RU2274664C2 - Method of control over the process of the bulk materials pelletizing - Google Patents

Abstract

FIELD: metallurgy; methods of pelletization of the bulk materials.

SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular, to the method of control over the process of the bulk materials pelletizing, mainly, the iron-ore charges pelletizing. In the process of the bulk materials palletizing conduct the check of humidity of the concentrate, consumption of bentonite, limestone and water. Calculate the optimal value of the humidity of the charge, calculate the redundant volume of the water necessary for the optimal run of the palletizing process. The invention will allow to increase efficiency and the rate of palletizing process and to reduce duration of the pelletization.

EFFECT: the invention allows to increase efficiency and the rate of palletizing process and to reduce duration of the pelletization.

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Description

The invention relates to the pelletizing of bulk materials, mainly iron ore blends. It can be used in the manufacture of pellets from finely ground materials.

Known methods of pelletizing control do not allow with sufficient efficiency to solve the problems of pelletization, to increase the uniformity of the particle size distribution and the strength of raw pellets.

Closest to the invention in terms of technical nature and the achieved result is a method of controlling the pelletizing process, which consists in determining the set value of the flow rate of water into the pelletizer, the flow rate of suitable raw pellets and, based on the comparison result, affect the flow rate of water into the pelletizer [1].

However, the method [1] does not allow with sufficient efficiency to control the process of production of pellets, because the crumpled material does not lead to optimal parameters, since the materials coming into the pelletizing process are waterlogged and bentonite and limestone are added to the material to improve the quality of the pellets and reduce the degree of waterlogging, the amount of which is difficult to choose minimally sufficient.

The technical task is to create conditions for optimal pelletization, improve the particle size distribution and strength of raw pellets, as well as pelletizing time.

The essence of the proposed method lies in the fact that they control the humidity of the concentrate, as well as the consumption of bentonite (hardening additive) and limestone (fluxing additive), calculate the theoretical value of the optimal humidity for pelletizing W _theory based on a mathematical model of optimal granulation [2]. Typically, bentonite is added in an amount of 0.5-1.5% by weight of the dry concentrate, and limestone consumption is calculated based on the basicity of the charge, which is determined by the ratio of limestone and silica CaO / SiO ₂ contained in the charge. For pellets, this value ranges from 0.15 to 1.27 (depending on the process technology). Using the optimum moisture value W _meop , the excess (insufficient) volume of water is determined. Depending on the volume of water in the mixture (excess or insufficient), either an additional amount of bentonite is supplied to the mixture to absorb excess moisture, or water is supplied to the mixture to compensate for its insufficiency.

The calculation of the excess amount of water contained in the mixture after the addition of bentonite (0.5% of the mass of dry concentrate) and limestone (depending on the basicity of the mixture) is performed by the expression

- избыточный объем воды в шихте;Where

- excess volume of water in the mixture;

W _K is the humidity of the concentrate;

X _B , X _And - swelling of bentonite and limestone, respectively;

V _B , V _And - volumetric flow rate of bentonite and limestone, respectively;

g is the proportion of limestone in the mixture, calculated depending on the basicity of the mixture;

W _theory - the calculated moisture content of the mixture, optimal for pelletizing.

Depending on the calculation results, we adjust the composition of the charge.

, то более в шихту никаких добавок делать не требуется и процесс окомкования сыпучих железорудных материалов будет оптимальным.If the amount of water received

, then more than in the charge no additives are required and the process of pelletizing bulk iron materials will be optimal.

, то для достижения оптимальности процесса грануляции в шихту необходимо добавить недостающий объем воды, равный

.If the received volume of water

, then to achieve the optimality of the granulation process, it is necessary to add the missing volume of water equal to

.

в шихту должно быть дополнительно добавлено определенное количество связующих веществ, таких как бентонит и известняк, находящихся в соответствующих этим материалам пропорциях. Расчет количества добавок осуществляется с использованием выражения (1), принимая

:At

a certain amount of binders, such as bentonite and limestone, in proportions corresponding to these materials must be added to the charge. The calculation of the amount of additives is carried out using the expression (1), taking

:

- добавка бентонита, необходимая для поглощения избыточного количества воды в шихте;Where

- the addition of bentonite, necessary to absorb excess water in the mixture;

V _B - the addition of bentonite to the concentrate, is 0.5% of the mass of dry concentrate.

Here is an example of using a method for controlling the process of pelletizing bulk materials.

After the moisture content of _Wt = 11% was controlled to the waterlogged iron ore concentrate of the Poltava Mining and Processing Plant weighing 1000 kg, bentonite was added as a strengthening additive in the amount of V _B = 5 kg / t, which corresponds to 0.5% of the volume crumpled material, as well as limestone as a binder, the amount of which is determined based on the basicity of the charge. The limestone addition was V _И = 119 kg / t. After that, the optimal humidity for pelletizing was calculated on the basis of a mathematical model of optimal granulation [2], which for the above material was W _meop. = 9.515%. The swelling of bentonite is equal to X _B = 1.9 srvc. (bentonite of the Gunbrisk deposit). Swelling of limestone is equal to X _AND = 1.2 srvc. The proportion of limestone in the charge is g = 1.15. Then, the excess volume of water in the charge was determined by the expression (1). As a result of the calculations, the following results were obtained:

, то для оптимального ведения процесса окомкования необходимо добавить небольшое количество бентонита для поглощения избыточной влаги. Расчет добавки бентонита осуществляется по выражению (2):Thus, since

, for optimal process of pelletizing, it is necessary to add a small amount of bentonite to absorb excess moisture. Calculation of the additive of bentonite is carried out according to the expression (2):

Thus, the total volume of bentonite obtained, which is necessary both as a strengthening additive (5 kg / t) and to absorb excess moisture in the charge (1.4 kg / t), is 6.4 kg / t, which corresponds to 0, 64% of the concentrate volume. This bentonite content is necessary and sufficient for optimal pelletizing.

. Исходя из того, что полученное значение объема избыточного количества воды меньше нуля, в шихту необходимо добавить недостающий объем воды 3,8 л/т воды для достижения оптимальности процесса окомкования.When the humidity of the concentrate W _k = 10.5% after the addition of 5 kg / t of bentonite and 119 kg / t of limestone (the required number of additives), using the formula (1), we obtained the value

. Based on the fact that the obtained value of the volume of excess water is less than zero, it is necessary to add the missing volume of 3.8 l / t of water to the mixture to achieve the optimum pelletizing process.

Literature

1. USSR Copyright Certificate No. 1703708, cl. C 22 V 1/14, 1990.

2. Chernetskaya I.E., Isaev E.A. To the question of modeling the porosity of bulk material // News of higher educational institutions. Ferrous metallurgy, No. 1, 2002. - S.5-7.

Claims (1)

A method of controlling the process of pelletizing bulk materials, including controlling the humidity of the concentrate, the consumption of bentonite, limestone and water, characterized in that they calculate the optimal value of the moisture content of the charge and calculate the excess volume of water in the charge by the expression:

Where

- excess volume of water in the mixture; W _K is the humidity of the concentrate; X _B , X _And - swelling of bentonite and limestone, respectively; V _B , V _And - volumetric flow rate of bentonite and limestone, respectively; g is the proportion of limestone in the mixture; W _TEOP - design charge moisture, optimal for pelletizing, and according to the calculations, bentonite is fed into the charge to absorb excess moisture or water, which is necessary for optimal conduct of the pelletizing process.