WO1991015427A1

WO1991015427A1 - Process for converting bayer sodalite into zeolite of type a

Info

Publication number: WO1991015427A1
Application number: PCT/CA1991/000104
Authority: WO
Inventors: George Dennison Fulford; Bettina Louise Longino; Paul Michael Simmons; Prasad Shrikrishna APTÉ
Original assignee: Alcan International Limited
Priority date: 1990-03-30
Filing date: 1991-04-02
Publication date: 1991-10-17
Also published as: AU7576491A

Abstract

This invention provides an improved process for converting sodium aluminosilicate such as may be obtained from byproducts the Bayer process, into a Zeolite of Type A. The process comprises dissolving the aluminosilicate in a dilute acid such as dilute sulfurous hydrochloric, nitric, or sulfuric acid. After filtering the Bayer sodalite solution, aqueous base is added until the pH exceeds 12 and a Zeolite precursor gel is formed. The resulting Zeolite precursor gel is aged for 3 to 20 hours at a temperature of between about 70° and about 90 °C to form a Zeolite of Type A. Zeolites made in accordance with the present invention may be used as building agents for detergents, molecular sieves, desiccants and ion exchange media.

Description

PROCESS FOR CONVERTING BAYER SODALITE INTO ZEOLITE OF TYPE A

BACKGROUND OF THE INVENTION

5 1. Field of the Invention

This invention relates to a process for converting sodium aluminosilicates, particularly the Bayer process desilication product known as Bayer sodalite, such as ■JO produced as a waste product of the Bayer process for extraction of aluminum from Bauxite, into a Zeolite of Type A.

2. Description of the Prior Art

15

Red mud is a leaching residue from the Bayer process for producing alumina from Bauxite, and is so named because of the red/brown color caused by its iron oxide content. According to a paper by Gerhardt Haake entitled "Red Mud — 0 a Waste or a Valuable By-Product?" appearing in Neue Hutte. Vol. 33, pp. 424-429 (November 1988), the amount of red mud resulting from aluminum production is estimated to be 30-35 million tons annually. At present, most of the red mud is impounded in mud lakes or lagoons. 5

This, however, is not an ideal solution to the problem of disposal of red mud. Mud lakes require a significant amount of land because the solids settle at a very slow rate. It is not unusual to have a mud lake of several hundred acres associated with each Bayer process 0 plant site, and the mud lake must be carefully maintained to minimize the chance of contamination of nearby water sources. Even with careful maintenance, increasing pressure from environmental agencies and groups together with increasingly scarce land resources have created a need to 5 find uses for red mud or its constituents in order to minimize the amount of red mud which must be disposed in lagoons or ponds.

Accordingly, attempts have been made to find uses for red mud and to convert red mud into as many useful products as possible. Processes are known for increasing the specific gravity of red mud solids in order to enable use of the products as weighting agents in drilling slurries or fluids or as the solid phase of a slurry used to seal crevices and fissures exposed by drilling and excavation.

Japanese patent disclosure (Kokai No. 63-286,526) reports on attempts to use red mud generated as a by-product of the Bayer process to prepare a Zeolite of Type A. According to the example contained in that disclosure, sodalite from red mud can be converted into Zeolite of Type A by sintering refinery red mud in air at 800°C and then immersing the sintered product in an aqueous solution of hydrochloric acid in water (1:1), which is heated on a sand bath to dissolve iron oxide and other impurities. The Zeolite particles may be collected by filtering the liquid, and then rinsing and drying the filtrate.

Of course, other investigators have attempted to improve methods for making Zeolites, and to convert various starting materials into Zeolites. For example, a Japanese patent (laid open no. 81200/1979) discusses methods of manufacturing Zeolites by reacting a silicon source such as water soluble silicates, colloidal silica, pulverized silica or natural/synthetic aluminosilicates such as clays with one or more organic acids such as oxalic, formic, acetic or humic acids. Methods for preparing Zeolite by hydrother al treatment of clinoptilolite are disclosed in U.S. Patent Nos. 4,401,634 and 4,427,524, while U.S. Patent No. 4,271,130 enumerates a process for the production of Zeolite A from kaolin.

