FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
Title of invention:
SELECTIVE DISPERSION-FLOCCULATION METHOD FOR BENEFICIATING ALUMINA RICH
IRON ORE SLIMES
Applicant
TATA Consultancy Services Limited A company Incorporated in India under The Companies Act, 1956
Having address:
Nirmal Building, 9th Floor,
Nariman Point, Mumbai 400021,
Maharashtra, India
The following specification particularly describes the invention, and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention generally relates to the field of iron ore processing and, more particularly, to a method of beneficiating alumina rich iron ore fines and slimes using selective dispersion flocculation technique.
BACKGROUND OF THE INVENTION
India, with an annual production of around 67 million tones, is currently the fifth largest producer of crude steel in the world. The steel production in India is expected to double within next few years. Its annual iron ore production will soon be more than 300 million tons. Out of a total production of 218.6 million tonnes of iron ore produced in the year 2009-10, a record 117.4 million tonnes (consisting of 13.2 million tonnes of lumps and 104.2 million tonnes of sinter fines) were exported. With a production capacity of 32 million tonnes per annum and an annual production of over 20 million tonnes, India is also the largest producer of sponge iron (directly reduced iron, DRI). Iron ores and ore fines concentrates are thus needed to satisfy increasing domestic demand of blast furnace (BF) and DRI grade products. Considering that the proven reserves of iron ore in India are not large (comparing it with the projected demand of this precious commodity in the next decade), the optimum utilization of our iron ore resources is an urgent national priority.
India is currently producing all the possible marketable products of iron ore, namely iron ore lumps, ore concentrates, pellets, iron oxide powder and iron ore sinter. The immediate technological challenge facing the industry is to deal with the problem of processing alumina rich iron ore fines and slimes. For the sustainable growth of iron ore industry which is beset with extremely serious problems of shortage of land and water in those states where iron ore deposits are found, it is absolutely imperative that the state-of-the-art mineral processing technology is utilized to achieve the desirable target of zero waste production in the industry.
Indian hematite ores are typically rich in iron but contain unusually high alumina (as high as seven percent) and in some cases, problem of high phosphorous content is also noted. The current practice of iron ore washing in India results in three products, namely coarse ore lumps, directly charged to blast furnace, the classifier fines, (3-5% alumina) which with or without beneficiation are fed to sintering plants (and now also to peptization plants after beneficiation and grinding to desired fineness) and the slimes (6-10% alumina) which are currently discarded as waste. It is therefore well recognized that in order to enhance the competitive edge of Indian iron and steel industry, an efficient alumina removal technology for Indian iron ores is absolutely essential.

Iron ores are being beneficiated all around the world including until recently at Kudremukh in India. Several techniques such as spirals, floatex density separators, jigs, multi-gravity separator, low and high intensity magnetic separator, conventional as well as column flotation, selective dispersion - flocculation are all part of current industrial practice globally. Recent advances include Batac jigs, packed flotation column, packed column jigs and centrifugal concentrators like Falcon Concentrator, Kelsey jigs and Knelson Concentrator for the beneficiation of iron ore slimes. Until very recently the processing of hematite ores in India did not involve any beneficiation except for whatever rejection of silica (and to some extent alumina) occurs during washing and classification of crushed ores. More recently however, two important breakthroughs have occurred in India: commissioning of a jigging plant by Tata Steel and commissioning of a beneficiation-cum- peptization plant by Essar Steel and that has opened up new opportunities in India for commissioning beneficiation plants for iron ores.
Tata Steel commissioned a Batac jig of 300 tonnes per hour capacity at Noamundi to beneficiate sinter fines to achieve alumina content less than 2%. Essar pioneered the pellet route of utilizing hematite ore fines (similar to what was practiced for more than two decades in Kudremukh till the beneficiation plant there had to be closed down for environmental reasons). A state-of-the-art iron ore fines processing plant including a 267 kilometers long slurry pipeline was commissioned by Essar in recent past. Essar is currently operating an 8 million tonnes per annum pellet plant in Visakhapatnam based on the beneficiated fines and slimes being pumped from NMDC's Balladilla iron ore mine. The beneficiation flow sheet includes gravity separation (spirals) of the coarser fraction after desliming and high intensity magnetic separation of the finer fraction. The concentrates thus produced assay less than 2.5% by weight of combined silica and alumina content and are further ground to produce a feed acceptable for the peptization circuit. The Essar group has also announced to set up another 8 million tonnes per annum pellet plant as a part of its integrated steel unit in Orissa.
A number of research groups in India have explored the possibility of reducing alumina in iron ore fines and slimes through appropriate mineral separation techniques. A critical review of the earlier R&D investigations clearly indicates that in addition to magnetic separation and gravity separation (which have been extensively employed in earlier investigations on beneficiation of Indian iron ores), there is a need to examine if froth flotation and selective dispersion-flocculation are likely to be more effective in the separation of alumina containing minerals in Indian iron ores. Considering the particle size distribution of Indian iron ore slimes (which are likely to be even finer, if finer crushing is resorted to for the production of even lower alumina content in lumps and fines), these two processes appear to be extremely promising, provided the appropriate reagents are available.

