JP3589629B2 - Magnesium / calcium composition and method for producing the same - Google Patents

Description

【０００９】
本発明で使用可能なカルシウム化合物としては、炭酸カルシウム（ＣａＣＯ_３）が最も好適であるが、その他に、フッ化カルシウム（ＣａＦ_２）、塩化カルシウム（ＣａＣｌ_２）、臭化カルシウム（ＣａＢｒ_２・６Ｈ_２Ｏ）、ヨウ化カルシウム（ＣａＩ_２・ｎＨ_２Ｏ）、乳酸カルシウム（Ｃａ〔ＣＨ_３ＣＨ（ＯＨ）ＣＯＯ〕_２・５Ｈ_２Ｏ）、珪酸カルシウム（Ｃａ_２ＳｉＯ_４）、メタ珪酸カルシウム（ＣａＳｉＯ_３・ｎＨ_２Ｏ）、珪フッ化カルシウム（Ｃａ〔ＳｉＦ_６〕・２Ｈ_２Ｏ）、硝酸カルシウム（Ｃａ（ＮＯ_３）_２・４Ｈ_２Ｏ）、亜硝酸カルシウム（Ｃａ（ＮＯ_２）_２・Ｈ_２Ｏ）、硫酸カルシウム（ＣａＳＯ_４・２Ｈ_２Ｏ）、亜硫酸カルシウム（（ＣａＳＯ_３）_２・Ｈ_２Ｏ）、蓚酸カルシウム（ＣａＣ_２Ｏ_４・Ｈ_２Ｏ）、リン酸カルシウム（ＣａＨＰＯ_４・２Ｈ_２Ｏ）、クロム酸カルシウム（ＣａＣｒＯ_４・２Ｈ_２Ｏ）、過塩素酸カルシウム（Ｃａ（ＣｌＯ_４）_２・４Ｈ_２Ｏ）、Ｄ−グルコン酸カルシウム（Ｃａ〔ＨＯＣＨ_２（ＣＨＯＨ）_４ＣＯＯ〕_２）、サリチル酸カルシウム（Ｃａ〔ＨＯＣ_６Ｈ_４ＣＯＯ〕_２・２Ｈ_２Ｏ）、水酸化カルシウム（Ｃａ（ＯＨ）_２）、酸化カルシウム（ＣａＯ）等が挙げられ、これらのうちの１種または２種以上を混合して用いることができる。
【００１０】
本発明で使用可能な強酸としては、例えば、硫酸、希硫酸、塩酸、希塩酸、硝酸等が挙げられる。特に５０％以下の希硫酸、例えば１５％希硫酸が好適に用いられる。ここで、強酸とは、水溶液系で酸解離指数ｐＫが３．０以下のものをいう。本発明では、このような強酸を用いて、反応混合物のｐＨを３．０以下、好ましくは０．５ないし２．０に維持することが肝要である。強酸の添加量は、例えば１５％希硫酸の場合、塩化マグネシウムおよび酸化マグネシウム１００重量部、あるいは塩化マグネシウム、酸化マグネシウムおよびカルシウム化合物１００重量部に対して３０〜１００重量部（酸成分として４．５〜１５重量部、水成分として２５．５〜８５重量部）である。
【００１１】
本発明では、例えば所定形状の型内に、塩化マグネシウム（常温では安定な六水和物（［Ｍｇ（Ｈ_２Ｏ）_６］Ｃｌ_２）、つまり六水塩の構造）と、酸化マグネシウム（ＭｇＯ）と、カルシウム化合物と、強酸（水成分）とを加えて攪拌・混合する。原料の添加順序は特に限定されない。例えば先に液状の強酸を型内に入れておき、ここにマグネシウム源、カルシウム源である上記金属塩類を任意の順に、または同時に添加して攪拌・混合してもよく、あるいは先に上記塩類をすべて型内に投入しておき、この粉体混合物に対して強酸の水溶液を注いで攪拌・混合してもよい。
【００１２】
型は、生成するマグネシウム・カルシウム構造体を所望の形状に成形するために用いる。したがって、複数の割り型を集合させてその内部に所定形状の空所を形成する閉塞式のものや、上面が開放した開放式のもの等が好ましく採用可能である。開放式では、上記したように、型の空所に原料を順に加えていくことが容易にできる。しかし、これに限らず、原料をすべて加えた反応混合物を予め別に調製しておき、それを型の空所に流し込んでもよい。特に、閉塞式では、密閉状態の空所内に空気を抜きつつ反応混合物を注入することにより、該空所を反応混合物で充填させることができて好ましい。
【００１３】
本発明では、基本的には、塩化マグネシウムを１、酸化マグネシウムを１、カルシウム化合物を２のモル比で配合する。ここで、酸化マグネシウムの配合割合を高くすれば反応混合物の安定性、すなわち可使時間が増大し、カルシウム化合物の配合割合を高くすれば反応生成物である組成物（構造体）の強度が増大する。したがって、酸化マグネシウムは、塩化マグネシウム１に対し、１〜１０のモル比で配合することができる。また、カルシウム化合物は、塩化マグネシウム１および酸化マグネシウム１〜１０に対し、２〜２０のモル比で配合することができる。強酸は、前述したように、塩化マグネシウムおよび酸化マグネシウム１００重量部に対して、例えば３０〜１００重量部を配合する。
【００１４】
