CN204154669U - A kind of active lime apparent digestion conversion rate determinator - Google Patents

Abstract

The utility model relates to a device for measuring the apparent digestion conversion rate of active lime, which is characterized in that the device comprises the following components, a speed controller (1), a computer (2), a temperature sensor (3), a support platform (4), a stirring device (5), heat preservation container (6) and thermocouple (7). The computer of the device automatically draws the temperature rise curve and displays it automatically, which is intuitive and clear.

Description

A device for measuring apparent digestion conversion rate of active lime

technical field

The utility model patent relates to a device for measuring the apparent digestion conversion rate of active lime.

Background technique

The lime digestion project team of Chongqing Institute of Science and Technology conducted in-depth research on the digestion of quicklime on the basis of the knowledge of previous experiments. After searching relevant literature, we learned that the expression methods of the activity of quicklime are as follows:

(1) Wet digestion curve and temperature rise curve method

CaO and H ₂ O can undergo intense hydration reaction, and the exothermic effect of the reaction should be 65.2KJ/molCaO. With good insulation and sufficient excess water, the reaction rate of lime can be measured as a function of temperature with time, given the amount of material and sufficient mixing. The standards formulated according to this principle include the American Society for Testing and Materials (ASTM): ASTMc100, the German Standardization Institute standard DINEN12485, and the People's Republic of China Building Materials Industry Standard JC/T478.1.

(2) Specific surface area and lattice structure

Calcination conditions are closely related to the crystal size, specific surface area, and porosity of the generated lime, so the activity of quicklime can be expressed by the surface area. Glasson studied the effect of calcination conditions on lime activity through changes in surface area and lattice structure. The decomposition of limestone and calcium hydroxide in vacuum or in air was studied at different temperatures and times. According to the experiment, the calcination process can be divided into three parts: ① Limestone begins to decompose, forming CaO crystals, but still maintains the original CaCO ₃ structure, which does not directly affect the surface area, but the undecomposed limestone may be sintered, so the surface area decreases slightly. ②CaO begins to recrystallize, the original CaCO ₃ crystal structure begins to transform into a more stable CaO crystal structure, and the surface area begins to increase. ③ CaO crystals start to sinter, of course, this process has already started before ② is completed.

(3) Hydrochloric acid consumption rate

According to the test method of metallurgical lime activity in the original Ministry of Metallurgical Standard ZBQ27002-85, measure 2L of water at 40±1°C and pour it into a 3L beaker, start the stirrer, wait until the temperature is constant at 40±1°C, add 8-10 drops of phenolphthalein , pour 50g of lime sample with a particle size of 1-5mm at one time, when the phenolphthalein starts to turn red, titrate with 40mol/L hydrochloric acid until the red color disappears, if the red color appears again, continue to drop hydrochloric acid until the red color disappears in the mixture. disappear, record the consumption of hydrochloric acid at the 10th minute. This method is feasible for ordinary metallurgical limestone, but for lime with high lime activity, the phenolphthalein indicator is colorless in an alkaline solution with a high pH value, and the end point cannot be correctly judged, resulting in large errors in titration results.

In the research, the influence of field conditions on the activity of quicklime was simulated. After the quicklime was mixed with water, Ca ²⁺ and OH- were first reacted to form a supersaturated solution of calcium hydroxide, and then solid phase calcium hydroxide was crystallized. The activity of lime milk is mainly manifested in the dispersibility of Ca(OH) ₂ particles. The higher the dispersibility, the finer the calcium hydroxide particles and the larger the reaction surface area. When quicklime is highly active, due to its large surface area, high porosity and other factors, the digestion reaction rate is fast, so that the concentration of Ca2+ and OH- in the liquid phase rises sharply, and the supersaturation also increases sharply. Calcium hydroxide in this solution The formation speed of the crystal nuclei is fast and the growth of the crystal nuclei is slow, and highly dispersed solid-phase calcium hydroxide can be obtained. Therefore, for the same quicklime or under the same operating conditions, the greater the apparent digestion rate of quicklime, the greater the rate of lime milk. The higher the reactivity. Therefore, it is also most suitable to use wet digestion curve to reflect the digestion process of lime.

The test method based on the wet digestion curve mainly expresses the reactivity of quicklime or milk of lime produced by apparent digestibility and apparent digestion conversion rate.

(1) Apparent digestibility

Apparent digestibility is expressed by digestion time (Δt). Under other conditions being the same, comparing the effect of a certain condition on lime digestion, the shorter the total digestion time, the faster the apparent digestion rate of lime and the higher the activity of lime milk produced.

(2) Apparent digestion conversion rate

The apparent digestion conversion rate represents the proportion of CaO in lime hydrated to Ca(OH) ₂ , expressed by the total temperature rise (ΔT) of the solution during the digestion process. It is mainly determined by the CaO content in the lime and the digestion operation conditions, and is also related to the ions in the digested water.