One of the more important findings of earlier investigations is that alumina in Indian iron ore slimes occurs in the form of two distinct mineral constituents namely, gibbsite (hydrated aluminium oxides) and kaolinite {and other clay minerals in minor quantities). Even though not adequately quantified, the liberation studies also indicate that a substantial portion of alumina is present in the liberated form and hence amenable to separation by physical means. Relative occurrence of gibbsite and kaolinite differs from deposit to deposit and hence ore mineral characterization on a representative sample of the particular deposit is absolutely essential and the appropriate flow sheet must be developed accordingly.
Moreover, it has been observed that froth flotation process for concentrating iron ores received a big impetus in USA immediately after the Second World War due to the dwindling resources of direct shipping iron ores in the Lake Superior District. Flotation of iron ores essentially for silica removal has been reviewed extensively in literature. The iron ore industry in Minnesota and Michigan in US uses cationic flotation of silica from magnetic taconites at a rate of 40 million tons per annum. Column flotation technology for rejecting fine silica using a variety of cationic amines has also been commercialized in iron ore industry including at Kudremukh in India.
Several iron ore producers in Brazil employ reverse flotation separation of silica from iron ore minerals for producing pellet quality concentrates. It has been reported that the presence of gibbsite and/or kaolinite as the major alumina containing minerals in iron ores does dictate the choice of beneficiation flow sheet in Brazil. While kaolinite does not interfere with flotation selectivity, gibbsite tends to contaminate the flotation concentrate as it is depressed together with iron oxides and hydroxides during the reverse cationic flotation process. These technical challenges are remarkably close to what the present invention intends to resolve.
To conclude the technical problems faced by the Indian iron industry is that the beneficiation of alumina rich iron ore slimes has remained an unsolved problem. One of the important technological challenges facing the iron ore industry in India is to find commercially viable technologies to process and beneficiate alumina rich iron ore fines and slimes. It is believed by many that magnetic separation can be a suitable solution, but none has looked upon selective dispersion-flocculation route as a possible alternative due to lack of availability of suitable reagent. No commercial process is yet available. Flotation is an established commercial process in iron ore industry for removing silica and phosphate impurities. The reduction of alumina containing minerals (kaolinite and gibbsite) by flotation is however not investigated adequately and thus remains a challenging problem yet to be solved. The key to developing a successful flotation separation process for Indian iron ores and ore slimes is thus to find a selective flotation reagent for this separation, particularly for separating the iron oxide from gibbsite impurities.

