The adsorption of polysaccharides onto mineral surfaces: an acid/base interaction

Liu, Qingxia; Zhang, Yahui; Laskowski, J.

doi:10.1016/s0301-7516(00)00018-1

Cited by 280 publications

(140 citation statements)

References 32 publications

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“…35,36 Giles et al 37 found that the dissolution of Ca(OH) 2 at low stirring rate is controlled by the diffusion of calcium and hydroxide ions away from the surface, while the dissolution is surface controlled at an intensive stirring. Since it is generally accepted that polysaccharides adsorb on mineral surfaces through hydrogen bonds or chemical complexation process in which C-2, C-3 and C-6 hydroxyl groups play crucial roles, [38][39][40] the inhibition of Ca(OH) 2 dissolution is likely to occur. In other words, the presence of dextrane may cause progressive Ca(OH) 2 accumulation in the systems containing higher concentrations of dextrans.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Calcium Carbonate by Semicontinuous Carbonation Method in the Presence of Dextrans

Kontrec¹,

Ukrainczyk²,

Babić-Ivančić³

et al. 2011

Croat. Chem. Acta

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Abstract. Precipitated calcium carbonate (PCC) was prepared by means of semicontinuous carbonation of Ca(OH) 2 suspension, at 35 and 45 °C and in the presence of non-ionic dextran and dextran sulfate. The carbonation process was regulated at different predetermined values of electrical conductivity, that corresponded to different concentrations of dissolved Ca(OH) 2 : 0.5 mS cm. The results of physicalchemical characterization of the product showed that calcite was the only polymorphic modification obtained in the whole range of experimental conditions investigated. In addition, it was found that morphology, crystal size distribution and specific surface area of PCC strongly depended on the electrical conductivity / concentration of dissolved Ca(OH) 2 , at which the process was performed: predominantly scalenohedral crystals of higher surface area (about 5 m 2 g −1) were produced at higher electrical conductivity, while at lower electrical conductivity predominantly rhomohedral calcite crystals of relatively low specific surface area were obtained. In the system of the highest electrical conductivity, κ 25 = 5.0 mS cm, and at 35 °C, the addition of non-ionic dextran significantly influenced the process by preventing the regulation. The crystals that appeared were in the form of irregular aggregates of high specific surface area, S ≈ 29 m 2 g −1. FT-IR and TG analyses indicated that the non-ionic dextran was adsorbed onto the calcite surface, most probably by relatively strong and specific interactions between oxygen from the hydroxyl groups of dextran molecules and calcium ions from the crystal surface. On the contrary, the anionic dextran (dextran sulfate) exerted minor effects in the course of semicontinuous carbonation process and in the properties of the final product, PCC. However, the analysis of the precipitate indicated that dextran sulfate was adsorbed at the surfaces, most probably by the weak and non-specific electrostatic interactions. (doi: 10.5562/cca1746)

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Section: Resultsmentioning

confidence: 99%

Synthesis of Calcium Carbonate by Semicontinuous Carbonation Method in the Presence of Dextrans

Kontrec¹,

Ukrainczyk²,

Babić-Ivančić³

et al. 2011

Croat. Chem. Acta

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“…Temperatures lower than 25 °C were not considered. It is well known in the literature that the greater the proportion of amylopectin the lower the temperature required for the starch gelatinization [10]. A linear model was obtained with fit (r 2 ) around 98%, which can be considered adequate.…”

Section: Resultsmentioning

confidence: 79%

“…Retrogradation occurs spontaneously when starch solutions are stored at low temperatures at neutral pH. Amylose's retrogradation may occur within a period of four to five hours after the gelatinization, while the amylopectin retrogrades only 10% within 100 days [10].…”

Section: Introductionmentioning

confidence: 99%

Temperature Influence in Cornstarch Gelatinization for Froth Flotation

Silva¹,

Sousa²,

Silva³

et al. 2016

IPCBEE

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Abstract. Starches are widely used as depressant in froth flotation operations in Brazil due to their efficiency, increasing the selectivity in the inverse flotation of quartz depressing iron ore. Starches market have been growing and improving in recent years, leading to better products attending the requirements of mineral industry. The major source of starch used for iron ore is the cornstarch, which need to be gelatinized, by heat or sodium hydroxide (NaOH) addition, prior its use. This stage has a direct impact on industrials costs, once the lowest consumption of NaOH in gelatinization provides better control of the pH in the froth flotation and reduce the amount of electrolytes present in the pulp. In order to evaluate the influence if the temperature in the NaOH consumption gelatinization tests were carried out with temperatures ranging from 25 to 65 °C , measuring the volume of NaOH. All tests were performed in triplicate. A linear model correlating the temperature and the NaOH need for the cornstarch gelatinization had been stablished. This model can allow mineral industries to optimize the NaOH amount used to prepare the depressant to be used in froth flotation. For example, the reduction in NaOH could easily reaches 480 L per ton of cornstarch when performing gelatinization with cornstarch solution at 35 °C when compared to 25 °C .

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“…Temperatures lower than 25° C were not considered. It is well known in literature that the greater the proportion of amylopectin, the lower the temperature required for the starch gelatinization (Liu, Zhang and Laskowski, 2000). A linear model was obtained with fit (r 2 ) around 98%, which can be considered adequate.…”

Section: Methodsmentioning

confidence: 77%

“…Larger starch molecules need more gelatinization time compared to smaller starch molecules. Liu, Zhang and Laskowski (2000) showed that the temperature needed for gelatinization decreases when increasing the amylopectin content. Retrogradation occurs spontaneously when starch solutions are stored at low temperatures at neutral pH.…”

Section: Introductionmentioning

confidence: 99%

Temperature influence in cornstarch gelatinization for froth flotation

Silva

Peres

et al. 2017

REM, Int. Eng. J.

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Starches are widely used as depressant in froth flotation operations in Brazil due to their efficiency, increasing the selectivity in the inverse flotation of quartz, depressing iron ore. The starch market has been growing and improving in recent years, leading to better products attending the requirements of the mineral industry. The major source of starch used for iron ore is the cornstarch, which needs to be gelatinized, by heat or sodium hydroxide (NaOH) addition (also known as caustisized starch), prior its use. This stage has a direct impact on industrials costs, since the lower consumption of NaOH in gelatinization provides better control of the pH in the froth flotation and reduces the amount of electrolytes present in the pulp. In order to evaluate the influence of temperature on the NaOH consumption, gelatinization tests were carried out with temperatures ranging from 25 to 65 °C, measuring the volume of NaOH. All tests were performed in triplicate. A linear model correlating the temperature and the NaOH need for the cornstarch gelatinization has been stablished. This model can allow mineral industries to optimize the NaOH amount used to prepare the depressant used in froth flotation. For example, the reduction in NaOH could easily reach 480 L per ton of cornstarch when performing gelatinization with the cornstarch solution at 35 °C instead of 25 °C (reduction of approximately 34% in the NaOH consumed).

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The adsorption of polysaccharides onto mineral surfaces: an acid/base interaction

Cited by 280 publications

References 32 publications

Synthesis of Calcium Carbonate by Semicontinuous Carbonation Method in the Presence of Dextrans

Synthesis of Calcium Carbonate by Semicontinuous Carbonation Method in the Presence of Dextrans

Temperature Influence in Cornstarch Gelatinization for Froth Flotation

Temperature influence in cornstarch gelatinization for froth flotation

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