すべての原料を混合した反応混合物はそのまま静置して養生させる。この間、反応物を加熱したり加圧することは一切必要がない。したがって、反応混合物は収縮や膨張等を起こすことがなく、製品の寸法精度が担保される。およそ１２時間以上養生させると、型の空所通りの形状に硬化した白色の組成物が生成する。組成物の表面は組織が緻密で滑らかである。必要に応じて水洗いをし、乾燥させる。上記したように、反応物は、養生期間中、収縮したり膨張したりしない。したがって、組成物には空所の形状および寸法が正確に移し取られる。例えば反応混合物をガラス製のビーカ内に放置すると、ビーカが割れたり、ビーカとの間に隙間ができたりすることなく、ビーカの内部形状をそのまま反映した円柱状の構造体が得られる。したがって、壁材や天井材等の薄くて広がりのある成形物や、大型で凹凸のある成形物であっても、反り返ったり、歪んだり、あるいは内部応力で割れたりせず、寸法精度よく製造できる。
【００１５】
このようにして得られた本発明に係るマグネシウム・カルシウム組成物は、一軸圧縮強度が７．８４×１０^７〜１．１８×１０^８Ｐａ（８００〜１２００ｋｇｆ／ｃｍ^２）と、代表的なコンクリートの圧縮強度１．５×１０^７〜４．０×１０^７Ｐａに劣らず、床材や舗装材にも使用できるほどの強度を有する。また、曲げ強度も３．９２×１０^７〜４．９０×１０^７Ｐａ（４００〜５００ｋｇｆ／ｃｍ^２）と、代表的なアルミナセラミックスの曲げ強度２．９４×１０^８〜３．９２×１０^８Ｐａ（３０〜４０ｋｇｆ／ｍｍ^２）と比べても見劣りすることがない。さらにヤング率も大きく弾性変形し難い。加えて、脆くなく、耐衝撃性に優れ、衝撃に対しては割れたり欠けたりせずに打痕や窪みが生成する。つまり、塑性変形をするほど高靭であり、その結果、切削や研削、穴開け等の機械加工を施こしてもクラックや割れ欠けが生じず加工性に優れる。
【００１６】
本発明に係る組成物は、外壁材、屋根材、かわら、高級調度品、室内装飾品、洗面台、バスタブ、カウンタやテーブル等に用いられる化粧板、パネル類等、従来よりセメントやコンクリート、セラミックス等が用いられていた用途一般に広く好ましく適用できる。
【００１７】
以下、具体例により本発明をさらに詳しく説明するが、本発明は以下に示す実施例に限定されるものでないことはいうまでもない。
【００１８】
【実施例】
［実施例１／配合モル比＝１：１：２］
１００ｍｌビーカに、塩化マグネシウム六水和物〔分子量２０３．３で計算・以下同様〕２０．３３ｇ（０．１ｍｏｌ）と、酸化マグネシウム〔４０．３〕４．０３ｇ（０．１ｍｏｌ）と、炭酸カルシウム〔１００〕２０ｇ（０．２ｍｏｌ）とを入れ、ガラス棒でよく攪拌しながら、１５％希硫酸７．３ｇ（酸成分〔９８〕１．１ｇ：０．０１１ｍｏｌ／水成分〔１８〕６．２ｇ：０．３４ｍｏｌ）を加えて混合した後、常温、常圧で１２時間放置したところ、ビーカ内に反応混合物が固化した太い円柱状の白色組成物が生成した。混合物放置時の液温は平均２３℃、ｐＨは２．６であった。デシケータに一夜間入れてさらに乾燥させた。
【００１９】
［比較例］
１５％希硫酸に代えてクエン酸およびリンゴ酸水溶液を用いて上記と同様に混合物を常温、常圧で１２時間放置・養生したが、混合物は固化しなかった。混合物放置時の液温は平均２３℃、ｐＨは３．５であった。
【００２０】
［実施例２／配合モル比＝１：１：２］
１０００ｍｌビーカに、１５％希硫酸２４４ｇ（酸成分３６．６ｇ：０．３７ｍｏｌ／水成分２０７．４ｇ：１１．５ｍｏｌ）を入れ、ガラス棒でよく攪拌しながら、塩化マグネシウム六水和物２０３．３ｇ（１ｍｏｌ）と、酸化マグネシウム４０．３ｇ（１ｍｏｌ）と、炭酸カルシウム２００ｇ（２ｍｏｌ）とをこの順に添加して混合した。ガラス板に四角い型枠を貼り付け、その中に上記混合物を流し込み、常温、常圧で１２時間放置したところ、型枠内に上記混合物が固化した矩形状の白色組成物が生成した。混合物放置時の液温は平均１９℃、ｐＨは１．５であった。水洗いし、デシケータに一夜間入れて十分乾燥させた。
【００２１】
［実施例３／配合モル比＝１：１０：１１］
５００ｍｌビーカに、１５％希硫酸６１ｇ（酸成分９．２ｇ：０．０９３ｍｏｌ／水成分５１．８ｇ：２．９ｍｏｌ）を入れ、ガラス棒でよく攪拌しながら、塩化マグネシウム六水和物２０．３３ｇ（０．１ｍｏｌ）と、酸化マグネシウム４０．３ｇ（１ｍｏｌ）と、炭酸カルシウム１１０ｇ（１．１ｍｏｌ）とをこの順に添加して反応混合物を調製した。この混合物を実施例２と同様に四角い型枠内に流し込み、常温、常圧で放置したところ、およそ２０時間後に混合物が十分固化して矩形状の白色組成物が得られた。混合物放置時の液温は平均１７℃、ｐＨは２．１であった。水洗いし、デシケータで十分乾燥させた。
【００２２】
［実施例４／配合モル比＝１：１：２０］
５００ｍｌビーカに、塩化マグネシウム六水和物２０．３３ｇ（０．１ｍｏｌ）と、酸化マグネシウム４．０３ｇ（０．１ｍｏｌ）と、炭酸カルシウム２００ｇ（２ｍｏｌ）とを入れ、ガラス棒でよく攪拌しながら、１５％希硫酸２５ｇ（酸成分３．８ｇ：０．０３８ｍｏｌ／水成分２１．２ｇ：１．１８ｍｏｌ）を加えて混合した。この混合物を実施例２と同様に四角い型枠内に流し込み、常温、常圧で放置したところ、およそ１２時間後に混合物が十分固化して矩形状の白色組成物が得られた。混合物放置時の液温は平均１８℃、ｐＨは２．４であった。水洗いし、デシケータで十分乾燥させた。