Previous efforts to convert sodium aluminosilicates, such as Bayer sodalite, usually denoted as 3 (Na_jO.Al_jO_j.SiO_g^H_jO) .Na₂X, where X usually represents C0₃=or S04*=but may also represent 2 OH-2A10₂- etc., into Zeolite A have involved the use of high temperatures or expensive mineral or organic acids.

SUMMARY OF THE INVENTION

The principal object of the present invention, therefore, is to provide a process for converting a sodium aluminosilicate, such as Bayer sodalite and cancrinite from the Bayer process either admixed or separate from red mud, which are also called Bayer process desilication products, into a Zeolite of Type A. Preferably, the process will use other by-products of Bayer process such as spent Bayer process liquor and S0₂ gas separated in smokestack scrubbers.

The process comprises dissolving sodium aluminosilicate containing material in dilute aqueous acid such as dilute aqueous hydrochloric, sulfuric, sulfurous or nitric acid to form a sodium aluminosilicate solution. A Zeolite precursor gel is formed from the sodium aluminosilicate solution by raising the pH of the sodium aluminosilicate solution to a pH of about 12 or higher. The Zeolite precursor gel is aged from about 3 to about 20 hours at a temperature of between about 70° and about 95°C to form a Zeolite of Type A.

The foregoing process can be used to form a Zeolite of Type A derived from sodium aluminosilicate such as the sodalite found in red mud. This Zeolite can be used as a detergent building agent to replace sodium triphosphate, thought to be an environmentally objectionable material, or as molecular sieves, desiccants, or as an ion exchange medium. The Zeolites of the present invention can also be advantageously used as an absorbent medium suitable for the separation of nitrogen and oxygen from air using pressure swing or vacuum swing adsorption techniques.

Further features and advantages of the invention will become evident upon reference to the following detailed description taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photomicrograph of a Zeolite of Type A product obtained in accordance with the process of the present invention;

FIG. 2 is a photomicrograph of an amorphous product obtained from Bayer sodalite;

FIG. 3 is a photomicrograph of EZA, a commercial Zeolite A marketed by Ethyl Corp. ;

FIG. 4 is a photomicrograph of a sodalite crystal;

FIG. 5 is a photomicrograph of a Zeolite of Type A product, having traces of Zeolite X therein obtained in accordance with the process of the present invention; and

FIG. 6 is a photomicrograph of Zeolite of Type A product having traces of Zeolite X therein obtained in accordance with the process of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with the present invention. Zeolite of Type A may be obtained by converting Bayer process desilication product such as Bayer sodalite or similar sodium aluminosilicates. The process of the invention can make Zeolite of Type A from any sodium aluminosilicate containing material, but preferably employs a waste sodium aluminosilicate such as the Bayer process desilication product in one of two forms: the common low temperature form, which is called Bayer sodalite, and the high temperature form which is called cancrinite. The Bayer process desilication product can either be admixed with the Bayer process red mud solids, or the Bayer sodalite can be obtained from the Bayer process as a solid waste product separate from the red mud. This separation is achieved by seeded post-desilication of the Bayer liquor after separation of the red mud solids, as described in G.D. Fulford and P.G. Cousineau, Liσht Metals 1987 (R.D. Zabreznik, ed.), pp. 11-17 (AIME, Warrendale, Pennsylvania,

1987) . Scale removed from Bayer liquor heat exchangers also provides another source of Bayer process desilication product as a separate stream.

The process of making a Zeolite of Type A of the invention preferably uses other by products of the Bayer process such as Bayer process liquors and SO-, gas separated in smokestack scrubbers. In either case, the total amount of solid waste to be discarded from the Bayer process is reduced by the amount of Bayer sodalite or similar sodium aluminosilicate formed in the Bayer process which can be converted into a useful Zeolite product.

The process comprises in a broad sense selectively dissolving the Bayer process desilication product such as Bayer sodalite or similar sodium aluminosilicates from the rest of the red mud solids (mainly iron and titanium minerals) and then separating the reduced amount of red mud solids remaining for disposal. Alternatively, where Bayer sodalite or similar sodium aluminosilicates exist as a separate solid waste stream, they are dissolved, and optionally filtered to remove any traces of insoluble impurities which may have been present in this stream. In either case, a dilute acid is used to dissolve the Bayer sodalite or similar sodium aluminosilicate.

