FIELD

[0001] This disclosure relates to a wet flue gas desulfurization (FGD) scrubber liquid additive product that prevents mercury re-emission from the scrubber liquid back into the flue gas from coal-fired power plants or other industrial processes.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims benefit of priority pursuant to 35 U.S.C. § 119(e) of U.S. provisional patent application No. 63/064,626 entitled “Advancements In Amended Silicates For Mercury Re-Emission Mitigation From Wet FGD Scrubbers,” filed on 12 August 2020, which is hereby incorporated by reference in its entirety.

BACKGROUND

[0003] Coal-fired power plants and some other industrial facilities release a small amount of mercury, from the coal or other fuel burned, and release the volatilized mercury into the flue gas. Because mercury is a volatile metal, this mercury is often released from the facility stack and emitted into the atmosphere, where the mercury, depending on its form, may deposit regionally in lakes, rivers, and oceans, or travel the globe before finally collecting on the earth’s surfaces or waters. Once mercury finds its way into the soil beneath shallow-water surfaces, it can be transformed by sulfur-reducing micro-organisms into methylmercury, a highly toxic and bioaccumulating organic form of mercury, which tends to work its way up the fish chain to yield concentrations in the fish we eat that are harmful to human health - causing damage to the fetus of pregnant women, reducing cognitive development in children and adolescents, and having many other harmful impacts to humans health.

[0004] The most stable form of mercury in the environment and the natural state of mercury normally discovered in the environment is mercuric sulfide, HgS, or cinnabar, which is also the form of mercury found in coal. When coal or other fuels containing mercury are burned, the mercury is liberated through the flame to form elemental mercury in the process furnace, followed sometimes by transformations into oxidized mercury, depending what gas constituents exist in the flue or other process gas. For example, if halides are present and the activation energy barrier low enough, either through catalytic activity or reaction components that form favorable reactions, then the mercury may be transformed into mercuric halides, which are easily collected and solubilized in the wet FGD scrubbers.

[0005] Once collected in the scrubber, the dissolved mercury may either (1 ) be transformed into a mercuric sulfide form and precipitated out with the solids, (2) be reduced by bad actors in the scrubber liquid (such as iron oxides, which tend to reduce mercuric halides back to the elemental form, which subsequently re-emit into the flue gas and out the stack), or (3) build up in the wet FGD scrubber liquid in the mercuric-halide form until the equilibrium concentration of the scrubber liquid has been exceeded, and the mercuric halide re-emits back into the gas flow and eventually out the stack.

SUMMARY

[0006] Disclosed herein are methods of partitioning mercury from a liquid into a solid, the method comprising admixing a solution containing mercury with a sorption media, wherein the sorption media comprises a sulfur species chemically bonded to a support substrate, wherein the additive may be produced by chemically reacting a metal sulfate with a first metal sulfide in the presence of the support substrate to form a second metal sulfide, and wherein the second metal sulfide may be deposited on the support substrate, and wherein the first metal sulfide may be Na ₂ S and the second metal sulfide may be selected from CuS, Cu ₂ S, CuS ₂ , ZnS, FeS, Fe ₂ S ₃ , FeS ₂ , Fe ₃ S ₄ , Fe ₂ S ₃ , mackinawite, pyrrhotite, troilite, SnS, SnS ₂ , MnS, MgS, NaS, Na ₂ S, K ₂ S, TiS, TiS ₂ , CaS, I n ₂ S ₃ , AI ₂ S ₃ , SiS ₂ , and GeS ₂ , and derivatives or combinations thereof. In many embodiments, the support substrate may be a moderate or a low-swelling clay, and may swell about 0.001% to about 25% in water, for example the moderate or the low swelling clay may be selected from a group consisting of kaolinite, kaolin clay, china clay, paper-recycling waste clay, fly ash obtained from a coal-fired power plant or other industrial facility or process, illite, micaceous minerals, halloysite, dickite, nacrite, serpentine, antigorite, chamosite, greenalite, cronstedtite, makatite, kanemite, kenyaite, attapulgite, palygorskite, sepiolite, allophane, quartz, talc, pyrophyllite, muscovite, phlogopite, biotite, glauconite, penninite, clinochlore, daphnite, anauxite, bravaisite, pyrophyllite, mullite, metakaolin, and mixtures thereof. In many embodiments, the support substrate may have an average diameter of about 0.5 to about 50 microns. In some embodiments, the metal sulfate may be FeSO4, and the first metal sulfide may be Na ₂ S and the second metal sulfide may be FeS.

