non-toxic binder material to encapsulate the benign waste material. One advantage of the present invention is the use of newly encapsulated benign waste as a safe insulating and fire-blocking material in buildings and other structures. Another advantage of the present invention is that the method does not emit toxic materials and is therefore safe for the operator and end user.

It is a further object of the present invention to provide a method for producing a lightweight structural material. The present invention is characterized by room-temperature encapsulation of large amounts of widely used waste materials with relatively small amounts of inorganic binder. One advantage of the present invention is that it is a low cost process for using non-renewable waste materials in a blown or pumpable production process for ultimate use as building materials.

It is another object of the present invention to provide a structural material that is partially comprised of benign waste material. The invention is characterized by a high volume ratio of waste material to binder material. One advantage of the present invention is the production of a lightweight strong structural material that can replace traditional materials. Another advantage of the present invention is that non-biodegradable and sometimes hazardous materials can be used without danger and non-flammable when used in a structure.

It isanother object of the present invention to provide a process for preparing a near term skin material. The invention is characterized by a high weight ratio of shell material to binder of the invention. One advantage of the present invention is the ability to provide the desired molded shape or structure to the recent casing material until a substantial portion of the activity is reduced or eliminated.

Briefly, the present invention provides a method for adjusting the reaction temperature of a ceramic forming process comprising providing a solution comprising a monovalent alkali metal; mixing the solution with an oxide powder to form a binder; contacting said binder with the bulk material to form a slurry; the slurry is aged.

The invention also provides a crystalline ceramic waste object comprising a potassium-containing ceramic binder and a waste material chemically stabilized and encapsulated by the binder.

The method for stabilizing and encapsulating red mud is to give a predetermined structure to red mud, mix red mud with a solution containing a monovalent alkali metal to form a slurry, and age the slurry.

A method of producing a structural product from benign waste material includes preparing an inorganic oxide, reacting the prepared inorganic oxide with phosphoric acid to produce an acidic solution, mixing the acidic solution with particles of the waste material to produce a slurry, and aging the slurry. Also provided is a structured product comprised of a structured material containing waste particles and an inorganic binder encapsulating the waste particles.

Also provided is a non-combustible structural material comprising a polystyrene foam and an inorganic binder encapsulating the polystyrene foam.

Also provided is a structural product or substrate comprising a potassium-containing ceramic binder and benign waste stabilized and encapsulated by the binder.

Brief description of the drawings

These and other objects of the present invention will be readily understood by the following detailed description and the accompanying drawings, wherein:

FIG. 1 is a temperature diagram illustrating the effect of adding a carbonate solution to a ceramic treatment fluid in accordance with features of the present invention;

FIG. 2 is a graph showing the compressive strength of a representative waste object in accordance with features of the present invention;

FIG. 3 is a graph illustrating the porosity of a representative ceramic body according to features of the present invention; and

FIG. 4 is a schematic representation of a method for producing a structure from a ceramic binder and a benign material according to a feature of the present invention.

Description

The present application provides a method of using ceramic materials to encapsulate waste materials for safe handling and production of structural products containing the waste materials. First, a waste encapsulation method for a safety disposal process is explained:

encapsulation treatment

The encapsulation process disclosed herein provides two methods to chemically control the reaction temperature during ceramic formation. Both methods are used to form large end-use waste from various waste streams containing fly ash, cement, silica, bayer process waste (red mud), electrolysis waste, pyrophoric materials, salt mixtures, volatile materials such as mercury, lead,cadmium, chromium and nickel, and unstable compounds that cannot be treated by conventional high temperature techniques such as vitrification. The present invention may also be used to stabilize secondary waste streams generated by thermal processing processes, such as vitrification and plasma furnace processes. Radioactive materials, such as those containing uranium, plutonium, thorium, americium, fission products, and any other radioactive isotopes, may also be stabilized using the present method. Radiated lead, hazardous metals, flue gas desulfurization waste residues may also be stabilized and/or encapsulated using the present method.

The present invention can also be used to stabilize certain RCRA organisms. The inventors have found that a portion of these organics do not inhibit the curing of the phosphate ceramic. In one aspect, organic matter such as naphthalene and dichlorobenzene are captured by activated carbon, which in turn is stabilized in a phosphate matrix by the method claimed herein. This stable process can be used in the case of mixed wastes where the mixed wastes contain trace organic matter, such as polychlorinated substituted biphenyls, dioxins, dichlorobenzene, naphthalene, etc. Thus, the process of the present invention is superior to encapsulation processes in which cement is employed, where the cement cannot be stabilized in the presence of organic matter.

The method can also be used to stabilize and solidify waste materials containing salts such as chlorides, nitrates, nitrites, sulfites and sulfates. Conventional cement technology cannot stabilize these waste streams.

The fly ash can be consolidated by the present process to 80% of its original volume. The inventors' experiments showed that there was good reaction and bonding between the amorphous reactive silica from the fly ash and the bottom ash containing the phosphate matrix. The formation of strong silicon-phosphorus bonds from this reaction can be used to stabilize hazardous silica compounds, such as asbestos. The present invention also encapsulates and stabilizes silica based filler aids, such as vermiculite and perlite, which are useful for removing contaminants from liquid waste streams.

Both temperature control methods produce a final body of super strength with a uniform high density and improved microstructure compared to typical methods of ceramic forming.

The outstanding feature of the low temperature ceramic waste forming process is an acid-base reaction, as described in equation 1 below. In general, the reaction produces a phosphate of MgO (magnesium phosphate):

reaction scheme 1

The acid-base reaction reacts the waste component with an acid or an acid phosphate. These reactants are capable of chemically stabilizing the waste material. In addition, the encapsulation of the waste in the phosphate ceramic formed from the reaction products allows the waste components to be physically encapsulated. The physical encapsulation of the waste is particularly noteworthy in terms of product strength when producing the structures (discussed above), and also imparts fire, chemical, moisture and weather resistance to the final body.