【００２３】
［耐水中崩壊試験］
養生材齢３日後の実施例１〜４の各組成物を最大長さが１０ｍｍ以下の破片となるように叩き割り、水道水を入れたビーカに投入して、５分間攪拌−３分間静置のユニットを２０回繰り返した後、破砕物の状態や水の濁り具合を観察した。いずれの場合も破砕物は短時間で沈降し、上澄み液は白濁等しなかった。一夜間水中に没したまま放置して翌日同じテストを行なったが結果は同じであった。
【００２４】
［圧縮強度試験］
養生材齢７日後の実施例１〜４の各組成物から直径約８ｍｍ、長さ約１０ｍｍの円柱状供試体を切り出し、該供試体の両端面を石膏混入セメントペーストでキャッピングした後、定速型万能試験機を用いて一軸漸増圧縮荷重を加えて最大荷重を求め、数１に従って圧縮強度を算出した。結果を表１に示す。
【００２５】
【数１】

【００２６】
【表１】

【００２７】
［曲げ強度試験］
同じく養生材齢７日後の実施例１〜４の各組成物に関して、ＪＩＳ Ｒ５２０１に準拠し、最大荷重を求め、曲げ強度を算出した。結果を表２に示す。
【００２８】
【表２】

【００２９】
［耐衝撃試験］
同じく養生材齢７日後の実施例１〜４の各組成物に対して、直径３ｃｍのスチールボールを１ｍの高さから自由落下させたが、いずれの場合も成形物は割れたり欠けたりせず、またクラックも生じず、表面がわずかに窪んだ。
【００３０】
【発明の効果】
以上のように、本発明によれば、高い曲げ強度・圧縮強度を有し、耐衝撃性・加工性に優れた高靭性組成物が提供される。本発明に係る組成物は常温常圧セラミックスとでも称すべきもので、焼成・焼結して製造するファインセラミックスに比べて寸法安定性に優れ、穏和な条件で省エネ・省コストに作製できる。本発明に係る組成物は、セメント、コンクリート、セラミックスの代替として建築材料や各種成形品等に広く好ましく適用可能である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dense and strong composition that can be used as a substitute for cement, concrete and ceramics.
[0002]
[Prior art]
As is well known, cement as an inorganic glue, particularly hydraulic cement and concrete containing it, are strongly alkaline, and become neutralized by exposure to acid rain, and become brittle or fall off. Occurs. Ceramics, especially fine ceramics using alumina, zirconia, silicon nitride, etc., have excellent corrosion resistance and environmental resistance, and have hard and strong functions. Cracks and cracks are likely to occur. In addition, the production method is also severe, for example, the raw material powder to which the binder is added is pressed and molded at a pressure of 9.8 × 10 ⁷ Pa or more by a press molding machine or the like, and then fired at a temperature of 1200 to 1400 ° C. Not only does this require a large amount of energy, but also in that case the product shrinks inevitably, making it difficult to ensure dimensional accuracy.
[0003]
[Problems to be solved by the invention]