[0007] Also disclosed are slurry additives for the capture of mercury from a liquid phase into a solid phase, comprising a support substrate coated with a metal sulfide, wherein the particulate support is suspended in water. In many embodiments, the metal sulfide may be selected from CuS, Cu ₂ S, CuS ₂ , ZnS, FeS, Fe ₂ S ₃ , FeS ₂ , Fe ₃ S ₄ , Fe ₂ S ₃ , mackinawite, pyrrhotite, troilite, SnS, SnS ₂ , MnS, MgS, NaS, Na ₂ S, K ₂ S, TiS, TiS ₂ , CaS, ln ₂ S ₃ , AI ₂ S ₃ , SiS ₂ , and GeS ₂ , and derivatives or combinations thereof, and or the support substrate may have an average diameter of about 0.5 to about 50 microns, and/or may swell about 0.001% to about 25% in water. In many embodiments the support substrate may be a moderate or a low swelling clay, and may be selected from the group consisting of kaolinite, kaolin clay, china clay, paperrecycling waste clay, fly ash obtained from a coal-fired power plant or other industrial facility or process, illite, micaceous minerals, halloysite, dickite, nacrite, serpentine, antigorite, chamosite, greenalite, cronstedtite, makatite, kanemite, kenyaite, attapulgite, palygorskite, sepiolite, allophane, quartz, talc, pyrophyllite, muscovite, phlogopite, biotite, glauconite, penninite, clinochlore, daphnite, anauxite, bravaisite, pyrophyllite, mullite, metakaolin, and mixtures thereof. In many embodiments, the slurry additive may aid in capturing about 99.9% of mercury in the liquid phase, for example wherein the liquid is a scrubber liquid.

[0008] Also disclosed are methods of capturing about 99.9% of mercury in a scrubber liquid, the method comprising admixing a scrubber liquid containing mercury with a slurry additive, wherein the slurry additive comprises a talc coated with FeS.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 are photographs showing oxidation after 1 week (left), and the top layer scraped off (right).

[0010] FIG. 2 is a photograph showing separation occurring at the top of the container.

[0011] FIG. 3 is a photograph showing separation occurring at the bottom of the container.

[0012] FIG. 4 is a photograph showing trays with the disclosed product formulation at various % solids: from left to right: 40%, 35%, 30%, and 15%.

[0013] FIG. 5 shows one embodiment of the disclosed product diluted from 30% to 15% solids with water 1 week post manufacture.

[0014] FIG. 6 shows a laboratory setup for mixing additive into slurry samples at constant temperature - left and right are two different preparations.

[0015] FIG. 7 a bar graph depicting the percentage of mercury partitioning to the liquid phase of the slurry. [0016] FIG. 8 a bar graph depicting percentage of mercury partitioning to the solid phase of the slurry.

DETAILED DESCRIPTION

[0017] Oxidized mercury in the process gas stream is generally easily collected by wet FGD scrubbers. However, the dissolved mercury is not stable, nor sequestered until the mercury reacts to form sulfides in the scrubber liquid that precipitate out on solids within the scrubber slurry and are ultimately removed by the scrubber solids-removal system. While the mercury is still dissolved within the scrubber liquid, it is susceptible to chemical transformation, change, and re-emission back into the gas stream. The disclosed inventive product is an advancement of existing Amended Silicate products used for preventing mercury re-emission from wet scrubbers.

