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Hexavalent chromium reducing agent and preparation method thereof, cement and preparation method thereof

A hexavalent chromium and reducing agent technology, applied in the field of building materials, can solve the problems of poor stability, ineffective effect, and easy oxidation of ferrous sulfate, and achieve good reducing performance

Active Publication Date: 2015-04-08
CHINA BUILDING MATERIALS ACAD
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, other reducing agents have also been studied in the prior art, such as sodium thiosulfate, sodium sulfite and ascorbic acid, but the effects are not obvious
[0004] However, the inventors have found that ferrous sulfate has poor stability and is easily oxidized during the preparation of cement, and once ferrous sulfate is oxidized, it no longer has the ability to reduce the water-soluble hexavalent chromium in cement

Method used

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  • Hexavalent chromium reducing agent and preparation method thereof, cement and preparation method thereof
  • Hexavalent chromium reducing agent and preparation method thereof, cement and preparation method thereof
  • Hexavalent chromium reducing agent and preparation method thereof, cement and preparation method thereof

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preparation example Construction

[0033] The embodiment of the present invention provides a kind of preparation method of hexavalent chromium reducing agent, comprises the following steps:

[0034] The raw materials of the hexavalent chromium reducing agent are mixed and ground to obtain the hexavalent chromium reducing agent.

[0035] Wherein, the raw materials of the hexavalent chromium reducing agent include stannous salt for providing stannous ions, ferrous salt for providing ferrous ions and a stabilizer. The stannous salt is counted as stannous ion, the ferrous salt is counted as ferrous ion, and the stabilizer is counted in parts by weight, including the following components: 5-12 parts by weight of stannous ion, 29-59 parts by weight of ferrous ion and 1-5 parts by weight of stabilizer. The added amount of the stabilizer is preferably 3-5 parts by weight.

[0036] The ferrous salt in this step can be one or more in ferrous sulfate, ferrous chloride, ferrous bromide, ferrous hydroxide, ferrous sulfide...

Embodiment 1

[0045] Add 10 parts by weight of stannous sulfate and 80 parts by weight of ferrous sulfate into a mixer and stir evenly, then add 2.5 parts by weight of bentonite, and stir evenly to obtain a hexavalent chromium reducing agent.

[0046] The prepared conventional grade 42.5 cement raw materials were mixed to form a cement batch, and the cement batch was mixed and ground with the hexavalent chromium reducing agent prepared in this example, and prepared into cement according to the cement preparation process of grade 42.5. Wherein, 100 g / t of hexavalent chromium reducing agent is added for every 1 ppm of water-soluble hexavalent chromium ions in the cement batch.

Embodiment 2

[0048] Add 15 parts by weight of stannous sulfate and 100 parts by weight of ferrous sulfate into a mixer and stir evenly, then add 3 parts by weight of sodium lignosulfonate, and stir evenly to obtain a hexavalent chromium reducing agent.

[0049] The prepared conventional grade 42.5 cement raw materials were mixed to form a cement batch, and the cement batch was mixed and ground with the hexavalent chromium reducing agent prepared in this example, and prepared into cement according to the cement preparation process of grade 42.5. Wherein, 100 g / t of hexavalent chromium reducing agent is added for every 1 ppm of hexavalent chromium ions in the cement batch.

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Abstract

The invention discloses a hexavalent chromium reducing agent and a preparation method thereof, a cement and a preparation method, which belong to the building material field, and the hexavalent chromium reducing agent and the cement solve the problems of poor stability of the water-soluble hexavalent chromium reducing agents and high water-soluble hexavalent chromium content in cement in prior art. A main technical scheme is characterized in that the raw materials of the hexavalent chromium reducing agent comprise tin salt, ferrous salt and a stabilizing agent; wherein, ferrous salt is metered by ferrous ions, tin salt is metered by stannum ions, the stabilizing agent is metered by weight part, the hexavalent chromium reducing agent comprises the following components: 5-12 weight part of stannum ions, 29-59 weight part of ferrous ions and 1-5 weight part of stabilizing agent. The raw materials of the hexavalent chromium reducing agent are mixed and ground to the hexavalent chromium reducing agent. The hexavalent chromium reducing agent, a cement clinker, gypsum and a mixing material are mixed and ground to prepare the cement with low percentage content of water-soluble hexavalent chromium ions. According to the invention, water-soluble hexavalent chromium ions in cement can be reduced to trivalent chromium, so that content of water-soluble hexavalent chromium ion in cement can be reduced.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a hexavalent chromium reducing agent for reducing water-soluble hexavalent chromium in cement to trivalent chromium to reduce the content of water-soluble hexavalent chromium in cement, a preparation method thereof and cement and its preparation method. Background technique [0002] Chromium is an inevitable trace element in cement clinker and cement, and it mainly exists in two valence states of 3+ and 6+. The water-soluble hexavalent chromium in cement is highly toxic, which will not only cause serious adverse symptoms to the human body, cause skin pain and ulceration, form cement dermatitis or eczema that is difficult to cure, but also cause the soil to be uncultivable and groundwater undrinkable. Serious consequences. Aiming at the harm caused by water-soluble hexavalent chromium, the European Union issued a special decree requiring that the content of water-soluble hexava...

Claims

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Application Information

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IPC IPC(8): C04B22/14C04B22/12C04B24/18
Inventor 范磊李锐文寨军彭明强曹志峰刘晨倪竹君崔健韩颖
Owner CHINA BUILDING MATERIALS ACAD
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