RU2114789C1 - Method for preparing flocculant solution - Google Patents

Abstract

FIELD: technology for preparing solutions of high molecular weight flocculants and may be used by flotation and concentration of slime. SUBSTANCE: flocculant is fed into solution, the process is carried out at 35-55 C. Then temperature of solvent is elevated and flocculant is dissolved, the process takes place by mixing at 50-75 C. EFFECT: decreased duration of the process; increased completeness of dissolution of flocculant; increased efficiency of flocculant action. 2 tbl

Description

 The invention relates to a technology for the preparation of solutions of flocculants used for thickening finely divided products, flotation and clarification of solutions in the processing of various types of minerals, for example, potash ores.

 In the processing of potash ores containing clay-carbonate easily sludge-containing water-insoluble impurities, a preliminary flotation separation of these sludges from the ore is carried out with their subsequent thickening and forwarding to storage. To ensure flotation and thickening of sludge, a solution of a high molecular weight flocculant polyacrylamide is introduced into the suspension [1].

 The technology for preparing flocculant solutions involves introducing a flocculant into a solvent (water) and dissolving the flocculant with stirring to obtain a solution of the desired concentration. Given the high cost of high molecular weight flocculants, an important factor in their application is the creation of optimal conditions for the production of working solutions that provide high efficiency of the flocculant at each stage of its use.

 Currently, the preparation of aqueous solutions of polyacrylamide (PAA) is carried out by loading it into water at normal temperature and prolonged stirring to obtain a working solution concentration of 0.1 - 0.15% [2].

 The disadvantage of this method is the long dissolution time, reaching 24-30 hours, while in some cases even such a dissolution time does not provide complete dissolution of the flocculant. This leads to significant costs for installed equipment for the preparation of flocculants and its increased costs.

It is known that the dissolution process can be intensified by increasing the temperature of the water at which dissolution is carried out. To this end, it is recommended to dissolve at a temperature of 20 - 40 ^o C with a maximum permissible upper limit of 50 ^o C (prospectuses of manufacturers of polyacrylamide flocculants Dow Chemical Compahy and Kemira - prototype). The disadvantage of this method is still a significant dissolution time (15 to 20 hours).

 The aim of the invention is to develop a technology for the preparation of working solutions of high molecular weight flocculants, which provides for the reduction of production costs and increase the efficiency of flocculants.

This goal is achieved by loading the flocculant into the water at a temperature of 35 - 55 ^o C with a subsequent increase in water temperature and the implementation of the dissolution of the flocculant at a temperature of 50 - 75 ^o C.

 The proposed method was tested in a laboratory setting with the assessment of the flocculating ability of PAA working solutions in the operation of sedimentation (thickening) of sludge and flotation activity when using PAA for flotation deslamination of potassium ore.

 The flocculating activity of the obtained PAA solutions was evaluated by the rate of sedimentation of clay sludge extracted from potash ore and washed from salts to a negative reaction to a chlorine ion. The effectiveness of PAA during flotation of sludge was determined by the amount of extraction of insoluble residue in the foam product. For flotation experiments, potassium ore of the Solikamsk deposit of the following composition was used: KCl - 27%, NaCl - 71%, clay-carbonate insoluble residue - 2%.

 The preparation of the flocculant solution was carried out by loading the sample (1 g) into water (1 l), followed by dissolution with mechanical stirring (the number of revolutions of the laboratory stirrer was 100 rpm). In the process of dissolution, a sample was periodically taken to determine the concentration of PAA, and after dissolution was completed, the flocculating activity of the resulting solution and its effectiveness in the flotation of sludges were determined.

 Example 1. Analog.

A PAA sample was loaded into water at normal temperature (20 ^° C) and dissolution was carried out at this temperature.

 Example 2. The prototype.

A PAA sample was loaded into water at a temperature of 30 - 80 ^o C and dissolution was carried out at a temperature at which the flocculant was loaded.

 Example 3. The proposed method.

A PAA sample was loaded into water at a temperature of 30-60 ^° C, then a temperature was raised to 50-80 ^° C, and dissolution was carried out at this temperature.

 The results of the tests are presented in table. 12.

The results of tests on the kinetics of PAA dissolution by known and proposed methods showed (Table 1) that the dissolution rate of PAA by the proposed method is much higher. In accordance with this, as can be seen from the generalized data on the preparation of PAA and testing it in the operations of flotation deslamination of potassium ores and sedimentation (thickening) of sludge (table 2), when loading flocculant at a temperature of 35 - 55 ^o C and subsequent dissolution at a temperature of 50 -75 ^o C provides complete dissolution of the loaded amount of flocculant with a significantly shorter dissolution time than by known methods.

 Obtained by the proposed method, the solutions of flocculant are characterized by greater flocculating activity. The rate of sedimentation of clay sludge increases by 20-30% (rel.), Which reduces the consumption of PAA in the operation of thickening sludge. The use of these solutions for sludge flotation can increase the selectivity of the flotation de-slurry of potash ores, the loss of potassium chloride (useful component) with sludge product is reduced by 30 - 40% (rel.).

When loading flocculant at a temperature of more than 55 ^o C decreases the completeness of dissolution of the flocculant due to the formation of poorly soluble colloidal aggregates of the polymer. This leads to a decrease in the flocculating and flotation activity of PAA solutions.

The loading of PAA at a temperature of 35 - 55 ^o C and subsequent dissolution at a temperature of more than 75 ^o C does not lead to a further decrease in the dissolution time, but is accompanied by additional energy costs.

 The proposed method for the preparation of flocculant solutions can significantly reduce the preparation time of PAA, increase the completeness of dissolution of the flocculant and increase its effectiveness in flotation and sludge thickening operations.

 The method was tested in experimental industrial conditions at JSC Silvinit and confirmed the results of laboratory tests.

 The method can be applied at mining and processing enterprises, in particular at the factories of JSC Silvinit and JSC Uralkali.

 Implementing it allows you to reduce operating costs.

Claims (1)

A method of preparing a flocculant, including loading the flocculant into a solvent and dissolving it with stirring, characterized in that the flocculant is loaded into the solvent at 35 - 55 ^o C, after which the temperature of the solvent is increased and the flocculant is dissolved at 50 - 75 ^o C.

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