How we can prepare aluminium hydroxide sol from peptization?

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The question is how it can be prepared by peptization? 

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Peptization: This is the process of converting of freshly prepared precipitates of a substance into colloidal form under the influence of a substance called peptizing agent, which may be any dispersion medium or some other substance. For example, colloidal starch is prepared by adding a paste of starch to boiling water. Here water acts as peptizing agent as well as dispersion medium.
Freshly formed precipitate of ferric hydroxide, Fe(OH)3, is peptized by ferric chloride, FeCl3, solution. Similarly, a sol of aluminium hydroxide (Al(OH)3) is obtained by adding insufficient quantity of very dilute HCl solution to freshly precipitated aluminium hydroxide.