SU1291567A1 - Raw mixture for producing white cement clinker - Google Patents

Abstract

The invention relates to the technology of building materials and may find application in the production of white and colored cements clinker. The purpose of the invention is to reduce fuel consumption for firing and increase furnace productivity. The raw material mixture for nq - white cement clinker contains, wt%: clay 8-16.5, sand 2-7, finely ground silicon carbide 0.5-8 and known to the rest. -2 table. to with | W | «1 el 05

Description

The invention relates to the technology of building materials and can be used to obtain white and colored cements.

The aim of the invention is to reduce fuel consumption and increase furnace productivity.

Raw mixture is obtained as follows.

One raw material — known, clay and sand — is ground to complete passage through a 008 sieve. Silicon carbide is pre-ground to a specific surface of 400-600 and injected into the raw mix instead of part of a silica-containing component. The mixture is homogenized, granulated, and then calcined in an oven.

When the raw material mixture containing silicon carbide is fired at 1100–1300, silicon and carbon included in the additive are simultaneously oxidized, with additional heat released in a given temperature range, which ensures heating of the material and reduction of fuel consumption for firing.

The compositions of the raw mixes are given in table. one.

When determining the rate of clinker formation, samples with a diameter of 13mm and a height of 15-17 mm from the raw mix (Table 1), pressed at a pressure of 208 MPa, are placed on a stand with a magnesium filling, covered with a corundum crucible (to reduce heat loss to the environment). ) and burned in a laboratory electric furnace with a gradual rise in temperature before and isothermal aging for 30 minutes. The furnace is heated at a rate of 20 degrees / min. Then the samples are rapidly cooled in air.

In order to determine the activity and whiteness of the cement, the samples after calcination, spread out together with 5 wt. L of dihydrate gypsum to a specific surface of 320-340.

The test results obtained cements are given in table. 2

And: s table. 2 it follows that the main effect is achieved through the use of an additive of silicon carbide in the optimal dosage. The change in the ratio of the raw components of the mixture is reflected only in the magnitude of the theoretical effect of clinker formation and does not exceed 1% of the practical fuel consumption.

At the same time, silicon carbide provides for rapid internal heating of the material in the section of the rotary kiln, where heat exchange between the gas flow and the material layer is difficult (1100-1300 s) and the temperature difference between them usually reaches 300-400 ° C.

Thus, even the minimum dosage of silicon carbide in the raw mix (0.5 wt.%) Will increase the furnace productivity by 16.7% and reduce the specific heat consumption of clinker roasting by 14.5%. The optimal dosage of silicon carbide significantly increases these indicators.

At the same time, although the heat removal from the addition of aluminum powder is 37 kcal / kg clinker, no significant heating of the mixture is observed, since aluminum burns out at a temperature before the main chemical reactions have not yet begun, and the heat released is spent on heating the exhaust gases and gets lost with them.

Claims (1)

Invention Formula The raw mix for white cement clinker, including 40, clay, sand and an additive, is that, in order to reduce fuel consumption and increase furnace productivity, it contains as an additive fine silicon carbide in the following ratio Components May, 7 ,. Clay Sand Thin ground silicon carbide Known to Order 1169/27 Circulation 588, Subscription VNIIPI USSR State Committee on affairs of inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, st. Project, 4 table 2