As mentioned above, a problem associated with the above discussed reaction sequence is the presence of a relatively low pH in the reaction liquid as a result of the presence of phosphoric acid. The low pH makes some waste unstable during encapsulation and the higher reaction temperature makes the final waste body very weak.

Two methods for reducing the exotherm of the acid-base reaction are disclosed below: method #1 phosphoric acid is pretreated with a carbonate, bicarbonate or hydroxide of a monovalent alkali metal to buffer the acid prior to mixing with the oxide or hydroxide. A representative reaction for Process #1 is illustrated in equation 2 below:

reaction formula 2

Wherein M is a monovalent alkali metal selected from potassium, sodium, lithium. The M 'oxide is an oxide powder, wherein M' is a metal selected from Mg, Al, Ca and Fe. As mentioned above, M' may also be a hydroxide thereof.

Method #2 discloses splitting the acid used and mixing the oxide powder with dihydrogen phosphate and forming the ceramic at a higher pH. Illustrating method #2 are the following equations 3-5:

reaction formula 3

Reaction formula 4

Detailed description of reaction 5 solid waste production

First, the solid waste may be treated by grinding the waste uniformly, preferably with a particle size of 8 to 10 micrometers (μm). However, the particle size may be in the range of about 4 microns to several millimeters.

The fly ash and cement waste may first be mixed with the starting oxide or hydroxide powder using a vibratory shaker or any conventional mixer. The weight percent of the mixture varies at its juncture, but can range from about 15% oxide to 50% oxide. Generally, an average weight percentage of oxide to solid waste (50: 50) may be sought. However, the inventors have succeeded in encapsulating and stabilizing single component fly ash in a ratio of up to 85% by weight fly ash to 15% by weight MgO powder, which makes this technique particularly attractive for use in landfill situations where single component fly ash is a major concern.

The mixture of the above powders was then added to a pretreated phosphoric acid solution (method #1) or to a dihydrogen phosphate solution (method #2) to form a reaction slurry. The slurry is mixed using a mixer for 10 to 30 minutes as it forms a viscous paste. The paste was poured into a mold and cured for several hours. Generally, no pressure is applied to the slurry being molded at once. The slurry achieved sufficient strength over a period of about 1 day.

The shape of the mold may vary depending on the shape of the final placement location and may be selected from a variety of geometries including cubic, pyramidal, spherical, planar, conical, trapezoidal, rectangular, and the like. Molds having the typical 55 gallon cylindrical shape and size are commonly used for waste disposal purposes. Details of liquid waste processing

The temperature regulated encapsulation process of the present invention provides a simpler route for the end user when dealing with liquid waste than conventional encapsulation processes. For example, acidic phosphate systems can be prepared by adding the phosphate in situ to a liquid, similar to the process employed in the cement industry. Thus, liquid waste materials, such as tritiated water, are easily and cost-effectively encapsulated using this process.

If only the liquid is encapsulated and stabilized, method #1 or method #2 may be employed. In method #1, the waste liquid is first combined with an acid to form a pH-modified solution. This modified solution is then mixed with the oxide powder. Optionally, a waste liquid may be added to the oxide powder to produce a slurry, which is then mixed with an acid.

In method #2, the liquid waste is mixed with a dihydrogen phosphate solution. Next, oxide powder is added. As mentioned above,an alternative method is to first mix the liquid waste with the oxide powder and add the dihydrogen salt solution.

The inventors have found that good results are obtained with a ratio of acid to water selected in the range of about 37: 63 to 50: 50. The ratio of acid to water is most preferably 50: 50. If the liquid waste contains more than the required amount of water, a relatively small amount of water is added to the acid so that the percentage of water in the liquid waste-acid mixture is as high as 50%.

Where a liquid-solid waste stream is included, the liquid portion of the waste stream has been prepared directly as described above. The resulting liquid waste-acid mixture is then mixed with a mixture of solid waste and oxide powder in a percentage range similar to that described above for solid waste processing. When a powder mixture containing MgO and dibasic basic phosphate is used, good results are produced with a weight percent oxide to phosphate selected from the range of about 87: 13 to 77: 23. Details of phosphate and oxide reactants

Several phosphate systems can be employed to stabilize the desired chemical, radioactive, and mixed waste streams. Some final phosphate ceramic bodies include, but are not limited to, phosphates of Mg, Mg-Na, Mg-K, Al, Zn, and Fe, and these metals can be prepared from raw oxide and hydroxide powders (e.g., method # 1). In method #2, the metal in the final phosphate ceramic body is prepared from the raw powder and dihydrogen phosphate. Typical dihydrogen phosphate salts for use in method #2 include, but are not limited to, potassium, sodium, and lithium phosphates. The acid component may be a concentrated or dilute phosphoric acid or phosphate solution, such as a dibasic or tribasic sodium or potassium or aluminium phosphate. The curing time of the paste formed by this reaction is from a few hours to a week. The phosphate had full strength after about three weeks.

The oxide powder may be pre-treated with an acid to make the reaction good. One technique involves firing the powder at a temperature of about 1200 to 1500 ℃, typically 1300 ℃. The inventors have found that the firing step can modify the surface of the oxide particles in a number of ways to facilitate ceramic formation. Firing to bind the particles together and form crystals; this reduces the reaction rate, promoting the formation of ceramics. The rapid reaction tends to form unwanted powder precipitates.

Another technique to improve the reaction is to wash the powder with dilute nitric acid followed by water.

A variety of oxide and hydroxide powders may be employed to produce ceramic systems including, but not limited to, MgO, Al (OH)₃、CaO、FeO、Fe₂O₃And Fe₃O₄。

MgO and Al (OH)₃The powder may be provided by industrial supply mechanisms such as Baxter scientific Products, McGaw Park, III inois.

The various iron oxides listed above may actually be added as part of a waste stream, such as that generated in connection with soil, and may also be added to low temperature oxidation systems that employ iron compounds to destroy organics. Method # 1-pH adjustment of acid solution

Unexpectedly, the inventors have found that when the acid is pretreated with a carbonate, bicarbonate or hydroxide of a monovalent metal (such as K, Na, Li and Rb) prior to the acid-base reaction, a reduction in the reaction temperature results. It was also unexpected that the inventors have found that the addition of alkali metal compounds containing potassium (e.g. K)₂CO₃) More crystalline waste is produced which is not affected by weather, pressure and leaching.

