CN112876123B

CN112876123B - Cement hexavalent chromium reducing agent, and preparation method and application thereof

Info

Publication number: CN112876123B
Application number: CN202110175123.9A
Authority: CN
Inventors: 曹志伟; 苏静
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2022-09-02
Anticipated expiration: 2041-02-09
Also published as: CN112876123A

Abstract

The invention provides a cement hexavalent chromium reducing agent, and a preparation method and application thereof. The cement hexavalent chromium reducing agent comprises the following components in parts by weight: 40-50 parts of ferrous sulfate, 5-20 parts of sodium metabisulfite, 10-20 parts of sodium thiosulfate, 0.5-1 part of stannous chloride, 1-5 parts of organic reducing agent and 1-3 parts of dispersing agent. The cement hexavalent chromium reducing agent has low cost and good reducibility and stability, can stably reduce hexavalent chromium in cement into trivalent chromium, and is beneficial to practical popularization and application.

Description

Cement hexavalent chromium reducing agent, and preparation method and application thereof

Technical Field

The invention relates to the technical field of cement additives, in particular to a cement hexavalent chromium reducing agent and a preparation method and application thereof.

Background

In the production process of portland cement clinker, chromium is one of the inevitable trace elements in the raw materials. Typically, portland cement contains between 100-300ppm chromium and the oxidizing and alkaline conditions in the cement kiln promote the formation of hexavalent chromium. Hexavalent chromium has strong oxidizability, can permeate human tissues, and is classified as an extremely toxic substance; meanwhile, the hexavalent chromium compound has strong water solubility, and workers are easily contacted with the skin when operating cement mortar or concrete, possibly causing allergy and allergic eczema. Therefore, if hexavalent chromium is not properly treated, it will cause a great hazard to the human body and the environment.

At present, reducing agents are generally used to reduce the hexavalent chromium content to a low level, and the commonly used reducing agents include ferrous sulfate and the like. The ferrous sulfate has low cost and good solubility, but is easy to oxidize and absorb moisture, has unstable chemical property, is easy to harden and lose efficacy, thereby reducing the using effect; therefore, the ferrous sulfate must be used in large amount, which greatly increases the production cost of cement.

CN108545982A discloses a cement hexavalent chromium reducing agent, which is prepared from the following raw materials in percentage by mass: 10-20% of stannous salt, 25-40% of ferrous salt, 15-25% of divalent manganese salt, 5-15% of antimony oxide, 10-20% of organic reducing agent and 5-10% of stabilizing agent. The cement hexavalent chromium reducing agent is added with a large amount of stannous salt, and although the stannous salt has a good reducing effect, the stannous salt is expensive and is not beneficial to reducing the production cost.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a cement hexavalent chromium reducing agent, a preparation method and an application thereof.

The invention provides a cement hexavalent chromium reducing agent which comprises the following components in parts by weight: 40-50 parts of ferrous sulfate, 5-20 parts of sodium metabisulfite, 10-20 parts of sodium thiosulfate, 0.5-1 part of stannous chloride, 1-5 parts of organic reducing agent and 1-3 parts of dispersing agent.

In the present invention, the organic reducing agent is at least one selected from the group consisting of N, N-dimethylaniline and phenylhydrazine.

In the present invention, the dispersant is selected from at least one of triethanolamine, diethanolisopropanolamine, and ethylene glycol.

The inventor finds that if the stannous chloride content in the cement hexavalent chromium reducing agent is reduced, the reduction effect of the cement hexavalent chromium reducing agent is greatly influenced; by adopting the specific composition, a better reduction effect can be obtained under the condition of low stannous chloride content, and meanwhile, the production cost is greatly reduced, thereby being particularly beneficial to practical popularization and application.

The invention also provides a preparation method of the cement hexavalent chromium reducing agent, which comprises the following steps: uniformly mixing ferrous sulfate, sodium metabisulfite, sodium thiosulfate, stannous chloride, an organic reducing agent and a dispersing agent in parts by weight.

