Method and system for producing low-alkalinity sulphoaluminate cement with new mineral system using steel slag

Patent metadata

Field	Value
Publication number	US-2021130234-A1
Application number	US-202017257112-A
Country	US
Kind code	A1
Filing date	Feb 28, 2020
Priority date	Apr 15, 2019
Publication date	May 6, 2021
Grant date	—

Abstract

A method and system for producing low-alkalinity sulphoaluminate cement with a new mineral system using steel slag. The method includes the following steps: evenly mixing and homogenizing ground steel slag with dry desulfurization gypsum, aluminum ash and carbide slag according to a set ratio; and conveying the homogenized raw meal to a rotary kiln for calcination to obtain cement clinker, where the calcination temperature is 1200° C.-1270° C., and the calcination time is 20-60 min; the alkalinity modulus of the homogenized cement raw meal is 0.81-0.9, and the Fe2O3 content is 8-13%. The method breaks through the requirements on contents of calcium, aluminum and iron in traditional sulphoaluminate cement production, and realizes application of a large amount of steel slag.

First claim

What is claimed is:

1 . A method for producing sulphoaluminate cement from steel slag, comprising the following steps:
evenly mixing and homogenizing ground steel slag with dry desulfurization gypsum, aluminum ash and carbide slag according to a set ratio; conveying the homogenized raw meal to a rotary kiln for calcination to obtain cement clinker, wherein the calcination temperature is 1200° C.-1270° C., and the calcination time is 20-60 min, wherein an alkalinity modulus of the homogenized cement raw meal is 0.81-0.9, the raw meal contains 32-40 parts by weight of CaO, 6-12 parts by weight of SiO 2 , 20-28 parts by weight of Al 2 O 3 , 8-13 parts by weight of Fe 2 O 3 , and 10-18 parts by weight of SO 3 , and an alumina-sulfur ratio is 1.3-2.0.

2 . The method of claim 1 , wherein the homogenized raw meal contains 32-35 parts by weight of CaO, 6-12 parts by weight of SiO 2 , 20-25 parts by weight of Al 2 O 3 , 10-13 parts by weight of Fe 2 O 3 , and 10-15 parts by weight of SO 3 .

3 . The method of claim 1 , wherein the alumina-sulfur ratio of the homogenized raw meal is 1.3-1.8.

4 . The method of claim 1 , wherein the fineness of outlet ground steel slag meets that a sieve residue of a 0.08 mm square hole sieve is within 10%.

5 . The method of claim 4 , wherein the fineness of outlet ground steel slag meets that the sieve residue of the 0.08 mm square hole sieve is 4%-8%.

6 . The method of claim 1 , wherein the homogenization is grinding homogenization or homogenization treatment in a homogenization equipment.

7 . The method of claim 1 , wherein main mineral phases in the cement clinker comprise calcium sulphoaluminate, gehlenite and calcium sulfoaluminate ferrite, accounting for 40-65%, 5-20% and 10-25% by mass respectively.

8 . The method of claim 7 , wherein the main mineral phases in the cement clinker comprise calcium sulphoaluminate, gehlenite and calcium sulfoaluminate ferrite, accounting for 50-65%, 5-20% and 15-25% by mass respectively.

9 . The method of claim 1 , further comprising a step of mixing and grinding the cement clinker and gypsum to prepare the sulphoaluminate cement.

10 . A system for producing low-alkalinity sulphoaluminate cement with a new mineral system using steel slag, comprising a dryer, a grinder, a batching equipment, a homogenization equipment and a rotary kiln, wherein
the dryer is configured to dry steel slag, desulfurization gypsum, aluminum ash and carbide slag; the dried steel slag is ground in the grinder; the desulfurization gypsum, the aluminum ash, the carbide slag and other materials are added into the grinder according to a set ratio for homogenization treatment, or the steel slag, the desulfurization gypsum, the aluminum ash and the carbide slag are mixed in the batching equipment according to the set ratio, and then are subjected to the homogenization treatment in the homogenization equipment; and the homogenized cement raw meal is calcined in the rotary kiln to obtain cement clinker.

Assignees

• Univ Shandong

Inventors

• Wang Xujiang
• Wang Wenlong
• Li Jingwei
• Mao Yanpeng
• Zhang Chao
• Wu Changliang

Classifications

• C04B7/323 Primary

  Calcium aluminosulfate cements, e.g. cements hydrating into ettringite · CPC title

• C04B7/434

  Preheating with addition of fuel, e.g. calcining · CPC title

• C04B7/52

  Grinding {; After-treatment of ground cement} · CPC title

• C04B7/147 Primary

  Metallurgical slag · CPC title

• C04B7/24

  Cements from oil shales, residues or waste other than slag · CPC title