[0018] Disclosed herein are mercury-capture additives for use in scrubber liquid that help to prevent or substantially reduce re-emission of mercury into the gas stream. In many embodiments, the disclosed additive products may aid in capturing substantially all of the mercury in a solid portion of the scrubber liquid that may allow for removal by a scrubber solids- removal system. Also disclosed are methods of making the disclosed additives, and systems and methods for using the disclosed additives. In many embodiments, the additive may be a slurry of solid and liquid that can be added to the scrubber liquid.

[0019] The disclosed additives may comprise various components, ingredients, or compounds in addition to an aluminosilicate- or clay-based substrate. Thus, in one embodiment, the disclosed compositions comprise a substrate and a metal sulfide coating. In many embodiments the additive may be in the form of a slurry with a solid portion and a liquid portion. In many embodiments, the slurry may be of various percentages of solids, and may be used at about 15% solid, for example at greater than about 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, and less than about 30%, 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, or 6%. As used herein, the term ‘about’ may refer to a number that varies by +/- 10% or less than 10%.

Substrate

[0020] The substrates may be comprised of various materials. In many embodiments, the substrate is one or more clays selected from non-swelling particulate supports, selected from a group consisting of kaolinite, kaolin clay, china clay, paper-recycling waste clay, fly ash obtained from a coal-fired power plant or other industrial facility or process, illite, micaceous minerals, halloysite, dickite, nacrite, serpentine, antigorite, chamosite, greenalite, cronstedtite, makatite, kanemite, kenyaite, attapulgite, palygorskite, sepiolite, allophane, quartz, talc, pyrophyllite, muscovite, phlogopite, biotite, glauconite, penninite, clinochlore, daphnite, anauxite, bravaisite, pyrophyllite, mullite, metakaolin, and mixtures thereof. In various embodiments the particulate support is selected from the group consisting of talc, fly ash, kaolin clay, metakaolin, illite, attapulgite, palygorskite, saponite, allophane, quartz, and mixtures thereof.

[0021] In most embodiments, the substrate is a clay with moderate or low-swelling characteristic. The swelling of the clay may be measured by various methods. In one embodiment, the clay does not swell or swells less than about 25% by volume, when exposed to water. In other embodiments, the clay swells less than about 25%, 24%, 23%, 22%, 21 %, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 1 1%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1 %, and more than about 0.001%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 1 1%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, or 25%.

[0022] The substrate may have various sizes. In many embodiments, the average diameter of the substrates may be from about 0.5 to about 50 microns. In many embodiments, the average diameter may be greater than about 0.1 pm, 0.2 pm, 0.3 pm, 0.4 pm, 0.5 pm, 0.6 pm, 0.7 pm, 0.8 pm, 0.9 pm, 1.0 pm, 2.0 pm, 3.0 pm, 4.0 pm, 5.0 pm, 7.0 pm, 6.0 pm, 8.0 pm, 9.0 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm, 40 pm, 45 pm, or 50 pm, and less than about 55 pm, 50 pm, 45 pm, 40 pm, 35 pm, 30 pm, 25 pm, 20 pm, 15 pm, 10 pm, 9.0 pm, 8.0 pm, 7.0 pm, 6.0 pm, 5.0 pm, 4.0 pm, 3.0 pm, 2.0 pm, 1 .0 pm, 0.9 pm, 0.8 pm, 0.7 pm, 0.6 pm, 0.5 pm, 0.4 pm, 0.3 pm, or 0.2 pm.

Metal sulfide coating

[0023] The disclosed compositions comprise a metal-sulfide coating. In most embodiments, the metal sulfide is selected from one or more of CuS, CU2S, CUS2, ZnS, FeS, Fe ₂ S ₃ , FeS ₂ , Fe ₃ S ₄ , Fe ₂ S ₃ , mackinawite, pyrrhotite, troilite, SnS, SnS ₂ , MnS, MgS, NaS, Na ₂ S, K ₂ S, TiS, TiS ₂ , CaS, ln ₂ S ₃ , AI ₂ S ₃ , SiS ₂ , and GeS ₂ , and derivatives thereof. In many embodiments, the metal sulfide is a combination of iron sulfide forms.