Further, as can be identified in FIGS. 1-3, a potassium-containing compound (e.g., K) is present in the pre-reaction mixture₂CO₃、KHCO₃And KOH), the more crystalline the final product. This high crystallinity is associated with higher pressure and reduced porosity.

Decomposition of carbonates to hydroxides with CO evolution in the pretreatment process₂. This causes the acid to be partially neutralized, which in turn reduces the reaction rate and the rate of heat release. Generally, the pH of the reaction slurry is raised from zero to about 0.4 to 1.

Thus, overheating of the slurry is avoided by the mechanism of pH adjustment. Secondly, as fully disclosed above, the use of potassium carbonate produces more crystals and therefore more stable phosphate complexes. Example 1

K₂CO₃Buffer solution

5, 10 and 15% by weight of potassium carbonate K₂CO₃Added to a 50 wt% dilute phosphoric acid solution. The resulting solution was allowed to equilibrate for several hours. During the equilibration process, the pH of the solution is respectivelyFrom near 0 to 0.4, 0.6 and 0.9. After equilibration, 100 grams of the solution was mixed with 50 grams of the oxide powder. Oxide powder with a ratio of calcined MgO and boric acid of 85 wt.% MgO to 15 wt.% boric acidAnd (4) reacting.

While adding the mixture of MgO and boric acid to the acid solution, the temperature of the slurry was measured at a phosphate concentration in the range of 0-10%. Fig. 1 depicts the temperature increase in each case. System A is wherein K is not added₂CO₃And (4) simulating. The maximum temperature reached by the system was 45 ℃ in a 50 ml volume of sample. For the composition from 5% and 10% K₂CO₃The temperature rise of the prepared systems B and C is respectively 8 ℃ and 2 ℃. When 15% by weight of K is added to the acid before the reaction₂CO₃There was no significant temperature increase.

X-ray diffraction analysis of the sample showed a change from 15% K₂CO₃The crystallinity of the prepared sample is high. From 5% and 10% by weight of K₂CO₃The samples made were more vitrified. As shown in Table 1, X-ray diffraction studies of the samples demonstrated a single mineral phase, which corresponded to the desired low solubility constant of the final product. This excellent end product, chemically bonded composite ceramic, is designated herein as MKHP.

Table 1: by adding K₂CO₃Mineral composition for preparing ceramics

Mineral phases	Chemical structural formula	By weight%
Mineral phases	Chemical structural formula	By weight%	Magnesium potassium phosphate Boron phosphorus magnesium stone Magnesium phosphorus stone The remaining magnesium oxide	MgKPO₄·6H₂O Mg₃B₂(PO₄)₂(OH)₆·6H₂O MgHPO₄·3H₂O MgO	52 24 14 10

Unexpectedly, the magnesium potassium phosphate (MPK) is prepared by adding only K₂CO₃New components in the resulting material. MPK represents a good phase of the waste body matrix with a dissolution constant of 10^-11It is 10 times the constant^-6The magnesium phosphorus stone is lower by 5 orders of magnitude. All phases shown in table 1 have very low solubility in groundwater, whereas borophosphomagnesite and magnesium phosphoite are natural minerals that are stable in groundwater environments.

The porous nature of the sample varies over a wide range. At K₂CO₃In the 5-and 10-wt% samples, the glass phase of the samples was much, while the amount of fracture was large and thus porous. By contrast, K₂CO₃The 15% sample had an open porosity of about 6.1%. Its density was 1.77g/cc and its closed porosity was 10.2 vol%. The compressive strength was approximately 3700 psi. Example 2

K₂CO₃Buffer solution + dust

The matrix material disclosed in example 1 was used in example 2. The starting powder composition was 70 wt% fly ash, 25.5 wt% calcined MgO, and 4.5 wt% boric acid. The solution used was 50% of K₂CO₃Buffered H₃PO₄. The solution is poured into a mixer, such as a cement mixer, and the powder is slowly added until the powder mixes with the solution for about 48 minutes. 1000 ml of a cylindrical sample was prepared.

The maximum temperature during mixing and curing is about 50 ℃ to 60 ℃. These temperatures are even with less weight percent of K₂CO₃And will not rise. For example, when 10 wt.% K is used₂CO₃When this is done, the maximum temperature obtained is 56-58 ℃ even at higher volumes (1200 ml).

The inventors have found that if K is not present₂CO₃In the final product, where magnesium phosphate is the predominant crystalline phase in the material, the concentration of MgO is high.

Data for compressive strength and porosity for the material prepared in example 2 are presented in figures 2 and 3. These figures show that when K₂CO₃When the content is increased, the strength is increased and the porosity is decreased. When K is in solution₂CO₃At 15% by weight, the compressive strength was 8750psi (which is twice that of portland cement), while the porosity was reduced by 7.5%. Example 3

Sodium carbonate

5, 10 and 15 wt% sodium carbonate (Na)₂CO₃) Added to a dilute solution of 50 wt.% phosphoric acid and the resulting solution allowed to equilibrate for several hours. The pH of the solution increased from zero to about 2.3 in this step. 100 grams of this solution was reacted with 30 grams of a mixture of calcined MgO and boric acid (85% MgO and 15% boric acid) and 70 grams of fly ash.

Determination of 5 wt.% Na₂CO₃The nature of the sample. The density was 1.7g/cc and the open porosity was 8.6 vol%. Analysis of the microstructure of the sample showed that the sample was essentially glassy except for the airborne particles. This method shows that all glassy phase materials can be prepared by the above method. Example 4

Hazardous material + MKHP

Two differentwaste streams of hazardous materials are processed. With 0.5% by weight of Ce added as oxide³⁺And Ce⁴⁺As U³⁺、⁴⁺And Pu³⁺、⁴⁺To strengthen iron oxideIron chloride waste stream (95 wt.% Fe)₂O₃+ 5% by weight of FeCl₃). Then added as oxidation0.5% by weight of Ce added⁴⁺As U⁴⁺And Pu⁴⁺A substitute for (1).