Importantly, the selectivity of any reagent can be proved with pure minerals but to obtain desired selectivity on natural iron ore slime samples is a very difficult task. The key to solving this problem lies in developing selective reagents for the separation of iron oxide minerals from associated gangue minerals like quartz, gibbsite, kaolinite and other gangue minerals.
OBJECTIVES OF THE INVENTION
The principle object of the present invention is to provide a selective combination of reagents that can facilitate beneficiation of iron ore slimes and fines and separate hematite from alumina-kaolinite- minerals and other gangue mineral constituents.
Other major object of the present invention is to produce a concentrate assaying approximately 69% iron and less than 2% aluminium residue for meeting the specifications of blast furnace grade and /or direct reduction (DRI) grade marketable product.
Another object of the present invention is to achieve desirable target of minimal waste production from the iron ore slimes and fines processing industry wherein slimes containing 6-10% of alumina is discarded as waste.
Another significant object of the invention is to better utilize the natural resources, and ensure higher mine output in terms of marketable products.
It is another object of the present invention to provide higher quality value added products leading to higher blast furnace and sinter plant productivity.
One of the other objects of the present invention is to provide a reagent combination effective in beneficiating the iron-rich bauxite deposits.
SUMMARY OF THE INVENTION
Before the present methods, systems, and hardware enablement are described, it is to be understood that this invention is not limited to the particular systems, and methodologies described, as there can be multiple possible embodiments of the present invention which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments

only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.
The present invention envisages a method of beneficiating alumina rich iron ore slimes and fines by employing selective dispersion flocculation route for the separation of iron oxide minerals from associated gangue minerals like quartz, gibbsite, kaolinite and other minerals.
In the preferred embodiment of the invention a method for beneficiating iron ore slimes and fines using a selective dispersant flocculant combination is used wherein the method comprises of the following steps: suspending the slime in water for agitation; conditioning the agitated slime with a selective dispersant selected from a class of synthetic polymers, the dispersant being identified based on molecular modeling computations ; reconditioning the settled slime with the flocculant selected from a class consisting of starch based natural polymers, the flocculant being identified based on molecular modeling computations; and allowing the slime to settle for a predetermined time interval.
One of the other preferred embodiments of the present invention discloses a selective combination of reagents for beneficiating iron ore slimes and fines based on molecular modeling computations, the combination comprising a selective dispersant selected from a class of synthetic polymers and a flocculant selected from a class consisting of starch based natural polymers.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing summary, as weJI as the following detailed description of preferred embodiments, are better understood when read in conjunction with the appended drawings, wherein like elements are given like reference numerals. For the purpose of illustrating the invention, there is shown in the drawings example constructions of the invention; however, the invention is not limited to the specific methods and system disclosed. In the drawings:
Figure 1 depicts a block diagram of an integrated approach practiced for the beneficiation of high alumina iron ores.
Figure 2 (a) represents optimized complexes for starch with Hematite showing strong Osearch-Fe chemical bonding and Figure 2 (b) represents optimized complexes for starch with Gibbsite showing weak hydrogen bonding (indicated by dotted lines).
Figure 3 is a block diagram illustrating the process flow of beneficiating the iron ore slime in accordance with one of the preferred embodiments of the present invention.

Figure 4 (a), (b) and (c) is a representation of the results obtained on subjecting the slime sample to characterization by particle size analysts, wet chemical analysis and X-Ray Diffraction respectively in accordance with one of the disclosed embodiments of the present invention.
Figure 4 (a') represents the slime characterization results obtained on performing particle size analysis on natural iron ore samples, in accordance with one of the other disclosed embodiments of the present invention.
Figure 5 is a tabular representation of the dispersion-flocculation results obtained using selective reagent combination with changing pH conditions in accordance with a disclosed embodiment of the present invention.
Figure 6 shows the effect of settling time on the iron ore sample during beneficiation process, according to a preferred embodiment of the present invention.
Figure 7 represents the effect of pulp density on the iron ore recovery process, in accordance with one exemplary embodiments of the present invention.
Figure 8 is a comparative study of the results obtained using various flocculant-dispersant combinations, in accordance with one of the embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Some embodiments of this invention, illustrating all its features, will now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.
It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred systems and methods are now described.