In the case where the Bayer sodalite or similar sodium aluminosilicate is admixed with the red mud, careful selection of the temperature of dissolution and of the strength of the acid will help ensure that the Bayer sodalite (or similar sodium aluminosilicate) is dissolved completely without dissolving any significant amounts of the other major red mud constituents, such as the iron and titanium minerals present therein. Any dilute mineral acid solution in water can be used for this purpose, typically at temperatures around room temperature. For example, dilute aqueous hydrochloric acid solutions can be conveniently used to dissolve Bayer sodalite selectively from a solid mixture in red mud or to dissolve a separate Bayer sodalite waste stream. It is advantageous, however, to use an aqueous solution of S0₂ gas (such as can be recovered by scrubbing the stack gases of installations burning sulfur-containing fuels) to form an aqueous sulfurous acid solution. This reduces the operating costs, consumes undesirable byproducts, and also minimizes environmental problems.

In the first step of one preferred embodiment of the process, the washed waste stream of red mud solids containing Bayer sodalite is preferably slurried in a quantity of water sufficient to hold the dissolved sodalite in solution when the dissolution is complete. Preferably, the slurry contains between about 3 and about 5 grams of Bayer sodalite per 100 ml of water, although the slurry may be made with from about 1 to about 6 grams or more of Bayer sodalite per 100 ml of water. Next, concentrated, mineral acid, such as hydrochloric, nitric, sulfuric, or sulfurous acid, is added until the water is sufficiently acidic to dissolve the Bayer sodalite solids. Typically, the required pH is in the range of about 1.5 to about 3.0, but preferably ranges from about 2.0 to about 3.0; at this range of pH's the other major red mud constituents, if present, other than possibly some minor calcium minerals are not dissolved. It is also possible to slurry the washed waste solids in a 0 dilute solution of a mineral acid or sulfurous acid of the appropriate concentration.

The required acidity can also be obtained by passing by bubbling or otherwise dissolving S0₂ gas into the aqueous 5 slurry to form sulfurous acid in situ, or by directly adding aqueous sulfurous acid obtained from scrubbing stacks used to clean exhaust gases from the fuel burned in connection with the Bayer process, and this efficient use of waste gases avoids having to discharge S0₂ gas into the 0 atmosphere. Whichever acid is used, it is preferably added in small portions to the slurry until a pH of between about 3.5 and about 1.5 is reached. Alternatively, the slurry can be formed with dilute aqueous acid, which can be agitated to dissolve the sodium aluminosilicate added thereto. When the 5 desired level of acidity is reached, only inert impurities such as muscovite and iron containing materials will remain undissolved. Any undissolved solids are then separated from the acidic solution by filtration, sedimentation, centrifugation, or other means, preferably by pressure ^ filtration when a volatile acid such as sulfurous acid is used.

The large solid/liquid separation operation may be avoided by starting with separated solid sodium 5 aluminosilicates rather than with the total red mud stream containing Bayer sodalite or other sodium aluminosilicates admixed with red mud solids. Nevertheless, the selective leaching of the Bayer sodalite or similar sodium aluminosilicates from admixtures with the red mud solids is possible when a separate waste stream of Bayer sodalite is not available for any reason.

After removing undissolved solids from the acid solution of the Bayer sodalite or similar sodium aluminosilicates, the pH of the filtrate is raised to a pH in excess of about 12, and most preferably between about 12 and about 13.5. The preferred reagents (bases) for raising the pH are a 5-8N solution of sodium hydroxide or Bayer liquor, a caustic aluminate solution. If Bayer liquor is used, it should preferably have a caustic soda concentration in the region of 200 g/L (expressed as equivalent Na₂C0₃) and an alumina to caustic ratio of 0.3 to 0.4. It should be apparent to one of ordinary skill in the art that using spent Bayer liquor provides the additional advantage of making use of another by-product of the Bayer process in carrying out the present invention.

An important and advantageous aspect of the present invention involves the production of a suitable precursor gel which can be aged to form the Zeolite of Type A product. It has been found that a suitable precursor gel can be reliably and reproduceably made if the pH of the acidic sodalite solution is rapidly increased to a pH of over 12 to 13.5. This can be accomplished by adding a sufficient amount of an aqueous base rapidly or all at once, that is, without pauses or delays at intermediate pH values and generally with vigorous agitation. The appropriate amount of-base to be added can be determined by first titrating a small portion of the acidic solution with an aqueous base such as aqueous sodium hydroxide, to determine the volume of aqueous base needed to raise the pH to the desired level of alkalinity, for example between 12 and 13.5. With this information, the correct amount of base to be added to the entire remaining volume can be measured out, and rapidly added to the acidic sodalite solution with vigorous agitation.