The second waste stream was an iron phosphate waste stream (FePO) fortified with Pb 0.5 wt% representing a hazardous component added as soluble nitrate₄)。

Both waste streams were stabilized by the carbonate modification process of process # 1. Ce³⁺、Ce⁴⁺And Pb contents of 8.7ppm,<0.09ppm, and<0.2ppm, respectively. When the regulatory limit for Pb up to 5ppm is scheduled to be regulated down to 0.37ppm, the results show that the encapsulation step of the present invention provides an acceptable control method.

Process # 2-dihydrogen phosphate

Instead of adding carbonate to the reactants to lower the reaction temperature, the inventors devised a simple process to achieve the same result. This 2 nd method is to react the monobasic phosphate of potassium, sodium, lithium or any other monovalent alkali metal with an oxide to produce a phosphate ceramic. This method forms ceramics at higher pH while reducing heat generation. A representative ceramic formed by this method is magnesium potassium phosphate hexahydrate (MKP), which is generated by the reaction mechanism of the above reaction formula 5.

The inventors have found that to avoid the presence of acid in the initial reaction slurry, the initial pH is about 6.2. With dissolving KH₂PO₄The situation is consistent with an exothermic process and the inventors have found that the temperature of the slurry is slightly reduced during initial mixing. However, as the MgO dissolution and reaction proceeds, the temperature of the slurry rises to about 30 ℃. Example 5

Preparation of MKP ceramics

Mixing 1 mole of calcined and ground MgO with 1 mole of ground potassium dihydrogen phosphate (KH)₂PO₄) And mixing the crystals. The mixture was slowly added to 5 moles of water to form a paste. When the paste was mixed well, it was poured into a cylindrical mold having a diameter of 1 cm and a volume of 20 ml. After about 1 hourA hard ceramic body is obtained.

X-ray diffraction analysis showed that all major peaks were MKP. It should be noted that there is no peak of monopotassium phosphate indicating that it has all reacted.

The open porosity determined by the water flooding method was 2.87 vol%. The density was 1.73 g/cc. The theoretical density is given as 1.88g/cc and the total porosity is calculated as 8.19 vol%. Thus, the closed porosity (i.e., pores that are inaccessible from the outside of the sample) is 5.33 g/cc. These values indicate that the MKP is more dense than the magnesium phosphate ceramic with a total porosity of about 30%. Example 6

MKP + dust

The MKP ceramic synthesized in example 5 was used to prepare a dust-laden waste object. Samples were prepared using three different powders, which were calcined MgO and KH₂PO₄Mixtures in molar ratios of 1: 1, 1.5: 1 and 2: 1. These powders and fly ash were mixed in equal proportions using a storage tank and a feeder. The final mixture of powders was mixed with 5 moles of water at a slow but constant rate in a cement mixer to form a slurry.

The slurry was poured into 1.5 gallon and 1 liter moulds. The final mixture of powders was made by stirring the powders in water and using a 20 ml cylindrical die with a diameter of 1 cm. All samples cured after about 1 hour and hardened completely after one week.

Unlike the starting materials described in examples 1 and 2, the temperature of the slurry did not increase during mixing and curing. This solves the problem of evaporation of contaminants due to heat generated during the mixing step in the prior art. The inventors have found that the temperature of the slurry prior to curing generally does not exceed 30 ℃. Thus, neither water nor waste components generate volatiles. Once the slurry begins to cure, the temperature rises. However, the highest temperature (about 75 ℃) is reached when the sample solidifies into a rigid whole and therefore does not contribute to the size of the final waste object. Furthermore, the inventors have found that the temperature increase is not proportional to the size of the material, but actually decreases as the size of the material decreases. This facilitates the encapsulation of 55 gallon size target waste.

The method of the present invention uses MKP to produce a superior final ceramic body. The open porosity value of the waste object was about 4.18 vol%. The measured density was 1.8 g/cc. The predicted theoretical density given is 2.05g/cc and the total porosity is 8.9 vol%, which is much lower than the values for the prior art magnesium phosphate ceramics. The closed porosity was calculated to be 4.72 vol%. The compressive strength of the sample was 6734psi, which is 50% stronger than Portland cement concrete. Example 7

Boric acid + MKP + dust

A sample of the dust-laden waste object was prepared using an MKP matrix and a calcined MgO powder to which 0-5 wt% boric acid was added. The addition of boric acid retards the rise in temperature of the reaction slurry. Thus, the addition of boric acid facilitates largescale processing of the waste stream, which requires more time to mix and pour into the slurry. Example 8

CaCO₃Stabilization

As mentioned above, CaCO₃Decomposing in low pH environment. As a result, carbon dioxide can be emitted from the reaction slurry if the waste stream contains the compound. The gas evolved makes the solidified product porous and therefore permeable to groundwater. The strength is also affected.

Producing a cement slurry, i.e., a cement-containing waste stream. The composition of the waste stream is listed in table 2 below:

table 2: composition of cement waste stream

Composition of	Weight percent of
Composition of	Weight percent of	Activated carbon Floating dust Water (W) Concrete and its production method Plaster of paris Hematite Fe₂O₃ Alumina oxide Perlite	10 10 10 50 10 3 3 1.5

Samples were prepared by two methods. In the first method, H is used₃PO₄A slurry is formed as the reaction acid and a waste stream containing about 30% by volume of waste material is produced. During the first method, the slurry produces fine CO₂Air bubbles, which make the sample porous.

When the samples were used as disclosed in examples 5 and 6 above, KH was used₂PO₄MKP process as an acid phosphate, free of CO₂And (4) generating. The comparison of sample values is shown in Table 3 below.

Table 3 shows that the waste body produced by the MPK process is more dense and contains a relatively small amount of open voids, thus illustrating that the process of the present invention is superior to processes employing large amounts of acid.

