Solana blockchain. How am i able to generate non-public key?

   const solanaWeb3 = require("@solana/web3.js");
const solanatoken = require("@solana/spl-token");

  var wallet = solanaWeb3.Keypair.generate();
  console.log("public key...", wallet.publicKey);
  console.log("secret key...", wallet.secretKey);

  console.log("secret key...", JSON.stringify(wallet.secretKey.toString()));`enter preformatted text here`

i got

public key… PublicKey {
_bn: <BN: b5ec974285759f4004555c6890e045a4ce857c6a056895d77dd209c054e76556>
secret key… “211,55,244,72,160,174,33,152,24,226,97,172,91,91,47,3,148,83,99,188,150,111,153,248,253,237,31,223,194,194,199,0,181,236,151,66,133,117,159,64,4,85,92,104,144,224,69,164,206,133,124,106,5,104,149,215,125,210,9,192,84,231,101,86”

how i can get private key, like kNykCXNxgePDjFbDWjPNvXQRa8U12Ywc19dFVaQ7tebUj3m7H4sF4KKdJwM7yxxb3rqxchdjezX9Szh8bLcQAjb
for use on phantom wallet?
docs: https://solana-labs.github.io/solana-web3.js/classes/Keypair.html