The invention also provides application of the cement hexavalent chromium reducing agent in producing cement.

The invention also provides a cement production method, which comprises the following steps: the cement hexavalent chromium reducing agent is added into cement clinker.

The invention does not strictly limit the addition amount of the hexavalent chromium reducing agent in the cement; for example, the addition amount of the cement hexavalent chromium reducing agent can be 0.5-1 per mill.

The invention also provides cement produced according to the cement production method.

Specifically, the content of hexavalent chromium in the cement is less than or equal to 10 ppm.

The implementation of the invention has at least the following advantages:

1. the cement hexavalent chromium reducing agent has reasonable composition, and the components are matched with each other, so that hexavalent chromium in cement can be stably reduced into trivalent chromium, and the cement hexavalent chromium reducing agent has excellent reducibility and stability;

2. the cement hexavalent chromium reducing agent has the advantages that the dosage of ferrous sulfate and stannous chloride is less, and the cost of the reducing agent is greatly reduced.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms also include the plural forms unless the context clearly dictates otherwise, and further, it is understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, devices, components, and/or combinations thereof.

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The cement hexavalent chromium reducing agent of the embodiment comprises the following components in parts by weight:

uniformly mixing ferrous sulfate, sodium metabisulfite, sodium thiosulfate, stannous chloride, N-dimethylaniline and triethanolamine by using a mixer according to the weight parts to obtain the cement hexavalent chromium reducing agent.

Example 2

uniformly mixing ferrous sulfate, sodium metabisulfite, sodium thiosulfate, stannous chloride, phenylhydrazine and ethylene glycol by using a mixer according to the weight parts to obtain the cement hexavalent chromium reducing agent.

Example 3

uniformly mixing ferrous sulfate, sodium pyrosulfite, sodium thiosulfate, stannous chloride, N-dimethylaniline and diethanolisopropanolamine by a mixer according to the weight parts to obtain the cement hexavalent chromium reducing agent.

Example 4

Comparative example 1

The cement hexavalent chromium reducing agent of the comparative example consists of the following components in parts by weight:

comparative example 2

test example 1

The hexavalent chromium reducing agents for cement of examples 1 to 4 and comparative examples 1 to 2 were added to the ball-milled 42.5 grade cement clinker in an amount of 0.5% o, and the mixture was mixed uniformly to prepare a sample.

The hexavalent chromium content of 0d and 90d is measured by using the limit and the measuring method of water-soluble chromium (VI) in GB 31893-2015 cement, and the result is shown in Table 1.

TABLE 1 test results of hexavalent chromium content and rupture/compression strength in cement

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The cement hexavalent chromium reducing agent is characterized by comprising the following components in parts by weight: 40-50 parts of ferrous sulfate, 5-20 parts of sodium metabisulfite, 10-20 parts of sodium thiosulfate, 0.5-1 part of stannous chloride, 1-5 parts of organic reducing agent and 1-3 parts of dispersing agent; wherein the organic reducing agent is selected from at least one of N, N-dimethylaniline and phenylhydrazine, and the dispersing agent is selected from at least one of triethanolamine, diethanol monoisopropanolamine and ethylene glycol.

2. The method for preparing a hexavalent chromium reducing agent for cement according to claim 1, comprising: uniformly mixing ferrous sulfate, sodium metabisulfite, sodium thiosulfate, stannous chloride, an organic reducing agent and a dispersing agent in parts by weight.

3. Use of the cement hexavalent chromium reducing agent of claim 1 in the production of cement.

4. A method of producing cement, comprising: adding the cement hexavalent chromium reducing agent of claim 1 to cement clinker.

5. A method of producing cement according to claim 4 characterised in that the amount of hexavalent chromium reducing agent added to the cement is between 0.5 and 1 thousandths.

6. A cement produced by the cement production method according to claim 4.

7. A cement according to claim 6, characterized in that the hexavalent chromium content of said cement is less than or equal to 10 ppm.