Table 3: physical properties of chemically bonded waste objects

Parameter(s)	H₃PO₄Stability of	KH₂PO₄
Parameter(s)	H₃PO₄Stability of	KH₂PO₄	pH of acid solution Open porosity (volume percent) Density of	0.2 28～33 1.2～1.3	4 6.2 1.77

Example 9

Red mud + MKP

Refining bauxite to produce alumina produces a large amount of residue, known as red mud. Red mud consists of approximately 50% by weight of inorganic oxides, other compounds and hazardous metals. A large amount of red mud is produced each year.

When combined with the phosphate ceramic binder of the present invention, a large volume of red mud is easily stabilized. If a reactant slurry containing red mud is poured as a barrier, it not only binds to the matrix soil, but also penetrates into the cracks in the soil and quickly hardens to form a non-porous ceramic layer. For example, red mud ceramics prepared by the process of the present invention have low porosity (. apprxeq.2 vol%) and high compressive strength (4944 psi). Such materials have low porosity and high durability under acidic and alkaline conditions, thus making them ideal for mining, pool liners, brick wall liners, lagoon liners, and fast setting grouts.

A variety of red mud waste materials can be used to produce the final structure. The red mud waste materials used by the inventors were produced from gibbsite bauxite. It is basically dry soil collected from around the red mud waste pond. Its content is about 50 wt% iron oxide (Fe)₂O₃) Alumina (Al) of 16.5 wt%₂O₃) About 3 wt% Silica (SiO)₂) Calcium oxide (CaO) 5.7 wt%, and titanium oxide (TiO 6.8 wt%)₂) X-ray diffraction analysis showed hematite (α -Fe)₂O₃) Goethite (α-FeOOH), calcium carbonate (CaCO)₃) Boehmite (gamma-AlOOH), anatase (TiO)₂) And bayerite (β -AlOOH) are the major crystalline phases the inventors have unexpectedly learned that the hydrated phases, boehmite, bayerite, and goethite, favor the formation of phosphate bonds during the binding step.

The amorphous character of the alumina and silica components of red mud discussed above plays a major role in ceramic bonding. The inventors have found that smaller particles of amorphous material are characterized by being susceptible to acid-base reactions and thus favouring the curing reaction during ceramic formation.

As noted above, MgO forms magnesium phosphate to participate in the exothermic reaction when reacted with phosphoric acid and the acid phosphate solution. The reaction can be controlled by using calcined MgO and by adjusting the rate of addition of the solid phase (i.e. red mud powder + oxide + boric acid) to the solution.

In one embodiment, the calcined MgO is first mixed with red mud powder in the specific weight percentages listed in Table 4. The crushed dried red mud is an ultra-fine material having more than 60% by weight of particles smaller than 10 mm. Particle sizes in the range of 1 to 5 mm have good results so grinding of the red mud is generally not required before combining with MgO.

The dry mixture is then reacted with phosphoric acid or acid phosphate by continuous stirring. This produces a low viscosity paste which thickens as the reaction proceeds. The paste was then poured into a cylindrical mold having a diameter of 1.9 cm. After about 15 minutes a dense ceramic body is formed which takes 2 to 24 hours to fully harden. Samples were stored for three weeks prior to the experiment.

FIG. 4: physical properties of red mud ceramic bodies

Content of waste (wt%)	Maximum particle size (millimeter)	Density of (g/cm³)	Open porosity (％)	Compressive strength (psi)
Content of waste (wt%)	Maximum particle size (millimeter)	Density of (g/cm³)	Open porosity (％)	Compressive strength (psi)	40 40 50 50	5 1 5 5	2.19 2.1 2.26 2.29	0.82 1.09 2.98 1.94	4944 4294 2698 2310

The density was determined by weighing the sample and determining the size and volume. Open porosity was determined by water immersion in which a pre-weighed sample was immersed in water at 70 ℃ for 2 hours. The sample was then cooled in water and removed from the water. Excess water was removed from the surface of the sample and the sample was weighed again to determine the amount of water filling the opening. Higher weights (compared to the pre-impregnated weight) create open pores in the sample, so open porosity can be calculated.

Using Instron for compression mode^TMThe equipment measures the compressive strength.

The waste content of the sample is 40-55 wt%. By way of example, a scrap content of 40% by weight means that the 40 g sample is red mud, 60 g is water and binder. The density of the sample containing red mud was slightly higher than that of the pure matrix (binder) material, which was 1.73gm/cm³. The density of the red mud is about 3.3g/cm³。

As shown in table 2, the open porosity of the samples containing red mud is low compared to the value of ≈ 20 wt% of cement. In addition, the compressive strength of the sample containing 40% by weight is higher than 4000psi for Portland cement concrete.

Scanning Electron Micrograph (SEM) and energy dispersive X-ray (EDX) analysis of the fractured red mud sample revealed a glass region and a particle region. These regions all bond well. The glass phase breaks when the particulate phase shows only fragments emanating from the glass phase. The elemental composition of each phase is provided in table 5 below. The values contained therein are the average of three values determined at three different points of each phase.

The particles are advantageous over red mud, and the glassy phase is the phosphate matrix. As mentioned above, the particulate phase is found to be rich in red mud elements, such as Fe and Al, while the glass phase is rich in magnesium phosphate elements, such as Mg and P.

Table 5: elemental distribution of glass phase and particle phase of red mud ceramics

Phase (C)	Element(s)
Phase (C)	Element(s)					Glass phase Particulate phase	Fe 5.78 23.66	Al 4.7 18.6	Mg 23.53 5.3	P 34.23 16.2	Others 31.76 36.2

The large amount of phosphate and a portion of the magnesium in the particulate phase indicate that the phosphate bonds here have Fe and Al as cations.

The relatively small disruption in the particulate phase (red mud) portion of the sample indicates that the strength of the material of the present invention is due to the presence of this phase. Increasing the strength of the ceramic requires either a reduction in the amount of glass phase or a reinforcement of the glass phase with the particles. One method of enhancement is to add a finer red mud to the starting powder to facilitate more consistent distribution and better particle strengthening. Grinding red mud prior to mixing with oxide powder is one method of obtaining such finer red mud materials.

