JP4155932B2 - Alumina cement and amorphous refractory - Google Patents

Description

The present invention relates to slag generated when a petroleum waste catalyst and a reducing agent are melted and refined, calcium aluminate produced using a CaO source as a raw material, alumina cement using the same, and an amorphous refractory.

Alumina cement generally uses limestone or quick lime as a CaO raw material, refined alumina, bauxite, aluminum residual ash, etc. as an Al2O3 raw material, and pulverizes clinker produced by a firing method or a melting method alone, or alumina is used as a clinker. And various additives are added and mixed and pulverized. A general method for producing alumina cement and its characteristics are widely known (for example, Non-Patent Document 1).
Refractory Vol.29, pp368-374 (1977)

In recent years, as part of dealing with environmental problems, there has been a strong demand for reducing the environmental load in waste treatment processes, and attention has been focused on waste melting treatment (for example, Non-Patent Document 2). A method for recovering useful metals from vanadium-containing waste (Patent Document 1), a method for recovering valuable metals from Mo-based waste catalysts (Patent Document 2), and the like are known.
Refractory, vol55, pp.168-173 (2003) JP 2000-204420 A JP 2001-214223 A

On the other hand, a petroleum waste catalyst (alumina waste catalyst) carrying a transition metal such as cobalt, nickel, copper, vanadium, molybdenum and platinum used in petroleum refining has not been effectively used so far.

In view of the above situation, an object of the present invention is to effectively utilize slag generated when melting and refining a petroleum waste catalyst and a reducing agent as a raw material for producing calcium aluminate.

That is, the present invention is a calcium aluminate produced from slag generated when melting and refining a petroleum waste catalyst and a reducing agent and a CaO source as raw materials, the petroleum waste catalyst, petroleum coke unburned ash and metallic aluminum It is a calcium aluminate produced from slag and quicklime produced when melting and refining.

Furthermore, as minerals, one or more of CaO.2Al2O3 (hereinafter referred to as CA2), 12CaO.7Al2O3 (hereinafter referred to as C12A7), 3CaO.Al2O3 (hereinafter referred to as C3A), CaO.Al2O3 (hereinafter referred to as CA) and amorphous. 1 or 2 selected from the group consisting of transition metal oxides, SiO2, Fe2O3, TiO2, and MgO, and having a CaO / Al2O3 molar ratio of 1.0 to 2.0. The calcium aluminate characterized by containing 5 to 30% by mass in terms of oxide. Moreover, it is an alumina cement containing these calcium aluminates, and is an amorphous refractory containing the alumina cement and a refractory aggregate.

  According to the present invention, it is possible to effectively use a petroleum waste catalyst generated in petroleum refining as a raw material for calcium aluminate and alumina cement.

As a result of various investigations on the effective use of wastes that are the subject of environmental problems, the present inventor has found that the transition metal-supported alumina catalyst that has not been used effectively so far has been subjected to waste (slag) generated during refining of transition metals. ) To establish a technology to produce calcium aluminate.

The present inventor is selected from the group of CA2, C12A7, and C3A in calcium aluminate in order to satisfy various characteristics such as pot life, fluidity, hardening characteristics, and strength development characteristics that are characteristic of alumina cement. Cobalt, nickel, copper, and vanadium, which are preferable to contain minerals other than seeds, CA and amorphous, and have a CaO / Al2O3 molar ratio of 1.0 to 2.0 and are not removed during refining. , Molybdenum, platinum and other transition metal oxides, SiO2, Fe2O3, TiO2, MgO may contain 5-30% by mass in terms of oxide, existing alumina The inventor has obtained the knowledge that it exhibits almost the same performance as cement, and has completed the present invention.

Calcium aluminate according to the present invention uses a slag refined from a petroleum waste catalyst as an alumina source, blends a CaO source such as limestone and quicklime to a predetermined component ratio, and melts in a gasification melting furnace. Or it is a clinker obtained by baking with a kiln. Hereinafter, the present invention will be described in detail.

The petroleum waste catalyst according to the present invention is a used desulfurization catalyst containing a transition metal oxide provided in a desulfurization apparatus such as hydrodesulfurization in the fields of petroleum refining and gas processing. We investigated whether slag after recovering useful metals from these used desulfurization catalysts could be reused as an aluminum source, and made it possible to effectively use industrial waste that had been disposed of in the past. Here, the transition metal oxide refers to transition metals supported in the catalyst. For example, the hydrodesulfurization catalyst contains Co, Ni, Cu, V, Mo, Pt and the like.