The present invention explores the possibility of achieving selective separation amongst hematite- alumina- kaolinite minerals, the mineral constituents representative of Indian iron ore slimes by a selective dispersion-flocculation route. The Indian iron ore slime is rich in iron minerals like hematite and goethite along with aluminum minerals like kaolinite and gibbisite. The two well known families of commercially available flocculants namely starch based natural polymers and polyacrylamide (PAM) - polyacrylic acid (PAA) family of synthetic polymers have been extensively worked upon. Also, the modification has been made to both starch as well as polyacrylamide to enhance selectivity of separation of hematite from kaolinite and gibbsite. The judicious combination of selective dispersant -flocculant combination is needed to achieve the desired selectivity of separation.The present invention has demonstrated that iron oxide minerals can be separated from associated clay minerals by an appropriate selective flocculation process.
The key to solving the problem of iron ore slimes thus lies in developing selective reagents (flocculants, dispersants and flotation collectors) for iron oxide - gibbsite separation. This is by no means a trivial task but any breakthroughs on this front will have far-reaching impact on the iechno-economlcs of processing alumina-rich iron ore slimes. These reagents are not only essential for solving the problem of alumina rich iron ore slimes but those will also have a significant impact on the beneftctation of iron-rich bauxite deposits in India. The results of using the novel reagent combination will be further significant in the processing of Indian red muds, rich in alumina and iron oxide. A sustained and systematic interdisciplinary effort by researchers has already been made in this direction, but with limited accomplishments so far. A schematic diagram showing the basic technological elements of such an integrated strategy to utilize alumina rich iron ore deposits in the country is presented in Figure 1.
The present invention overcomes this technological challenge faced by the iron ore industry today in India of processing alumina rich iron ore fines and slimes. The invention has developed selective reagents for the separation of iron oxide minerals from associated gangue minerals like quartz, gibbsite. kaolinite and montmorillonite. The invention employs state-of-the-art molecular modeling techniques for the selection/design of selective, tailor-made reagents for this separation, The reagents thus identified are tested for their separation efficiency through selective dispersion - flocculation experiments on natural iron ore slimes samples (Joda Mines) assaying 61.87 % iron (Fe), 3.88% aluminium (Al) contained hematite, goethite, magnetite, kaolinite and gibbsite minerals. The experiments have also been conducted for natural iron ore samples collected from Barsua mines that assays 61.27% iron (Fe) and 4.17% of aluminium residues.
As discussed, the selective combination of starch as flocculent and Polyvinylpyrrolidone (PVP) as dispersant is identified based on molecular modeling computations, the description thenceforward

shall explain the art of employing the molecular modeling techniques for such selection. The known quantum mechanical modeling theory namely, Density Functional Theory (DFT), as implemented in the PWScf code of the Quantum Espresso suite is applied to identify the promising flocculant for flocculation studies. The computations involved the optimization of the bulk and slab structures of hematite and gibbsite (the main alumina containing mineral) for validation with extant literature, followed by calculation of the interaction energies of various molecules, viz. xanthate, carboxylic acid and starch on hematite and gibbsite surfaces using the expression:

where Ecomplex is the total energy of the optimized starch-mineral complex, and Esurface and Estarch are the total energies of the Isolated mineral surface and starch molecule respectively.
The present invention employs the generalized gradient approximation (GGA) for the exchange-correlation functional in above DFT calculations. Vanderbilt ultrasoft pseudo-potentials is used for describing the ionic cores. The Kohn-Sham wave functions are expanded using a plane-wave basis-set up to a kinetic energy cutoff of 30 Ry and charge density with a cutoff of 180 Ry. Structural relaxations are performed until the total force on each atom is less than 0.01 eV/bohr.
The Table 1 below shows that starch is found as the most promising reagent for flocculation experiments exhibiting strong selectivity towards the hematite surface (Eint = -74 kcal/mof) vis-avis gibbsite (Ejnt = -11 kcal/mof). The difference is explained in Figure 2(a) and 2(b) which shows that there is strong chemical bonding between O-atoms on starch and Fe-atoms on hematite compared to only weak hydrogen bonding between starch and OH-groups on the gibbsite surface. Hence, starch was chosen as the flocculant for the flocculation experiments on iron ore slimes.