Mercury Capture

[0024] The disclosed additives are useful in capturing mercury from the liquid phase into the solid phase. In many embodiments, the disclosed additives may allow for 99% or more of liquid phase mercury to be transitioned to the solid phase. In some embodiments, the amount of mercury remaining in the liquid phase may be less than 6.0%, 5.0%, 4.0%, 3.0%, 2.0%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, or 0.2%, and more than 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 2.0%, 3.0%, 4.0%, or 5.0%. In many embodiments, the disclosed additives may enhance removal of mercury from the liquid phase by more than 2X, 3X, 4X, 5X, 6X, 7X, 8X, 9X, 10X, 15X, 20X, 30X, 40X, 50X, 60X, 70X, 80X, 90X, or 100X, compared to other products, such as NaHS.

Additive Manufacture

[0025] The disclosed additive may be manufactured by various methods. In some embodiments the manufacture includes admixing the particulate support and the iron sulfide in a solvent to form a slurry. In some embodiments the manufacture may include admixing the particulate support with metal sulfate and sodium sulfide. In most embodiments, the particulate support, metal sulfate, and sodium sulfide are in proportions sufficient to cause a rapid and significantly complete reaction between the metal sulfate and the sodium sulfide, whereby the product of reaction is a transition-metal sulfide that deposits on the surface of the non-swelling particulate support, but all remains in the slurry form.

Procedure 1

[0026] This procedure describes the preparation HgX-FGD additive. To a slurry of FeSO ₄ (125 lbs.) in water (180 gallons), talc (438 lbs.) is added in slowly under high shear mixing. Mixing is continued until the slurry is smooth and chunks are dispersed. To this, a solution of sodium sulfide (63.4 lbs.) in water (48 gallons) is added with slow mixing speed (to prevent excessive splatter). Upon noticing a consistent black color, mixing speed can be increased to continue the mixing to obtain a smooth and homogeneous slurry. Kaolin or other non-swelling clay could be used in place of talc. Alternatively, talc may be mixed first in the water, followed by the addition of the chemicals, one at a time.

Procedure 2

[0027] This procedure describes an alternate approach for the preparation of HgX-FGD additive. To a slurry of FeSO ₄ (125 lbs.) in water (228 gallons), talc (438 lbs.) is added slowly under high shear mixing. Mixing is continued until the slurry is smooth and chunks are dispersed. To this, solid sodium sulfide flakes (63.4 lbs.) are added with slow mixing speed (to prevent excessive splatter). Upon noticing a consistent black color, mixing speed can be increased to continue the mixing to obtain a smooth and homogeneous slurry. Kaolin or other non-swelling clay could be used in place of talc. Alternatively, talc may be mixed first in the water, followed by the addition of the chemicals, one at a time.

Storage and shipping:

[0028] The slurry manufactured according to procedure 1 or procedure 2 should be shipped and stored with minimal headspace in a sealed container. In many embodiments, direct sunlight and freezing are also avoided.

Oxidation/Discoloring:

[0029] The oxidation seen (appearance of orange-ish coloration at slurry surface; see FIG. 1 , below) in the hood test indicates formation of iron oxide in the presence of atmospheric oxygen. Measurements confirmed the absence of H ₂ S formation when the oxidation film forms and the film protects the rest of the slurry from oxidation if the slurry is not allowed to actively dry out or is agitated. However, any oxidation should be avoided, as it destroys the metal- sulfide in the slurry, which is the active component that sequesters mercury in the scrubber.

Freeze/Thaw cycling:

[0030] Freezing may prevent oxidation but after 2 cycles may result in significant slurry separation. The slurry left at room temp took several hours to thaw completely.

Separation:

[0031] Without a surfactant or other anti-separation aid, the slurry will separate if left static for ~1-2 days, and once separated and then re-mixed, sample will take < 5 hours to separate again. The separation can occur on the top (FIG. 2) or bottom (FIG. 3) of the container up to 40% solids slurries as calculated on a mass basis. 30% slurries pictured.