In the method of recovering useful metals from the used desulfurization catalyst, the used catalyst is first oxidized and roasted, and C, S, and N components in the waste are decomposed and removed as CO ₂ , SO _x and NO _x . Thereafter, it is mixed with a reducing agent and heated to recover the transition metal alloy. At this time, slag is by-produced. This slag is mainly composed of aluminum, and it is possible to produce calcium aluminates having various compositions by adding a CaO source such as limestone or quicklime and subjecting it to melting or sintering treatment.

Although the reducing agent according to the present invention varies depending on the type of transition metal, iron, aluminum, silica and coke are common. In the present invention, as the reducing agent, it is preferable to use asphalt after petroleum refining, unburned ash of petroleum coke (incinerated ash containing combustible components), which is a residue after further fractionation of pitch, and aluminum. .

Co, Ni, Mo, V, Cu, and Pt can be recovered by the following reaction when metallic aluminum is used as a reducing agent during heat reduction.
3CoO + 2Al → 3Co + Al2O3
3NiO + 2Al → 3Ni + Al2O3
MoO3 + 2Al → Mo + Al2O3
3CuO + 2Al → 3Cu + Al2O3
3PtO + 2Al → 3Pt + Al2O3

The calcium aluminate of the present invention is obtained by preparing a slag obtained by refining a waste catalyst and a CaO source such as limestone or quicklime so as to have a predetermined component ratio, and melting or baking in a gasification melting furnace or the like in a kiln. It is characterized by containing at least one mineral selected from the group consisting of CaO · 2Al2O3, 12CaO · 7Al2O3, 3CaO · Al2O3, CaO · Al2O3 and amorphous.

Impurities include SiO2, Fe2O3, TiO2, MgO, and transition metals, which exist in the form of 2CaO · Al2O3 · SiO2, 4CaO · Al2O3 · Fe2O3, CaTiO3, MgAl2O4, MgO, transition metal oxides. ing. Among these, 4CaO · Al2O3 · Fe2O3 accelerates hydration of cement, and 2CaO · Al2O3 · SiO2 slows hydration of cement. On the other hand, CaTiO3, MgAl2O4, MgO, and transition metal oxides hardly affect the hydration reaction of alumina cement.

The CaO / Al2O3 molar ratio of calcium aluminate is 1.0 to 2.0, and the total amount of SiO2, TiO2, MgO, Fe2O3 and transition metal oxides is 5 to 30% by mass in terms of oxide, It is preferable from the standpoint of strength development and fire resistance. When the CaO / Al2O3 molar ratio is less than 1.0, the initial strength may decrease. On the other hand, when the CaO / Al2O3 molar ratio is more than 2.0, the rapid hardening becomes strong and workability may not be sufficiently secured.

When impurities such as SiO2, TiO2, MgO, Fe2O3 and transition metal oxides increase, the properties such as fire resistance, strength development, volume stability of the cured product at high temperature, and spalling resistance will be deteriorated. In addition, the corrosion resistance to slag may be reduced.

When producing the calcium aluminate clinker of the present invention by the melting method, the slag as the Al2O3 source and the CaO source are mixed or mixed and pulverized at a predetermined ratio, and at a high temperature of 1500 ° C. or higher in a melting furnace such as a gasification melting furnace. It is preferable to melt until there is no unreacted raw material, and to cool by contacting with high-pressure air or water.

The clinker may be pulverized and mixed after mixing the clinker, or may be mixed. The clinker pulverizer is not particularly limited, and a pulverizer usually used for finely pulverizing a lump can be used. For example, a roller mill, a jet mill, a tube mill, a ball mill, and a vibration mill can be used.

The amorphous amount in the clinker according to the present invention can be adjusted by the cooling rate of the molten or baked high-temperature clinker. The amorphous amount can be obtained, for example, by Rietveld analysis performed based on a powder X-ray diffraction pattern.

The particle size of the clinker is one of important quality control items because it is related to fluidity, curing characteristics, and strength development. The particle size of the pulverized clinker is preferably 2000 cm 2 / g or more, more preferably 3500 cm 2 / g or more, and further preferably 4000 to 6000 cm 2 / g in terms of the specific surface area by the Blaine method. Outside this range, fluidity and strength development may be deteriorated.

The average particle diameter of the clinker is preferably 20 μm or less because of excellent fluidity and pot life at high temperatures, and more preferably 1 to 15 μm. The average particle diameter according to the present invention is a median diameter, and is obtained by a particle size distribution measuring method generally used such as a laser diffraction method or a laser scattering method.

It is preferable to add alumina to the alumina cement according to the present invention for the purpose of improving fire resistance and corrosion resistance. Alumina here refers to an Al2O3 source such as aluminum hydroxide or calcined alumina, which is sintered or melted by a firing device such as a rotary kiln or a melting device such as a gasification melting furnace, and pulverized to a predetermined size, Sifted. The mineral composition is aluminum oxide, such as α-Al2O3 or β-Al2O3, which is called sintered alumina, calcined alumina, easily sintered alumina, etc., and usually contains 90% by mass or more of Al2O3 Most preferred is the use of α-Al2O3.