Molecule Interaction Energy
(-kcal/mol)

Hematite Gibbsite
Xanthate
Ethyl carboxylic acid
Starch 21 36 74 5
41 11
Table 1: Comparison of computed interaction energies for hematite and gibbsite surfaces
The current invention presents starch based natural polymers, particularly corn starch as the most selective flocculant that shall be used in combination with a synthetic polymers based

dispersant, particularly Polyvinylpyrrolidone (PVP) to beneficiate the natural iron ore slimes and fines. Starch is a polysaccharide based natural polymer having high affinity towards hematite, which is a natural flocculant for selective fiocculation. Out of these, corn starch has been selected as the flocculant The selective combination of corn starch as a flocculant and Polyvinylpyrrolidone as the dispersant yields 68% by weight of iron ore with a recovery of 75% of iron values. The concentrate assays approximately 69% of iron and less than 2% of aluminium after the beneficiation process.
In accordance with an embodiment of the present invention, the method of beneficiating the alumina rich iron ore is presented that deals with obtaining acceptable quality iron ore concentrate in single step of dispersion fiocculation using a very selective dispersant and flocculant combination of Polyvinylpyrrolidone and corn starch respectively. Referring now to Figure 3, the received slime sample has feed grade of 61.87 % total iron (Fe), 3.88% aluminium (Al) and associated hematite, goethite, magnetite, kaolinite and gibbsite minerals. The sample is now subjected to detailed characterization by particle size analysis, chemical analysis and X-Ray Diffraction {XRD). The slime sample is suspended in, preferably distilled water at 1% pulp density at a given pH (9.5, 10.5 or 11.5). The pulp density can though, vary in the range of 1-10% and the pH can be maintained between 4 to 12. However, the experimental results have proved that a pH of 11.5 creates a most ideal environment for maximum iron recovery from the ore. The solution is agitated by way of ultrasonification using a sonifier for a period of five minutes. It shall be however understood that the method may employ any means of agitating the solution known to a person skilled in the art and the invention by no means is restricted to the use of ultrasonification method. However, to derive the best possible results ultrasonification mechanism is deployed for the purposes of the present invention.
The slurry thus prepared is put in a flocculator for conditioning and the sample is further conditioned with the Polyvinylpyrrolidone (PVP) dispersant, as shown in Figure 3. The concentration of Polyvinylpyrrolidone (PVP) dispersant is maintained between 0.5ppm to 2 ppm and the results have revealed that the concentration of 1ppm has found to be preferable in obtaining the enhanced iron grade. The slurry is conditioned for 30 minutes at 100 rpm for selective agglomeration of iron ore particles. The slurry is further conditioned with causticized starch of concentration varying between 10- 200 ppm for 3 minutes at 40 rpm. The stirring is then stopped and the suspension is allowed to settle under natural gravity for 1 to 30 minutes. After the designated settling time, the supernatant solution is decanted, both settled and dispersed samples are dried, weighed and analyzed by wet chemical analysis and XRD.

BEST MODE/EXAMPLE OF WORKING OF THE INVENTION
The preceding description has been presented with reference to various embodiments of the invention. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, spirit and scope of this invention.
An embodiment of the proposed method of beneficiating the iron ore is explained herein for enabling the person skilled in the art to realize the invention without requiring any undue experimentation.
The reagents thus identified are tested for their separation efficiency through selective dispersion -fiocculation experiments on natural iron ore slimes. The successful results on the natural Iron ore slime samples collected from Joda Mines, India are presented in Figures 4(a), (b) and (c); Figure 5; Figure 6 (a) and Figure 7. Referring to Figure 4 (a) the results of slime characterization are depicted when the slime sample is subjected to particle size analysis. The slime characterization is also performed for sample taken from Barsua Mines assaying 61.27% Fe and almost 4.17% of aluminium residues, as shown in Figure 4(a'). The Barsua sample is a mixture of coarse and fine particles while the sample collected from Joda mines is very fine.
Figure 4(b) represents wet chemical analysis performed on the received iron ore sample for characterization. It shows the grade (purity) of the slime sample.
Referring to Figure 4(c), results of XRD experimentation as performed on the feed (received slime sample) are presented. XRD of as received slime samples reveal the types of mineral present in the sample. Here, the XRD analysis of settled and dispersed fractions revealed that alumina containing minerals like clay and gibbsite remain in the dispersed phase. The gibbstte and kaolinite contents in the flocculated fraction are reduced thereby indicating separation of hematite from gangue minerals.
Effect of pH: The variations in the grade of concentrate, iron recovery, aluminium content and % LOI (Loss on Ignition) with varying slurry pH is shown in Figure 5. The pH of slurry is maintained at 9, 10.5 and 11.5 with PVP as the dispersant and corn starch as flocculant. This pH range is observed only for experimental purposes, and can be selected from a range of 4 to 12. The concentration of PVP is varied between 0-1 ppm while of corn starch is made variable between 0-