Slurry dilution/max solids:

[0032] A 40% solids test resulted in a slurry that had the consistency of pudding and would be difficult to pump and transfer. A 35% slurry was also very thick and showed characteristics of shear thinning. A 30% slurry flows very well and would be easily pumped, and therefore is the recommended concentration for production without specialized transfer equipment. Figure 4 below contains pictures of 40%, 35%, 30%, and 15% solids loading slurry for reference. In some embodiments, the product may be manufactured and shipped as 30 to 40% solid. In some embodiments, the product may be diluted with water before use. In most embodiments, the slurry may be produced at a solids percentage of less than about 50%, 45%, 40%, 35%, 30%, 25%, 20%, or 15%, and greater than about 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 45% and combined with the mercury containing liquid after dilution to a working solids concentration of greater than about 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, and less than about 25%, 20%, 19%, 18%, 17%, 6%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, or 6%.

[0033] In some embodiments, a surfactant may be added to avoid formation of foam upon dilution and mixing of slurry product. Figure 5 shows agglomeration of slurry, in the absence of a surfactant when 30% solids slurry was diluted to 15% solids slurry by adding water.

Previous Amended Silicate technology

[0034] Metal sulfides amended onto clay-particle surfaces, have been used to control mercury from coal-fired power plants in many different ways, including: by injecting Amended Silicates upstream of a wet FGD scrubber, where the Amended Silicates are collected in the scrubber liquid after helping to oxidize the mercury, and once in the scrubber liquid, the Amended Silicates react with dissolved oxidized mercury, transforming it into mercuric sulfide, which quickly precipitates out of the scrubber liquid with the solids discharge, before the concentration of mercury in the scrubber liquid has the chance to build up to the equilibrium concentration or has a chance to be reduced to elemental mercury by bad-acting slurry components such as iron oxide.

[0035] Herein is described test results comparing advanced Amended-Silicate slurry product to prevent re-emission in wet FGD scrubbers with NaHS, a leading competitive product for preventing mercury re-emissions from wet FGD scrubbers.

[0036] Scrubber liquor slurry from a wet FGD scrubber at a full-scale coal-fired power plant was used to conduct laboratory tests. The baseline mercury concentration of the solids and liquid components of the slurry were measured. Subsequently, four identical 438 mg slurry samples, each diluted with approximately 400 ml water, were used to test three different scrubber additives. The tests were designed to determine how effective the additives were at reacting with the mercury in the slurry to form mercuric sulfide and thus transfer the mercury from the liquid phase to the solid phase, preventing mercury re-emission.

[0037] In order to yield results that were more clearly distinguishable, and to allow the ability to discern clearly between the effectiveness of the different additives, the concentration of mercury in the scrubber liquid was spiked with additional mercury, in an amount of about 3 times that of the mercury concentration originally in the scrubber liquid. Mercuric nitrate, Hg(NO ₃ )2, was the mercury standard used to increase the concentration of mercury in the slurry.

After spiking, the total amount of mercury in each sample was approximately 3.0 mg.

[0038] The three different scrubber slurry additives were (1 ) NaHS, a leading commercial scrubber slurry additive; (2) a slurry of metal sulfide particles, NOT amended to a substrate; and (3) a version of the disclosed advanced version of Amended Silicates for mercury re-emission prevention from wet FGD scrubbers. Advanced means that while the other Amended Silicate products have been shown to be capable of sequestering mercury from scrubber liquor, they were not designed specifically for this application, and this presently disclosed product was designed for that purpose, and as such it demonstrated surprisingly enhanced effectiveness at sequestering mercury from scrubber liquor. As disclosed here, the presently disclosed additive is an advanced version of Amended Silicates. It is a combination of metal sulfides amended to the surface of non-swelling clay or mineral particles, formed by reacting metal sulfate with sodium sulfide in solution. The resulting slurry is an effective mercury re-emission prevention product.