Alternatively, a suitable Zeolite of Type A precursor gel can be obtained by adding the acidic sodalite solution to a sufficiently large excess of aqueous base such as aqueous NaOH or Bayer liquor having a pH in the range of 12 or upwards. By using an excess amount of an aqueous base of sufficiently high pH, the rapid addition of the acidic sodalite solution quickly raises the pH of the resulting solution to the desired range. Agitation during this step can be advantageous, but is not critical and need not be vigorous.

Once the Zeolite of Type A precursor gel has been obtained, the gel together with its alkaline mother liquor is heated to approximately 70-95^βC, and aged for up to 22 hours without further major agitation to form the desired Zeolite of Type A. Preferably, if the aging temperature is about 70°C, the precursor gel and mother liquor should be aged for about 5-8 hours. On the other hand, if the precursor gel is aged at about 90°C, 3-5 hours of aging should suffice to allow crystallization of the Zeolite of Type A product. Following the completion of the aging process, the solid Zeolite of Type A product can be washed with water and dried.

The following examples, which are provided to illustrate the invention, are given to further facilitate the understanding of the operation of the present process and are not intended to be limiting. EXAHP S I

Our previous experimentation has shown that relatively high pH levels were necessary for complete reprecipitation of a crystalline solid after aging from an initial acidic solution of sodalite. Run SZ9 involved lowering the pH using HC1 and then raising it again to two different levels. The upper pH values chosen for these trials were 12.00 and 13.50. Three different runs identified as SZ9-1, SZ9-2 and SZ9-3 were attempted. A clean 8N NaOH solution was used for two of the runs (SZ9-1 and SZ9-2) and a sample of spent liquor from the Bayer process (200 g/L caustic soda (expressed as equivalent Na₂C0₃) , alumina to caustic ratio 0.3) was used for run SZ9- 3. A slurry of 3.500g of sodalite in 100 mL distilled water was the starting material in each case. This slurry was acidified to dissolve the sodalite and then raised to the required pH by one of the caustic solutions. In all cases, precipitation of a white, flaky gel began almost immediately upon addition of base. By the time the pH of the solution reached 3.0 to 4.0, the solution had thickened with the presence of the gel so that stirring became temporarily almost impossible. Addition of further caustic with vigorous stirring thinned the solution. When the solutions had reached the desired pH levels, they were aged for 22 hours at 70°C, cooled and the solids were filtered off, washed and dried. The solids in run SZ9-2 filtered much more slowly than the solids from the other two solutions did. Further tests indicated that the solid in SZ9-2 had not crystallized but was still amorphous. Also, when weighing the dried solids from SZ9-1 and SZ9-3, they appeared to be continuously gaining weight, indicative of active desiccant properties. This suggested that the products of runs SZ9-1 and SZ9-3 were zeolites, while the solid product of run SZ-2 was an amorphous solid. Results of this run are summarized in Table 1: TABLE I

Sample Caustic Final pH XRD I.D. Solution Analysis of Product

SZ9-1 8N NaOH 13.50 major: Zeolite of Type A minor: muscovite

SZ9-2 8N NaOH 12.00 major: amorphous minor: muscovite NaCl

SZ9-3 Bayer 13.50 major: Zeolite of Type A liquor* minor: muscovite

*200 g/L caustic expressed as equiva¬ lent Na₂C0₃

The foregoing table demonstrates that the pH should preferably be raised above about 12.00 for recrystallization to zeolite to occur. Remarkably, Example 1 demonstrates that the particular form of the caustic had little effect on the final product. The amount of zeolite produced had almost the same mass as the sodalite starting material. The traces of muscovite noted in the product were due to their presence in the Bayer sodalite used as starting material.

EXAMPLE 2

The dried composition obtained in run SZ9-3 was subjected to further testing to help identify the products. Figure 1 contains scanning electron photomicrographs of the Zeolite of Type A produced in the SZ9-3 run taken at 5,000 x magnification. Small, cubic crystals (Zeolite crystals) are evident. Photographs of amorphous product of run SZ9-2 are shown in Figure 2 at 5,000 x magnification.