Based on the above theories of apparent digestibility and apparent digestion conversion rate, we propose to use the definition of apparent digestion conversion rate to visually represent the reactivity of quicklime or milk of lime produced.

(3) Apparent digestion conversion rate

The apparent digestion conversion rate is expressed by the ratio of the total temperature rise (ΔT) of the solution during the digestion process to the digestion time (Δt). The faster the apparent digestion and conversion rate, to a certain extent, the faster the digestion rate and the higher the activity of lime.

Utility model content

The purpose of the utility model patent is to provide a device for measuring the apparent digestion conversion rate of active lime, which is characterized in that the device comprises the following parts, a speed controller (1), a computer (2), a temperature sensor (3), a support platform ( 4), stirrer (5), insulation container (6) and thermocouple (7);

There is a stirrer (5) on the support platform (4), and the bottom of the stirrer has a stirring rod and a stirring blade, and the stirring rod and the stirring blade go deep into the inside of the thermal insulation container (6) for stirring, and the thermal insulation container (6) ) is a thermal insulation container, and the thermal insulation container (6) has a thermocouple (7), the thermocouple (7) is connected to the temperature sensor (3), and the agitator (5) is connected to the speed controller (1), Both the speed controller (1) and the temperature sensor (3) are controlled by a computer (2).

The agitator (5) is a JJ-1A precision booster electric agitator with a rotating speed adjustable between 1-3000r/min.

Described thermocouple (7) adopts PT100 high precision thermocouple.

The computer screen can display the rotational speed of the agitator and the temperature of the heat preservation container in real time, and record the temperature variation curve with time.

Beneficial effect:

The computer automatically draws the temperature rise curve, automatically calculates the apparent digestion and conversion rate of the active lime sample, uses a stepping motor to drive the agitator, and the speed is adjustable and controllable throughout the whole process, uses PT100 high-precision thermocouples for temperature measurement, and the computer automatically draws the temperature Ascending curve, automatic display, intuitive and clear.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Below in conjunction with specific embodiment, further set forth the utility model.

A device for measuring the apparent digestion conversion rate of active lime, characterized in that the device comprises the following components, a speed controller (1), a computer (2), a temperature sensor (3), a support platform (4), and an agitator (5) , insulation container (6) and thermocouple (7);

There is a stirrer (5) on the support platform (4), and the bottom of the stirrer has a stirring rod and a stirring blade, and the stirring rod and the stirring blade go deep into the inside of the thermal insulation container (6) for stirring, and the thermal insulation container (6) ) is a thermal insulation container, and the thermal insulation container (6) has a thermocouple (7), the thermocouple (7) is connected to the temperature sensor (3), and the agitator (5) is connected to the speed controller (1), Both the speed controller (1) and the temperature sensor (3) are controlled by a computer (2).

The agitator (5) is a JJ-1A precision booster electric agitator with a rotating speed of 1-3000r/min.

Described thermocouple (7) adopts PT100 high precision thermocouple.

The computer screen can display the rotational speed of the stirrer and the temperature of the heat preservation container in real time, and record the change curve.

It should be understood that these embodiments are only used to illustrate the present utility model and are not intended to limit the scope of the present utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by the appended claims of the application.

Claims (4)

1. A device for measuring the apparent digestion conversion rate of active lime, characterized in that: the device comprises the following parts, a speed controller (1), a computer (2), a temperature sensor (3), a support platform (4), an agitator (5), insulation container (6) and thermocouple (7); A stirrer (5) is arranged on the support platform (4), and a stirring rod and a stirring blade are arranged at the bottom of the stirrer, and the stirring rod and the stirring blade go deep into the inside of the thermal insulation container (6) for stirring, and the thermal insulation container (6) ) is a thermal insulation container, and the thermal insulation container (6) has a thermocouple (7), the thermocouple (7) is connected to the temperature sensor (3), and the agitator (5) is connected to the speed controller (1), Both the speed controller (1) and the temperature sensor (3) are controlled by a computer (2). 2. a kind of active lime apparent digestion conversion rate measuring device as claimed in claim 1, is characterized in that: described agitator (5) is JJ-1A precision booster electric agitator, and rotating speed is 1-3000r/min between. 3. A device for measuring the apparent digestion conversion rate of active lime as claimed in claim 1, characterized in that: the thermocouple (7) adopts a PT100 high-precision thermocouple. 4. A device for measuring the apparent digestion conversion rate of active lime as claimed in claim 1, characterized in that: the temperature of the agitator rotating speed and the heat preservation container can be displayed in real time on the computer screen, and the change curve is recorded.