Structured product encapsulated by a loose matrix

Unlike previous attempts to produce stable structural materials from bulk materials, the present method produces an amorphous, more flowable substance by using a low volume percentage of binder to produce the final body. The resulting ceramic formulation is sufficiently amorphous and has low crystallinity to ensure good flowability and extended working time of the material. Encapsulation of the waste particles by the use of a binder is easier to perform during the formation of the final slurry, making the amorphous phase very similar to the polymer formulation.

Many of the details disclosed above in connection with solid and liquid waste preparation for waste deposition processes are applicable to the preparation of structural products from non-benign waste. In summary, waste materials that may be used in the production of structural components include, but are not limited to, dust, electrolytic waste, wood, plastic, rubber, cellulose, textiles (e.g., carpet chips), polystyrene foam, and mixtures thereof. Products made by the methods of structural component preparation include blown insulators, particle board, packaging materials, bricks, tiles, wall materials, and engineered partitions and shielding systems.

A general embodiment of the process of the present invention is indicated by reference numeral 10 in figure 3. First, the oxide 12 is added in one or both of the calcination pretreatment step 14 and the boric acid addition step 16. These two steps serve to slow down the reaction process.

The resulting dried mixture 18 is then reacted with about 50-60 wt% diluted phosphoric acid 20 to form an acidic solution or binder 22. To promote flowability of the resulting solution, a weight percentage of 55 wt% or less is preferred, for example 55 grams of dry mixture to 45 grams of diluted 50 wt% phosphoric acid. Concentrated acids tend to make the reaction more vigorous. This results in a thick slurry that is not conducive to encapsulating the particles.

The waste particles 24 that may be subjected to the pre-treatment screening step 23 are then thoroughly mixed with a binder. The mixing step 26 may ensure that the waste particles are completely encapsulated or coated by the binder.

The resulting slurry is pressed into the desired shape 28 either without pressure or at low pressure (about 1,000 psi), depending on the waste material being bonded. For example, processes that encapsulate wood waste typically require pressurization, primarily because the wood surface is not significantly involved in the ceramic forming reaction. In this case, the binding force is mainly from the phosphoric acid phase encapsulating the wood particles. When high water content waste materials such as slurries and benign waste materials are used to produce structural products, a concomitant change in the acid to water ratio is required.

The inventors of the present invention have found that the added volume of waste material in the final product can vary from about 50 to 90% by volume by weight. For use in insulation and building reinforcements, the composition of the mixture is adjusted to change it to a pumped slurry (50% by volume of waste) or a blown particulate mixture (80-90% by volume of waste) to help fill the gap.

The slurry comprising the above-mentioned benign waste is pressed into a desired shape. The acid-base reaction between the oxide and phosphoric acid results in the formation of phosphate on the surface of the particles so that a thin coating of phosphate binder, which is water repellent, encapsulates the individual particles. This results in the formation of a structural product in which the waste particles are protected by the binder to provide strength to the product and also to provide the ability to resist fire, chemical attack, moisture and other weather conditions.

Some advantages of the resulting embodiments are adhesives based on commercially available polymers. Unlike polymeric binders, phosphoric acid binders are non-flammable. Also, some polymer components are often explosive, while inorganic phosphate binders are safe in comparison. During the preparation of phosphate bonded products, non-toxic chemicals or vapors are released. Finally, phosphate-based binders improve the hardness and long-term stability of the structural product compared to conventionally used organic binders. Detailed description of the boric acid/oxide preparation Process

In general, boric acid is added when it is desired to carry out the reaction slowly, for example when it is desired to prolong the processability of the material. The inventors of the present invention have found that boric acid forms a glassy phase coating the oxide particles so that the oxide cannot react immediately with phosphoric acid.

A wide variety of oxides, such as those listed above, may be used in the process of the present invention. Other oxides, e.g. Fe₃O₄、Zr(OH)₄ZrO, TiO₂Are also suitable. Zr (OH) is available from Atomeric Chemicals Corporation, Farmingdale, NY₄。

The mixing of the oxide with boric acid is strictly controlled to maintain the resulting dry mixture components at an optimum weight%. The wt% may be selected in the range of about 5 wt% boric acid/oxide to 25 wt% boric acid/oxide. The preferred wt% is 10 wt% boric acid/oxide, e.g., 10 grams boric acid per 90 grams oxide, to form a dry mixture.

In general, the rate of addition of the powder to the acid solution should be such that the temperature of the reaction solution is maintained below 100 ℃. The time required for controlled mixing is generally from 30 minutes to 1 hour. If the heat from the exothermic reaction (associated with the above process) is dissipated by cooling the reaction vessel, the mixing time can be reduced. The inventors of the present invention have found that when the resulting oxide powder-solid waste mixture contains less than 50% by weight of waste, it is more desirable to cool the reaction vessel. Example 10

Foamed polystyrene insulating material

The inventors of the present invention have found that polystyrene particles can be completely coated with a thin layer of a water-resistant phosphate binder phase using themethod disclosed above. The uniform coating of the styrofoam particles may not only provide structural stability but may also impart fire, chemical, moisture and other weather resistance. These characteristics are all superior to more specific insulating substances, as shown in table 1.

The resulting adhesive-covered expanded polystyrene material provided excellent R values, as described in table 6. For example, thermal conductivity measurements, using a modified radiant heat wire testing technique (developed by ant laboratories, Pittsburgh, PA), indicated that the thermal resistance of the material prepared by the method of the present invention was about 4.5h.ft.^2°F/BTU (fiber glass is 2-3 h.ft.^2°F/BTU and cellulose were 3.5h.ft.^2°F/BTU). The excellent R value indicates that the phosphate ceramic binder coated styrofoam can save more energy when used as an insulation product.