In view of the above situation, the present invention can be used as a substitute for cement, concrete, and ceramics, for example, for building materials such as exterior wall materials and roofing materials, decorative boards, furniture, decorative articles, various molded articles, and the like. An object of the present invention is to provide a composition at low energy and low cost under mild conditions that do not apply high temperature and high pressure.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies and studies to solve the above problems, and as a result, mixed a magnesium source of magnesium chloride and magnesium oxide with a calcium source such as calcium carbonate at a predetermined molar ratio to obtain a strong acid such as sulfuric acid. It has been found that a structure excellent in strength and impact resistance at room temperature and pressure with good dimensional accuracy without shrinkage or swelling when left in the presence of is obtained, and completed the present invention.
[0005]
That is, the present invention relates to a magnesium / calcium composition obtained by reacting magnesium chloride, magnesium oxide, and a calcium compound at normal temperature and normal pressure in the presence of a strong acid.
[0006]
The present invention also provides a method of mixing magnesium chloride, magnesium oxide, and a calcium compound in a molar ratio of 1: 1 to 10: 2 to 20 at normal temperature, normal pressure, and in the presence of a strong acid, and allowing the mixture to stand for 12 hours or more. The present invention relates to a method for producing a magnesium-calcium composition to be cured by heating.
[0007]
The composition according to the present invention, for example, the formula _{(Mg X · Ca Y · (} H 2 O) 2 (X + Y)) indicated by, as shown in Chemical Formula 1, 2 to magnesium and / or calcium atoms (ions) It is considered to have, as a basic skeleton, a crystal structure (for example, a cadmium chloride type structure belonging to a trigonal system) in which twice as many water molecules are coordinated.