For comparison, a sample of a commercially available Zeolite A (EZA "Ethyl" Zeolite A, Ethyl Corporation, Baton Rouge, LA) was also analyzed at this time. X-ray diffraction (XRD) analysis showed the major component to be Zeolite A having minor traces of sodalite and a Nitrogen form of the Zeolite A (as opposed to the more typical sodium form) . Figure 3 shows a microphotographs of this commercial sample taken at 5,000 x magnification. Also, a photomicrograph of a well formed sodalite crystal taken at 10,000 x magnification is shown for comparison in Figure 4. Long, narrow prismatic crystals of cancrinite, which is a high temperature form of Bayer sodium aluminosilicate, appear in the background.

EXAMPLE 3

In the SZ9 runs discussed above in Examples l and 2, there was some contamination of the Zeolite of Type A by muscovite which had been carried through as an impurity with the sodalite. Therefore, an attempt was made to remove this impurity. Run SZ12 was performed almost exactly the same as run SZ9-1 except on a larger scale (25.00g sodalite in 400 ml distilled water) and with the addition of a pressure filtration step after acidification in an attempt to separate the solid muscovite that was contaminating the zeolites in run SZ9. Addition of the filtration step resulted in a pure Zeolite of Type A.

EXAMPLE 4

In an attempt to optimize the conditions for recrystallization, run SZ14 started with the same quantities of reactants as run SZ12 in Example 3, and followed the same basic procedure. After acidifying the solution, caustic solution was added with vigorous agitation. When the slurry became very thick (around pH 3.0 to 4.0) it was split into two parts. One half of the divided slurry was again divided into two parts. One of these two parts was filtered immediately, and the residue was dried for chemical analysis. The other half was aged for 20 hours at 70°C, filtered, and then the residue was dried. Both solutions filtered very slowly, indicating that recrystallization had most likely not taken place. The pH of the other half of the original solution was raised to pH 13.50 with continuous vigorous agitation. The resulting precursor gel was then also divided in half with one part being aged for 20 hours at 70°C and the other being aged for the same time at 95^βC. Both of these slurries filtered well and their residues were dried. X-ray diffraction analysis confirmed that the first two samples, SZ14-1 and SZ14-2, were completely amorphous. The last two samples had Zeolite of Type A as their major components but also showed faint traces of Zeolite X. Figures 5 and 6 present photomicrographs of the two samples (SZ14-1 and SZ14-2) at 5,000 x magnification. The crystals are very well formed in both cases.

EXAMPLE 5

A further run was conducted using S0₂ as the acidification medium on a sample of Bayer sodalite prepared by allowing a kaolinite-containing raw material to react with Bayer liquor containing a very low concentration of dissolved phosphorus. S0₂ was bubbled or passed into a slurry of 3.500 grams sodalite in 100 mL water to lower the pH to 2.50. The remainder of the procedure followed Example 1 above, and resulted in relatively pure Zeolite of Type A with only traces of sodalite remaining.

Subsequently, this run was repeated using a second sample of sodalite prepared by allowing a similar kaolinite containing raw material to react with a different Bayer plant liquor containing the more usual concentration of dissolved phosphorous at 0.1 g/L (expressed as equivalent P₂0₅) . In this repeated run, the final product obtained after forming the precursor gel by raising the pH of the solution to about pH 13.5 by the addition of NaOH and aging the precursor gel at about 90^βC overnight, was mainly Zeolite PA, a variety of Zeolite A containing a small amount of phosphorus held in the insoluble form in the skeleton of the zeolite. As indicated in D.W. Breck, "Zeolite Molecular Sieves—Structure, Chemistry and Use," Krieger Publishing Company, Malabar, Florida (1984) , Zeolite A and Zeolite PA are very similar in many respects, and can be used interchangeably for several of the main applications of Zeolite A.

