Calcium nitrate(V) is very soluble in water, in contrast to calcium iodate(V). For this reason, a certain amount of calcium iodate(V) was industrially synthesized by an exchange reaction between calcium nitrate(V) and potassium iodate(V), and then purified.

Thank you for this suggestion Andrzej ! But again formation of KIO3 needs either electrolysis or chlorination, which not feasible for me. So I am seeking a new route of synthesis where no electrolysis, chlorination at any stage required. But I really thanking your goodness for this clue.

The simplest industrial way is - oxidation of K-iodide with chlolrine into k-iodate, thene xchange with a water-soluble Ca-salt (as it was written by Andrzej). I am attaching a patent about it.

Chlorine free method is oxidation of KI with oxygen, but ti is possible to perform in industrial scale only in melt. Please see the attached patents how have to do it.

The other patent is for the oxygen+KI reaction is the following

About chlorination of KI. I know, chlorination is an inconvenient thing, e.g. at industrial scale. However, I used a very comfortable way for chlorination, when I prepared chlorine hydrate in situ from cold HCl and cold hypochlorites during strong chilling (around 0 °C at atmospheric pressure). Chlorine hydrate (Cl2.xH2O) as solid is a very comfortable material is in equilibrium with the solution above it, and can react as chlorine with KI. You can control the evolution rate of chlorine from it with adjusting the temperature without outer chlorine source. I suggest taking into consideration this possibility. You can find some basic parameters about chlorine hydrate in the attached file or in my RG page.

Thank You Mr Laszlo for your providing literature. I am still thinking to make it by some another route also. But for this your given hints will make me much comfortable.

You can prepared KIO3 from the reaction of I2 with KOH

Industrial method for preparation of calcium iodate is reaction between calcium chloride and iodic acid. Iodic acid can be produced by oxidizing iodine with chlorine in an aqueous solution.