[0008]
Embedded image

[0009]
The calcium compounds usable in the present invention, calcium carbonate (CaCO ₃₎ is most preferred, other calcium fluoride _(CaF 2), calcium chloride (CaCl _2), calcium bromide (CaBr ₂ · 6H ₂ O), calcium iodide _{(CaI 2 · nH 2 O)} , calcium lactate (Ca _[CH 3 _CH (OH) COO] ₂ · _{5H 2} O), calcium silicate _(Ca 2 _SiO 4), calcium metasilicate (CaSiO ₃ · _nH 2 O), silicofluoride fluoride calcium (Ca [SiF _6] · _2H 2 O), calcium nitrate _{(Ca (NO 3) 2 ·} 4H 2 O), calcium nitrite _{(Ca (NO 2) 2 ·} H ₂ O), calcium sulfate _{(CaSO 4 · 2H 2 O)} , calcium sulfite _{((CaSO 3) 2 · H} 2 O), calcium oxalate (CaC ₂ O ₄ .H ₂ O), calcium phosphate (CaHPO ₄ .2H ₂ O), calcium chromate (CaCrO ₄ .2H ₂ O), calcium perchlorate (Ca (ClO ₄ ) ₂ .4H ₂ O), D- calcium gluconate (Ca [HOCH _{2 (CHOH)} 4 COO] _2), calcium salicylate (Ca _[HOC 6 _H 4 COO] ₂ · _2H 2 O), calcium hydroxide (Ca _(OH) 2), calcium oxide (CaO And the like, and one or more of these can be used as a mixture.
[0010]
Examples of the strong acid that can be used in the present invention include sulfuric acid, diluted sulfuric acid, hydrochloric acid, diluted hydrochloric acid, and nitric acid. In particular, 50% or less diluted sulfuric acid, for example, 15% diluted sulfuric acid is preferably used. Here, a strong acid refers to an aqueous solution having an acid dissociation index pK of 3.0 or less. In the present invention, it is important to maintain the pH of the reaction mixture at 3.0 or less, preferably 0.5 to 2.0, using such a strong acid. The amount of the strong acid added is, for example, in the case of 15% diluted sulfuric acid, 30 to 100 parts by weight per 100 parts by weight of magnesium chloride and magnesium oxide or 100 parts by weight of magnesium chloride, magnesium oxide and a calcium compound (4.5 as an acid component). To 15 parts by weight, and 25.5 to 85 parts by weight as a water component).
[0011]
In the present invention, for example, magnesium chloride (a hexahydrate stable at normal temperature ([Mg (H ₂ O) ₆ ] Cl ₂ ), that is, a hexahydrate structure) and magnesium oxide (MgO ₂ ) are placed in a mold having a predetermined shape. ), A calcium compound, and a strong acid (water component) are added and stirred and mixed. The order of adding the raw materials is not particularly limited. For example, a liquid strong acid is first placed in a mold, and the above-mentioned metal salts as a magnesium source and a calcium source may be added in any order or simultaneously and stirred and mixed, or the above-mentioned salts may be added first. All of the powder mixture may be charged into a mold, and an aqueous solution of a strong acid may be poured into the powder mixture and stirred and mixed.
[0012]
The mold is used to shape the resulting magnesium-calcium structure into a desired shape. Accordingly, a closed type in which a plurality of split dies are assembled to form a cavity of a predetermined shape inside the open type, an open type in which the upper surface is open, and the like can be preferably used. In the open type, as described above, it is easy to sequentially add the raw materials to the cavity of the mold. However, the present invention is not limited to this, and a reaction mixture containing all of the raw materials may be separately prepared in advance, and then may be poured into the cavity of the mold. In particular, the closed type is preferable because the reaction mixture is injected into the hermetically closed space while bleeding air so that the space can be filled with the reaction mixture.
[0013]
In the present invention, basically, a magnesium chloride, a magnesium oxide, and a calcium compound are blended in a molar ratio of 1, 2 and 2, respectively. Here, increasing the mixing ratio of magnesium oxide increases the stability of the reaction mixture, that is, the pot life, and increasing the mixing ratio of the calcium compound increases the strength of the composition (structure) as a reaction product. I do. Therefore, magnesium oxide can be blended in a molar ratio of 1 to 10 with respect to 1 of magnesium chloride. The calcium compound can be blended in a molar ratio of 2 to 20 with respect to 1 of magnesium chloride and 1 to 10 of magnesium oxide. As described above, for example, 30 to 100 parts by weight of the strong acid is mixed with 100 parts by weight of magnesium chloride and magnesium oxide.