[0039] The mass of each of the three re-emission chemicals added to the respective slurry samples was based on equivalent sulfur atoms. The mass of sulfur added from the additives was 3.6 grams, corresponding to actual mass of additives from approximately 7 to 13 grams, depending on the molecules of sulfide and water dilution in the additive.

[0040] The slurry was heated to 65.5 °C (150 °F), which is the typical operating temperature of wet scrubbers, on a heated stir plate and continually stirred with a magnetic stir bar, prior to adding the re-emission prevention additive. An example of the setup is shown in Figure 6 below. Then, each additive was introduced into the slurry while it was continually held at the constant temperature of 65.5 °C. Following which, the slurry with the additive mixed in was continually stirred and held at that temperature for 60 minutes.

[0041] The slurry was filtered while still hot, at the end of the 60 minutes, yielding a liquid filtrate and residual solids samples, which were both analyzed for their mercury concentration. The percentage of mercury partitioning to the liquid and solid phases was then calculated, by dividing the mass in each by the total mass. The additive yielding the highest percentage of mercury partitioning to the solids is the most effective mercury re-emission additive.

[0042] Figures 7 and 8 show the results. Figure 7 contains the results of the mercury concentration remaining in the slurry liquid phase, and Figure 8 contains the results of the mercury remaining in the solid phase. As shown, the most effective product was the advanced Amended Silicate product.

[0043] Furthermore, the NaHS, a highly successful product in the market as of 2020, is a product that is much more effective than other previous Amended Silicate products for mercury control, when used to prevent mercury re-emission from wet scrubbers. Therefore, the results for the advanced Amended Silicate product compared with the results for the NaHS product, also prove that the advanced Amended Silicate product for control of mercury reemission is much more effective than previous Amended Silicate products - in fact, surprisingly and unexpectedly so.

[0044] In the comparison of mercury re-emission product performances, shown in Figures 7 & 8, HgX-FGD (A) is a slurry of metal sulfides and other minerals, HgX-FGD (B) is a slurry of advanced Amended Silicates, with metal sulfides amended to the surface of nonswelling particle substrates. NaHS is sodium hydrosulfide, which is a leading commercial product for the prevention of mercury re-emissions from wet FGD scrubbers.

[0045] A first embodiment is an advancement of Amended Silicates for prevention of mercury re-emission from wet flue-gas desulfurization (FGD) scrubbers.

[0046] A second embodiment is an advancement of Amended Silicate mercury-re- emission-prevention-additives for wet FGD scrubbers, whereby the advancement yields a product that shows superior performance to leading scrubber re-emission additives of the day and of previous Amended Silicate products.

[0047] Another embodiment is an advanced Amended Silicate for mercury re-emission prevention, composed of a non-swelling clay substrate such as talc or kaolin clay.

[0048] Still another embodiment is a process of preparing an advanced Amended Silicate wet FGD scrubber re-emission additive that includes admixing a particulate support and an iron sulfide in a solvent to form a slurry with particle diameters of about 0.2 to about 50 microns.

[0049] Yet another embodiment is a process of preparing an advanced Amended Silicate wet FGD scrubber mercury re-emission prevention additive that includes admixing a particulate support with metal sulfate and sodium sulfide, in proportions sufficient to cause a rapid and significantly complete reaction between the metal sulfate and the sodium sulfide, whereby the product of reaction is a transition-metal sulfide that deposits on the surface of the non-swelling particulate support. [0050] Yet another embodiment is an application of the advanced product, by injecting the advanced Amended Silicate product slurry directly into the scrubber liquid, where it reacts with dissolved mercury to form mercuric sulfide on the surface of the injected slurry product particles, which are then removed by the wet FGD scrubber particulate discharge.