EXAMPLE 6

Run SZ18 was performed to assess the effects of aging time at 70°C on zeolite formation. A slurry of 25.00 grams of sodalite in 400 mL distilled water was again made. It was run through the normal procedure (using HC1 as the acid) until the Zeolite precursor gel in alkaline mother liquor was obtained. At this point it was split into three equal portions which were aged at 70°C for 3, 5 and 8 hours respectively. After aging, the samples were filtered and dried as usual. Filtration improved with increased aging time suggesting more complete formation of zeolite. X-ray Diffraction analysis results are presented in Table 2.

Table 2

Sample Aging Time X-Ray Diffraction

(hours) Analysis

70°C

SZ18-1 3 major: hydroxysodalite trace: Zeolite of Type A trace: NaCl

SZ18-2 5 major: Zeolite of Type A minor: NaCl trace: Bayer sodalite trace: hydroxysodalite SZ18-3 8 major: Zeolite of Type A minor: NaCl

EXAMPLE 7

Run SZ19 was performed using the same procedure as run SZ18 with the precursor gel in mother liquor again being split into three parts, except that this time the gel was aged at 90°C for 2, 3.5 and 5 hours respectively. Again filtration progressively improved with aging time. Analysis of the resulting solids demonstrated that the first sample was mostly hydroxysodalite with Na₂C0₃ and NaCl as minor components. The other two samples, however, consisted of very pure Zeolite A. This run showed that by increasing the aging temperature from 70^βC to 90°C, the time required for forming a Zeolite of Type A could be reduced from 5-8 hours (example 6) to as little as 3.5-5 hours.

EXAMPLE 8

3.5 g of Bayer sodalite was slurried in 100 mL water, and the pH was reduced to approximately 2.5 by addition of HC1. Traces of insoluble impurities present in the sodalite were filtered off. The clear acidic solution was then run slowly into approximately 250 mL of 5N NaOH solution with very gentle stirring, producing the precursor gel under high pH conditions. The gel was aged in its mother liquor without further agitation for 20 hours at 70°C, and the resulting solid phase was filtered, washed with water, and dried. XRD analysis indicated that the product was a clean Zeolite of Type A.

Claims

Claims :

1. A process for converting a sodium aluminosilicate containing material into a Zeolite of Type A, wherein the sodium aluminosilicate is treated with an acid,

5 characterized in that: the sodium aluminosilicate is dissolved in dilute aqueous acid to form a sodium aluminosilicate solution; the pH of said sodium aluminosilicate solution is raised to a pH in excess of about 12 in order to form a 10 Zeolite of Type A precursor gel; and said Zeolite of Type A precursor gel is aged from about 3 to about 20 hours at a temperature of between about 70°C and about 95°C to form a Zeolite of Type A.

2. A process in accordance with Claim 1,

15 characterized in that said material contains Bayer sodalite from the production of alumina by the Bayer process.

3. A process in accordance with Claim 1, characterized in that said material contains Bayer

20 sodalite admixed with red mud, and said dilute aqueous acid selectively dissolves said sodalite.

4. A process in accordance with Claim 1, characterized in that said material contains a Bayer process desilication product.

25 5. A process in accordance with Claim 2 or 3, characterized in that about 1 to about 5 grams of said Bayer sodalite is dissolved into about 100 ml. of dilute aqueous acid.

6. A process in accordance with Claims 1-5,

30 characterized in that said dilute aqueous acid is dilute aqueous sulfurous, sulfuric, nitric or hydrochloric acids, and wherein the pH of said aluminosilicate solution ranges from about 1.5 to about 3.

7. A process in accordance with Claims 1-6,

'35 characterized in that the pH of the solution is raised by rapidly adding a sufficient amount of an aqueous base in one portion with vigorous agitation, and said pH in excess of about 12 is a pH in the range from about 12 to about 13.5.

8. A process in accordance with Claim 7, characterized in that said aqueous base is sodium hydroxide solution or Bayer liquor.

9. A process in accordance with Claim 2 or 3, characterized in that the step of rapidly raising the pH of said sodalite solution to a pH of between about 12 and about 13.5 is carried out by adding said sodium alumino- silicate solution to an excess amount of Bayer liquor or aqueous sodium hydroxide such that the pH of the resulting solution is between 12 and about 13.5.

10. A process in accordance with Claim 2 or 3, characterized in that after dissolving the sodalite into solution, this sodalite solution is separated from any undissolved substances contained therein.

11. A Zeolite of Type A, characterized in that it is in the form produced by the process of Claims 1-10.