[0014]
The reaction mixture obtained by mixing all the raw materials is left to cure as it is. During this time, there is no need to heat or pressurize the reactants. Therefore, the reaction mixture does not shrink or expand, and the dimensional accuracy of the product is ensured. After curing for approximately 12 hours or more, a white composition is formed that has hardened to the shape of the mold cavity. The surface of the composition is dense and smooth in texture. Rinse and dry as necessary. As mentioned above, the reactants do not shrink or expand during the curing period. Therefore, the shape and dimensions of the cavity are accurately transferred to the composition. For example, if the reaction mixture is left in a glass beaker, a columnar structure that reflects the internal shape of the beaker as it is without breaking the beaker or forming a gap with the beaker can be obtained. Therefore, even a thin and wide molded product such as a wall material or a ceiling material, or a large and uneven molded product can be manufactured with high dimensional accuracy without warping, distortion, or cracking due to internal stress. .
[0015]
The magnesium-calcium composition according to the present invention thus obtained has a uniaxial compressive strength of 7.84 × 10 ^{7 to} 1.18 × 10 ⁸ Pa (800 to 1200 kgf / cm ² ), which is a typical concrete. Compressive strength of 1.5 × 10 ^{7 to} 4.0 × 10 ⁷ Pa, and has a strength that can be used for floor materials and pavement materials. Also, the bending strength is 3.92 × 10 ^{7 to} 4.90 × 10 ⁷ Pa (400 to 500 kgf / cm ² ), and the bending strength of typical alumina ceramics is 2.94 × 10 ^{8 to} 3.92 × 10 ^8. It is not inferior to Pa (30 to 40 kgf / mm ² ). Furthermore, Young's modulus is large and it is difficult to elastically deform. In addition, it is not brittle, has excellent impact resistance, and produces dents and depressions without cracking or chipping upon impact. In other words, the higher the degree of plastic deformation, the higher the toughness. As a result, even if mechanical processing such as cutting, grinding, or drilling is performed, cracks and cracks are not generated and the workability is excellent.
[0016]
Compositions according to the present invention, exterior wall materials, roofing materials, tiles, luxury furnishings, upholstery, wash basins, bathtubs, decorative plates used for counters and tables, panels and the like, conventionally cement, concrete, ceramics It can be widely and preferably applied to applications in which the use of the compound has been used.
[0017]
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, needless to say, the present invention is not limited to the examples described below.
[0018]
【Example】
[Example 1 / mixing molar ratio = 1: 1: 2]
In a 100 ml beaker, 20.33 g (0.1 mol) of magnesium chloride hexahydrate (calculated based on a molecular weight of 203.3; the same applies hereinafter), 4.03 g (0.1 mol) of magnesium oxide [40.3], and calcium carbonate 20 g (0.2 mol) of [100] was added, and 7.3 g of 15% diluted sulfuric acid (1.1 g of an acid component [98]: 0.011 mol / 6.2 g of a water component [18]) was sufficiently stirred with a glass rod. : 0.34 mol), and the mixture was allowed to stand at normal temperature and normal pressure for 12 hours. As a result, a thick columnar white composition in which the reaction mixture was solidified was formed in the beaker. The liquid temperature when the mixture was left was 23 ° C. on average, and the pH was 2.6. It was placed in a desiccator overnight to further dry.
[0019]
[Comparative example]
The mixture was left and cured for 12 hours at normal temperature and normal pressure using citric acid and malic acid aqueous solution instead of 15% diluted sulfuric acid, but the mixture did not solidify. The liquid temperature when the mixture was left was 23 ° C. on average, and the pH was 3.5.
[0020]
[Example 2 / Molecular ratio = 1: 1: 2]
In a 1000 ml beaker, 244 g of 15% diluted sulfuric acid (36.6 g of an acid component: 0.37 mol / 207.4 g of a water component: 11.5 mol) is added, and 203.3 g of magnesium chloride hexahydrate is stirred well with a glass rod. (1 mol), 40.3 g (1 mol) of magnesium oxide, and 200 g (2 mol) of calcium carbonate were added in this order and mixed. A square mold was attached to a glass plate, and the mixture was poured into the mold, and allowed to stand at normal temperature and normal pressure for 12 hours. As a result, a rectangular white composition in which the mixture was solidified was formed in the mold. The liquid temperature when the mixture was left was 19 ° C. on average, and the pH was 1.5. It was washed with water and put in a desiccator overnight to dry it sufficiently.
