SU1096220A1 - Method for producing lime suspension in production of calcined soda - Google Patents

Abstract

A method for producing limestone suspension in the production of calcium, Nirod soda, which includes quenching lime with a distiller liquid and separating solid sediment from the target product, characterized in that, in order to increase the degree of extraction of the active calcium oxide into the product, lime is treated with an aqueous solution of glyceri water before quenching to increase the degree of extraction of active calcium oxide into the product. at the CaOazd mass ratio: NaCl: 1: La: L (la), 5 a 0.18 - 0.27; where b 0,1 - 0,8.

Description

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This invention relates to methods for producing calcareous soda:; and to be used in the chemical industry, in particular in the production of soda ash.

A known method for producing a lime suspension, which includes quenching lime with distiller liquid, separating the solid residue from the target product and intensive mechanical stirring in special containers for 30 minutes.

The disadvantage of this method is the low degree of extraction of CaOsshg into suspension, equal to 0.45-0.48 kg7kg, when slaking lime with distiller fluid containing 110-120 g / l of chlorion (the degree of extraction of CaOo few is expressed as the ratio of the mass of CaOoiw in the lime suspension to mass of the same component contained in the original lime).

The closest to the invention to the technical essence and the achieved result is a method of obtaining lime suspension, which includes slaking lime with a distiller liquid in the presence of an additive — a salt of a multivalent metal, in particular aluminum acetate, and separating the solid residue from the target product 2J.

The disadvantage of this method is the low degree of CaOon extraction, equal to 0.54-0.58 kg / kg, when slaking lime with distiller liquid containing 110-120 g / l of chlorine ion.

The purpose of the invention is to increase the degree of CaOc / Ki recovery into the product.

The goal is achieved by the proposed method of obtaining lime suspension, which includes the treatment of lime with an aqueous solution of sodium chloride at a mass ratio

 : fJ shuffle : Ug O 1: bo: b {1-c4, where a: 0.18-0.27;

L 0.1-0.8,

hygiene treated lime distiller fluid and the separation of the solid residue from the target product.

The essence of the method consists in controlling the speed of individual stages of the hydration reaction: reducing the reaction rate in the initial period and accelerating the reaction in the middle and at the end of the process. This is achieved by a certain sequence of changes in the composition of the water-salt media in the reaction zone. Thus, during the pretreatment of lime with a solution of sodium chloride, the open pores of the material are filled with a solution and, apparently, sodium chloride is adsorbed on the active sites of the surface of calcium oxide. When the pretreated lime is subsequently contacted with a distiller liquid, sodium chloride prevents the penetration of calcium chloride into the zone of a heterogeneous hydration reaction for some time. At the same time, the rate of hydration reaction is maintained at a sufficiently low level, which contributes to the normal course of the process of dispersing lime and the formation of a stable lime suspension. Subsequently, as the calcium chloride contained in the quenching distiller liquid penetrates into the zone of the hydration reaction, its rate increases and reaches a value characteristic of slaking lime with water.

In carrying out the method, the degree of CaOO) nd) recovery into the suspension is 0.82-0.86 kg / kg.

When the value is (less than 0.18 (i.e., below the specified interval); the effectiveness of the method will decrease, since the lack of sodium chloride and excess water in the zone of the start of the hydration reaction will cause the initial stage of the hydration process to be more intense than acceptable. The degree of recovery CaOavtw will decrease, for example, at C 0.15 to 0.72 kg / kg. The upper limit of the parameter O- is determined by the solubility of VaC, i.e. the region of existence of sodium chloride solution.

When the value of b is less than 0.1 (i.e., below the specified interval), the efficiency of the method will decrease, since a lack of sodium chloride will cause a more intensive than acceptable course of the initial stage of the hydration process. CaOaf recovery rate. for example, if 07 decreases to 0.7 kg / kg. If the value of b is greater than 0.6 (i.e., above the upper limit for this parameter), then the efficiency of the method will also decrease, since a relatively large amount of sodium chloride will slow down the hydration process not only in the initial period of its occurrence, but also in the subsequent period . This will lead to a decrease in the degree of CaOact recovery, for example, at 95 to 0.66-0.7 kg / kg (or to a significant increase in the reaction volume of the lime slaking apparatus), and to a deterioration in its stability.

The method is carried out as follows.

Lime is fed to a quencher, where it is briefly pretreated with a solution of sodium chloride at a mass ratio of

CaOaKmiVaCe: HjO 1: 6 (1-ОD where About 0.1Ь-0.27; Ь 0.1-0.8.

The treated lime is quenched with distribution fluid. The calcareous lime suspension obtained in Reeulatatara is quenched from the solid residue.

(waste slaked) and sent to the consumer.

Example. 526 kg of lime containing 442 kg of the CaOoi m component, 43 kg of CaCO3, 28 kg of CaOnesi g, 13 kg of impurities treat 15.2 kg of 44.2 kg of sodium chloride solution containing 11.9 kg of VaC and 32.3 kg of HjO. Parameter a. 1i, 0.27, b H2 / g / / 2 0.1. The ratio of Saookg:

rNaCC: HjjU. 1: 0.027: 0.073.

Pretreated lime is quenched with a distiller liquid, taken in the amount of 1654.2 kg and containing 87.9 kg of A / act, 171.3 kg of CaClt and 1395 kg of HjO (118 g of chlorion per 1 l). As a result of quenching, 1571.9 kg of lime suspension containing 480.5 kg of Ca tOH) j

(364 kg in terms of Caoicz),

1b kg of CaCOj, 12 kg of CaOneT, 4 kg of solid impurities, 93.6 kg of WaC, 160 kg and 805.8 kg of 214.5 kg of solid waste, containing 26 kg of C.aOOli, 27 kg of CaCO3, 16 kg of CaOweokr, 9 kg solid impurities, 6.2 kg L / ace, 11, 3 kg CaC, 68.6 kg Ca (OHJj / (52 kg in terms of CaO o ": g) and 50.4 kg HiO. 438 kg evaporated in the quenching process water. The degree of removal of CaO is 0.82 kg / kg 364/442.

Examples of the implementation of the method with other parameters of management are presented in the table.

five

An analysis of the data presented shows that the advantage of the described technical solution in comparison with the known ones is to increase the degree of extraction in the lime suspension. The recovery rate is increased to 0.82 - 0.86 kg / kg as compared with 0.57 kg / kg in Cj; noco6y-n-prototype.

Claims (1)

1 METHOD FOR PRODUCING LIME SUSPENSION IN THE PRODUCTION OF CALCINATED SODA, including quenching lime with distillation liquid and separating the solid precipitate from the target product, characterized in that, in order to increase the degree of extraction of active calcium oxide into the product, lime is treated with an aqueous ratio of sodium chloride before mass quenching CaOcr: NaCl: НрО ⁼ 1: 0о: b (1 — aj, where α = 0.18 - 0.27; b = 0.1 - 0.8. ω CZ The invention relates to methods for producing lime suspension and can be used in the chemical industry, in particular in the production of soda ash.