Insulation products are generally prone to moisture and tend to sag, loosening their structural integrity over a period of time. The aging test of the material of the present invention was performed according to ASTM D2126(ASTM = american society for testing and materials), according to which the material was exposed to a harsh environment for a period of time while closely monitoring the dimensional changes of the material. The material was exposed to a temperature of 38 ℃ and a humidity of 98% by weight for 3 weeks. The change in volume of the test body after two weeks was about 2% by weight. This is better than 20% by weight of the cellulosic insulation, and also better than the values observed in the fiberglass mass.

Table 6: ceramic bonded styrofoam insulation with fiberglass and

comparison of cellulosic insulation

Is mainly characterized in that	Bonded poly Styrene foam	Fiber glass	Cellulose, process for producing the same, and process for producing the same
Is mainly characterized in that	Bonded poly Styrene foam	Fiber glass		Density (lb/ft)³)	2.0	0.4-1.0	2-3.5
R value (thickness 1 inch)	4.5	2-3	3-3.5	Density (lb/ft)³)	2.0	0.4-1.0	2-3.5
R value (thickness 1 inch)	4.5	2-3	3-3.5	Fire resistance	Non-combustible	Non-combustible	Non-combustible
Water absorption	Less than 4% by weight	1-2％	5-20％	Fire resistance	Non-combustible	Non-combustible	Non-combustible
Water absorption	Less than 4% by weight	1-2％	5-20％	Dimensional stability	≈2％	Sedimentation was observed	≈20％
Harmfulness to health	Lowest level of	Height of	Lowest level of	Dimensional stability	≈2％	Sedimentation was observed	≈20％
Harmfulness to health	Lowest level of	Height of	Lowest level of	Cost of materials	Low/blowing or pumping	Height of	Is low in

In general, a wide range of waste particle sizes can be used when preparing structured products using the process of the present invention. When polystyrene foam is used, particle sizes of 2 mm to 5 mm are used and the best results are obtained when the particles and binder are mixed in a weight ratio of 1: 2. The optimum amount of polystyrene foam added to the final product is about 7.5% by weight, which corresponds to about 85-90% by weight of the volume percent of the final product. Example 11

Wood waste

The inventors of the present invention have found that when the method of the present invention is carried out using wood waste, a particle board having a value of excellent flexural strength can be prepared. For example, a sample containing 50 wt% wood and 50 wt% adhesive exhibits a flexural strength of about 1,500 psi. The samples containing 60 and 70 wt% wood exhibited flexural strengths of 400 and 300psi, respectively.

Generally, the size of the wood particles of suitable size is 1 to 5 mm long, 1 mm thick and 2 to 3 mm wide.

Further, once the wood and adhesive are thoroughly mixed, the test specimens are pressed to shape on the order of about 2650psi for about 30 to 90 minutes.

The above examples are not intended to limit the disclosed methods. Likewise, other non-gaseous streams may also be substantially stabilized using the same process, in addition to the various waste materials listed above as being useful in the encapsulation process employed. For example, electrolysis cell residues, bayer sand, ash produced at the site of a plant and any other mining waste residues can be stabilized by the process and used as structural components. When the cell residue was mixed with magnesium phosphate hexahydrate at a 50: 50 weight ratio, a ceramic body was formed having a density of 2.9 grams per cubic meter, a porosity of 2.17% and a compressive strength of 4.210psi, the latter comparable to portland cement products. According to the data disclosed above, when a higher proportion (60% by weight) of the scrap, in this case the residue of the electrolyzer, is used, values are obtained which are slightly lower than those obtained when 50% by weight are used. The density was reduced to 2.0 g/cc, the porosity increased to 2.6 wt% and the compressive strength reduced to 3,402 psi.

Although the present invention has been described with reference to the details of the illustrated embodiments, these details are not intended to limit the scope of the invention, as defined in the appended claims.

For example, method #2 due to the waste encapsulation method uses KH₂PO₄And due to KH₂PO₄Containing conventional fertiliser constituents, i.e. potash (K)₂O) and phosphorus (P)₂O₅) Therefore, method #2 can be used to produce high potash and high phosphate fertilizer fertilizers to stabilize contaminated soils.

Also, given that red mud contains high concentrations of oxides, red mud can be mixed with MKP to produce a stable waste form, otherwise produced using method # 2. This improvement may eliminate the need to feed and pre-treat oxides such as MgO during red mud stabilization.

Finally, a hybrid structure product and method for producing a hybrid structure product is produced by combining the potassium-containing phosphate disclosed in the Wate-Encapsulation Detail DESCRIPTION of the DETAILED DESCRIPTION with the phosphate used in "Structure; a representative loose waste material of Products via Bulk substrate encapsulation section is obtained. As noted above, the inventors have unexpectedly found that potassium-containing phosphates provide highly crystalline, which are more resistant to breakage than other phosphates which are more vitrified and broken. Products produced by the interdigitation process include, but are not limited to, blown insulation, particle board, packaging materials, bricks, tiles, wall materials, and engineered barriers and concealment systems.

Claims

1. A method for adjusting a reaction temperature during ceramic formation, comprising:

a.) providing a solution comprising a monovalent alkali metal;

b.) mixing said solution with an oxide powder to form a binder;

c) contacting said binder with the bulk material to form a slurry; and

d.) curing the slurry.

2. The method of claim 1 wherein the monovalent alkali metal containing solution further comprises phosphoric acid and a compound selected from the group consisting of M-carbonate, M-bicarbonate, M-hydroxide, and mixtures thereof, wherein M is a monovalent alkali metal.

3. The method of claim 2, wherein the weight percent of said compound to phosphoric acid is selected from the group consisting of about 5: 95 to about 15: 85.

4. The method of claim 1, wherein the monovalent alkali metal is selected from the group consisting of lithium, sodium, potassium, and combinations thereof.

5. The method of claim 1, wherein the oxide is selected from the group consisting of calcined MgO, mixed with calcined MgO, Mg (OH)₂、Al(OH)₃、FeO、Fe₂O₃、Fe₃O₄CaO crushed dibasic sodium phosphate crystals, or a combination thereof.

6. The method of claim 1, wherein the binder and the bulk material are combined in an amount that the predetermined weight percentage of oxide powder to bulk material is between about 15: 85 and 50: 50.