[0051] Yet another embodiment is that the advanced Amended Silicate product, including the product manufactured with the disclosed manufacturing method, contain active metal sulfides similar to that of Amended Silicates based on previously-patented technology, only the Advanced Products are more effective at preventing mercury re-emission from wet FGD systems. As with the previous Amended Silicate products, the metal sulfides on the surface of the advanced Amended Silicate products are a combination of metal sulfides selected from the following list of metal sulfides: CuS, Cu ₂ S, CuS ₂ , ZnS, FeS, Fe ₂ S ₃ , FeS ₂ , Fe ₃ S ₄ , Fe ₂ S ₃ , mackinawite, pyrrhotite, troilite, SnS, SnS ₂ , MnS, MgS, NaS, Na ₂ S, K ₂ S, TiS, TiS ₂ , CaS, ln ₂ S ₃ , AI ₂ S ₃ , SiS ₂ , and GeS ₂ .

[0052] Advancements in Amended Silicate technology for mercury re-emission prevention in wet FGD scrubbers, yielding more effective performance, lower product injection rates, and ease of product use.

[0053] The advanced Amended Silicate product, wherein the particulate support is a non-swelling clay or mineral compound.

[0054] The advanced Amended Silicate, wherein the non-swelling particulate support is selected from a group consisting of an aluminate, a silicate, an aluminosilicate, and a mixture thereof.

[0055] The advanced Amended Silicate product, wherein the non-swelling particulate support is selected from a group consisting of kaolinite, kaolin clay, china clay, paper-recycling waste clay, fly ash obtained from a coal-fired power plant or other industrial facility or process, illite, micaceous minerals, halloysite, dickite, nacrite, serpentine, antigorite, chamosite, greenalite, cronstedtite, makatite, kanemite, kenyaite, attapulgite, palygorskite, sepiolite, allophane, quartz, talc, pyrophyllite, muscovite, phlogopite, biotite, glauconite, penninite, clinochlore, daphnite, anauxite, bravaisite, pyrophyllite, mullite, metakaolin, and mixtures thereof.

[0056] The advanced Amended Silicate product, wherein the non-swelling particulate support is selected from the group consisting of talc, fly ash, kaolin clay, metakaolin, illite, attapulgite, palygorskite, saponite, allophane, quartz, and mixtures thereof. [0057] A process of manufacturing the advanced Amended Silicate product, wherein the slurry product is produced by chemically reacting a metal sulfate with an alkaline sulfide or other metal sulfide found in group I A or HA of the periodic table, in the presence of the non-swelling substrate, whereby metal-sulfide reaction products deposit and coat the non-swelling substrate.

[0058] Alkaline or other metal sulfides referred to in the claim above may be potassium sulfide, magnesium sulfide, calcium sulfide, or sodium sulfide.

[0059] A process of manufacturing the advanced Amended Silicate product, wherein the slurry product is produced by chemically reacting a metal sulfate with a sodium sulfide in the presence of the non-swelling substrate, whereby metal-sulfide reaction products deposit and coat the non-swelling substrate.

[0060] A process of manufacturing the advanced Amended Silicate product, wherein the slurry product is alternatively produced by mixing metal sulfide with solvent (including, for example, water) in the presence of the non-swelling substrate, whereby metal-sulfide deposits and coats the non-swelling substrate.

[0061] The advanced Amended Silicate product, where the product slurry may be produced and shipped to customers with a solids content of about 30%, and then subsequently diluted to about 15% on site, before use.

[0062] The advanced Amended Silicate product, where the product slurry is injected directly into the wet FGD scrubber slurry (either directly into the reaction chamber or into the slurry recycle loop), where the metal sulfides in the advanced Amended Silicate product scavenge the dissolved mercury compounds to form mercuric sulfide on the surfaces of the slurry particles that are removed with the scrubber solids.

[0063] While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description. As will be apparent, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the detailed description is to be regarded as illustrative in nature and not restrictive.

[0064] All references disclosed herein, whether patent or non-patent, are hereby incorporated by reference as if each was included at its citation, in its entirety. In case of conflict between reference and specification, the present specification, including definitions, will control. [0065] Although the present disclosure has been described with a certain degree of particularity, it is understood the disclosure has been made by way of example, and changes in detail or structure may be made without departing from the spirit of the disclosure as defined in the appended claims.