Furthermore, in the present invention, for the purpose of improving fluidity, it is possible to use additives such as a curing retarder, a curing accelerator, a fluidizing agent, etc., which are usually blended in an amorphous refractory.

Examples of the curing accelerator include hydroxides such as Ca (OH) 2, Li2CO3, NaOH, KOH, and lithium salts. Among these, lithium salts have a strong curing accelerating action. Further, examples of the retarder include carboxylic acids, alkali metal carbonates, boric acids, polyacrylic acids, polymethacrylic acids, and alkali salts such as hexametaphosphoric acid, tripolyphosphoric acid, and pyrophosphoric acid.

The method of blending the additive is not particularly limited, and each additive is blended so as to have a predetermined ratio, and a crushed pulverizer, a V-type blender, a cone blender, a nauter mixer, a pan-type mixer, It can be mixed uniformly using a mixer such as an omni mixer or mixed with a clinker at a predetermined ratio, and then mixed and pulverized by a pulverizer such as a vibration mill, a tube mill, a ball mill, and a roller mill. .

As the refractory aggregate according to the amorphous refractory of the present invention, the refractory aggregate usually used in the amorphous refractory can be used. Specifically, molten magnesia, sintered magnesia, natural magnesia, And magnesia such as light calcined magnesia, magnesia spinel such as fused magnesia spinel and sintered magnesia spinel, alumina such as fused alumina, sintered alumina, light calcined alumina, and easily sintered alumina, silica fume, colloidal silica, light calcined alumina , And ultra-fine powder such as easy-sintered alumina, etc., fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, quartzite, rholite, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick Scrap, pottery scrap, silicon nitride, boron nitride, silicon carbide, and silicon nitride The use of an is possible.

Especially for the amorphous refractories of the present invention, from the aspects of corrosion resistance, durability, and fire resistance, magnesia, magnesia spinel, chamotte, alumina, silicon carbide, and ultrafine powder, as well as oil pitch, tar, scaly graphite, etc. One or two or more refractory aggregates selected from carbon aggregates are blended, and used in low cement castable types with 99 to 92 mass% refractory aggregate and 1 to 8 mass% alumina cement. It is preferable to do.

The method for producing the amorphous refractory according to the present invention is not particularly limited, but in accordance with the usual method for producing an irregular refractory, each constituent raw material is blended in a predetermined ratio to obtain a V-type blender. It is possible to mix evenly using a mixer such as a cone blender, a nauter mixer, a bread mixer, and an omni mixer, or to directly weigh into a kneader when performing kneading at a predetermined ratio. is there.

The petroleum waste catalyst was heated to 800 ° C. in an electric furnace for oxidation roasting. Metal aluminum was added as a reducing agent in an amount equal to or more than the chemical amount necessary for the reduction of the transition metal oxide, and heated and melted at 1850 ° C. in a high-frequency furnace to produce an alumina raw material. Quick lime is used as a CaO raw material, and alumina and CaO raw materials are blended so that the mineral composition in the product becomes a predetermined ratio. After melting at 1500 ° C in a gasification melting furnace, the melt is rapidly cooled with high-pressure cooling air. Thus, calcium aluminate was produced. Next, the obtained calcium aluminate was adjusted to a brain value of 4800 ± 500 cm 2 / g by a batch type ball mill. Table 1-1 shows the mineral composition and chemical composition of calcium aluminate. Furthermore, a mortar test was performed according to JIS R2521. The results are shown in Table 1-2.

<Materials used>
(1) Al2O3 raw material: petroleum waste catalyst (used desulfurization catalyst including transition metal oxide)
(2) CaO raw material: Commercial quicklime
(3) Alumina cement: Alumina cement No. 1 manufactured by Denki Kagaku Kogyo (alumina cement for comparison)

<Evaluation method>
(1) Curing strength: The kneaded product was put into a 4 × 4 × 16 cm mold and cured in a constant temperature room at 20 ° C. for 24 hours, and then the compressive strength of the test piece was measured.
(2) Dry strength: The kneaded product was put into a 4 × 4 × 16 cm mold, cured in a constant temperature room at 20 ° C. for 24 hours, and then dried at 110 ° C. for 24 hours, and the compressive strength of the test piece was measured. .
(3) Mineral composition: As for the mineral composition in calcium aluminate, alumina cement was measured by the powder X-ray diffraction method, and the diffraction pattern was analyzed and quantified by the lead belt method.
(4) Amorphous: A known amount of a mixed powder of α-Quartz and alumina cement was measured by the X-ray diffraction method, and the diffraction pattern was analyzed and quantified by the lead belt method.