[0021]
[Example 3 / mixing molar ratio = 1: 10: 11]
In a 500 ml beaker, 61 g of 15% diluted sulfuric acid (9.2 g of acid component: 0.093 mol / 51.8 g of water component: 2.9 mol) is put, and while stirring well with a glass rod, 20.33 g of magnesium chloride hexahydrate (0.1 mol), 40.3 g (1 mol) of magnesium oxide, and 110 g (1.1 mol) of calcium carbonate were added in this order to prepare a reaction mixture. This mixture was poured into a square mold as in Example 2 and allowed to stand at normal temperature and normal pressure. After about 20 hours, the mixture was sufficiently solidified to obtain a rectangular white composition. The liquid temperature when the mixture was left was 17 ° C. on average, and the pH was 2.1. It was washed with water and thoroughly dried in a desiccator.
[0022]
[Example 4 / mixing molar ratio = 1: 1: 20]
In a 500 ml beaker, 20.33 g (0.1 mol) of magnesium chloride hexahydrate, 4.03 g (0.1 mol) of magnesium oxide, and 200 g (2 mol) of calcium carbonate were added, and with good stirring with a glass rod, 25 g of 15% dilute sulfuric acid (3.8 g of acid component: 0.038 mol / 21.2 g of water component: 1.18 mol) was added and mixed. This mixture was poured into a square mold in the same manner as in Example 2 and allowed to stand at normal temperature and normal pressure. After about 12 hours, the mixture was sufficiently solidified to obtain a rectangular white composition. The liquid temperature when the mixture was allowed to stand was 18 ° C on average, and the pH was 2.4. It was washed with water and thoroughly dried in a desiccator.
[0023]
[Water collapse test]
Three days after the curing material age, each composition of Examples 1 to 4 was broken into pieces having a maximum length of 10 mm or less, put into a beaker containing tap water, and stirred for 5 minutes to stand for 3 minutes. After repeating this unit 20 times, the state of the crushed material and the turbidity of water were observed. In each case, the crushed material settled out in a short time, and the supernatant liquid did not become cloudy. The same test was performed the next day after leaving it submerged in water overnight, but the results were the same.
[0024]
[Compression strength test]
A cylindrical specimen having a diameter of about 8 mm and a length of about 10 mm was cut out from each of the compositions of Examples 1 to 4 7 days after the curing material age, and both end faces of the specimen were capped with a gypsum-containing cement paste, and then subjected to a constant speed. The maximum load was determined by applying a uniaxial gradually increasing compressive load using a die universal testing machine, and the compressive strength was calculated according to Equation 1. Table 1 shows the results.
[0025]
(Equation 1)

[0026]
[Table 1]

[0027]
[Bending strength test]
Similarly, for each of the compositions of Examples 1 to 4 7 days after the curing material age, the maximum load was determined and the bending strength was calculated according to JIS R5201. Table 2 shows the results.
[0028]
[Table 2]

[0029]
[Impact test]
Similarly, a steel ball having a diameter of 3 cm was freely dropped from a height of 1 m to each of the compositions of Examples 1 to 4 after the curing material age of 7 days. In any case, the molded product did not crack or chip. The surface was slightly depressed without cracks.
[0030]
【The invention's effect】
As described above, according to the present invention, a high toughness composition having high bending strength and compressive strength, and excellent in impact resistance and workability is provided. The composition according to the present invention should be referred to as a normal-temperature and normal-pressure ceramic, and is superior in dimensional stability to fine ceramics produced by firing and sintering, and can be produced under mild conditions with low energy and cost. The composition according to the present invention is widely and preferably applicable to building materials, various molded products, and the like as a substitute for cement, concrete, and ceramics.

Claims (2)

A magnesium-calcium composition obtained by reacting magnesium chloride, magnesium oxide, and a calcium compound at normal temperature, normal pressure and in the presence of a strong acid. Magnesium, characterized by mixing magnesium chloride, magnesium oxide, and a calcium compound in a molar ratio of 1: 1 to 10: 2 to 20 at normal temperature, normal pressure and in the presence of a strong acid, and allowing the mixture to stand for 12 hours or more. -A method for producing a calcium composition.