40ppm. It is observed that with the concentration of PVP maintained at 1ppm and of corn starch at 40ppm, there is maximum recovery of iron (Fe) at pH 11.5. Thus for a given dispersant -flocculent combination one has to find the optimum pH for best separation and maximum recovery of iron values from slimes.
Effect of settling time: While the concentrate is allowed to settle under natural gravity, the impact of settling time on the concentrate is studied. The concentration of the combinative reagents PVP and corn starch is maintained at 1ppm and 40ppm respectively. Also, the pH of slurry is maintained at 11.5. Referring to Figure 6, it is observed that recovery of iron values and overall yield of the product can be enhanced substantially by increasing the settling time. It is important to note that the quality of upgraded product does not change (%Fe and % Al) remain same while increasing the settling time. With a settling time of 30 minutes, an upgraded product containing 68.87% Fe and 1,84% Al was obtained at 68.05% yields with 76.22% iron recovery.
With pulp density maintained at 1%, PVP concentration at 1ppm, Corn Starch concentration at 40ppm and allowing the slime to settle for 30 minutes with 15 min ultrasonication, the results obtained with natural iron sample collected from Barsua Mines is shown in Figure 6(a'). While the natural iron ore sample contains 61.27% iron and 4.17% of aluminium residues, the ore is grounded to obtain a sample assaying 53.67% of iron and 7.18% of aluminum residues for flocculation experiments. An upgraded product containing 60.41% of iron and 4.98% of aluminium residues is obtained as shown in Figure 6(a'). Effect of Pulp Density: The effect of varying pulp density on the recovered grade of iron concentrate is shown in Figure 7. With the pulp density varying and corn starch concentration, it can be derived that it is possible to achieve the product of acceptable quality with increased pulp density. It is important to note that in order to increase productivity at the industrial scale, higher pulp density is required. Typically, dispersion - flocculation plants are run at 10-15% pulp density for maximum benefit. The present invention is able to produce beneficiated product with more than 68% Fe content at the pulp density as higher as 10%. This makes the process commercially viable without compromising on the quality of the product and higher throughput. The experiments have also been conducted using variable range of dispersant-flocculant combination using preferable process parameters vis a vis maintaining pH between 9.5 to 11.5 and allowing settling time between 1-30 minutes. The various dispersants used are polyvinyl pyrrolidone, polyethylene oxide, sodium hexametaphosphate and sodium silicate. The results obtained thereon are shown in Figure 8 which reflects that the present invention employs the most suited reagent combination form maximum iron recovery and best yields.
INDUSTRIAL APPLICABILITY OF THE INVENTION

The innovation is useful in recovering iron values form iron ore slimes which are currently being dumped as waste. This will also solve a big environmental issue as currently large amount of water and area of land are locked up in slime ponds. In order to accomplish the task of developing zero waste technology for Indian iron ores, it is important to find appropriate means of utilizing the ultra-fine iron-rich alumino-silicate residue obtained during the beneficiation of iron ore slimes. Amongst several industrially useful products being explored world-wide, made from waste materials, eco-cements are perhaps the most promising.
Considering the large volumes of cement and concrete products consumed and the rates of growth anticipated in the buildings/construction industry in India, it is only natural that efforts are being made to incorporate industrial and mining wastes as substitutes for raw materials, admixtures, fillers, binders etc. in the construction industry. For example, the use of granulated blast furnace slag, volcanic ash, certain kinds of fly ashes and other materials having adequate lime reactivity in cement and concrete applications is now a standard industrial practice. Standard specifications are for instance, available in almost all the countries for blended cements. Since there are stringent specifications on the quality of raw materials permitted in the manufacture of Portland cements with respect to composition and the presence of certain impurities such as phosphate, chloride, sulfate, iron oxide, titania, magnesia, etc., the use of waste products is obviously limited. Recent work on special cements, in particular those based on novel alinite and sulpho-aluminate type solid solution cementitions phases, however indicates that good quality cement/concrete products could be manufactured almost exclusively from wastes such as the one produced during the beneficiation of iron ore slimes. These cements are thus called eco-cements.
In addition to converting wastes into value added products of commercial significance both these classes of cements are also energy efficient as compared to portland cement. The cement was used as a binder (a substitute for Portland cement) during the peptization of the same tailings sands. The pellets were required for subsequent heap leaching in order to recover the residua! gold from the tailings. All the properties specifications such as pellet strength and permeability for this particular application were met or exceeded by alinite cements. It was established during trials that alinite cements were indistinguishable from Portland cement in all respects and can replace it as an inexpensive substitute binder.
The challenge lies in finding appropriate sinks for industrial and mining wastes such as the residue produced during the beneficiation of iron ore slimes. Based on the application of present work on cements, this approach of producing eco-cements from iron rich alumino-silicate residue produced during the beneficiation of iron ore slimes is befitting.