7. The method of claim 1, wherein the monovalent alkali metal containing solution is dihydrogen phosphate.

8. The method of claim 7, wherein the dihydrogen phosphate is mixed with the oxide powder in a molar ratio of about 1: 1 to 2.5: 1.

9. The method of claim 1, wherein the monovalent alkali metal is selected from the group consisting of Li, Na, and K.

10. The method of claim 1, wherein the bulk material is ground into particles having a diameter of about 4 microns to about 75 microns.

11. The method of claim 2, wherein the phosphoric acid is a 10 wt% to 50 wt% diluted solution.

12. The method of claim 1, wherein the bulk material is selected from the group consisting of fly ash, cement, silica, red mud, electrolytic waste, radioisotopes, irradiated lead, hazardous metals, flue gas desulfurization residue, and mixtures thereof.

13. A crystalline ceramic waste containing

a.) a potassium-containing ceramic binder; and

b.) waste material chemically stabilized and encapsulated by the binder.

14. The ceramic waste object of claim 13 wherein the binder comprises a binder comprising magnesium potassium phosphate,

Chemical compositions of borophosphomagnesite, magnesium phosphomagnesite, and magnesium oxide.

15. The ceramic waste object of claim 13 wherein the particles of the waste material range from 5 microns to 5 millimeters.

16. The ceramic waste object of claim 13 wherein the weight percentage of the waste matrix in the waste object is from 10 wt% to 85 wt%.

17. The ceramic waste object of claim 13 wherein the waste matrix is selected from the group consisting of fly ash, cement, silica, red mud, electrolytic waste, radioisotopes, irradiated lead, hazardous metals, flue gas desulfurization residue, and mixtures thereof.

18. A method of stabilizing and encapsulating red mud comprising:

a.) providing red mud having a predetermined structure;

b.) mixing red mud with a solution containing a monovalent alkali metal to form a slurry; and

c.) curing the slurry.

19. The method of claim 18 wherein the monovalent alkali metal containing solution further comprises phosphoric acid and a compound selected from the group consisting of M-carbonate, M-bicarbonate, M-hydroxide, and mixtures thereof, wherein M is a monovalent alkali metal.

20. The method of claim 18 wherein the monovalent alkali metal containing solution is dihydrogen phosphate.

21. A method of making a structural product from benign waste material comprising:

a.) preparing an inorganic oxide;

b.) contacting the prepared inorganic oxide with phosphoric acid to produce an acidic solution;

c.) mixing the acidic solution with waste particles to produce a slurry; and

d.) curing the slurry.

22. The method of claim 21, wherein the inorganic oxide is selected from the group consisting of MgO, mixed with MgO, Al (OH)₃、Zr(OH)₄Crushed crystals of dibasic sodium phosphate of CaO, iron oxide, and combinations thereof.

23. The method of claim 21, wherein the step of preparing the inorganic oxide further comprises calcining the oxide.

24. The method of claim 21, wherein the step of preparing the inorganic oxide further comprises calcining the oxide and mixing the calcined oxide with boric acid to form a mixture having a weight ratio of oxide to boric acid of from about 5: 95 to about 15: 85.

25. The method of claim 24, wherein the mixture is mixed with phosphoric acid in a weight ratio of the mixture to phosphoric acid of about 50: 50 to 60: 40 to form the acidic solution.

26. The method of claim 24, wherein the mixture is mixed with phosphoric acid in a weight ratio of the mixture to phosphoric acid of about 55: 45 to form the acidic solution.

27. The method of claim 21, wherein the acidic solution is present in the slurry in a weight ratio to the waste particles in the slurry of from about 2.5: 97.5 to 15: 85.

28. The method of claim 21, wherein the acidic solution in the slurry is present in a weight ratio to the waste particles in the slurry of about 15: 85.

29. A construction material comprising:

a.) waste particles; and

b.) an inorganic binder encapsulating the waste particles.

30. The construction material of claim 29 wherein the scrap particles have a particle size of about 4 to 75 microns.

31. The construction material of claim 29 wherein the waste particles are a bulk material selected from the group consisting of fly ash, electrolytic waste, wood, plastic, rubber, cellulose, textile, polystyrene foam, and mixtures thereof.

32. The construction material of claim 29 wherein the inorganic binder is a phosphate ceramic.

33. The construction material of claim 32 wherein the phosphate ceramic further comprises an element selected from the group consisting of magnesium, sodium, aluminum, zirconium, and mixtures thereof.

34. A construction material according to claim 32 wherein the phosphate ceramic is magnesium phosphate hexahydrate.

35. The construction material of claim 29 wherein the waste material comprises about 80 to 90 volume percent of the material.

36. The construction material of claim 29 wherein the binder is present in an amount of from 2.5% to 15% by weight of the binder to the scrap material.

37. A non-combustible structural material comprising

a.) polystyrene foam particles; and

b.) an inorganic binder encapsulating the polystyrene foam.

38. The construction material of claim 37 wherein the particle size ranges between about 2 mm and 5 mm.

39. The construction material of claim 37 wherein the polystyrene foam is present in an amount of about 7.5% by weight of the construction material and 80 to 90% by volume of the construction material.

40. The structural material of claim 37, wherein the structural material is an insulator having a thickness of 1 "and an R value greater than 4.

41. A structural product comprising:

a.) a potassium-containing ceramic binder; and

b.) waste materials that are chemically stable and encapsulated with the binder.

42. The structured product of claim 41, wherein the binder has a chemical composition selected from the group consisting of potassium magnesium phosphate, borophosphomagnesite, magnesium phospholite, and magnesium oxide.

43. The structured product of claim 41, wherein the scrap material has a particle size in the range of between about 4 microns and 5 millimeters.

44. The structural product of claim 41, wherein the weight percentage of scrap material in the structure is approximately 10% and 85% by weight.

45. The structural product of claim 41, wherein the waste material is a bulk material selected from the group consisting of fly ash, electrolytic waste, wood, plastic, rubber, cellulose, textiles, polystyrene foam, and mixtures thereof.