Α-Al 2 O 3 was added in an amount (part by mass) shown in Table 2 to 100 parts by mass of the calcium aluminate produced in Example 1, and the CaO content was adjusted to 18% by mass. Mixing 3 parts by mass of this alumina cement, 76 parts by mass of sintered alumina aggregate, 3 parts by mass of silica fume, 18 parts by mass of finely divided alumina, and 0.05 parts by mass of sodium tripolyphosphate and 0.03 parts by mass of boric acid as a dispersant, A regular refractory was produced. Next, 6.0 parts by mass of water was added, and after kneading for 5 minutes with a mixer, the characteristics at 20 ° C. were evaluated. The results are shown in Table 2.

<Materials used>
(1) Sintered alumina: Trade name “Sintered Alumina SRW” manufactured by Showa Denko
(2) Fine powder alumina: Trade name “AM21 alumina” manufactured by Sumitomo Chemical Co., Ltd.
(3) Silica fume: trade name “Microsilica U-971” manufactured by Elchem
(4) Sodium tripolyphosphate: Reagent grade 1 manufactured by Kanto Chemical Co., Inc.
(5) Boric acid: Ishizu Pharmaceutical reagent grade 1
(5) α-Al2O3: Sinterable alumina A-172 manufactured by Showa Denko KK

<Evaluation method>
(1) Fluidity: The kneaded material was left in a constant temperature room at 20 ° C. for a predetermined time, and then tapped 15 times to measure the flow value.
(2) Pot life: In a constant temperature room at 20 ° C., the kneaded product was transferred to a polyethylene bag, and the time required for curing with a finger was measured to determine the pot life.
(3) Curing time: When the kneaded material was left in a constant temperature room at 20 ° C., the time from the injection of water until the exothermic temperature reached the maximum was measured using a temperature recorder, and was defined as the curing time.
(4) Curing strength: The kneaded product was put into a 4 × 4 × 16 cm mold and cured in a constant temperature room at 20 ° C. for 24 hours, and then the compressive strength of the test piece was measured.
(5) Drying strength: The kneaded product was put into a 4 × 4 × 16 cm mold, cured in a constant temperature room at 20 ° C. for 24 hours, and further dried at 110 ° C. for 24 hours, and the compressive strength of the test piece was measured. .

As shown in Table 2, the amorphous refractory of the present invention exhibited inferior characteristics compared to the conventional products.

20 parts by mass of calcium aluminate of Example 1 and 80 parts by mass of the following refractory aggregate were blended and mixed for 20 minutes with an omni mixer manufactured by Chiyoda Giken Kogyo Co., Ltd. to produce an amorphous refractory. To 100 parts by mass of this amorphous refractory, 9.0 parts by mass of water, 0.05 parts by mass of sodium tripolyphosphate as a dispersant, and 0.03 parts by mass of boric acid were added and kneaded.
The kneading was performed in a constant temperature room at 20 ° C., and evaluation was performed in the same manner as in Example 2. The results are shown in Table 3.

<Aggregate>
(1) Sintered alumina: Moralco T-60 particle size 3,360-1,190 μm: 28 parts by mass (2) Sintered alumina: Moralco T-60 particle size 1,190-590 μm: 17 parts by mass (3) Sintered alumina: Moralco T-60 particle size 590-297 μm: 15 parts by mass (4) Sintered alumina: Moralco T-60 particle size 297 μm below: 14 parts by mass (5) Sintered alumina: Moralco T-60 particle size 45 μm below : 6 parts by mass

As shown in Table 3, the amorphous refractory according to the present invention has a longer pot life, sufficient fluidity, and no problem in curing time and strength than those obtained by blending conventional commercial alumina cement. Met.

Claims (3)

And slag generated when melting the oil spent catalyst and a reducing agent refining, a calcium aluminate prepared from the CaO _{material, CaO · 2Al 2 O 3,} 12CaO · 7Al 2 O 3, 3CaO · Al 2 One or more minerals selected from the group of O ₃ , CaO · Al ₂ O ₃ and amorphous, CaO / Al ₂ O ₃ molar ratio is 1.0 to 2.0, and SiO ₂ , An alumina cement containing calcium aluminate in which the total amount of TiO ₂ , MgO, Fe ₂ O ₃ and transition metal oxides is 5 to 30% by mass in terms of oxide . The alumina cement according to claim 1, wherein the reducing agent is petroleum coke unburned ash and metallic aluminum, and the CaO raw material is quicklime. An amorphous refractory containing the alumina cement according to claim 1 or 2 and a refractory aggregate.