The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. The listing of steps within method claims do not imply any particular order to performing the steps, unless explicitly stated in the claim.

We claim:
1) A method for beneficiating iron ore slimes and fines using a selective dispersant flocculant combination thereof, the method comprising; suspending the slime in water for agitation;
conditioning the agitated slime with a selective dispersant selected from a class of synthetic polymers, the dispersant being identified based on molecular modeling computations; reconditioning settled slime with the flocculant selected from a class consisting of starch based natural polymers, the flocculant being identified based on molecular modeling computations; and allowing the slime to settle for a predetermined time interval.
2) The method of claim 1, wherein the slime when suspended in water is of 1 -10% pulp density, preferably 1%.
3) The method of claim 1, wherein the water is maintained at a pH 4 to12, and preferably 11.5.
4) The method of claim 1, wherein the agitation is achieved by ultrasonification using a sonifier.
5) The method of claim 1, wherein the dispersant used is Polyvinylpyrrolidone.
6) The method of claim 1, wherein the dispersant is of concentration in a range of 0.5 to 2 ppm.
7) The method of claim 1, wherein density functional theory is employed as the molecular modeling technique for selecting the dispersant flocculant combination.
8) The method of claim 1 and 7, wherein generalized gradient approximation technique is used for exchange correlation energy functional in the density functional theory.
9) The method of claim 1, wherein the agitated slime is conditioned at the rate of 100 rpm for 30 minutes.
10) The method of claiml, wherein the gangue materials that gets separated from the settled slime include quartz, gibbsite, kaolinite or other gangue minerals or a combination thereof.
11) The method of claim 1, wherein the flocculant used for reconditioning is causticized corn starch.
12) The method of claim 1, wherein the flocculant is of concentration in a range of 10 to 200 ppm.
13) The method of claim 1, wherein the settled slime is reconditioned at the rate of 40 rpm for 3 minutes.

14) The method of claim 1, wherein the slime is allowed to settle for a time varying between 1 to 30 minutes and preferably 30 minutes.
15) The method of claim 1, wherein the beneficiation process yields approximately 68% by weight of iron ore with approximately 69% of iron recovery and about less than 2% of aluminium residue.
16) A selective combination of reagents for beneficiating iron ore slimes and fines, the combination comprising a selective dispersant selected from a class of synthetic polymers and a flocculant selected from a class consisting of starch based natural polymers, the said selection being based on molecular modeling computations.
17) The reagents of claim 16, wherein the dispersant used is Polyvinylpyrrolidone.
18) The reagents of claim 16, wherein the flocculent used is causticized corn starch.
19) The reagents of claim 16, wherein density functional theory is employed as the molecular modeling technique for selecting the dispersant flocculant combination.
20) The reagents of claim 16 and 19, wherein generalized gradient approximation technique is used for exchange correlation energy functional in the density functional theory.
21) The reagents of claim 16, wherein the beneficiated iron ore yield is approximately 68% by weight and the ore comprises of approximately 69% of iron and about less than 2% of aluminium residue.